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This thesis treats the subject of increased energy efficiency in buildings. Swimming facilities, a building type designed for improving public health and well-being, are documented in the literature as having considerable potential for reducing energy consumption. Considering the building type as a complex building category, with all their inherently connected variables and processes, it is important to focus on both the design and the operational phases. This thesis is proposing a continuous rating system, as an operating tool. This can prevent costly operational flaws by quickly disclosing incidents and making the operation staff aware. In the context of energy use an energy prediction model was developed in this work that represents the baseline for the energy use in a swimming facility. The baseline represented the expected energy use for the considered time period. The model was found to be a powerful tool for continuous supervision of the energy performance of the facility. By applying this model, an operator can quickly reveal possible operational disruptions/irregularities. The energy prediction model produced in this work can easily be deployed either in a spreadsheet or in the building automation reporting system. It is therefore applicable for existing and new buildings which are equipped with thermal and electric energy meters. Regarding the design phase, this research addressed the paradox in the complexity of the building. While complex buildings such as swimming facilities should be analyzed by dynamic simulation tools in the planning phase, this is seldom done due to the demanding and time-consuming task of modeling such complex systems and phenomena. Therefore, a simplified model for simulation-based design of swimming facilities was developed and compared with a validated detailed model of a swimming pool air handling unit (AHU), which is the most complex device in a swimming facility. In conclusion, the results of this PhD project can contribute to more sustainable swimming facilities in existing and new buildings.

Globale kjølebehov er i stadig økning og handlinger må derfor gjøres for å sørge for at driftingen av VVS-systemer blir mer klimavennlige og så energieffektive som mulig. Tradisjonelle kjølemaskiner inneholder kjølemidler som kan være miljøskadelige og krever energi av høy kvalitet, som elektrisitet, for og driftes. Kjøling ved hjelp av befukting fjerner dette problemet da det ikke krever noen spesielle kjølemidler. På den andre siden avhenger slik kjøling på uteforholdene og kan gi utilstrekkelig kjøling. Kjøling ved hjelp av sorpsjonhjul kan løse disse problemene da den absolutte fuktigheten i tilluften reduseres før befuktningskjølingen skjer. Sorpsjonshjul drives av termisk energi, noe som kan forsynes av fornybare energikilder som solenergi. En forenklet modell av et sorpsjonshjul er utviklet i bygningssimuleringsverktøyet IDA ICE. Ytelsen av hjulet har blitt analysert for et standard norsk kontorbygg og sammenlignet med adiabatisk kjøling og tradisjonell kjøling med kjølemaskin. Modellen av sorpsjonshjulet er en fortsettelse på en modell som ble utviklet høsten 2021 ved spesialiseringsemne foran denne masteroppgaven. Ytelsen av den forbedrede modellen er avhengig av fire forskjellige parameter i stedet for to, og regenereringstemperaturen settes nå ut fra det faktiske behovet for å redusere energibehovet. Modellen klarer å fjerne fukt og samtidig holde entalpien konstant, og opprettholder derfor de termodynamiske egenskapene for sorpsjonshjul. Anvendte systemer i Norge er også analysert for å få kunnskap om konfigurasjoner, parameter og kontrollstrategier brukt i praksis. Få bygninger i Norge benytter sorpsjonskjøling på grunn av høye investeringskostnader. Resultatet fra simuleringene tyder på at adiabatisk kjøling klarer å senke kjølebehovet uten å påvirke den termiske komforten i bygget, da fuktigheten i tilluften er uendret. Om en adiabatisk befukter legges til på tilluftsiden fører det til enda lavere kjølebehov, men mot noe dårligere termisk komfort og økt PPD. Ved sorpsjonskjøling ble det klart at settpunkt for aktivering av hjulet har stor påvirkning på energibehovet for regenerering. Ved endring av settpunkt fra 16 C til 20 C ble energibehovet for regenerering senket med cirka 51%. Resultatene fra studiet er basert på netto energibehov, hvilket betyr at energiproduksjon og tap ikke er tatt hensyn til. En videre studie med fokus på levert energi er foreslått for å få en mer grundig sammenligning. En slik sammenligning bør inkludere utnyttelsen av fornybare energikilder, som solfangere, for å få det fulle potensialet fra sorpsjonskjøling. Global cooling demands are on the rise and actions must therefore be taken to make the operation of HVAC systems more climate-friendly and as energy-efficient as possible. Traditional vapor compression refrigeration cycles possess refrigerants that could be environmentally harmful and require high-grade energy, as electrical energy, for operation. Evaporative cooling techniques dismiss this problem as it does not require any special refrigerants. On the other hand, these evaporative cooling techniques rely on outdoor conditions and may produce insufficient cooling. Rotary desiccant cooling can address these issues as the absolute humidity of the supply air is reduced before being introduced to the evaporative cooler. Desiccant wheels are operated using thermal energy, which can be supplied by lower-grade renewable energy sources like solar energy. A simplified model of a rotating desiccant wheel has been developed in the building simulation tool IDA ICE. The performance of the desiccant cooling system has been analyzed for a Norwegian office building and compared to indirect evaporative cooling (IEC) and traditional mechanical cooling. The desiccant wheel model is a continuation of a model that was made in Fall 2021 for a specialization project ahead of this master thesis. The performance of the improved model is dependent on four different parameters rather than two, and the regeneration temperature is now set according to the demand to reduce the energy need. The model is successful in removing moisture while keeping the enthalpy of the air constant, meaning the thermodynamic principles of desiccant wheels are maintained. Applied systems in Norway are also analyzed to gain knowledge of actual configurations, parameters and control strategies used. Few buildings in Norway possess desiccant cooling, mostly because of high investment costs. The results of the simulated cases indicated that the AHU configuration with IEC manages to reduce the cooling energy need without influencing the thermal comfort of the building, as the humidity on the supply side remains unchanged. Combining direct- and indirect evaporative cooling resulted in further reduction of cooling energy need, but with slightly reduced thermal comfort. The activation set-point of the desiccant wheel was found to be significant for the energy need due to regeneration of the wheel. Increasing the activation set-point from 16 C to 20 C led to a reduction in regeneration energy need of about 51%. The results of this study is based on net energy need, meaning energy production and losses are not considered. A further study with more focus on delivered energy is therefore suggested to get a more thorough comparison. A such comparison should include the utilization of renewable energy production, as solar thermal collectors, to get the full potential out of the desiccant cooling system.

The transition from a conventional energy system to a decarbonized energy system requires an increasing penetration of intermittent renewable energy sources, which brings more fluctuations to the electricity grid. Therefore, increased flexibility is required on the demand side. This thesis focuses on the energy flexibility of residential buildings by activating their thermal mass. Model predictive control (MPC) is acknowledged to be an appropriate control method for this purpose. The thesis addresses MPC using grey-box linear models of the building thermal dynamics. The research is split into two main parts, namely modeling and control. The modeling part can also be further split into data collection and model identification subsections. In the data collection part, the experiments for collecting the data are designed for both virtual and field experiments. The experimental design includes the selection of the excitation signal, the training period, and for field experiments, the influence of the sensor location and dynamics. Thus, different experiments with various excitation signals and training periods have been executed. The results show that the identified parameters are strongly dependent on the types of excitation and the training period for deterministic grey-box models. On the contrary, the identified parameters are less dependent on the excitation signal for stochastic grey-box models. Furthermore, there is no specific period of the space-heating season that is more suited to train a linear time invariant (LTI) grey-box model since weather conditions including solar radiation vary significantly during the entire space-heating season. In the model identification part, a suitable model structure is first investigated using different resistance-capacitance (RC) networks based on existing standards for building energy modeling (like the EN13790 and VDI 6007 standards) and the knowledge of building physics. The model selection is based on the structural and practical identifiability, the physical plausibility and the prediction performance of the grey-box model. The results show that for a mono-zone grey-box model, the second-order model is an appropriate trade-off between overfitting or poor model fidelity. The optimizer for the training of the model parameters is also investigated by comparing the parameters identified using traditional gradient-based optimization routines and global optimization routines. Results reveal that global optimization performs better than gradient-based optimization. The influence of data preprocessing on the grey-box modeling is investigated by using a low-pass filter as well as the influence of input data alignment using anti-causal shift (ACS). Results show that the pre-processing of data does not have a large influence on deterministic models. However, for stochastic models, the parameter values are significantly influenced by the data pre-processing. The identified parameters are strongly correlated with the sampling time (Ts). ACS can prevent the parameter value and variance from getting non-physical for large Ts. Pre-filtering only has a limited influence with ACS, while the pre-filtering influence without ACS does not have a clear trend. Some research is done in this thesis to compare the performance between grey-box and black-box models in the case of deterministic models. Results show that the second-order black-box model shows a similar performance to the second-order grey-box model. However, the physical interpretation of the hidden states and parameters is unknown for black-box models. In the control part, the performance of conventional MPC based on LTI models and adaptive MPC that are able to recalibrate the model parameters during operation is compared. The adaptive MPC is designed to overcome the influence of varying weather conditions during the heating season. Two different candidates for this adaptive control are investigated. Partially Adaptive MPC only updates the effective window area of the grey-box model. The Fully Adaptive MPC updates all the parameters of the grey-box model. Results show that the Partially Adaptive MPC is not able to deliver satisfactory prediction performance due to the limited number ofparameters updated. The Fully Adaptive MPC outperforms the conventional MPC based on LTI models, especially in avoiding thermal discomfort. Different types of models (e.g., ARX, NARX, SVM) are also compared in an MPC experiment in a supporting paper of this thesis. Results show that the seven states black-box statespace model has the best performance among the MPCs in the study. Using multistep ahead prediction error as the objective function when training the model is beneficial for guaranteeing its prediction performance.

Etter at Norge sluttet seg til i Parisavtalen i 2015, ble det satt som mål å redusere landets klimagassutslipp med 50 til 55 %, sammenlignet med 1990-nivået, innen 2030 [1]. Det ble derfor i 2016 vedtatt at energibruken knyttet til den eksisterende bygningsmassen skal reduseres med 10 TWh innen 2030 [2]. Energioppgradering av eksisterende boliger kan dermed være et viktig bidrag for å nå målene i Parisavtalen. Denne masteroppgaven er en del av OPPTRE, som er et forskningsprosjekt finansiert av Forskningsrådet [3]. Målet er å foreslå kostnadseffektive energirenoveringer for boliger som tilsvarer nesten nullenergibygg. Forslagene skal ha høy arkitektonisk kvalitet og lavt klimafotavtrykk. Seks eksisterende boliger bygd i perioden 1950 til 1990 utgjør grunnlaget til forskningsprosjektet. Det har blitt foreslått energioppgraderinger til disse gjennom en arktitektkonkurranse, hvor vinnerforslagene har formet grunnlaget for det videre arbeidet i OPPTRE-prosjektet. Arbeidet utført i denne masteroppgaven er en fortsettelse på arbeidet utført i Johansen og Kjellberg sin masteroppgave [4]. Johansen og Kjellberg har undersøkt kostnads- og energieffektiviteten, og miljøpåvirkningen til to av husene fra arkitektkonkurransen med ulike varme- og ventilasjonsløsninger, samt tre ulike oppgraderingsnivå av bygningskroppen. For å undersøke energieffektiviteten ble simuleringsprogrammet IDA ICE benyttet, mens kostnadseffektiviteten ble evaluert metodene beskrevet i NS-EN 15459-1. I arbeidet med masteroppgaven, har simuleringsmodellene fra det tidligere arbeidet blitt revidert og validert. For å validere simuleringsmodellene, har årsvarmefaktoren til de simulerte varmepumpesystemene blitt sammenlignet opp mot årsvarmefaktoren til lignende systemer i faglitteratur. Videre har evalueringen av energi- og kostnadseffektiviteten til de ulike kombinasjonene med energiforsyning sammen med de tre renoveringsnivåene blitt raffinert. I tillegg har to nye oppvarmingsløsninger blitt tatt med i vurderingen. De økonomiske virkningene av nye effektbaserte tariffer for nettleie, som er planlagt å innføres iløpet av 2022, blitt undersøkt. Til slutt har optimale oppvarmingsløsninger blitt foreslått for de tre renoveringsnivåene for de to boligene. Disse forslagene tar utarbeidet etter nøkkeltallsindikatorer innen energi og kostnadseffektivitet, samt termisk komfort. Resultatene viser at oppgradering av oppvarmingsløsningen er mer gunstig ved lavere renovasjonsnivå. Investeringskostnaden spiller en stor rolle for kostnadseffektiviteten, og de billigere kombinasjonene fører i de fleste tilfellene til lavere livsløpskostnader. Ved høyere renoveringsnivå, er oppgraderinger knyttet til ventilasjon og varmtvannsoppvarming mest kostnadseffektivt på grunn av lavere romoppvarmingsbehov. Tariffer for nettleie med effektbasert fastledd påvirker kostnadseffektiviteten til de ulike kombinasjonene i liten grad. Likevel viser en følsomhetsanalyse utført i oppgaven at de dyrere og mer effektive kombinasjonene oppnår høyere kostnadseffektivitet dersom satsene på det effektbaserte fastleddet økes. Basert på nøkkeltallsindikatorene relatert til energi- og kostnadseffektivitet, samt termisk komfort, gjør rimeligere kombinasjoner det bedre enn dyrere og mer effektive kombinasjoner. Dette blir tydeligere ved høyere renoveringsnivå, hvor energisparepotensialet til de mest effektive kombinasjonene reduseres. By committing to the Paris agreement in 2015, Norway set a goal of reducing the country’s greenhouse gas emissions by 50% to 55% compared to the emission levels in 1990 by 2030 [1]. Therefore, the motion of reducing the annual energy consumption of the existing building stock by 10 TWh by 2030 was carried in 2016 [2]. Energy retrofitting of existing residential buildings can therefore play a part in Norway’s efforts to reach the goals in the Paris agreement. This thesis is a part of OPPTRE, which is a research project supported by the Research Council of Norway [3]. OPPTRE aims to propose a cost effective Nearly Zero Energy level of retrofit for small wooden dwellings in Norway with high architectural quality and low environmental impact. The basis of the research project is six existing dwellings built in the period 1950-1990. Proposed energy upgrades for the six dwellings have been made in an architecture competition. The winning proposals of the competition have formed the basis for the rest of the OPPTRE-project. The work conducted in this thesis is a continuation of the previous work carried out in Johansen and Kjellberg’s master’s thesis [4]. Johansen and Kjellberg investigated the economic, energy and environmental performance of different heating supply combinations with three different renovation levels for two of the houses from the architecture competition. The energy performances were evaluated through simulation models in IDA ICE, while the methods described in NS-EN 15459-1 are used for the evaluation of economic performance. During the work with this master’s thesis, the simulation models from the previous work have been revised and validated. In order to validate the models, the SPF of the simulated models have been compared with the SPF of similar systems found in a literature review. The evaluation of the energy and economic performance of the heating supply combinations with the three renovation levels have been refined from the previous work. Additionally, two new combinations have been investigated. Furthermore, the effects on the economic performance of different grid tariff models, which are supposed to be induced during 2022, are looked into. Finally, optimal heating supply combinations for each renovation level of the two dwellings have been proposed. These propositions are based on predefined key performance indicators related to energy and economic performance, and thermal comfort. The results show that upgrading the heating systems is more profitable at lower insulation levels. The investment costs is an important factor for the economic performance, and the cheaper combinations induce lower life cycle costs in most cases. With increasing renovation levels, upgrades related to the ventilation system and the heating of DHW is the most cost efficient due to the low space heating demand. Grid tariffs with fixed fees based on monthly power peaks yield marginal differences in terms of economic performance. However, a sensitivity analysis show that increasing the rates of the power based fixed fee can make the more expensive and efficient heating systems more cost effective compared to cheaper combinations. Based on the performance indicators related to energy performance, cost effectiveness, and thermal comfort, combinations with low investment costs outperform more expensive and efficient combinations. This becomes more evident at higher insulation levels, where the energy saving potential of the efficient heating supply combinations is reduced.

I forbindelse med Parisavtalen i 2015, satte Norge seg som mål å redusere drivhusgassene med 50% innen 2030. I 2019 gikk 23% av Norges energiforbruk til private husholdninger ifølge Statistisk Sentralbyrå. Videre er mer enn halvparten av dem eneboliger bygget av tre. Dette betyr at det eksisterer et betydelig energisparingspotensial hvis alle disse boligene ble energioppgradert. Målet med denne masteroppgaven har vært å evaluere kostnads-, energi- og miljøytelsen til forskjellige VVS-løsninger som potensielt kan implementeres i norske trehus. Dette blir undersøkt på grunn av det store energibesparelsespotensialet, av den hensikt å informere sluttbrukere og til slutt å bidra til å nå det nasjonale klimamålet. Hvordan "prebound" og "rebound"-effektene påvirker kostnadseffektiviteten vil også bli undersøkt. Denne masteroppgaven er relatert til NTNU/SINTEFs OPPTRE-prosjekt. OPPTRE-prosjektet har som mål å foreslå et nesten nullenerginivå ved renovasjon av eneboliger bygget av tre. Det er seks hus i OPPTRE-prosjektet, representative for typisk norsk arkitektonisk stil. To av disse husene skal i denne masteroppgaven analyseres og bygningskroppen skal renoveres til tre nivåer av energieffektivitet. Ulike metoder brukes til å evaluere de tre ytelsesaspektene i denne studien. Standarden NS-EN 15459 (2017) ble hovedsakelig brukt til kostnadseffektivitetsanalysen. Når det gjelder energiytelsen, ble det gjort simuleringer i energisimuleringsprogramvaren IDA ICE. Nøkkelresultatet fra simuleringen er bygningens årlige energibruk. For å vurdere miljøpåvirkningen brukes CO2-faktorer for å konvertere energiforbruket til tilsvarende CO2-utslipp fra de forskjellige VVS-løsningene. "Prebound"- og "rebound"-effektene utforskes gjennom kompensasjon i energiforbruket. Dette innebærer lavere energiforbruk i det eksisterende huset og høyere energiforbruk i de renoverte scenariene. Masteroppgaven belyser at renovering av eneboliger kan bidra til å redusere energibruken i den norske bygningsmassen ved å investere i kostnads- og energieffektive tiltak med lav miljøpåvirkning. Man kan konkludere med at flere av de utvalgte VVS-kombinasjonene er optimale, avhengig av energieffektiviteten til bygningskroppen og type enebolig. Resultatene indikerte i tillegg at optimal kombinasjon avhenger av hvordan man veier investeringens kostnadseffektivitet, energieffektivitet og miljøpåvirkning opp mot hverandre. In the Paris Agreement of 2015, Norway agreed on aiming at a 50% reduction of greenhouse gas emissions by 2030. According to Statistisk Sentralbyrå, private households were responsible for around 23% of Norway's energy consumption in 2019. More than half of these private households were wooden dwellings. This means that there is a significant potential for energy savings if these wooden dwellings were to undergo an energy retrofit. The objective of this master's thesis has been to evaluate the cost-, energy- and environmental performance of different HVAC-combinations that could potentially be implemented in Norwegian wooden detached dwellings. This is investigated because of the potential for considerable energy savings and for the purpose of enlightening end users. Ultimately, the thesis hopefully contributes to reaching the national climate target. The impact of the prebound and rebound effects on the cost effectiveness will also be explored. This master's thesis is related to the NTNU/SINTEF’s project named OPPTRE. The OPPTRE-project aims at proposing a nearly Zero Energy Building (nZEB) level for deep energy retrofit of wooden detached dwellings. There are six houses in the OPPTRE-project, representative of the typical Norwegian architectural style. Two of these houses are in this master's thesis going to be analyzed and deep energy retrofitted to three levels of energy efficiency of the building envelope. Different methods are used to evaluate the three performance aspects of this study. The standard NS-EN 15459 (2017) was mainly used for the cost performance assessment. Concerning the energy performance, simulations in the energy simulation software IDA ICE were done. The key output from the simulations is the annual energy consumption of the building. To assess the environmental impact, CO2-factors are used to convert the energy consumption into the equivalent CO2-emissions from the different HVAC-combinations. The prebound and rebound effects are explored through compensation in energy consumption. This implies calculating with lower energy consumption in the existing house and higher energy consumption in the retrofitted scenarios. This thesis shows that deep energy retrofitting detached wooden dwellings can contribute to reducing the energy use of the Norwegian building stock through cost-effective and energy-efficient measures with low environmental impact. In conclusion, several of the considered HVAC-combinations could be optimal, depending on the energy efficiency of the building envelope and type of detached wooden dwelling. The results indicated additionally that which combinations are optimal, depended on the weighing of the investment's cost effectiveness, energy efficiency and environmental impact.

Bygninger bidrar til verdens energibruk og utslipp av klimagasser. En foreslått løsning for å redusere energibruken i eksisterende bygninger er å implementere avanserte kontrollstrategier. Et forslag er modell prediktiv kontroll (MPC). Tidligere forskning på modell prediktiv kontroll har belyst potensialet denne kontrollstrategien har til å redusere energibruken ved å implementere den i eksisterende bygg. Modell prediktiv kontroll må være tilpasset bygget den skal kontrollere. Målet for oppgaven er å lage en forenklet emulator av et kontorbygg i Oslo for å kunne indeksere, sammenligne og eksperimentere på kontrollalgoritmen offline. Rammeverket for oppgaven presenterer oppdatert forskning om bygningssimulering og dens begrensninger. Det blir også belyst hvordan Modelica opptrer som et bygningssimuleringsverktøy og hvordan man kan kalibrere et bygg. Til slutt sammenligner rammeverket effekten av modell prediktiv kontroll mot regelbasert kontroll. Forskningen indikerer at MPC-er har stort potensiale med tanke på å redusere energibruken i bygninger og å redusere toppbelastningen, men MPC-er kan også bli optimalisert til å minimere andre objektfunksjoner avhengig av hva man ønsker at MPC-en skal kontrollere. Kontorbygget har åtte etasjer og en kjeller, men det er bare deler av kjelleren og andre til syvende etasje som er dekket av det vannbårne varmesystemet. SINTEF utførte målinger i bygget våren 2020. Disse målingene brukes for kalibreringsprosessen, og noen av de målte dataene brukes som inndata i den modellerte bygningen for å redusere antall ukjente i modellen. En værfil som inneholder værdata for 2020 er laget for å påse at den modellerte bygningen opplever det samme været som bygget hadde da målingene ble utført. Det første steget i kalibreringsprosessen er å kalibrere sjette etasje av bygget, ettersom det er færre feilkilder når man kun undersøker én etasje. Den nominelle effekten til radiatorene og varmebidraget fra personer, lys og utstyr er variert for å kalibrere modellen av sjette etasjen. Den nominelle effekten for vestkretsen er 35 W/m2 og for østkretsen er det 25 W/m2 for det vannbårne systemet. Varmetilførselen fra personer, lys og maskiner er satt til det samme som verdiene fra Standard Norge (2020), men etter 12. mars 2020 er varmeeffekten fra mennesker satt til 0 og maskiner og lys er satt til det laveste nivået. Modellen skal være kalibrert når den er innenfor grensene til de statistiske indeksene satt av ASHRAE. De samme inndataene som ble brukt for å kalibrere sjetteetasjen er brukt for å kalibrere hele bygget. Når modellen er kalibrert, er forskjellige regelbaserte kontroller testet på den kalibrert modellen. Under evalueringsprosessen brukes typiske værdata i modellen. De tre kontrollene som evalueres er en som har utekompenseringskurve med nattsenking, en som har utekompenseringskurve uten nattsenking og en siste kontroll som har utekompenseringskurve hvor pumpene skrus av på natten og i helgene. Utekompenseringskurven er optimalisert til hver kontroll for å oppnå innetemperatur i sonene innenfor akseptable nivåer. Kontrollen som har utekompenseringskurve uten nattsenking har høyest energibruk og har best innetemperatur gjennom året, mens kontrollen hvor pumpene skurs av på nettene og i helgene har lavest energibruk og flest timer utenfor akseptabel innetemperatur på 19 °C. Til slutt er det gjennomført en sensitivitetsanalyse av det modellerte bygget som har en regelbasert kontroll med utekompenseringskurve og nattsenking. Denne analysen belyser at solskjerming og varmeeffekten fra folk, lys og utstyr ikke påvirker energibruken i bygget til en stor grad, men mindre solskjerming i det modellerte bygget kan redusere antall timer under 19 °C med denne kontrollstrategien. Å endre nattsenkingen på utekompenseringskurven fra 10 til 15 °C fører til at bygget bruker 12 % mindre energi. Derimot øker dette antallet timer i arbeidstiden under 19 °C i bygget. Buildings contribute to the world’s energy consumption and greenhouse gas emissions. In order to reduce the energy use in buildings, it has been suggested to implement advanced control strategies of existing buildings. Among these control strategies, model predictive control (MPC) can be a promising option. Previous research on model predictive control has illustrated the energy saving potential of introducing said controls to existing buildings, but model predictive controls need to be optimized for the building in question. In order to benchmark, compare and experiment on the control algorithms offline, a simplified emulator of an office building in Oslo was created in this thesis. The aim of this thesis is to model the building in the Dymola/Modelica environment and calibrate it, and then apply different rule based control strategies and evaluate them. The framework in the thesis presents up to date research about building performance simulation and its limitations. It also highlights how Modelica performs as a building performance simulation (BPS) tool and how to calibrate a modelled building. Lastly, the framework compares the impact of MPCs on modelled buildings to rule based controls (RBCs). The research indicate the potential of MPCs on the energy use in buildings and the reduction in peak load, but MPCs can be optimized to minimize different objective functions depending on the desired outcome. The office building has eight floors and a basement, but it is only parts of the basement and the second to the seventh floor that are connected to the hydronic heating system. SINTEF conducted measurements in the physical building during the spring of 2020. These measurements are used for the calibration process, and some of the measured data are used as inputs to the modelled building to reduce the number of unknowns in the model. A weather file containing the measured weather in 2020 is created to ensure that the modelled building experiences comparable weather to the building in Oslo during the measurement period. The initial step in the calibration process is to calibrate the sixth floor of the building, as there are fewer sources of error when only one floor is considered. The nominal power of the radiators and the internal heat gains are varied in the model to obtain a calibrated model of the sixth floor. The nominal power for the West circuit is 35 W/m2 and 25 W/m2 for the East circuit. The internal heat gains in the models are the same as the values from Standard Norge (2020), but after the 12th of March there are no people present and the heat added by machines and lights are set to the lowest level. The model is calibrated once it is within the limits of statistical indices set by The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). The same inputs that were used to calibrate the sixth floor of the building are then applied to the entire building. The model of the sixth floor and the modelled building are within the tolerance levels as set by ASHRAE. Different RBC strategies are applied to the calibrated model once the modelled buildingis calibrated. During the evaluation of the controls, the modelled building experiences normal operating conditions such as typical meteorological data. The three controls considered for the evaluation is a weather compensated curve (WCC) with a night setback, a WCC without a night setback and a WCC where the pumps turn off at night. The WCC is optimized for each case to ensure that the indoor air temperature is within acceptable levels for all of the cases. The case without a night setback has the highest energy use and obtains the best indoor air temperature, whereas the case where the pumps turn off at night has the lowest energy use and has the most hours below acceptable indoor air temperature levels of 19 °C. Lastly a sensitivity analysis of the modelled building with a rule based control consisting of a WCC and a night setback is performed. It highlights that the level of blinds and internal heat gains do not impact the energy use in the building to a large degree, but assuming less blinds in the modelled building can reduce the number of hours below 19 °C in the building. Moreover, by reducing the night and weekend setback of the WCC from 10 to 15 °C the building consumes 12 % less energy. However, this significantly impacts the indoor air temperature in the building as the number of hours below 19 °C increase.

Denne masteroppgaven presenterer en omfattende gjennomgang av «cavity flow» benchmarket, med den hensikt å validere RANS turbulensmodeller for mikseventilasjonsformål. CFD brukes mer og mer for luftstrømmer inne i bygninger. Det kan være et kraftig verktøy for å optimalisere ventilasjonssystemer, og de siste tiårenes økning i tilgjengeligheten av datakraft har gjort CFD simuleringer mindre tidkrevende. To nylige studier har imidlertid stilt spørsmål ved nøyaktigheten av CFD simuleringer anvendt for innendørs luftstrømmer. I disse studiene har flere forskergrupper blitt spurt om å simulere to benchmarker, representative for mikseventilasjonsformål. En bekymringsfull spredning ble sett i resultatene, som indikerer at resultatet fra en CFD simulering er veldig avhengig av hvilke valg som blir gjort av brukeren. Disse studiene understreker nødvendigheten av å validere CFD opp mot representative benchmarker med tilgjengelige eksperimentelle data. For å adresse dette gir denne masteroppgaven en omfattende gjennomgang av de tilgjengelige «cavity flow» benchmarkene – representative for mikseventilasjon – med det overordnede målet å etablere en beste bruksmåte av RANS turbulensmodeller for mikseventilasjonsformål. Syv benchmarker presenteres i denne oppgaven. Deres geometri, strømningsregime, eksperimentelle oppsett og typen eksperimentelle data som er tilgjengelig introduseres først, før simuleringer av benchmarkene gjort av andre forskere presenteres i litteraturstudiet. Fokuset er på hvor bra to-liknings RANS turbulensmodeller greier å produsere resultater som gir samsvar med de eksperimentelle dataene. Dette er fordi resultatene fra den foregående prosjektoppgaven indikerte at valget av turbulensmodell er den enkelt input parameteren med størst påvirkning på resultatet, og RANS turbulensmodeller er mye brukt i industrien. Hvor godt turbulensmodellene har prestert i litteraturen oppsummeres før CFD simuleringer fra denne oppgaven presenteres. Ytelsen til turbulensmodellene varier betydelig fra benchmark til benchmark, noe som var forventet siden de representerer ulike utfordringer. Ingen av de testede turbulensmodellene greier å produsere tilfredsstillende resultater for alle benchmarkene, noe som understreker viktigheten av å velge en passende turbulensmodell for et spesifikt tilfelle. Resultatene indikerer at k-ε modellene gir best resultat for benchmarkene med fullt turbulent strømning, spesielt standard k-ε modellen. SST k-ω modellen gir dårligere samsvar med eksperimentene for de fullt turbulente benchmarkene og virker å overpredikere makshastigheten i en fullt turbulent vegg jet. For et benchmark i overgangsregime derimot, gir SST k-ω modellen best samsvar med de eksperimentelle dataene og standard k-ε modellen det verste. Det er dog ikke alltid helt klart hva som forårsaker endringen i ytelsen til turbulensmodellene fordi flere karakteristikker – geometri, strømningsregime og effekten av motstående trykkgradient – endres fra benchmark til benchmark. Resultatene indikerer også at innløpsverdiene for k og ε/ω har større påvirkning på resultatet for strømninger med lavt Reynoldstall enn høyt. Majoriteten av resultatene fra denne oppgaven stemmer overens med resultatene fra litteraturen, men SST k-ω modellen gir resultater som ikke stemmer med de fra litteraturen for to av tilfellene. Fra oppdagelsene i denne oppgaven gis det noen beste bruksmåte anbefalinger, men det trengs også videre arbeid for å konkludere på hva som forårsaker variasjoner sett i ytelsen til turbulensmodellene. Spesielt er det et behov for flere benchmarks som systematisk endrer en og en karakteristikk av gangen. Dette vil gi muligheten til å si med mer sikkerhet hvilke karakteristikker av «cavity flow» strømningen de forskjellige RANS modellene er kapable til å modellere korrekt. This master thesis presents an extensive review of the cavity flow benchmark, with the purpose of validating RANS turbulence models for mixing ventilation applications. CFD is used more and more in indoor airflows applications. It can be a powerful tool to optimize ventilation systems, and the last decades increase in the availability of computational power has made CFD simulations less time consuming. Two recent studies have, however, questioned the accuracy of CFD for indoor airflow applications. In these studies, several teams of researchers were asked to simulate two benchmark cases, representative for mixing ventilation applications. A concerning spread was seen in the results, indicating that the result from a CFD simulation is very dependent on the choices made by the user. To overcome this issue, these studies emphasized the need to validate CFD against representative benchmark cases with available experimental data. To address this, this thesis gives a comprehensive review of the available cavity flow benchmarks – representative for mixing ventilation applications – with the overall goal to establish a best practice use of RANS turbulence models for mixing ventilation applications. Seven benchmarks are presented in the thesis. The benchmark’s geometry, flow regime, experimental setup and type of experimental data are first introduced, before simulations of the seven benchmarks done by other researchers are presented in the literature review. The focus is on how well two-equation RANS turbulence models produce results that are in agreement with the experimental data. This is because the results from the preceding project assignment indicated that the choice of turbulence model is the single input parameter with the largest impact on the results, and RANS turbulence models are widely used in the industry. How well the turbulence models have performed in the literature is summarized, before the results from CFD simulations of the benchmarks from this thesis are presented. The turbulence model performance varies significantly from benchmark to benchmark, which was expected since the benchmarks represent different challenges. None of the tested turbulence models are capable of producing good results for all seven benchmarks, underlining the importance of selecting a suitable turbulence model for a given case. The results indicate that the k-ε models perform best for the benchmarks with fully turbulent flow, in particular the standard k-ε model. Furthermore, the SST k-ω model gives poorer agreement with experiments for the fully turbulent benchmarks and seems to overpredict the maximum velocity in a fully turbulent wall jet. For a benchmark in the transitional regime, however, the SST k-ω model gives the best agreement with the experimental data and the standard k-ε model the worst. However, it is not always clear what causes the change in turbulence model performance since several features of the flow – geometry, flow regime and magnitude of the adverse pressure gradient in the wall jet – change from benchmark to benchmark. The results also indicate that the inlet values for k and ε/ω have a bigger impact on the result for low Reynolds number flows, than high Reynolds number flows. The majority of the results from this thesis are consistent with the results from the literature, however, the SST k-ω model gives results that are inconsistent with literature for two of the benchmarks. From the discoveries in this thesis some best practice guidelines are given, but further work is also needed to conclude on what causes the variations seen in turbulence model performance. In particular, there is a need for additional benchmarks that systematically changes one feature at a time. This will give the opportunity to say with more certainty what features of the cavity flow the different RANS turbulence models are capable and incapable to model correctly.

The present work focuses on the development of a novel application that aims to better understand energy-related indoor occupant behaviour (OB). The thesis briefly introduces the key features of OB, presents the current state of the art and highlights the present challenges related to this field. The goal of the thesis is to present how potential challenges can be addressed with the use of a novel monitoring technique for in-situ occupant tracking. It is a depth registration technique that has practical implementations in various applications focusing on surface scanning. The main goal of the use of this technique in OB studies is to increase the quality of the measurement resolution to better understand the reasons for occupant activities regarding indoor energy use. It is expected that with an increase in the measurement resolution, it will be possible to observe and collect new information about occupants and their energy utilization. Therefore, it will be possible to detect avoidable waste of energy. The proposed monitoring technique has not previously been commercially implemented in this research domain. Thus, there were no guidelines allowing for quick implementation. The methodology presented in the thesis describes step-by-step all the basic information required to understand the ideas and proposals for device utilization. Extended explanations are included in the appendices, and each subchapter refers to relevant appendices. Beyond the direct monitoring of occupants, the thesis explains the use of the collected data and shows how the data can be implemented in an agent-based model (ABM). The proposed model focuses on direct simulation of an occupant’s activities by recreating these activities through the portrayal of the occupant as an agent. The main functionalities that are provided by the model enable simulation of occupant movement, sensation of the thermal environment, interaction with indoor appliances and decision-making processes. The results obtained from the simulation show that a novel approach for the simulation of occupants is achievable. The OB represented by the ABM can be implemented as a calculation engine, which considers the occupant’s actions as activity triggers. The model is designed to connect various scientific specialities that focus on OB aspects, and combines each of the aspects into one common platform. The communication between scientific specialities that can be initialised by the proposed platform will bring a greater understanding of energy-related OB. Consequently, it may lead to a greater reduction in the use of energy resources without compromising occupants’ indoor comfort.

I forbindelse med Parisavtalen i 2015, satte Norge seg som mål å redusere drivhusgassene med 50% innen 2030. I 2019 gikk 23% av Norges energiforbruk til private husholdninger ifølge Statistisk Sentralbyrå. Videre er mer enn halvparten av dem eneboliger bygget av tre. Dette betyr at det eksisterer et betydelig energisparingspotensial hvis alle disse boligene ble energioppgradert. Målet med denne masteroppgaven har vært å evaluere kostnads-, energi- og miljøytelsen til forskjellige VVS-løsninger som potensielt kan implementeres i norske trehus. Dette blir undersøkt på grunn av det store energibesparelsespotensialet, av den hensikt å informere sluttbrukere og til slutt å bidra til å nå det nasjonale klimamålet. Hvordan "prebound" og "rebound"-effektene påvirker kostnadseffektiviteten vil også bli undersøkt. Denne masteroppgaven er relatert til NTNU/SINTEFs OPPTRE-prosjekt. OPPTRE-prosjektet har som mål å foreslå et nesten nullenerginivå ved renovasjon av eneboliger bygget av tre. Det er seks hus i OPPTRE-prosjektet, representative for typisk norsk arkitektonisk stil. To av disse husene skal i denne masteroppgaven analyseres og bygningskroppen skal renoveres til tre nivåer av energieffektivitet. Ulike metoder brukes til å evaluere de tre ytelsesaspektene i denne studien. Standarden NS-EN 15459 (2017) ble hovedsakelig brukt til kostnadseffektivitetsanalysen. Når det gjelder energiytelsen, ble det gjort simuleringer i energisimuleringsprogramvaren IDA ICE. Nøkkelresultatet fra simuleringen er bygningens årlige energibruk. For å vurdere miljøpåvirkningen brukes CO2-faktorer for å konvertere energiforbruket til tilsvarende CO2-utslipp fra de forskjellige VVS-løsningene. "Prebound"- og "rebound"-effektene utforskes gjennom kompensasjon i energiforbruket. Dette innebærer lavere energiforbruk i det eksisterende huset og høyere energiforbruk i de renoverte scenariene. Masteroppgaven belyser at renovering av eneboliger kan bidra til å redusere energibruken i den norske bygningsmassen ved å investere i kostnads- og energieffektive tiltak med lav miljøpåvirkning. Man kan konkludere med at flere av de utvalgte VVS-kombinasjonene er optimale, avhengig av energieffektiviteten til bygningskroppen og type enebolig. Resultatene indikerte i tillegg at optimal kombinasjon avhenger av hvordan man veier investeringens kostnadseffektivitet, energieffektivitet og miljøpåvirkning opp mot hverandre. In the Paris Agreement of 2015, Norway agreed on aiming at a 50% reduction of greenhouse gas emissions by 2030. According to Statistisk Sentralbyrå, private households were responsible for around 23% of Norway's energy consumption in 2019. More than half of these private households were wooden dwellings. This means that there is a significant potential for energy savings if these wooden dwellings were to undergo an energy retrofit. The objective of this master's thesis has been to evaluate the cost-, energy- and environmental performance of different HVAC-combinations that could potentially be implemented in Norwegian wooden detached dwellings. This is investigated because of the potential for considerable energy savings and for the purpose of enlightening end users. Ultimately, the thesis hopefully contributes to reaching the national climate target. The impact of the prebound and rebound effects on the cost effectiveness will also be explored. This master's thesis is related to the NTNU/SINTEF’s project named OPPTRE. The OPPTRE-project aims at proposing a nearly Zero Energy Building (nZEB) level for deep energy retrofit of wooden detached dwellings. There are six houses in the OPPTRE-project, representative of the typical Norwegian architectural style. Two of these houses are in this master's thesis going to be analyzed and deep energy retrofitted to three levels of energy efficiency of the building envelope. Different methods are used to evaluate the three performance aspects of this study. The standard NS-EN 15459 (2017) was mainly used for the cost performance assessment. Concerning the energy performance, simulations in the energy simulation software IDA ICE were done. The key output from the simulations is the annual energy consumption of the building. To assess the environmental impact, CO2-factors are used to convert the energy consumption into the equivalent CO2-emissions from the different HVAC-combinations. The prebound and rebound effects are explored through compensation in energy consumption. This implies calculating with lower energy consumption in the existing house and higher energy consumption in the retrofitted scenarios. This thesis shows that deep energy retrofitting detached wooden dwellings can contribute to reducing the energy use of the Norwegian building stock through cost-effective and energy-efficient measures with low environmental impact. In conclusion, several of the considered HVAC-combinations could be optimal, depending on the energy efficiency of the building envelope and type of detached wooden dwelling. The results indicated additionally that which combinations are optimal, depended on the weighing of the investment's cost effectiveness, energy efficiency and environmental impact.

This paper describes theoretical analyses of typical detached Danish single family houses’ ability to provide thermal capacity and thus flexibility, in an electricity grid, if they were heated by individual heat pumps.A set of archetype house models have been set up for analyses of their ability for moving energy use in time by dynamic simulations in BSim (Wittchen et al., 2000-2019). The archetypes was established in order to analyse single-family houses constructed in different periods, usually related to shifts in building regulations or building traditions.Finally, results from archetype modelling are scaled to the total number of Danish single-family houses located outside district heating areas to estimate the future thermal capacity in these houses. Analyses showed that up to 99 % of the energy demand for space heating within peak hours can be moved outside peak hours, with acceptable influence on the indoor temperature.The paper describes the simulation approach and the results for different archetype houses as well as upscaling to nation-wide thermal storage potential. Moreover, the paper describes flexibility studies on selected houses based on both peak response and price signal response. This paper describes theoretical analyses of typical detached Danish single family houses’ ability to provide thermal capacity and thus flexibility, in an electricity grid, if they were heated by individual heat pumps. A set of archetype house models have been set up for analyses of their ability for moving energy use in time by dynamic simulations in BSim (Wittchen et al., 2000-2019). The archetypes was established in order to analyse single-family houses constructed in different periods, usually related to shifts in building regulations or building traditions.Finally, results from archetype modelling are scaled to the total number of Danish single-family houses located outside district heating areas to estimate the future thermal capacity in these houses. Analyses showed that up to 99 % of the energy demand for space heating within peak hours can be moved outside peak hours, with acceptable influence on the indoor temperature. The paper describes the simulation approach and the results for different archetype houses as well as upscaling to nation-wide thermal storage potential. Moreover, thepaper describes flexibility studies on selected houses based on both peak response and price signal response.

The effect of climate change on Danish office building energy performance was investigated. Local mean weather data and national design reference year are morphed into future weather files, and the output from a total of 313,000 EnergyPlus simulations was analysed. The results indicate that the current Danish building design practice is not appropriate if buildings designed today are to be resilient to climate change.

Monte Carlo simulations, sensitivity analysis and metamodeling are becoming popular in academia but are rarely applied in real building projects. In this case study, we demonstrate how a combined framework of these methods can aid decision-making in relation to building performance of nine 16-story residential buildings. We describe the processes before, during, and after a meeting between building engineers and the building owner. For preparation, BeDesigner was used to create, run, and analyse 5.000 Be18 simulations in roughly 4 hours. The meeting is initiated with a presentation of sensitivity analysis results to focus the attention towards the most influential design inputs. The 5.000 simulations are visualized with parallel coordinates plots in DataExplorer, which enable decision-makers to observe the consequences of different design choices and regulatory requirements. Real-time sensitivity analysis, TOR, highlights the parameters affected the most by the applied constraints, while histograms indicate favourable or disadvantageous design choices. However, no solutions exist among the 5.000 simulations, which is due to the vastness of the multi-dimensional input space and the decision-makers’ numerous requirements. Using metamodels, 500.000 additional input combinations are calculated and from this extensive dataset a variety of solutions are found. It becomes clear that a “norenewables” ambition necessitates costly countermeasures and makes it difficult to realize the architectural and indoor climate requirements. In conclusion, the combined framework improves the information quality for decision-making and significantly increase the likelihood of finding diverse, high-performing solutions within the same time-frame as traditional practice.

Svømmehaller er komplekse bygg som stiller høye krav til både bygningskropp og tekniske systemer. Et velfungerende ventilasjonsaggregat med optimal styring av temperatur- og fuktkontroll er svært viktig for å skape et godt inneklima og for å unngå fuktskader i bygningskonstruksjonen. Energibruken er svært høy sammenlignet med andre bygningskategorier, da store luftvolumer og vannmengder skal varmes opp til komfortable temperaturer. I tillegg er prosessen med avfukting av inneluften en svært energikrevende prosess som krever store luftmengder. Dette krever gode løsninger for å gjøre et svømmehallanlegg så energieffektivt som mulig. I denne masteroppgaven er det utviklet en modell av svømmehallen ved Dalgård skole og ressurssenter, hvor målet har vært å validere modellen med tanke på fordampning og det termiske energibehovet ved ulike poster i anlegget. Modellen er videre brukt til å se på hvilke løsninger som kan forbedres, for å redusere energibruken til svømmehallen. Dalgård svømmehall er et gammelt anlegg fra 1978, som gikk gjennom en delvis rehabilitering i 2014. Svømmehallen blir stort sett brukt av skolens elever, samt noen foreninger på kveldstid. Målinger ble gjennomført i perioden 25. februar til 11. mars, hvor det fortsatt var aktivitet i bassenget før anlegget ble stengt. Målinger av temperatur og relativ luftighet er gjennomført på flere steder i anlegget, og effektforbruk er målt i varmebatteriet til ventilasjonsaggregatet og i primærvarmeveksleren til bassengvannet. Disse målingene er videre brukt i beregninger av fordampningsrate og energibruk. Modellen av svømmehallen er utviklet i simuleringsverktøyet IDA ICE, basert på den tekniske dokumentasjonen til ventilasjonsaggregatet og observasjoner i anlegget. Resultatene viser et godt samsvar mellom simuleringer i modellen og beregninger gjort ut ifra målinger på flere punkter. Simulert fordampningsrate viste seg å være 8.5% høyere enn den som ble beregnet, og energibruken til oppvarming av bassengvann var 10% høyere enn det som ble målt. Når det gjelder varmeoverføringen i varmebatteriet i ventilasjonsaggregatet, ga simuleringene en 4.7% lavere gjennomsnittlig effekt enn det målingene viste. Den integrerte varmepumpen i ventilasjonsaggregatet var dessverre ute av drift i perioden målingene ble gjennomført. Det ble derfor gjennomført simuleringer både med og uten varmepumpe, for å se på hvilken effekt dette hadde på energiytelsen til anlegget. For den analyserte måleperioden ble energibruken til oppvarming av luft og vann redusert med henholdsvis 50.6 og 30.4%. En årssimulering viste at varmepumpen kunne redusere det totale energiforbruket til svømmehallen med 26%. Swimming pools are complex buildings that place high demands on both building bodies and technical systems. A well-functioning air handling unit with optimum control of temperature and humidity control is very important to create a good indoor climate and to avoid moisture damage in the building structure. Energy consumption is very high compared to other building categories, as large volumes of air and water are to be heated to comfortable temperatures. In addition, the process of dehumidifying the indoor air is a very energy-intensive process that requires large volumes of air. This requires good solutions to make a swimming pool system as energy efficient as possible. In this master thesis, a model has been developed of the swimming pool at Dalgård School and Resource Center, where the aim has been to validate the model with regard to evaporation rates and the thermal energy needs for various posts in the facility. The model is further used to investigate possible measures of improvement, which may reduce the energy consumption of the swimming pool. Dalgård swimming pool is an old facility from 1978, which went through a partial rehabilitation in 2014. The swimming pool is mostly used by the school's students, as well as some associations in the evening. Measurements were carried out between February 25 and March 11, where there was still activity in the pool before the facility was closed. Measurements of temperature and relative humidity have been carried out at several locations in the plant, and energy consumption is measured in the heating coil of the air handling unit and in the primary heat exchanger for the pool water. These measurements are further used in calculations of evaporation rates and energy consumption. The model of the swimming pool is developed in the simulation tool IDA ICE, based on the technical documentation of the ventilation unit and observations within the facility. Compliant results were found between simulations in the model and calculations based on measurements for several posts. Simulated evaporation rate was found to be 8.5% higher than the calculated and the energy consumption for heating of pool water was 10% higher than that measured. Regarding the heat transfer in the heating coil within the air handling unit, the simulations gave a 4.7% lower average power than the measurements showed. Unfortunately, the integrated heat pump in the air handling unit was out of order during the measurement period. Therefore, simulations were conducted both with and without heat pump, to see what effect this had on the energy performance of the facility. For the analyzed measurement period, the energy consumption for heating of air and water was reduced by 50.6 and 30.4% respectively. A one-year simulation showed that the heat pump could reduce the total energy consumption of the swimming pool facility by 26%.

Denne oppgaven omtaler ulike modelleringsstrategier for prediksjon av kjølebehov for bruk av prognose modellregulering(MPC) av kjølesystemer i kontorbygg. Ved å predikere kjølebehovet er det mulig å optimalisere reguleringen av kjølesystemer og redusere bruken av energi til kjøling. Energibruk til kjøling i norske kontorbygg har økt de siste ti årene . Samtidig er presset fra offentlige myndigheter om redusert energibruk i byggesektoren aldri har vært større. Prediksjon av kjølebehov gir muligheter til å produsere energi til kjøling på et tidspunktet før kjølebehovet inntreffer. Samtidig muliggjør det utnyttelse av mer optimale kjølesystemer og nøyaktig regulering. For MPC av kjølesystemer er det mulig bruke vær-, kjølefaktor-, energipris- og internlastprognose og forutse utviklingen til kjølebehovet frem i tid. Kjølebehovet avhenger i stor grad av værforholdene. Derfor er det motiverende at værprognoser fra metrologiske institutt har aldri vært bedre. Samtidig er energiprisprognose lett tilgjengelig fra Nord Pool som gir indikasjoner på når det er økonomisk gunstig å produsere energi til kjøling. Kombinasjonen av kjølemaskin og lager kan være et fornuftig kjølesystem for prognose modellregulering. Dette fordi lageret kan fungere som buffer i perioder der det er gunstig å produsere mens behovet er lavt. I tillegg ved bruk av MPC er det mulig å oppnå lavere reguleringstap og mer nøyaktig regulering. I MPC oppdateres prognosen i faste intervaller, eksempelvis hver time, for å korrigere for eventuelle feil. For optimal MPC er det avgjøreende å ha treffsikre systemmodeller for prediksjon. I den anledning har fire modeller blitt analysert med hensyn på treffsikkerhet, \say{Normalized root mean square error} NRMSE. De fire modellene er basert på bygningskroppen til ett standardisert kontorbygg. Disse er alle modellert for å predikere kjølebehovet til bygget. Det har blitt programmert en grå-boks modell i form av ett termisk nettverk. Grå-boks modellene benytter seg av fysiske prinsipper og målt bygningsdata. Videre har det blitt utviklet tre nevrale nettverk innenfor svart-boks metoden. Disse benytter seg av maskinlæringsteknikk og er avhengige av input- og outputen til det som modelleres og trenes basert på store mengder måledata fra bygget. Felles for de nevrale nettverkene viste seg å være høy treffsikkerhet for lengre treningsperioder, jo større mengde data dess bedre prediksjon av kjølebehov. Det termiske nettverket viste det motsatte. Samtidig kom det frem at de flerlagsforovernettverket(FN) fikk høyest NRMSE. I analyse av prediksjonen til FN ble forenklet MPC av kjølebehov utviklet med betingelser for maksimal effektkapasitet og minimal innetemperatur for kjølebehov. Det interessante ved prediksjonene til FN nettverket var at en typisk \say{gjennomsnittlig dag} i vår- og sommermånedene ga høyere NRMSE enn dag med maksimalt kjølebehov og solstråling. Avvikende tilstand ga lavere treffsikkerhet. Uavhengig av dette ser det like vel ut til at FN modellen har høyest presisjon i sin prediksjon av kjølebehov, med hele NRMSE på ca 95 prosent. Dette gjør at med de forutsetningene som er tatt i analysen konkluderes det med at kjølebehovet til ett standardisert kontorbygg kan predikeres med høy treffsikkerhet. Dette gjør kjølesystemer regulert med MPC kan ha mulighet til å utnytte presise prediksjoner og forutse utviklingen til byggets kjølebehov frem i tid. This thesis investigates different modelling strategies to predict cooling need for usage in model predictive control(MPC) of cooling systems in office buildings. Cooling need prediction enable optimization of the control of cooling systems and thereby reduce the energy usage related to cooling. During the last decade the usage of cooling energy has increased in Norwegian office buildings. Meanwhile the pressure on reduced energy consumption in the building sector from the Norwegian government has never been higher. Prediction of cooling need gives opportunities to produce cooling energy before the time cooling need occurs. In addition, the prediction gives opportunity to exploit more optimized cooling systems and more accurate control. With model predictive control of cooling systems it is possible to use predictions of weather, coefficient of performance, energy price and internal gains and foresee the development of cooling need for the next hours or days. Coefficient of performance depends on the outdoor temperature and the load factor of the cooling machine. Thus it might be predicted based on these factors. The forecast of the energy price is available at Nord Pool and gives indications of when it is economically beneficial to produce cooling energy. Cooling systems with cooling machine and thermal storage might be suitable for model predictive control. This due to possibility of using energy from storage meanwhile it is not economically beneficial to produce. Furthermore with predictive model control the prediction is updated with fixed intervals, example each hour or 15 minutes, to correct errors. For effective model predictive control it is crucial with accurate predictive system models. In relation to this, four different models based on the building envelope and balance of a standardized office building has been developed to predict cooling need. One of them was a grey-box model, thermal network. These models use the physical features of the building and measured data. Furthermore it has been developed three neural networks within the black-box method. These exploits machine learning and depend solely on measured data as input and output in the training process. In the analysis all three neural networks seem to have higher NRMSE for longer training periods, the more data the models was trained on, the more accurate predictions they produced. In terms of the thermal network model the network had the opposite response, it had higher NRMSE for lower amount of input data. In the end the feedforward neural network(FN) seemed to have the most accurate predictions. Moreover the predictions of the FN seemed to respond differently depending on weather. For a average day the accuracy seemed to be higher compared to a day with high solar radiation and a day when the cooling need was at its maximum. In colclusion, with the assumptions and considerations taken in this thesis it is possible to predict cooling need for uage in MPC with high accuracy. This makes it possible to forsee the cooling need for a office building many hours ahead.

Utnyttelse av energifleksibilitet i bygg er fremhevet som en av løsningene for å opprettholde balansen i fremtidens energisystem, hvor uregulerbare energikilder vil utgjøre en stadig større andel. Målet med denne masteroppgaven er å karakterisere energifleksibiliteten knyttet til varmelast i norske boligbygg, slik at denne fleksibiliteten kan implementeres i energiplanleggingsmodeller. Den termiske massen som finnes naturlig i bygg kan utnyttes til termisk energilagring, ved å periodisk øke og redusere varmelast relativt til referanselasten. Dette muliggjør flytting av varmelast til perioder med lavere forbruk, slik at effekttoppene i kraftnettet og energiprisene reduseres. Hvor mye varmelast som kan flyttes uten at det påvirker termisk komfort, blir undersøkt ved å bruke en kombinasjon av dynamiske simuleringer i IDA ICE og MATLAB. Gjennom å introdusere et sprang på referanselasten, kan sprangresponsen til innetemperaturen undersøkes. Termisk komfort blir evaluert ved å innføre en restriksjon på variasjonen i innetemperatur under aktiveringen av den termiske massen. Enkle modeller til å representere bygninger i energisystemanalyser blir undersøkt. En førsteordens og en andreordens modell er formulert på bakgrunn av de termiske egenskapene til bygg. Utledede ligninger for sprangrespons brukes til kurvetilpasning av modellene opp mot sprangresponsen for innetemperatur i IDE ICE. Modellparametere blir identifisert for å karakterisere bygningsfleksibiliteten, og inkluderer varmekapasitet, varmegjennomgangskoeffisient (U) og tidskonstanter. For å analysere innvirkningen av isolasjonsnivå og energieffektivitet på svingninger i innetemperatur og modellparametere, defineres fire variasjoner av bygningsmodellen i IDA ICE. Disse er basert på norske forskrifter og standarder, inkludert TEK87, TEK10, TEK17 og standard for passivhus. Simuleringene av modellene gjennomføres for hver måned i fyringssesongen. Både økning og reduksjon av referanselast var mulig i den lavisolerte bygningsmodellen for nesten alle månedene, med et potensial for endring på 4-6%. Parameteren U var gjennomgående høy, som er forventet på bakgrunn av tapene som forekommer i lavisolerte bygg, og den gjennomsnittlige verdien på tidskonstantene var 40 timer. Høyisolerte bygg har gjerne kortere fyringssesong, noe som reflekteres i resultatene ved at reduksjon av referanselast bare var mulig for de kaldeste månedene. Den potensielle økningen og reduksjonen av referanselast var 5-8%. Parameteren U ble redusert i takt med økende grad av isolasjonsnivå og energieffektivitet, hvorav tidskonstantene økte. Den gjennomsnittlige verdien på tidskonstantene for Passivhusmodellen var 150 timer. Nøyaktigheten til modellene ble vurdert opp mot IDA ICE gjennom en valideringsprosess. Førsteordens modellen klarte ikke å gjengi temperaturene fra IDA ICE, på grunn av manglende evne til å fange opp den raske dynamikken. Andreordens modellen klarte derimot å gjengi temperaturene med høy grad av nøyaktighet, med et avvik på 0.2-0.3 grader for de høyisolerte modellene, og 0.5-0.6 grader for den lavisolerte modellen. Disse avvikene endret seg heller ikke gjennom hele den simulerte perioden på tre uker. Andreordens modellen er dermed i stand til å ganske godt forutsi innetemperatur i bygninger, både på kort sikt og på lang sikt. Modelltilnærmingen er således bevist å fungere, og andreordens modellen kan potensielt brukes til å representere bygninger og tilhørende fleksibilitet i energiplanleggingsmodeller. Utilizing the energy flexibility of buildings for demand response is stated as one of the solutions for maintaining the instantaneous balance in future energy systems, where intermittent renewable energy sources becomes more prominent. The aim of this thesis is to characterize the demand response potential of space heating load in Norwegian residential buildings, in order to facilitate the implementation of demand flexibility into energy planning models. The embedded thermal mass in buildings can be utilized for thermal energy storage by periodically increasing and decreasing the space heating load relative to a reference heat load. This provides an opportunity to shift heat load to periods with lower demand, which could relieve grid stress, and reduce the energy costs for consumers. How much the heat load can deviate from a reference heat load, without affecting the thermal comfort, is investigated by using a combination of detailed dynamic simulations in IDA ICE and MATLAB. By introducing a step to the reference heat load profiles, the resulting step response of the indoor temperature could be analysed. Evaluations of the thermal comfort is done by introducing a restriction for the variation in indoor temperature during the thermal mass activation. Simple models to represent buildings in energy system analysis are investigated. Based on physical knowledge about the thermal dynamics of buildings, a first-order and a second-order model is developed. Related step response equations are used to fit the models to the indoor temperature response obtained by IDA ICE. Model parameters such as the thermal capacitance, the overall heat transfer coefficient (U) and time constants are identified to characterize the demand flexibility. Four variations of the building model used for the simulations are made, to study how indoor temperature fluctuations and model parameters are affected by insulation levels and energy performance. The model variations are defined based on Norwegian standards and regulations, including TEK87, TEK10, TEK17 and the passive house standard. Simulations were performed for each month of the heating season. It was found that the low insulated building had potential for both charging and discharging in nearly all months, with an allowed deviation in heat load of 4-6%. The parameter U was consistently high in all months, which is expected due to the amount of heat losses in low insulated buildings. The average value of the time constants was 40 hours. Due to the heating season being shorter in high insulated buildings, these models could only be discharged in the coldest months. The allowed deviation in heat load were found to be 5-8%. The parameter U decreased with higher insulation levels and better energy performance, while the time constants increased. The passive house model had an average time constant of 150 hours. From the validation of model accuracy versus IDA ICE, it was found that due to the lack of fast dynamics, the first-order model could not obtain similar temperatures to those computed by IDA ICE. The second-order model could however obtain close to similar temperatures, with a deviation of 0.2-0.3 degrees for the high insulated models, and 0.5-0.6 degrees for the low insulated model. Over the course of three weeks, the deviation was still not changing. The second-order model is thus able to fairly predict the indoor temperature in buildings, both in the short-term and in the long-term. The modelling approach is thus proved to work, and the second-order model can potentially be used to represent buildings and their flexibility in energy planning models.

Svømmeanlegg er svært energikrevende bygg med svært avansert luftbehandlingsanlegg sammenlignet med for eksempel bolighus eller kontorbygg. Spesielt det store behovet for avfukting er karakteristisk for svømmeanlegg. På grunn av høy innendørs lufttemperatur og bassengvannstemperatur er også varmebehovet ved slike anlegg stort. I den hensikt å forbedre slike bygg, de tilhørende tekniske installasjonene og styring er det viktig å skaffe innsikt i energibruken til de forskjellige delene i et slikt anlegg. Denne masteroppgaven tar for seg simulering av dynamisk termisk opptreden av en eksisterende svømmehall ved bruk av simuleringsverktøyet IDA ICE. Målet er å bestemme hvor nøyaktig slike simuleringer kan anslå termisk energibehov og dermed kunne være til nytte ved energieffektivisering av svømmeanlegg. Denne rapporten inneholder også et omfattende teorikapittel om bruk av svømmehaller, design av bygningskropp og luftbehandlingsanlegg. En del av Pirbadet, et svømmeanlegg i Trondheim, ble brukt for modellering og til å utføre målinger i. Pirbadets to helsebad og det tilhørende luftbehandlingsaggregatet ble modellert i IDA ICE. Målet var ikke å modellere en eksakt kopi av aggregatet i Pirbadet, men å lage en modell som sørger for det samme inneklimaet og som gjenvinner den termiske energien fra returlufta fra hallen. For å kunne validere modellen med virkeligheten ble det gjort målinger i luftbehandlingsaggregatet i Pirbadet. Det ble installert temperatursensorer og sensorer for relativ fuktighet for å kunne gjøre energiberegninger. I tillegg var det allerede to integrerte sensorer for volumstrøm som ble benyttet. Resultatene fra målingene i Pirbadet og simuleringene ble sammenlignet mot hverandre for å avgjøre om IDA ICE modellen var riktig med hensyn til termisk energibehov. Etterpå ble det termiske energibehovet til luftbehandlingsaggregatet undersøkt. IDA ICE bassengmodellen virker som ønsket når det gjelder fordamping sammenlignet med fordamping i Pirbadet. Sammenligner man derimot med teoretisk kalkulerte verdier er det stort sprik i resultatene. Fordampingen stemmer ganske godt overens med kalkulerte verdier fra metoden til Basin & Krumm som også i andre studier er fremhevet som passende. Varmebehovet fra ventilasjonssystemet viste seg å være mye høyere i virkeligheten enn i IDA ICE modellen. Dette kan være en indikasjon på at modellen har mindre varmetap enn virkeligheten og som en konsekvens også trenger mindre varmetilførsel i luftbehandlingsaggregatet. På grunn av forskjellig regulering er behovet for effekt i avfukteren ganske forskjellig i modellen og det som ble målt i Pirbadet. Det faktum at IDA ICE modellen ble modellert uten varmepumpe vil også ha innvirkning på bruken av avfukteren, da den er fordamperen til varmepumpa. For å kunne evaluere IDA ICE bedre vil man ha behov for å teste en modell som er bedre, i form av mer korrekt varmebehov, enn den utviklet i dette prosjektet. Swimming facilities are energy consuming buildings with highly advanced air conditioning systems compared to e.g. residential and office buildings. Especially the huge need of dehumidification is defining for swimming facilities. Due to high indoor air temperature and pool water temperature, also the heating need is huge in such facilities. In order to improve the buildings, their technical installations and procedure, a good understand of the energy needs for the different posts is essential. This master thesis aims to simulate the dynamic thermal behaviour of an existing swimming pool using the building performance simulation (BPS) tool IDA ICE. The goal is to determine how accurate these simulations can predict thermal needs and how this BPS tool can be used to build more energy efficient swimming pools. This report also contains an extensive literature review about use, design of the building envelope and air conditioning system. A part of Pirbadet, a swimming facility in Trondheim, was used for modelling and measurements. The two hot water pools and their belonging air handling unit (AHU) was modelled in IDA ICE. The purpose was not to model a copy of the AHU in Pirbadet, but to make a model that ensured the same indoor climate and recycled thermal energy from the return air. To be able to validate the model to the real system, there were performed measurements in the AHU in Pirbadet. There were installed temperature and relative humidity (RH) sensors, as well as the integrated volume flow sensors, to be able to do energy calculations for the AHU. The results from the measurements in Pirbadet and the simulations were compared to decide whether the pool and building model was correct in terms of thermal energy need or not. Afterwards the thermal energy need of the AHU was investigated. The IDA ICE pool model works as intended regarding evaporation rate compared to Pirbadet. Compared to theoretical calculations, there is a big leap in the results, but it corresponded quite good to the method of Basin & and Krumm. The heating need from the ventilation system was a lot higher for the real hall in Pirbadet than for the IDA ICE model. This indicates that the model has less heat loss than the reality and consequently has less AHU heating need as well. Due to a different control strategy, the dehumidifying power for the two cases are very different. The fact that the IDA ICE model was made without a heat pump also makes an impact on the use of the dehumidifier which is the evaporator of the heat pump. To be able to evaluate IDA ICE further, a more correct model in terms of heating need must be tested.

The transition to a sustainable energy system requires a shift to intermittent renewable energy sources, which call for increased flexibility on the demand side. Heat pumps offer the possibility to couple the electricity sector and the heating sector, and when connected to thermal energy storages, they can provide demand side flexibility. This thesis investigates the flexibility potential of residential buildings in Scandinavia, and more specifically in Norway. In this regard, three different boundary levels are considered: power grid level, building level, and heat pump system level. At the power grid level, a methodology to evaluate the hourly average CO2eq. intensity of the electricity mix, while also considering electricity trading is developed. In general, the CO2eq. intensity of the electricity mix may indicate the share of renewable energies in the mix. The proposed method is based on the logic of input-output models and avails the balance between electricity generation and demand. This thesis shows that it is essential to consider electricity imports and their varying CO2eq. intensities for the evaluation of the CO2eq. intensity in Scandinavian bidding zones. Generally, the average CO2eq. intensity of the Norwegian electricity mix increases during times of electricity imports since the average CO2eq. intensity usually is low because electricity is mainly generated from hydropower. This hourly CO2eq. intensity can be used as a penalty signal for demand response strategies applied to residential heating. At the building level, the flexibility potential of predictive rule-based controls (PRBC) in the context of Scandinavia and Norway is studied. For this purpose, demand response measures are applied to electricity-based heating systems, such as heat pumps and direct electric heating. In one case study, the demand response potential for heating a single-family residential building based on the hourly average CO2eq. intensity of six Scandinavian bidding zones is investigated. The results show that control strategies based on the CO2eq. intensity can achieve emission reductions if daily fluctuations of the CO2eq. intensity are large enough to compensate for the increased electricity use due to load shifting. Furthermore, the results reveal that price-based control strategies usually lead to increased overall emissions for the Scandinavian bidding zones as the operation is shifted to nighttime when cheap carbon-intensive electricity is imported from the continental European power grid. In another case study, the building energy flexibility potential of a Norwegian singlefamily detached house is investigated using PRBC. Four insulation levels are studied for this building: (1) passive house, based on the Norwegian standard for residential passive houses, (2) zero emission building, based on the LivingLab located at the Gløshaugen Campus at NTNU, (3) TEK10, based on the Norwegian building standard from 2010, and (4) TEK87, based on the Norwegian building standard from 1987. The three PRBC investigated aim at reducing energy costs for heating, reducing annual CO2eq. emissions and reducing the energy use for heating during peak hours. This last objective is probably the most strategic in the Norwegian context where cheap electricity is mainly produced by hydropower. It is shown that the price-based control does not generate cost savings because lower electricity prices are outweighed by the increase in electricity use for heating. The implemented price-based control would create cost savings in electricity markets with higher daily fluctuations in electricity prices, such as Denmark. For the same reasons, the carbon-based control cannot reduce the yearly CO2eq. emissions due to limited daily fluctuations in the average CO2eq. intensity of the Norwegian electricity mix. The PRBC that reduces the energy use for heating during peak hours turns out to be very efficient, especially for direct electric heating. As an example, for the ZEB insulation level and direct electric heating, the price-based control reduces the energy use during peak hours by 18%, and the carbon-based control by about 37%. The control strategy dedicated to reduce the energy use during peak hours leads to a 93% reduction. For air-source heat pumps, the control of the heat pump system is complex and reduces the performance of the three PRBC. Therefore, it is suggested to model a heat pump system with enough detail for a proper assessment of the building energy flexibility. The model complexity required to adequately describe the heat pump system behavior with regards to demand response of residential heating is investigated on the heat pump system level. In the course of this thesis, the influence of the modeling complexity of the heat pump system control on distinct energy-related and heat pump system-related performance indicators is studied. The results prove that the modeling complexity of the system control has a significant impact on the key performance indicators, meaning that this aspect should not be overlooked. If the heat pump operation is investigated in detail and a high time resolution is required, it is shown that a PI-controller leads to a smoother operation than a P-controller, but tuning of the controller is highly recommended. It is shown that the choice of the controller (Por PI) is not crucial as long as the control signal to the heat pump is not of importance and power is not investigated at very short time scales. Regarding demand response measures, a strong interaction between the prioritization of domestic hot water and the control of auxiliary heaters significantly increases electricity use of a bivalent mono-energetic heat pump system, if demand response is performed for both, domestic hot water and space heating. The electricity use for heating is only slightly increased if demand control using predictive rule-based control is performed for space heating only. To summarize, energy flexible buildings can play a major role in the transition towards a more sustainable energy system. The use of the hourly CO2eq. intensity as a penalty signal for demand response strategies applied to residential heating, can facilitate achieving the emission targets of the European Union. At the building level, different objectives of demand response, such as reducing operational costs, reducing CO2 emissions or increasing system efficiency are often incompatible and thus difficult to achieve at the same time when using PRBC. When aiming at a realistic control of the heating system of a single building, it is found that heat pump controller tuning and DHW prioritization of the heat pump are two significant aspects that should be considered regardless of the control strategy applied. The combination of heating system, heat distribution system, system control and building envelope is always case-specific and it is suggested that future work focuses on the design of a heat pump system that considers energy flexibility. In this PhD thesis, standard sizing of a heat pump system that is operated in an energy flexible way is applied.

Per 2018-01-01 er det 4,2 millioner bygninger i Norge, som til sammen står for cirka 36 % av Norges totale energiforbruk. Samtidig står bærekraftsspørsmål høyt på dagsordenen. Politiske og sosioøkonomiske drivere sørger for stadige innstramminger i krav til energieffektivitet. Nye smartmålere og et underdimensjonert strømnett gjør at også effektforbruk er viktig. Dessverre er det et kjent problem i byggebransjen at VVS-tekniske anlegg overdimensjoneres som et resultat av avvik mellom prosjektert og målt energibruk og topplast. Dette kan føre til lavere systemvirkningsgrader, økt ressursbruk, dårlig regulering og at miljøvennlige løsninger velges bort fordi man undervurderer besparelsene de kan medføre. Det overordnede målet med denne masteroppgaven er å forbedre dagens metode for beregning av effektbehov til oppvarming. Dette gjøres ved å gjennomgå relevant litteratur om emnet og utprøve nye metoder for beregning på fire eksempel-bygninger. Målt effekt til oppvarming er hentet fra bygningenes SD-anlegg og er sammenlignet med installert varmekapasitet. Dette er vurdert opp mot simuleringer i IDA ICE, hvor forskjellige metoder er testet ut. De fire eksempel-bygningene som er med i oppgaven er Baard Iversens veg 7 (GKBT), Otto Nielsens veg 12E (ONV12E), Sluppenvegen 17B (STG) og Vestre Rosten 69 (HENT). Alle disse er nyere høyisolerte kontorbygg i Trondheim. Varmepumpe og fjernvarme er brukt som grunnlast og topplast i samtlige bygg. For GKBT blir tilstedeværelse i cellekontor, møterom og total tilstedeværelse undersøkt. For HENT blir kun total tilstedeværelse undersøkt. Total tilstedeværelse i GKBT blir sammenlignet med flere relevante standarder, samt en relevant studie. Resultatene viste at tilstedeværelse fra NS 3031 og TS 3031 er innenfor det målte standardavviket for tilstedeværelse. Elektrisitet til belysning blir målt i GKBT og ONV12E, og deretter sammenlignet med relevante standarder. Sammenligning mellom GKBT og ONV12E viste at GKBT har litt høyere intensitet og tidligere oppstart enn ONV12E. Sammenligningen mellom GKBT og standarder viste at samtlige standarder overdriver intensiteten. Intensiteten fra NS 3701 passer best, mens varigheten ligger en plass mellom TS 3031 og NS 3701. Strøm til teknisk utstyr blir også målt på GKBT og ONV12E. Som for belysning er oppstarten for GKBT litt tidligere enn for ONV12E. Begge bygningene måler forbruk utenfor driftstiden. Sammenligningen mellom GKBT og standarder viste at alle standarder overdriver intensiteten, samt at alle antar at det ikke er noe forbruk utenfor driftstiden. Resultatene viste også at intensiteten til NS 3701 treffer best, mens TS 3031 treffer best på driftsperiode. Det konkluderes med at målt tilstedeværelse ikke gir ny innsikt, men støtter opp om funnene i litteraturstudiet. For lys kan det tyde på at intensiteten er overdrevet i standardene. Det samme gjelder for teknisk utstyr, men målingene tyder på at det er forbruk utenfor driftstiden. Internlaster anbefales å brukes i beregninger for dimensjonering av varmepumper, men det trengs mer forskning på internlaster da dette kan variere kraftig avhengig av type bygg og brukermønster. Sammenligning mellom målt og installert effekt til oppvarming antyder at tre av fire bygg har overdimensjonert topplast-system, mens to av fire bygg har overdimensjonert varmepumpe. Dette kan føre til dårligere regulering, høyere investeringskostnad, høyere driftskostnader og kortere levetid. Det blir i denne oppgaven foreslått å bruke bygningers tidskonstant for å ta hensyn til termisk masse når dimensjonerende utetemperatur bestemmes. Dette testes ved å simulere en sprangrespons for å finne tidskonstanten for hvert bygg. Varmesystemet blir deretter dimensjonert etter den resulterende dimensjonerende utetemperaturen basert på tidskonstanten ved en statisk simulering. Til slutt utføres det dynamiske simuleringer med faktiske værdata fra 2005-2018 for å se hvordan varmesystemene fungerer ved denne metoden. Antall timer hvor systemene ikke klarer å opprettholde settpunkt-temperatur blir logget. Resultatene viser at det vil oppstå noen timer med for lav innetemperatur i 2010. Dette er ikke uventet, da 2010 var det kaldeste året i Trondheim på 50 år. Med denne metoden ble beregnet topplast redusert med 11,9 % i forhold til statisk dimensjonering med dimensjonerende utetemperatur på -19 °C. Det konkluderes med at overdimensjonering av oppvarmingssystemer kan reduseres ved bruk av denne metoden. Dynamisk simulering er utført med målte værdata fra 2010 for å studere det resulterende romoppvarmingsbehovet. Internlaster er også inkludert for å se hvordan romoppvarmingsbehovet påvirkes. Det er simulert med og uten solstråling. For tilstedeværelse er verdier fra TS 3031 brukt, mens lys og teknisk utstyr er hentet fra NS 3701. Ved å inkludere 100 % internlaster ble beregnet topplast til romoppvarming redusert med 23,5 % uten solstråling og 24,1 % med solstråling, sammenliknet med beregninger uten internlaster. Det er også gjennomført en validering av modellen for GKBT, der målt effekt til oppvarming er sammenlignet med simulert effekt. Målte internlaster og værdata fra 2018 er brukt i simuleringen for å få så likt sammenligningsgrunnlag som mulig. Resultatene viste at simulert romoppvarmingsbehov var 10,9 % større enn det som ble målt, noe som tyder på at man kan oppnå relativt representative resultater med en enkel modell dersom innverdiene er korrekte. As of 2018-01-01 there are 4.2 million buildings in Norway, which together account for approximately 36 % of Norway’s total energy consumption. At the same time, sustainability issues are high on the agenda. Political and socioeconomic drivers are causing energy efficiency requirements to continuously get stricter. New, smart electricity meters and an undersized power grid make it relevant to study power consumption. Unfortunately, it is a known problem in the industry that HVAC systems are oversized as a result of discrepancies between calculated and measured energy consumption and peak loads. This can lead to poor system efficiency, increased resource usage, poor regulation, and that environmentally friendly solutions are eliminated because the potential savings are underestimated. The overall goal of this Master’s thesis is to improve today’s method for calculating space heating loads. This is done by reviewing relevant literature regarding the subject, and testing out different methods on four case buildings. Measured heating loads are extracted from the buildings’ building management systems and are compared to the installed heating capacities. The buildings are also simulated in IDA ICE, where different methods are tested. The four case buildings used in this thesis are Baard Iversens veg 7 (GKBT), Otto Nielsens veg 12E (ONV12E), Sluppenvegen 17B (STG), and Vestre Rosten 69 (HENT). All of the case buildings are modern highly-insulated office buildings located in Trondheim. Heat pump and district heating is used as base load and peak load respectively in all the buildings. In GKBT, occupancy in single offices, meeting rooms, and total occupancy are studied. For HENT, only the total occupancy is studied. Total occupancy from GKBT is compared to several relevant standards, and one relevant study. The results showed that NS 3031 and TS 3031 are within the range of the standard deviation of the measured occupancy. Electricity to lighting in GKBT and ONV12E is measured and compared; the results showing that the intensity at GKBT is somewhat higher, and starts earlier in the day. Lighting from GKBT is also compared to relevant standards; the results showing that the standards exaggerate the intensity compared to the measurements from GKBT. The intensity from NS 3701 fits best, while the duration is somewhere between TS 3031 and NS 3701. Electrical consumption to technical equipment is also measured at GKBT and ONV12E. As for lighting, the technical equipment in GKBT starts earlier in the day compared to ONV12E. Also, both of the buildings consume electricity outside operating hours. Comparing the measurements from GKBT to standards showed that all the standards exaggerate the intensity, and assumes zero intensity outside of the operating hours. NS 3701 matches the intensity from GKBT the best, while TS 3031 matches the duration the best. The measured occupancy do not give any new insights in occupancy patterns, but supports the findings in the literature review. For both lighting and technical equipment, it can be suggested that the intensity in the standards are exaggerated. Additionally, the measurements present consumption outside operating hours. Internal gains are recommended to be include in sizing of heat pumps, but further studies are needed before it is included in design of the peak load system, as internal gains can vary significantly from building to building and tenant to tenant. Comparison between measured heating load and installed heating capacities suggest that three of the four case buildings have oversized peak load systems, while two out of four have oversized heat pumps. This can lead to poor regulation, higher investment costs, higher operating costs, and shorter lifetime. This thesis suggests using the building time constant when choosing the design outdoor temperature, to account for thermal mass. This method is tested by simulating a step response to find the time constant for each building. The heating system is then sized by a steady state heat load simulation, using the design outdoor temperature based on the time constant. Then, several dynamic simulations are run with measured weather data from 2005-2018 to investigate how the heating system perform by using this method. Unmet hours are logged when the heating system is not able to ensure set-point temperature. The results showed that there are only a few unmet hours during the year of 2010. This is to be expected as 2010 was the coldest year in Trondheim the last 50 years. With this method, the calculated peak heat load was reduced by 11.9 % on average, compared to sizing with -19 °C. It is concluded that this method can reduce oversizing of peak load systems. Dynamic simulations with weather data from 2010, and internal loads, are run to investigate the resulting heat load. Two sets of simulations are conducted; with and without solar radiation. Occupancy from TS 3031 is used, while lighting and technical equipment are gotten from NS 3701. By including 100 % internal gains, the results showed an average reduction in the calculated space heating load by 24.1 % and 23.5 % with and without solar radiation respectively, compared to excluding internal gains entirely. A simple validation of the GKBT model is also conducted. Measured and simulated space heating load are compared. Measured internal gains and weather data from 2018 is used in the simulation to give the best basis for comparison possible. The results showed that the simulated space heating load was 10.9 % higher than measured. This suggest that it is possible to achieve relatively accurate results from simple building energy models when correct input values are used.

Demand side flexibility gained more and more research interest over the last years, as the generation of renewable power grows and challenges economical operation of power plants as well as grid stability. Several studies were already conducted and showed a large potential in the flexible use of plug loads as well as heating devices. However, there is a vast amount of parameters that influence this potential and need further investigation. This thesis tries to evaluate the influence of the heating distribution system on the en-ergy flexibility of residential buildings. Different building performance models were created for air heating, radiator heating, and floor heating. The case study building was a nearly zero emission building called Living Lab , located in Trondheim. The energy system consists in each case of a heat pump, domestic hot water and space heating tank, as well as solar thermal collectors and photovoltaic. The behavior of the different systems was assessed for a rule based control based on a schedule to shift electricity to off-peak hours as well as a price based signal which uses data from the day-head spot market. For the radiator system the consumption in peak hours was strongly decreased (up to 20%) when domestic hot water and space heating tank set points were included. When only activating the thermal mass, reductions of 10% were found. In contrast, the con-sumption in peak hours did not decrease or even grew for the floor heating case. The air heating cases showed little to no shifting potential. The total consumption and operational costs increased in each case, most pronounced with the schedule based set point variations for hot water and space heating tank.

The objective of this thesis is to evaluate the energy flexibility that Norwegian residential buildings can provide to the electricity grid, by applying rule-based control (RBC) strategies. Aspects that are assumed to influence the energy flexibility, such as the impact of internal heat gains and occupants preferences concerning thermal zoning of bedrooms are to be evaluated. The literature study showed that the energy flexibility is an ongoing area of investigation and there is currently no standard metrics to identify a buildings potential to offer flexibility. However, many studies have investigated the topic by applying RBC strategies, and some general properties to describe the buildings ability to offer flexibility exist. Besides, as the building stock gradually moves towards a more energy efficient standard, the impact of internal heat gains (IHG) is becoming increasingly important. However, realistic IHG profiles are difficult to model and several modelling approaches exist. In addition, the relevant literature demonstrates that there is a high level of dissatisfaction with too high bedroom temperatures in passive houses and that it is difficult to achieve this, due to a desire for higher temperatures in the rest of the building. Two different RBC strategies have been applied to evaluate the flexibility potential using the detailed dynamic simulation tool IDA ICE. Both control strategies adjust the set-point temperature (SPT) on the direct electric space heating system. One control strategy is based on a schedule for pre-defined peak hours (OPCS) and the other is based on the spot price (SPCS). Four different building types with different levels of insulation and construction modes are investigated. Overall, both RBC strategies showed potential for shifting the power and consumption use to off-peak hours for all the evaluated building types. The potential for shifting the power and energy consumption is higher for the highly insulated buildings, but the magnitude is much more significant for the less insulated buildings. Different IHG profiles have been evaluated in the context of energy flexibility. The results show that the timing of IHGs is important, especially for the highly insulated buildings. The results with a stochastic IHG profile distributed in both time and space achieved the largest potential for energy and power shifting, and this indicates that the flexibility potential might be under-estimated when modelling the IHGs according to the current practice. This is also supported by the aggregated result of 20 buildings with different stochastic IHG profiles. The type of radiator control is found to have an impact on the flexibility potential at a building level. However, when investigating several buildings together, the results indicate that the more predictable behaviour with proportional control can be used to describe the behavoiur of several buildings with thermostatic control. The increase of bedroom temperatures due to the implemented RBC strategies and IHGs is most significant for the highly insulated buildings. The influence of the RBC strategies on the bedroom temperatures is found to be largest in the colder months, as the impact of the IHGs becomes more dominant with lower heat loss from the building envelope. By decoupling the bedrooms from the RBC strategies, the temperatures are improved, but the improvement is dependent on the internal constructions of the building. Moreover, the flexibility potential is reduced by decoupling the bedrooms.

In the quest of improving energy performance in buildings, swimming facilities stand out due to their excessive consumption. When it comes to scientific research, few publications have addressed this type of facility compared to residential or commercial buildings. The specificity of natatoriums is due to complex processes that challenge indoor environment, building structure maintenance, and energy use in a great extent. Energy saving potential becomes all the more important as these processes are highly consuming and appear not to be optimally tackled. Large discrepancies in energy consumption exist among swimming facilities, and W. Kampel estimated the final annual energy consumption could be lowered by 28% in total in Norway. This study aims at analyzing energy use and power demand in natatoriums. Two models were built utilising the building performance simulation tool, IDA-ICE, along with the Ice Rinks & pool extension. The consumption per square meter of water surface within the model was slightly above the Norwegian statistical average of 4000 kWh/m_ws^2. The analysis brought a deeper understanding about both the software code related to the pool and the heating needs of swimming facility. Energy need due to evaporation appeared to be equivalent to the space-heating needs and even showed to have higher power peak values. Sensitivity analysis were run to investigate influences of key parameters. Four parameters stood out: the pool temperature set-point, the pool area, the n_50 infiltration coefficient, and the pool activity factor. Further analysis focused on the effect these parameters have on the system s behavior. Studies were conducted to explore whether a parameter triggers higher power demand from the air-handling unit or increased loss through the structure, or higher evaporation rate leading to higher energy demand for heating of the pool water. Finally, a comparison with the practical case of a swimming pool at Jøa was established thanks to data retrieved from sensors and energy meters set up there. The use of an integrated heat pump in the air-handling unit at Jøa can be misleading and then only domestic hot water consumption and thermal energy released to the pool are comparable. Both seem to be much higher in the IDA-ICE models. Due to short time framing and high complexity, a model gathering all specific features from Jøa still need to be built and further investigations are required.

The goal of this master thesis is to analyse and develop design methods for building integrated photovoltaic/thermal (BIPV/T) technology at the Green Energy Laboratory (GEL) at Shanghai Jiao Tong University (SJTU) in China. PV/T technology generates electrical and thermal energy in a smaller area, compared to solely PV panels and solar collectors. For a PV panel, the electrical efficiency will decrease when the surface temperature increases, typically during peak solar irradiation. The air or water circulating in the PV/T component cools the PV surface, maintaining higher efficiency and thus higher energy generation. A water based PV/T component has been calibrated and validated according to measurements conducted in Shanghai, China. Furthermore, the component was used to model a PV/T façade at the south wall of GEL. A façade integrated PV/T system utilising air as heat transfer medium was also modelled, but not validated, as no measurements were available for this component. The BIPV/T systems were optimised for five parameters; dead band, storage tank size, mass flow rate, tank inlet height from heat source and tank inlet height from mains water supply. Simulations have been conducted to analyse the effect of building integration, both on the building energy demand and the BIPV/T system operation. Simulations were carried out for the same building model with air based BIPV/T system, water based BIPV/T system, air based PV/T system, water based PV/T system and PV façade (BIPV). The results show that PV/T integrated to the building façade has negligible effect on the total energy demand of the building. The electrical efficiency was highest for the air based BIPV/T system and the water based BIPV/T showed the largest amount of collected thermal useful energy. The BIPV showed the highest electrical solar fraction, as a significant amount of fan energy required for operation of the air based BIPV/T system results in reduced solar fraction for that system.

In the work of reducing the energy consumption of buildings, the passive house concept has been developed as a possible solution. These buildings have a low energy need for space-heating and is therefore often equipped with a simplified system for heat distribution, such as a few low-temperature hydronic radiators. Previous research on energy efficiency of passive houses and thermal comfort for the occupants identified the need for temperature zoning inside dwellings. Occupants reported the desire for lower bedroom temperatures, a preference that according to previous studies has been difficult to achieve without compromising on the energy performance of the building. To investigate why it is difficult to achieve thermal zoning in super-insulated buildings, and to find possible solutions to the issue, a simulation model of a detached house was developed. Dynamic simulations was carried out with the building performance simulation tool IDA ICE. The influence of thermal mass, internal gains, solar gains, envelope performance levels and occupant behavior was investigated. The main factors that prevented thermal zoning was from the simulation results found to be related to internal and solar heat gains. The heat losses through the external construction are limited due to the super-insulated building envelope, and just large enough to balance the heat from internal and solar gains during milder periods. An additional heat loss has to be introduced in order to achieve a lower bedroom temperatures. This could be done by opening the bedroom window or supplying ventilation air at a lower temperature than the bedroom. Having cold bedrooms in the building gave a higher energy need for space-heating, even when the bedroom doors was closed all the time. This was linked to the cascade ventilation principle that residential buildings often are designed according to. As an attempt to solve this problem, a solution with both supply and return ventilation to the bedrooms was investigated. This solution was able to separate the bedrooms from the rest of the building to a greater extent, and thereby providing low bedroom temperatures at acceptable energy performance. The solution did however face the same energy performance issues as the conventional solution when high bedroom temperatures was desired during the day, and low bedroom temperatures was desired during the night. The whole issue with thermal zoning therefore boils down to occupant behavior and preferences. More focus should be put on designing robust buildings that minimize the negative impact that different occupant behavior has on the energy performance of the building. A good starting point is to accept the fact that people have different preferences when it comes to temperature levels inside dwellings, and to use this as a basis of design. The solution with supply and return ventilation from the bedrooms is contributing to increase the energy performance robustness when window ventilation is being used, but the issue with thermal zoning and energy performance needs further research.

Active displacement ventilation is an air supply method that reuses the warm and polluted air in the upper zone of the room for preheating, while sufficient indoor air quality and thermal comfort are still achieved in the zone of occupancy. Air with low temperature is supplied high on the wall with low velocity, and the air "falls" down to the lower zone due to buoyant effects. Well-designed active displacement ventilation has the potential of achieving thermal comfort and sufficient air quality with lower airflow rate and air temperature compared to displacement ventilation and mixing ventilation. CFD has been used to investigate vertical low velocity buoyant and isothermal jets, both free and along walls, since these are of relevance in the design of active displacement ventilation. Furthermore, cases of active displacement in a simple room situation were simulated for different airflow rates and temperatures. Displacement ventilation and mixing ventilation were also investigated to create a basis for comparison. In the investigation of jets, it was concluded that empirical relations and well-known jet theory for free jets, both buoyant and isothermal, correspond with the CFD simulations. Two turbulence models, RNG k-ε and Realizable k-ε, were used. When the vertical jets were moved next to a wall, it was observed that the maximum velocity was higher than for the free jets. As this result is contrary to what was expected it is assumed that the error lies in the CFD simulation. It is not clear to the author why the error occurred, but one hypothesis is that the k-ε models perform badly near walls. For the room simulations, it is concluded that empirical relations together with heat- and mass balance are useful tools for the prediction of the airflow pattern, CO2 concentration, and temperature in a room with active displacement ventilation. One must be aware of the restrictions on the diffuser size and number of diffusers per wall width to use the relations in the area where they are valid. The most energy efficient solution was when a flow rate of 7 l/(s·person) with temperature 10˚C was supplied. Displacement ventilation was in this thesis restricted to an inlet air temperature of 17˚C due to the risk of cold draught. Since the only heat loss from the room was through the ventilation duct, the flow rate for displacement ventilation had to be increased to 8 l/(s·person) to meet the requirement for thermal comfort. If the atmospheric environment was the only restriction, the flow rate could be reduced to 6 l/(s·person). Mixing ventilation was modelled as complete mixing ventilation, i.e. with homogenous CO2 concentration and air temperature. The most energy efficient solution was when the flow rate was 9 l/(s·person) and the air temperature was 11˚C. The methods were compared in a q0−Ti -chart to illustrate which combinations of flow rate and inlet air temperature that are suggested to use.

With the world facing climate changes there is a need for drastically reducing the energy consumption. In the building sector this can be effectively done be introducing super-insulated buildings, such as passive houses, in cold climate countries. The super-insulated building envelope enables for introducing a simplified space heating distribution system, with few heat emitters. This Master s thesis investigates the trade-off between thermal comfort and energy efficiency in two Norwegian row houses with a simplified hydronic heating distribution system, built according to the Norwegian passive house standard. It was performed temperature measurements during two separate two-week periods in March and April in the dwellings, along with detailed user interviews. The thermal comfort and energy efficiency was investigated using detailed dynamic building simulations (IDA-ICE). The calibration of the IDA ICE-model with the measurements reproduced satisfactory temperature levels in most rooms, although not perfect. It was performed yearly simulations with different control strategies to lower the bedroom temperature to a satisfactory level. Control strategies with window openings was able to introduce the lowest bedroom temperatures. Without door and window openings, supplying air with 16 ℃ appeared to be the best solution if the bedroom temperature wanted by the occupants is 14-16 ℃. This strategy resulted in a heating demand of 37.7 kWh/m2year with space-heating set point of 21 ℃. However, this strategy could possibly cause discomfort with the living room temperature mostly between 20-22 ℃, compared to the desired temperature of 22-23 ℃. If desired bedroom and living room temperature is 20 ℃ and 22 ℃ respectively, supplying air with 21 ℃ appeared the most suitable option, with a resulting heating demand of 34.1 kWh/m2year. Based on the building simulations performed and with the given conditions, it might be difficult to introduce substantial temperature zoning within this kind of building typology. If desiring 14-16 ℃ in the bedroom and 22-23 ℃ in the living room, occupants would have to enter some kind of compromise, and accept deviations from their desired temperature level. The possibilities for introducing such drastic temperature zoning inside dwellings with large temperature differences (5-10 ℃) between rooms, should be investigated further.

Many of the building concepts for current and future-efficient buildings are based on highly-insulated envelopes, such passive houses, zero emission buildings or nearly-zero energy buildings (nZEB). As the building is highly-insulated, it is possible to simplify the space-heating distribution system and reduce the number of heat emitters to a few elements. One solution is to use a hydronic distribution equipped with few low-temperature radiators, for instance, one in each floor as well as one in the bathroom. This solution reduces thermal losses from the pipes and the investment, but theoretically provides for less thermal comfort than complete loop. This Thesis investigates thermal conditions in the building with both systems. Studied cases contribute to the worst conditions, which may happen in the winter and also more probable situations in order to be as close to reality as possible. Two systems are investigated also in terms of efficiency. Losses from pipes are considered as recoverable internal gains, and two variables of distribution coefficient are counted.

The temperature in the atmosphere is rising as a cause of human influence, and it was found that the building sector in 2012 emitted 18.4 % of the greenhouse gas (GHG) emissions on the planet (Pachauri et al., 2014). A solution to reduce the GHG emissions in the sector is the zero emission building (ZEB) concept. Cost-optimisation of the heating and cooling system in a ZEB is a challenge, and therefore the NTNU-SINTEF Zero Emission Building activity and the International Energy Agency Annex 40 have been working on a design tool for the selection of renewable thermal energy supply systems for non-residential near Zero Emission Buildings (nZEB). This design tool is called Simulation tool for Nearly Zero Energy buildings heat Pump installations (NZEP) and has been developed through the work of three master theses and three project works. This thesis is an continuation of a project work, written in the fall of 2015, investigated the possibilities of comparing the components in the simulation model with measured data from the CC-system of Powerhouse Kjørbo (Skjerve, 2016). The main objective in this thesis is therefore to compare simulations performed on the main components of NZEP to field measurements from Powerhouse Kjørbo. These components are considered the heat pump block, storage tank block and ground source heat exchanger block, and the thesis therefore only deals with these components. Pressure losses and flow abilities for the chosen components are not investigated. Comparisons for single component and multiple component simulations have been performed. For both kinds of comparisons, the inputs are gathered from and the outputs are compared to measured values from the CC-system at Powerhouse Kjørbo. Based on the comparisons and the discussions presented in this thesis, it is concluded that: - The heat pump block simulates steady-state performance very well, but that the start-up of the block should be compared to measurements with a lower sample rate. - The storage tank block is producing temperatures with similar trends as the measured data, but that a sensor should be mounted in order to calibrate the simulation properly. - The GSHE block simulates similar temperatures out of the borehole in situations where the volume flow in the real borehole is constant. - The simulation of multiple components works very well, all though there are additional complications in implementing a control strategy for the system.

This paper investigates the thermal plume caused by wood stoves, with the main goal of integrating wood stoves in highly insulated buildings, ensuring an acceptable thermal environment. The physical theory behind thermal plumes are reviewed as an introduction before an experiment where measurements of the physical properties of a plume are investigated, using an electric stove to simulate the effect of a wood stove. The results show that the air speed and temperature distribution of a cross-section in a plume can be described with Gaussian functions, as expected. The goal is to figure out when the plume s air speed and temperature distribution becomes self-similar, which means that a new zonal model in the program EQUA, can be used properly, unlike the previous version where there was an error in the coding. The results from the experiment gives insight about when self-similarity is achieved in plumes.

The work in this thesis is done to evaluate four different questions. A literature survey in addition to three case studies are first used to determine the challenges of HVAC systems in buildings renovated to low-energy buildings and the development trend in the market. The literature and case studies showed that client expectations and budget, policies and regulations, everything working as a whole, and a high level of occupant control were all challenges and important factors affecting the success of a construction project. The three case studies had various systems installed, including ground source heat pumps, air-to-water heat pumps, heat recovery in air handling units and solar screens to name a few. The choice of these, however, depended on the building characteristics and its environment. The second part of the thesis evaluates firstly whether the HVAC systems in a school building, Stasjonsfjellet Skole, is able to achieve a satisfactory indoor climate, as well as whether the focus on reducing the energy use in the building has an adverse effect on the indoor climate. Through IDA ICE simulations of the building, in addition to a user survey, the HVAC systems were concluded to provide a somewhat sufficiently satisfactory indoor climate in the parts of the building, but not for every zone. Some of the zones had very high temperatures, daylighting levels and PPD levels. Furthermore, the users complained that the temperature in the building in general was too low. Although this was not consistent with temperature results from IDA ICE, the simulations showed a low RH level in the colder months of the year, which may cause discomfort for occupants even at moderate temperatures (Novakovic, et al., 2007). Furthermore, the generalization of the standards and regulations was concluded to result in the building having variable indoor climate levels from room to room, indicating that the generalized values are not adapted for the different requirements of the different rooms. I addition to the conclusions the indoor climate is not completely satisfactory in the building, the focus on reducing the energy use was concluded to have an adverse effect on the indoor temperature. Although there had been improvements to the indoor environment in the building, the lack of cooling caused the building to be too warm in the summer months. Also, given that the temperature was too low for the users due to the low RH levels and varying between the zones, showed that demand control of the HVAC systems to save energy may have an adverse effect on the user comfort. Lastly, the results and conclusions from the different case studies were evaluated as to whether they could be extended to other buildings. Although all buildings are different, similar school buildings may show similar results when the same systems are installed. Furthermore, the results and conclusions concerning the office buildings may be applied to other buildings as they are highly general. Although the solutions chosen will vary from building to building, the expectations and budget of the client, standards and regulations, optimally interacting systems and a high level of occupant control will all be difficulties and important factors for any construction project, whether it is a retrofitted or new one. Also, the conclusions concerning the generalization of standards and regulations and a need for shading and cooling, although dependent on building characteristics, will be applicable to any building.

Several changes in the previous Simulink model have been conducted. This have significantly reduced computational time and made the model more user friendly. A more realistic representation of the ground source and the cooling system have been implemented. Both short term, yearly and long term behaviour over several year have been evaluated. Due to limited time, it was not possible to implement a variable heat pump model into the Simulink model.

This master thesis investigates the Norwegian standard for calculating necessary power demand, NS-EN 12831:2003- Varmesystemer i bygninger - Metode for beregning av dimensjonerende effektbehov. In that context, it is also investigated how power demand affects heating systems financially and environmentally, but also in terms of comfort and indoor air quality. Improved energy efficiency are leading to a reduction in the power demand for heating purposes in buildings. However, there are few guidelines for how the power demand for heating should be calculated at room level or at building level and correspondingly little documentation on thermal comfort and power demand in low-energy and passive houses. Dimensioning heating systems correct is very important for comfort, energy and finance. Net power demand over the year should determine the distribution between base load and peak load. It is crucial that the estimated power demand correspond to real power demand in order to find the optimal distribution. Gross power demand is the basis for net power demand. A more realistic net power duration curve leads to a more profitable distribution between base load and peak load. If a safety margin is desirable, one should install an additional peak load, which is a cheap investment. That will not affect the operating costs appreciable, as it hardly will be in use. Buildings are complex and there could be many reasons why real power consumption do not match the calculated and intended power demand. Larger heat loss than calculated may be a result of an inaccurate calculation method, poor quality of the work in the construction phase and that the building is used in a different way than intended. Choosing a reasonable ventilation airflow at design conditions is important. In the winter, there is rarely any cooling demand, and the necessary ventilation airflow only depends on the airflow needed to ensure good indoor air quality. In passive houses and low-energy buildings it is cheaper to maintain good indoor air quality as the heat transfer coefficient is low and the heat recovery in the ventilation system has good efficiency. It would seldom make financial sense to reduce indoor air quality, neither thermal nor atmospheric. Especially in commercial buildings, where a small percentage drop in performance would constitute a major cost in terms of wages to non-productive time. The main improvement potential to the Norwegian standard, NS-EN 12831:2003, found in this master thesis is: One of the most obvious potentials for improvement is to include internal loads as lighting, computers and people to reduce the power demand. Especially at building level were one use a central heating system, in which the need of installed capacity will be reduced. At room level, one should be more careful and only include internal load that most certainly occurs at design conditions. The sum of the power demand at room level might then be larger than power demand at the building level, but it includes the uncertainty of using different rooms at different times. The calculation method for infiltration, particularly mechanical infiltration, have a potential for improvement. The American standard, ASHRAE 2013 takes into account that the airflow is not linear with the pressure difference across the building envelope. NS-EN 12831:2003 does not, but adds mechanical ventilation airflow as an addition, distributed by permeability. Heat release from ventilation fans and heat loss due to transmission and leakage from ducts are included in ASHRAE 2013, and is an improvement potential of the Norwegian standard. Heat release from the ventilation system in the investigated building is estimated to about 4,8kW at design conditions, which is 6,7% of calculated design power demand in the ventilation system. Clever control of the installed power is also a possibility. It is possible to drop night setback during the coldest periods or exploit installed capacity of domestic hot water. The Swedish standard, FEBY 12, seems to have the most detailed approach of how to choose design outdoor temperature. One finds the number of days in the n-days mean temperature method by calculating the heat storage in the actual building. FEBY 12 provides a method of grading the choice of design outdoor temperature based on heat storage in the building. Several buildings should be examined in order to conclude that the recommendations given in this thesis are the best options. It will be much easier having a simpler control principle than in the investigated office in this master thesis. Being able to play with the control of the building will also make it a lot easier to eliminate sources of error. Nevertheless, the main principles found in this master thesis should be considered reliable.

The work done in this master s thesis is a continuation of a previous thesis on an early decision tool on the heat pump (HP) integration in office buildings. The simulation tool (SimTool) proposed in this thesis enables the user to take decisions about the best energy supply system for an office building based on costs, energy performance and CO2 emissions. The original simulation tool was critically reviewed to formulate the improvements that should be implemented in the new tool. According to this review the main fields of improvement were found to be the modelling of the hydraulic system including the HP, the buffer tanks (BT) and the ground source model (GSM). Those requirements motivated the choice of Matlab/Simulink for the hydraulic system and Matlab as the executing program. To build up the different hydraulic systems in Matlab/Simulink the Carnot toolbox is used. The algorithm which allows the connection between those two tools as well as physical model behind the blocks used in Matlab/Simulink are shown in this report. The definition of the different building heating system (BHS) combinations was done based on the state of art for the HP integration in office buildings, since the final version of this SimTool should be able to design the best building heating system with the components available on the market. The implementation of the costs and the CO2 emissions is carried out in the same way as in the previous simulation tool. The SimTool was first proven by analysing the performance of the different components like BT, HP and GSM and comparing it with the results of the previous thesis. Afterwards the simulation tool was used to investigate the influence of different parameters on the system performance. The results of this analysis are shown in the report, and the main results are summarized below. - When deciding on which HP system to use in a certain office building it is very important to have accurate values for the cost parameters, since they have a big influence on the optimal coverage factor (OCF) of the HP. - The size as well as the layout of the BT has a strong impact on the HP-performance and the OCF.

Climate change and energy scarcity put higher requirements on the use of energy in the society today. Buildings are a major contributor to the energy use and much attention is placed on energy efficient solutions in building services. One promising technology is hydronic radiant heating systems (RHS), which use moderate temperature water that can be supplied efficiently by green energy sources such as heat pumps, solar collectors and district heating. However, complexity in design and operation often makes RHS less economically competitive to traditional heating systems. Proper design procedures and control strategies must be developed in order to make this an economic solution for the future. In this work a RHS installed at the Green Energy Laboratory (GEL) at the Shanghai Jiao Tong University (SJTU) is analyzed with the use of the simulation tool TRNSYS. A simulation model is built and validated against measurements from the actual system. The goal is to analyze the performance of the installed RHS for typical Chinese apartments in a Shanghai climate, with a focus on energy efficiency and thermal comfort. The heat source is assumed to be an air source heat pump. Simulations are performed for different control strategies, insulation levels, heat pump sizes and thermal storages. Results show that the installed RHS can supply the entire heat load for a typical building in Shanghai. It is shown that for colder climate a greater level of insulation is required, as the floor has a maximum heat output of about 50 W/m2 at a supply temperature of 45°C. On/off thermostat control of the flow to each zone is confirmed to be sufficient. A stable heat pump operation is achieved with a storage tank, as cycling time is increased. Simulations are performed on fan coil units (FCU) as an alternative heat emitting system and results show that total heat demand is reduced by 11 %. However, the heat pump performance is reduced due to higher supply temperatures and the total electricity consumptions for the two systems are similar. RHS is here affirmed as a good solution for Chinese residential buildings, but a more detailed analysis of thermal comfort and a financial analysis should be conducted to assess its market competitiveness.

The whole thesis was designed to investigate the relationship between energy efficiency and thermal comfort with regard to the way heat distribution in the passive house as well as control efficiency. In order to verify the assumed also performed simulations in the IDA Indoor Climate and Energy, which is a modern tool for simulation. When conducting the analysis of the influence, founded the air temperature in the building, the impact of heat distribution method, as well as closing the door openings and pipe insulation, on energy efficiency and thermal comfort in the test building (located in Trondheim, Norway). Considered temperature situations were divided into: - Stable temperature equal to 21ºC - Room temperature variable during the day - during the day and hour 7 am to 11 pm, the temperature is 21 degrees whereas at night - would fall to 19 degrees. - The last case, the most complicated, similarly as in the previous case that varies in temperature during the day, but in addition, during the year (at Christmas - 25.12 to 31.12), the temperature would drop to 16 degrees because of the absence inhabitants. Among the above-mentioned objectives in terms of comfort, most preferably dropped situation where temperature change followed only during the day. The most unfavorable in this respect turned out to be an option with the temperature at a constant level. The most efficient option is to maintain a constant air temperature in the room. This is due to the increased energy demand, which occurs when you need to increase the temperature from 19ºC (night) to 21ºC (day). Another factor that could have a potential impact on thermal comfort and energy efficiency model was the way the distribution of heat in the building. Two possibilities were taken into consideration: - Standard system - where one radiator falls on one room, two-pipe system - Simplified layout - lines also carried out a two-pipe system, and the heaters are located one on the floor. With the introduction of this assumption, it turned out that a change in the distribution of heat does not have too much impact on altering perception of comfort but only if we make the assumption unhindered flow of air masses (warm) between the two rooms. Otherwise (assuming no heat flow) streamlined solution causes a strong feeling of thermal discomfort caused by excessive fluctuations in temperature between the rooms. This is where there is the need to adopt and verify the assumptions next - door open / closed. The last inspected the condition insulate distribution lines to the radiator heating medium. In the absence of pipe insulation heat loss to the environment they were almost twice as high as when the pipes were insulated. This could affect the feeling of comfort in the case of high-temperature heating. Based on these studies it was concluded that the best solution due to thermal comfort, energy efficiency, and even the economic aspect is to simplify the heating distribution system with mandatory leaving the door open and establish a constant temperature equal to 21ºC in the analyzed object.

The increasing energy consumption and its consequences have led to a major need for energy saving measures. Therefore, the passive house concept has been introduced. Passive houses have a low heating demand, so that it is theoretically possible to simplify the space heating distribution system by for example reduce the number of radiators. It has therefore been investigated if one central heat source can give sufficient thermal comfort in a whole housing unit.Research shows, with the use of simulations for Belgian climate, that thermal comfort can be obtained in the whole dwelling if the internal doors are open. Thus, the air flows through these doors are central for the thermal comfort in passive houses. Different analytical models for the calculation of velocity and volume flows through large vertical openings are therefore presented and compared. These models, and thus the simulations are based on a set of assumptions which are assessed. Measurements were conducted to investigate if the assumptions are valid and if thermal comfort can be achieved in a real situation. First, laboratory measurements were conducted to see if the planned setup functioned. Then measurements were conducted in an actual passive house; velocity and temperature were measured in a doorway and the air and surface temperatures were measured on both sides of the aperture. Three different heat sources were used and placed in four different positions where one position was on the first floor. There were several factors in the passive house that can have affected the results; the measurements were done in a staircase, a frame was built around the stairs and the measurement equipment all had margins of error.The measurements gave a velocity profile which deviated some from the theory. While investigating this it was found that many of the central assumptions were invalid. The temperatures in the thermal zones were neither uniform nor with small and similar temperature gradients; the temperatures varied in both zones and the thermal gradients differed for the two rooms and could not be considered small. The results imply that there is heat transfer between the two air streams in the aperture which contradicts the assumption of this not being the case. The passive house also has a ventilation system while the theoretical models assume that there is no supply of ventilation air. The consequence of these assumptions being invalid is that the velocity profile is changed from a symmetric, parabolic shape to a non-symmetric, non-parabolic shape. The position of the neutral plane was also found to be affected by the supplied ventilation air rate. One central assumption was found to be valid; the results showed that there was one neutral plane in the middle of the aperture. The volume flows were calculated based on the measured velocities and neither the velocities nor the volume flows was equal to the analytical calculated values. Thus, it is concluded that the analytical models cannot be used to find exact values for velocity and volume flows. However, the majority of the models can be used to find indications for these magnitudes, especially for the volume flows. The discharge coefficient Cd was found to be varying so that one value cannot be used for all cases.The deviations from the theory were more evident for the cases with the heat sources located upstairs as the velocity profile and temperature distribution in the aperture differed from the other cases. The neutral plane was located higher up in the aperture and thus none of the central assumptions are valid. The theoretical models are therefore found inapplicable when the heat source is located above the aperture.Even though the measurement results do not match the theory completely there were no problems with the thermal comfort in the house during the measurement period. The settings for the heat sources are found to be important for the thermal comfort.

Thermal performance of the solar thermal systems are estimated using numerical methods and software since the solar processes are transitient in nature been driven by time dependent forcing functions and loads. The system components are defined with mathematical relationships that describe how components function. They are based on first principles (energy balances, mass balances, rate equations and equilibrium relationships) at one extreme or empirical curve fits to operating data from specific machines such as absorption chillers. The component models are programed i.e. they represent written subroutines which are simultaneously solved with the executive program. In this thesis for executive program is chosen TRNSYS containing library with solar thermal system component models. Validation of the TRNSYS components models is performed i.e. the simulation results are compared with experimental measurements. With the simulations are determined the long-term system performance i.e. data are obtained for the energy consumption, solar fraction, collector efficiency also it is performed parametric analysis to determine the influence of specific parameters like collector area, tilt and orientation, mass flow rate etc. to the system performance. In this thesis are considered only the residential buildings.

ynamical analysis of the boiler room behaviour will be conducted by using state of the art software packages and available libraries for modelling and simulation of the HVAC systems. Mathematical model for transient analysis of the one dimensional fluid flow in pipes will be presented, and special attention will be given to modelling of the heating equipment such as: boiler, pumps, valves and fittings as well as the standard control elements of the heating systems.Object oriented symbolic Modelica language for industrial applications will be used within Dymola software environment with extensive utilisation of the Buildings library* for HVAC components modelling, developed by Simulation and Research group at Lawrence Berkeley National Laboratory (http://www.lbl.gov/). Consumption side is not the primary subject of the current work and will be modelled as a simplified object/volume which is heated uniformly. Consumption side modelling will take into consideration the thermal capacity of the building as well as the thermal conductivity which will cover transmission and ventilation losses. Simplified model will be realised as a combination of measurements data reading and Finite Volume Model (FVM) of the Mechanical Engineering building. Fine tuning of the consumption side model will be done by using linear regression method.Numerical results of the boiler room model as well as the simplified consumption side model will be verified by comparison with available measurements data for predefined month in 2012/2013 heating season. Available data will be readings from hourly measurements of supply and return water temperatures from the boiler room, outside temperatures, boiler gas consumption and representative room temperature readings. Special attention will be given to highly transient situations, like after weekend days or similar.

Unfortunately the global conventional fuels in reserves are running out while the world energy consumption is increasing very fast. All scientists agreed that Renewable energies is one of the best solutions for energy supply in many parts of the world. Renewable energies are solar energy, wind energy, bio energy, geothermal energy, tidal energy, and hydropower. Approximately all these forms of energy are hampered by their high costs. Moreover, solar energy, wind energy and tidal energy are characterized by their intermittent nature, as they are not available all the time. This intermittent problem can be solved by energy storage.Energy storage components improve the energy efficiency of systems by reducing the mismatch between supply and demand. For this purpose, phase-change materials are particularly attractive since they provide a high-energy storage density at a constant temperature which corresponds to the phase transition temperature of the material. The aim of this thesis is to Is to describe the state of the art progress in applying PCM materials for energy storage (essentially in tanks), and opportunities of their future applications, describe physical properties of typically used PCM materials, present a mathematical model of the energy balance during the energy storage (charge) and energy discharge from the PCM material. Mathematical model is based on one-dimensional (1D) analysis. The mathematical model consist of charging process and discharging process. During charging process the heat transfer fluid passes through the storage tank in order to transfer its thermal energy to the phase change material tube. During the discharging process, the cold water passes through the storage tank to acquire the thermal energy stored by the phase change material tube. Different solutions utilizing PCM was assessed. It was presented different Phase Change Materials for energy storage. This assessment indicated that salt hydrates are the most energy intensive of the PCM possibilities. When we use the Paraffin for energy storage we had less energy stored then with salt hydrates used like medium for energy storage. This assessment indicated that when we use PCM as a medium for energy storage we accumulate significantly more energy than in the case when we use water as a medium for energy storage.There are some weaknesses in the PCM model. It was assumed that the temperature in the tank was uniform. This will not apply for the real case where the heat transfer fluid temperature will increase while transferring through the tank. For a realistic case, the temperature of the first elements will decrease rapidly because of large temperature difference between the heat transfer fluid and the PCMs in the tank.

The work of this Master thesis is a continuation of a project work. This defines qualitative and quantitative parameters needed to make a simulation tool for early-stage decision making with regards to the energy supply strategy for non-residential Zero Emission Building (ZEB). The work is based on the assumption that the heat pump (HP) technology will be one of the core technologies for the energy supply strategy in the ZEB concept. The simulation tool proposed should be able to find the best energy supply strategy for the building, and its design parameters. It is believed that the design parameters for the energy supply strategy are different for ZEB than for standard building concepts, both when it comes to the optimal HP power coverage factor factor and preferred energy supply strategy (combination of technologies).In this Master thesis, the algorithm and methodology behind a Beta-version simulation tool, similar to that proposed in the project report, is presented. The recommended energy supply strategy is determined based on technical-economic considerations. The explanation of the algorithm and methodology is followed by a proof of concept, where the simulation tool is tested on a benchmark office building. This is to check whether ZEBs have different design characteristics compared to other building concepts. As the simulation tool also can be use on different building standards, e.g. TEK10 and passive buildings, this can be verified.Through the first part of the thesis, the algorithm and methodology used to obtain the design characteristics for the energy supply system are presented. Various delimitations and simplifications are made, some being different than the concept proposed in the project report. The input parameters needed to perform the calculations are somewhat inaccurate, as the time to acquire them was limited. The original scope of the simulation tool presented in the project report would be to comprehensive for the Master thesis.Further, the benchmark building is presented and simulations on a TEK10, passive and ZEB are performed. To see if the simulation tool gives valid results, the outputs found for the TEK10 building are tested against some pre-defined expected range of results. These are reached, so that it is believed that the Beta-version simulation tool gives plausible output. Generally the energy supply strategies with low investment costs perform best, which are also the most CO2-emission intensive solutions.The findings for the passive office version of the benchmark building are also likely to be valid. Lower annual costs for the energy supply systems are found and particularly the operational costs, which are expected for a building with a more energy efficient envelope. It is also found that a lower HP power coverage factor is required to obtain a large energy coverage, and its physical interpretation is given.The ZEB building must counterbalance all CO2-emissions associated for operation of (here) the HVAC and domestic hot water (DHW) systems. As expected, for the ZEB office, the energy supply strategy design parameters have changed drastically. The cost optimal energy supply for the TEK10 and the passive office were relatively CO2-intensive, which is disadvantageous if these emissions would have to be counterbalanced. In general, the less CO2-intensive systems are the preferred ones to reach the ZEB balance. While for the more CO2-intensive alternatives, the optimum HP power coverage factor has gone up leading to higher energy coverage and thus less CO2-emissions.The results found in this thesis have a large degree of uncertainty. Their tendency should therefore only be seen as indications. However, also through a sensitivity analysis of the output, the simulation tool proves to perform as wanted and to give plausible results. The output is therefore considered as an acceptable proof of concept of the algorithm and methodology which could be used in a more advanced version of the simulation tool. To have a well functioning full scale version, the simplifications implemented in the algorithm should be checked and the system solutions included should be analyzed and evaluated before implementation.

The aim of this thesis is to determine the efficiency of the hydronic heating system implemented in building with passive envelopes. Thermal losses and energy consumption of the pump are relative values for determining the efficiency.The first step towards this aim is to provide theoretical background for better understanding of the hydronic system. The advantages of this system are also presented.Good knowledge of hydronic systems, first of all, modes of transport of the work fluid and heat distribution into the space, makes a good basis for the next step- designing the system.Once the system is designed, it is possible to create mathematical model. This model together with the input values given enables creation and a running of a simulation program.In the end the results from the simulation are obtained for a typical Norwegian house which satisfies recommendation for the passive house concept.The analyses of our results shows, in spite of the heat losses from the pipes and pump energy consumption, it is feasible to fulfill the prescribed limitations regarding the Passive house energy consumption. Unfortunately, the heat losses values are not negligible and it will eventually disturb thermal comfort.The method derived in this report as well as the simulation program presented can serve as a starting point for future investigation of an assortment of hydronic systems variations. One of the logical choices is certainly a system with insulated pipes. Such system could provide the key advantage of hydronic systems compared to other heating systems. In that way they could present themselves as the best heating solution for future buildings with passive envelopes.