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There is a strong interaction between the urban atmospheric canopy layer and the building energy balance. The urban atmospheric conditions affect the heat transfer through exterior walls, the long-wave heat transfer between the building surfaces and the surroundings, the short-wave solar heat gains, and the heat transport by ventilation. Considering also the internal heat gains and the heat capacity of the building structure, the energy demand for heating and cooling and the indoor thermal environment can be calculated based on the urban microclimatic conditions. According to the building energy concept, the energy demand results in an (anthropogenic) waste heat; this is directly transferred to the urban environment. Furthermore, the indoor temperature is re-coupled via the building envelope to the urban environment and affects indirectly the urban microclimate with a temporally lagged and damped temperature fluctuation. We developed a holistic building model for the combined calculation of indoor climate and energy demand based on an analytic solution of Fourier's equation and implemented this model into the PALM model. [ABSTRACT FROM AUTHOR]

There is a strong interaction between the urban and the building energy balance. The urban climate affects the heat transfer through exterior walls, the longwave heat transfer between the building surfaces and the surroundings, the shortwave solar heat gains and the heat transport by ventilation. Considering also the internal heat gains and the heat capacity of the building structure, the energy demand for heating and cooling and the indoor thermal environment can be calculated based on the urban climate. According to the building energy concept, the energy demand results in an (anthropogenic) waste heat, this is directly transferred to the urban environment. Furthermore, the indoor temperature is re-coupled via the building envelope to the urban environment and affects indirectly the urban climate with a time shifted and damped temperature fluctuation. We developed and implemented a holistic building model for the combined calculation of indoor climate and energy demand based on an analytic solution of Fourier's equation. The building model is integrated via an urban surface model into the urban climate model. [ABSTRACT FROM AUTHOR]

• A digital methodology for environmental performance analysis of urban buildings is proposed. • An automated workflow was run over 2187 iterations to inform the best energy performing urban residential buildings. • Results show the important role of BIPV technology in shifting towards nearly Zero energy districts. • Indicators for the energy performance of urban buildings with one-hour, one-month, and one-year resolution data. • Performance Indicators analyzed cover many aspects: thermal indoor comfort, visual comfort, energy needs, solar production and load match. • Influence of the urban residential building's morphological parameters on the energy performance metrics in the Mediterranean climate. • The proposed graphs provide a useful way to concentrate a large quantity of information and highlight the relevance of data science. Given the looming threats of climate change and the rapid worldwide urbanization, it is a necessity to prioritize the transition towards a carbon-free built environment. This research study provides a holistic digital methodology for parametric design of urban residential buildings with regard to the Mediterranean semi-arid climate zone of Morocco in the early design phase. The morphological parameters of the urban residential buildings, namely the buildings' typology, the distance between buildings, the urban grid's orientation, and the window-to-wall ratio, are evaluated in order to identify the key combinations of passive and active solar design strategies that determine the high energy performing configurations, based on the introduced Energy Performance Index (EPI), which is the ratio between solar BIPV production to maximum available installed BIPV capacity and the normalized thermal energy needs. Through an automated processing of 2187 iterations via Grasshopper, we simulate daylight autonomy, indoor thermal comfort and solar rooftop photovoltaic and building integrated photovoltaic (BIPV) energy potential. Then, we analyze the conflicting objectives of energy efficiency measures, active solar design strategies, and indoor visual comfort in the decision-making process that supports our goal of getting closer to net zero urban residential buildings. The digital workflow showed interesting trends in reaching a balanced equilibrium between performance metrics influenced by the contrasting impact of solar exposure on indoor daylight autonomy and thermal energy demand. Furthermore, the study's findings indicate that it is possible to achieve an annual load match exceeding 66,56 % while simultaneously ensuring an acceptable visual indoor comfort (sDA higher than 0.4). The findings also highlight the important role of the BIPV system in shifting towards the net zero energy goal, by contributing up to 30 % of the overall solar energy output and covering up to 20 % of the yearly self-consumption. Moreover, the energy balance evaluation on an hourly basis indicates that BIPV system notably enhances the daily load cover factor by up to 5.5 %, particularly in the case of slab SN typology, throughout the different seasons. Graphical representations of the yearly, monthly and hourly load matches and the hourly energy balance of the best performing configurations provide a thorough understanding of the potential evolution of the urban energy system over time as a result of the gradual integration of active solar electricity production. [ABSTRACT FROM AUTHOR]

Energy performance factors for thermally activated building systems considering the control strategy. There is still great uncertainty in the field of operation management of thermally activated building systems and, in particular, the thermally inert concrete core conditioning. Despite the widespread use of these systems in new non-residential buildings, a uniform management strategy has not yet been established. On the contrary, builders and users regularly criticize too high or low room temperatures during the transitional seasons and in the event of a change of weather or, in general, a lack of controllability. On the other hand, monitoring projects often show high thermal comfort in these buildings. Obviously, subjectively perceived comfort and objectively measured comfort differ here. At the same time, radiant heating and cooling concepts are energy-efficient when the control concept is adapted to their thermal inertia. Good control therefore ensures high thermal comfort and results in the lowest possible energy consumption. The calculation method based on energy performance factors (in accordance with DIN V 18599) offers a good opportunity to evaluate plant concepts, including their operational management strategy. This makes it possible to adapt the operation strategy for radiant heating and cooling concepts to a specific building and to evaluate it uniformly. [ABSTRACT FROM AUTHOR]

Mit der Messung des Wärme- und Kälteverbrauchs im Labor gelingt es, sowohl thermisch träge als auch agile Flächentemperiersysteme unter praxisnahen, dynamischen Bedingungen messtechnisch zu bewerten. Werden Nutzwärme- und Nutzkältebedarf berechnet und ins Verhältnis zu den gemessenen Verbräuchen gesetzt, können die Aufwandzahlen für die Nutzenübergabe ece für verschiedene Flächentemperiersysteme und in Kombinationen mit anderen Übergabesystemen unter verschiedenen Nutzungsbedingungen und für unterschiedliche Betriebsführungsstrategien bestimmt werden. Damit stehen Aufwandszahlen auf Basis kalorischer Messungen zur Verfügung, die je nach Aufgabenstellung entweder produkt- oder objektbezogen in der Planung komplexer Energiekonzepte verwendet werden können und die tatsächlichen Aufwandszahlen eh, ce für den Heizfall bzw. ec, ce für den Kühlfall genauer als Literaturwerte bzw. projektbezogen beschreiben. Measurement of energy expenditure factors of various radiant heating and cooling systems. The measurement of heating/cooling consumption is used to evaluate both thermally inert and agile radiant heating and cooling systems under realistic, dynamic conditions in a laboratory. If the net heating/cooling energy demand is calculated, the ratio between calculated demand and measured consumption defines the energy expenditure factor for the heat transfer ece. Thus, ece can be determined under different conditions of use and for different operation strategies and in combination with other heat transfer systems. This provides energy expenditure factors based on caloric measurement which are available either product or object specific. The actual energy expenditure factors eh, ce for the heating mode or ec, ce for the cooling mode can be used in the planning of complex energy concepts since these specific values are more accurate than literature values. [ABSTRACT FROM AUTHOR]

Highlights: [•] Impact of five cooling technologies are simulated in six European climate zones with Trnsys 17. [•] The ventilation strategies reduce the cooling energy need even in South Europe climate. [•] Constant ventilation controller can lead to a poor cooling performance. [•] Comparing radiant strategies with air conditioning scenario, the energy saving is predicted to within 5–35%. [ABSTRACT FROM AUTHOR]

Abstract: Monitored data from a low exergy building at Wentzinger Hof Freiburg was investigated for optimal energy operation. The first step was the investigation which involved the sub-division of building envelope into four balance boundaries and each boundary consists of its own active components such as geothermal bore well system, reversible heat pump system, buffer storage, heat exchanger and distribution system. The purpose of the analysis was to refine the monitored raw data to calculate the thermal energy consumption, auxiliary energy consumption and performance along the balance boundaries. The second step was the optimization and rating of the building envelope. The analysis yielded the performance and energy consumption for each boundary level. It was suggested from the optimization analysis that a considerable amount of energy can be saved through the optimized control strategies of active components, seasonal dead-band control and the operation of buffer storage. [Copyright &y& Elsevier]

Unter dem europäischen Programm Intelligent Energy for Europe (IEE) fanden sich acht europäische Partner zusammen, um im Rahmen des Projektes ThermCo Lüftungs- und Kühlenergiekonzepte für Nichtwohngebäude mit niedrigem Energieeinsatz im Hinblick auf die Energieeffizienz und den thermischen Raumkomfort zu bewerten (siehe Teil 1 dieser Veröffentlichung in Bauphysik 34 (2012), Heft 6. Mit Hilfe einer Simulationsstudie für ein typisches Bürogebäude wird das Potenzial unterschiedlicher Lüftungs- und Kühlstrategien unter Berücksichtigung von Energieeffizienz und Raumkomfort für verschiedene europäische Klimazonen bewertet. Die Ergebnisse weisen eine hohe Wirksamkeit von Nachtlüftungskonzepten im nord-europäischen Sommerklima mit verhältnismäßig niedrigen Außentemperaturen nach. Im mitteleuropäischen Sommerklima bietet das Erdreich ein ausreichend niedriges Temperaturniveau für den effizienten Einsatz von wassergeführten Flächentemperiersystemen. Im südeuropäischen Sommerklima kann eine aktive Kühlung über Luft die hohen und schnell fluktuierenden Kühllasten effizient abführen. Energy efficient cooling and ventilation concepts for thermal interior comfort: Simulation-based evaluation of cooling concepts in different European climate zones (Part 2). Under the framework of the European Program Intelligent Energy for Europe (IEE), the project ThermCo evaluates low-energy ventilation and cooling concepts for non-residential buildings all-over Europe using a standardized method based on existing monitoring data from best practice examples (part 1, in Bauphysik 6/2012). A simulation study investigates the potential of different ventilation and cooling strategies with regard to energy efficiency and thermal comfort in different European climates. The results demonstrate a high potential for night ventilation strategies in North-European climate with low ambient air temperatures. In the Mid-European climate, water based low-energy cooling technologies based on radiant cooling make use of the cool ground in summer. Active cooling provides good thermal comfort in South-European climate with high and fluctuating cooling loads. [ABSTRACT FROM AUTHOR]

Unter dem europäischen Programm Intelligent Energy for Europe (IEE) fanden sich acht europäische Partner zusammen, um im Rahmen des Projektes ThermCo Lüftungs- und Kühlenergiekonzepte für Nichtwohngebäude mit niedrigem Energieeinsatz im Hinblick auf die Energieeffizienz und den thermischen Raumkomfort zu bewerten. Die Analyse erfolgte auf Basis von detaillierten Langzeitmessungen über ein Betriebsjahr in acht Demonstrationsgebäuden in unterschiedlichen klimatischen Zonen Europas und einer standardisierten Datenauswertung. Im Quervergleich aller acht Gebäude werden die Kühlkonzepte gleichermaßen nach dem thermischen Kühlenergiebezug, dem thermischen Raumkomfort und dem Primärenergieeinsatz für die technische Gebäudeausrüstung und die Beleuchtung bewertet. Ein Energiekonzept ist erst dann zufriedenstellend, wenn mit möglichst geringem Energieeinsatz und bei hoher Anlageneffizienz ein guter thermischer Raumkomfort zur Verfügung gestellt werden kann. Mit entsprechenden Gebäudesignaturen werden diese Parameter in einen Zusammenhang gebracht und die Zielstellung überprüft. Detaillierte Komfortuntersuchungen nach der europäischen Komfortnorm DIN EN 15251:2007-08 geben Hinweise auf die Wirksamkeit der eingesetzten Kühltechnologien in den jeweiligen Klimazonen. Daraus lassen sich Handlungsempfehlungen ableiten. Energy efficient cooling and thermal interior comfort: comparison of eight European non-residential buildings. Under the framework of the European Program Intelligent Energy for Europe (IEE), the project ThermCo evaluates low-energy ventilation and cooling concepts for non-residential buildings all-over Europe using a standardized method based on existing monitoring data from best practice examples. The proposed approach is applied to eight demonstration projects in different climatic zones of Europe. The analysis is based on long-term monitoring campaigns in high-time resolution over one year of operation. In cross-comparison of all eight buildings, the cooling concepts are evaluated according to the thermal cooling energy consumption, the thermal interior comfort, and the building's total primary energy use for heating, cooling, ventilation, and lighting. [ABSTRACT FROM AUTHOR]

Abstract: Free-cooling by ventilation is one of the most energy efficient techniques for cooling. When ventilation is used for cooling, variable airflow rates should to be used in order to achieve comfortable room temperatures and to minimize the energy demand for mechanical ventilation. Thus, free-cooling, requires, obviously, the existence of a potential for cooling and needs control mechanisms for the airflow. In this study, the free cooling potential by ventilation for office buildings is evaluated by the free-running temperature. The free-running temperature approach is based on the energy balance of heat gains and losses. It is adapted to evaluate the potential for free cooling by ventilation of office buildings for which the gains through the walls are negligible as compared to the internal and solar gains. The free-running temperature of each office room considers solar and internal heat gains, outdoor temperature, indoor temperatures and ventilation air flow rates. The approach is applied to 14 office rooms in a passively cooled office building in Germany and is used to estimate the potential and to evaluate the total energy saving by free cooling by ventilation. The good fit between monitoring data and calculation procedure proves that the free cooling potential can be accurately estimated by using the difference between the comfort limits, i.e. the target value of the indoor temperature, and the free-running temperature. [Copyright &y& Elsevier]

Abstract: A detailed analysis of the heating and cooling performance of environmental heat sources and sinks is presented for 12 low-energy buildings in Germany. In particular, the analysis focuses on the given temperature levels and the efficiency performance of the environmental heat sources and sinks in summer and winter. The investigated buildings employ environmental heat sources and sinks – such as the ground, groundwater, rainwater and the ambient air – in combination with thermo-active building systems (TABS). These concepts are promising approaches for slashing the primary energy use of buildings without violating occupant thermal comfort. A limited primary energy use of about 100kWhprim/(mnet 2 a) as a target for the complete building service technology (HVAC and lighting) was postulated for all buildings presented. With respect to this premise, comprehensive long-term monitoring in fine time-resolution occurred over a period from two to five years. An accompanying commissioning of the building performance took place. Measurements include water supply and return temperatures of the environmental heat sources/sinks, the generated heating and cooling energy, efficiencies of the system, and local climatic site conditions. The comparative evaluation of the systems in all buildings identifies weak points and success factors of the plant. Besides, it characterizes the single component and points out further potential for optimization measures. The annual efficiency performance of the geothermal heat sources and sinks results in a seasonal performance factor of 8–10kWhtherm/kWhend, where the end energy use is electricity. The ground, groundwater, rainwater and even the ambient air constitute efficient heat sources/sinks. Energy is needed only for distributing the heat and cold and not for its generation. The choice of suitable plant components, the accurate design of the hydraulic system and the correct dimension of the environmental heat source/sink play a central role in achieving higher efficiencies. [Copyright &y& Elsevier]

Abstract: Sustainable low-energy office buildings attempt to harness the buildings architecture and physics to provide a high quality working environment with the least possible primary energy consumption. A promising approach to condition those buildings in summer employs the utilization of the building''s thermal storage activated by natural heat sinks (e.g., ambient air, ground water or soil) through night ventilation or thermally activated building systems (TABS). However, a certain room temperature cannot be guaranteed as occupants may influence the room energy balance by window opening, internal heat gains or sun shading control. Between 2001 and 2005, monitoring campaigns were carried out over 2 or 3 years in 12 low-energy office buildings which are located in three different summer climate zones in Germany. These climate zones are defined as summer-cool, moderate and summer-hot. The weather at the building site and the room temperatures in several office rooms were monitored by different scientific teams. The raw data are processed for data evaluation using a sophisticated method to remove errors and outliers from the database and to identify the time of occupancy. The comfort in all office rooms in each building is evaluated separately. For data presentation, these separate comfort votes per office room are averaged using the median instead of the arithmetic mean in order not to overestimate extremely cold or hot room temperatures. A comfort evaluation in these 12 low-energy office buildings indicates clearly, that buildings which use only natural heat sinks for cooling provide good thermal comfort during typical and warm summer periods in Germany. However, long heat waves such as during the extreme European summer of 2003 overstrain passively cooled buildings with air-driven cooling concepts in terms of thermal comfort. [Copyright &y& Elsevier]

Abstract: This article investigates building thermal mass control of commercial buildings to reduce utility costs with a particular emphasis on the individual impacts of both adaptive comfort criteria and of heat waves. Recent changes in international standards on thermal comfort for indoor environments allow for adaptation to the weather development as manifested in comfort criteria prEN 15251.2005 and NPR-CR 1752.2005 relative to the non-adaptive comfort criterion ISO 7730.2003. Furthermore, since extreme weather patterns tend to occur more frequently, even in moderate climate zones, it is of interest how a building''s passive thermal storage inventory responds to prolonged heat waves. The individual and compounded effects of adaptive comfort criteria and heat waves on the conventional and optimal operation of a prototypical office building are investigated for the particularly hot month of August 2003 in Freiburg, Germany. It is found that operating commercial buildings using adaptive comfort criteria strongly reduces total cooling loads and associated building systems energy consumption under conventional and building thermal mass control. In the case of conventional control, total operating cost reductions follow the cooling loads reductions closely. Conversely, the use of adaptive comfort criteria under optimal building thermal mass control leads to both lower and slightly higher absolute operating costs compared to the optimal costs for the non-adaptive ISO 7730. While heat waves strongly affect the peak cooling loads under both conventional and optimal building thermal mass control, total cooling loads, building energy consumption and costs are only weakly affected for both control modes. Passive cooling under cost-optimal control, while achieving significant total cost reductions of up to 13%, is associated with total energy penalties on the order of 1–3% relative to conventional nighttime setup control. Thus, building thermal mass control defends its cost saving potential under optimal control in the presence of adaptive comfort criteria and heat waves. [Copyright &y& Elsevier]

Abstract: This study focuses on the impact of the meteorological environment and the building''s thermal inertia on the indoor temperature performance in a passively cooled office building with night ventilation. Data from a long-term monitoring campaign and short-term measurements are used to identify the correlation between outdoor and indoor temperature in a building under ordinary use and to derive the energy balance of an office room. Temperature performance and energy balance are merged in a comprehensive thermodynamic model, which takes steady-state conditions, short-term and long-term dynamics into account. In contrast to extensive simulation studies, the presented method is based on a straightforward mathematical model using Fourier analysis of temperature time series and an energy balance model, which focuses on fundamental information. [Copyright &y& Elsevier]

In moderate climates, one promising approach to reduce the energy demand of office buildings for air conditioning without reducing comfort is passive cooling by night ventilation. The office building of DB Netz AG in Hamm (Germany) has been designed, constructed and monitored for a long period in the framework of the German research programme, “Solar Optimised Buildings”, SolarBau for short. Monitored data of room and ceiling temperatures in 12 office rooms, supply air flow rate and temperature in these office rooms, electricity consumption for each office room, climate and air temperatures in an adjacent atrium are evaluated by a new method for analysis which deals with short-term and long-term measurements and building simulation. The monitored data from the office building, which is used as such, are complemented by information from the building management system about the position of louvers and the shading devices. The contribution of simulation tools to the design of buildings with passive cooling by night ventilation is evaluated by a comparison between monitored data and simulation for a long period. [Copyright &y& Elsevier]

At the new institute building of Fraunhofer ISE, both mechanical and free night ventilation is used for passive cooling of the offices. The results from a long-term monitoring show, that room temperatures are comfortable even at high ambient air temperatures. In two offices, experiments were carried out in order to determine the efficiency of night ventilation dependent on air change rate, solar and internal heat gains. The aim is to identify characteristic building parameters and to determine the night ventilation effect with these parameters. The experiments (one room with and one without night ventilation) are evaluated by using both a parametric model and the ESP-r building simulation programme. Both models are merged in order to develop a method for data evaluation in office buildings with night ventilation and to provide a simple model for integration in a building management system. [Copyright &y& Elsevier]

In designing an earth-to-air heat exchanger (EAHX), a decision on design goals has to be made. If the air flow is given by the ventilation system and the construction site is known, the question is: is it more important to achieve a high specific energy performance based on the surface area of an EAHX, a high adoption of air temperature to ground temperature or a very small pressure loss? This paper deals with the performance of three EAHXs for mid European office buildings in service, with the aim of characterising their efficiency. A general method to compare EAHXs in operation will be introduced. First, the temperature behaviour is described by plots over time and characteristic lines, and compared by standardised duration curves. Second, the energy gain is illustrated by standardised graphs. Third, a parametric model is used to provide general efficiency criteria. Thermal efficiency should be defined by both the dynamic temperature behaviour and energy performance. [Copyright &y& Elsevier]

Since 2003, most European countries established heat health warning systems to alert the population to heat load. Heat health warning systems are based on predicted meteorological conditions outdoors. But the majority of the European population spends a substantial amount of time indoors, and indoor thermal conditions can differ substantially from outdoor conditions. The German Meteorological Service (Deutscher Wetterdienst, DWD) extended the existing heat health warning system (HHWS) with a thermal building simulation model to consider heat load indoors. In this study, the thermal building simulation model is used to simulate a standardized building representing a modern nursing home, because elderly and sick people are most sensitive to heat stress. Different types of natural ventilation were simulated. Based on current and future test reference years, changes in the future heat load indoors were analyzed. Results show differences between the various ventilation options and the possibility to minimize the thermal heat stress during summer by using an appropriate ventilation method. Nighttime ventilation for indoor thermal comfort is most important. A fully opened window at nighttime and the 2-h ventilation in the morning and evening are more sufficient to avoid heat stress than a tilted window at nighttime and the 1-h ventilation in the morning and the evening. Especially the ventilation in the morning seems to be effective to keep the heat load indoors low. Comparing the results for the current and the future test reference years, an increase of heat stress on all ventilation types can be recognized. [ABSTRACT FROM AUTHOR]

Mit längerfristigen Nutzerbefragungen in zwei unmittelbar benachbarten Bürogebäuden in Freiburg wurden das Temperaturempfinden der Nutzer und deren Zufriedenheit mit dem thermischen Raumkomfort zweimal täglich erfasst. Ein Bürogebäude wird im Sommer mit einem maschinellen Nachtlüftungskonzept konditioniert und das zweite verfügt über eine Betonkerntemperierung und eine Zu- und Abluftanlage. Auf Basis der vorhandenen Daten aus der Erhebung wurde mit Hilfe von Regressionsanalysen ein Modell zur Vorhersage der Komforttemperatur berechnet und mit den Modellen in DIN EN 15251 verglichen. User satisfaction with thermal comfort in office buildings applying environmental energy concepts. This paper presents results of a long-term evaluation of occupant perception of and satisfaction with thermal comfort in two neighbouring office buildings in Freiburg. They were obtained in field surveys by daily questioning and accompanying measurements in high temporal resolution. One office building is conditioned during summer according to a night-time ventilation concept and the second uses concrete core conditioning and a supply/exhaust ventilation system. Based on the survey data and a regression analysis, a model was calculated to predict the comfort temperature depending on the cooling concept employed. Results were compared to the comfort models of DIN EN 15251. [ABSTRACT FROM AUTHOR]

Abstract: To gain access to information on energy use in office buildings, the German Federal Ministry for Economy launched an intensive research and demonstration programme in 1995. In advance of the 2002 EU energy performance directive a limited primary energy coefficient of about 100kWhm−2 a−1 as a goal for the complete building services technology was postulated (HVAC+lighting) for all demonstration buildings to be supported. A further condition was that active cooling be avoided. Techniques such as natural or mechanical night ventilation or heat removal by slab cooling with vertical ground pipes as well as earth-to-air heat exchangers in the ventilation system were applied. An accompanying research was established to keep track of the results and the lessons learned from about 22 demonstration buildings realized and monitored until the end of 2005. As one outcome this paper summarises the energy performance of a selection of characteristic buildings together with an overview on the summer thermal comfort situations achieved. The research program will proceed during the next five years. Detailed reports and future results may be downloaded from the internet: www.enbau-monitor.de. [Copyright &y& Elsevier]

Hemp-based building envelopes have gained significant popularity in developed countries, and now the trend of constructing houses with hemp-clay blocks is spreading to developing countries like Morocco. Investigating the hygrothermal behavior of such structures under actual climate conditions is essential for advancing and promoting this sustainable practice. This paper presents an in-depth experimental characterization of a commercial hemp-clay brick that has been exposed to the outdoor environment for four years, in addition to field measurements on a building scale demonstration prototype. Additionally, the study simulates 17 representative cities to assess the hygrothermal performance and energy-saving potential in each of Morocco's six existing climate zones, using the EnergyPlus engine. The experimental campaign's findings demonstrate excellent indoor air temperature and relative humidity regulation within the hemp-clay wall building, leading to satisfactory levels of thermal comfort within hemp-clay wall buildings. This is attributed to the material's good thermal conductivity and excellent moisture buffering capacity (found to be 0.31 W/mK and 2.25 g/m2%RH), respectively). The energy simulation findings also point to significant energy savings, with cooling and heating energy reductions ranging from 27.7% to 47.5% and 33.7% to 79.8%, respectively, as compared to traditional Moroccan buildings. [Display omitted] • Experimental characterization of thermal conductivity, sorption isotherm, and moisture buffering capacity of hemp bricks. • Assessment of indoor thermal comfort and energy demand in a hemp-based building across 17 cities in Morocco. • Hemp-clay bricks demonstrated excellent humidity regulation with a moisture buffer capacity of 2.25 g/m2%RH. • Hemp-clay walls can achieve energy savings ranging from 27.7%–47.5% for cooling and 33.7%–79.8% for heating in Morocco. [ABSTRACT FROM AUTHOR]

The current methods used to assess the energy performance of ventilation devices do not consider all the aspects necessary for a comprehensive evaluation of decentralised ventilation concepts and can only be partially adapted to their needs. In order to improve the energy evaluation and to ensure the comparability of different systems, a calorimetric method was developed and implemented in test facilities for the evaluation of two decentralised devices: one equipped with a recuperative counter flow heat exchanger and one with a regenerative heat exchanger. This method, based on direct measurements of the heating load in an insulated test room, includes the effect of the electrical consumption of the fans on the energy performance of the ventilation devices. The calorimetric evaluation method was extended to a seasonal evaluation on the basis of a heating-degree-day method implemented for a warm, a cool and a moderate location in Europe: Athens, Strasbourg and Copenhagen. All the results are above 50% efficiency for both devices, even in Athens where the use of heat recovery ventilation is not usual. [ABSTRACT FROM AUTHOR]

Long-term monitoring campaigns were carried out in 35 German and 7 European office and administrative buildings, recording the operative room and ambient air temperature in fine time resolution. Further, short-term monitoring campaigns over two hot weeks in summer were conducted in non or partially retrofitted office buildings in Germany, built from 1960 to 1975. The buildings studied can be divided into six categories according to the cooling concept employed: without cooling, passive, air-based and water-based cooling, mixedmode cooling and full air conditioning. Thermal comfort in summer is evaluated in detail using a standardized methodology in accordance with the comfort standard DIN EN 15251:2007-08. Thermal comfort is quantified by measurements of operative room temperatures and local meteorological conditions. In addition, useful cooling energy and electricity consumption were recorded. It is clearly demonstrated that it is feasible and valuable to compare different cooling strategies based on a consistent methodology. Furthermore, this methodology can be applied in day-to-day practice in the planning, commissioning and operation of buildings since these parameters are well-established and easily accessible. [ABSTRACT FROM AUTHOR]

It is considered necessary to implement advanced controllers such as model predictive control (MPC) to utilize the technical flexibility of a building polygeneration system to support the rapidly expanding renewable electricity grid. These can handle multiple inputs and outputs, uncertainties in forecast data, and plant constraints, amongst other features. One of the main issues identified in the literature regarding deploying these controllers is the lack of experimental demonstrations using standard components and communication protocols. In this original work, the economic-MPC-based optimal scheduling of a real-world heat pump-based building energy plant is demonstrated, and its performance is evaluated against two conventional controllers. The demonstration includes the steps to integrate an optimization-based supervisory controller into a typical building automation and control system with off-the-shelf HVAC components and usage of state-of-art algorithms to solve a mixed integer quadratic problem. Technological benefits in terms of fewer constraint violations and a hardware-friendly operation with MPC were identified. Additionally, a strong dependency of the economic benefits on the type of load profile, system design and controller parameters was also identified. Future work for the quantification of these benefits, the application of machine learning algorithms, and the study of forecast deviations is also proposed. [ABSTRACT FROM AUTHOR]

The increasing installation numbers of ventilation units in residential buildings are driven by legal objectives to improve their energy efficiency. The dimensioning of a ventilation system for nearly zero energy buildings is usually based on the air flow rate desired by the clients or requested by technical regulations. However, this does not necessarily lead to a system actually able to renew the air volume of the living space effectively. In recent years decentralised systems with an alternating operation mode and fairly good energy efficiencies entered the market and following question was raised: "Does this operation mode allow an efficient air renewal?" This question can be answered experimentally by performing a tracer gas analysis. In the presented study, a total of 15 preliminary tests are carried out in a climatic chamber representing a single room equipped with two push-pull devices. The tests include summer, winter and isothermal supply air conditions since this parameter variation is missing till now for push-pull devices. Further investigations are dedicated to the effect of thermal convection due to human heat dissipation on the room air flow. In dependence on these boundary conditions, the determined air exchange efficiency varies, lagging behind the expected range 0.5 < ε a < 1 in almost all cases, indicating insufficient air exchange including short-circuiting. Local air exchange values suggest inhomogeneous air renewal depending on the distance to the indoor apertures as well as the temperature gradients between in- and outdoor. The tested measurement set-up is applicable for field measurements. [ABSTRACT FROM AUTHOR]

Optimisation based economic despatch of real-world complex energy systems demands reduced order and continuously differentiable component models that can represent their part-load behaviour and dynamic responses. A literature study of existing modelling methods and the necessary characteristics the models should meet for their successful application in model predictive control of a polygeneration system are presented. Deriving from that, a rational modelling procedure using engineering principles and assumptions to develop simplified component models is applied. The models are quantitatively and qualitatively evaluated against experimental data and their efficacy for application in a building automation and control architecture is established. [ABSTRACT FROM AUTHOR]