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Energy consumption data are required to perform analysis, modelling, evaluation, and optimisation of energy usage in buildings. While a variety of energy consumption data sets have been examined and reported in the literature, there is a lack of a comprehensive categorisation and analysis of the available data sets. In this study, an overview of energy consumption data of buildings is provided. Three common strategies for generating energy consumption data, i.e., measurement, survey, and simulation, are described. A number of important characteristics pertaining to each strategy and the resulting data sets are discussed. In addition, a directory of energy consumption data sets of buildings is developed. The data sets are collected from either published papers or energy related organisations. The main contributions of this study include establishing a resource pertaining to energy consumption data sets and providing information related to the characteristics and availability of the respective data sets; therefore facilitating and promoting research activities in energy consumption data analysis. [ABSTRACT FROM AUTHOR]

This paper presents the development of simplified, yet accurate models that predict the hourly electricity consumption of an institutional building. The models were developed to facilitate generalization to other buildings, by using readily available measurements of a relatively small number of variables related to the building operation. Measurements from a Canadian institutional facility, along with weather forecast information, were used to develop and validate this approach. Two artificial intelligence techniques, artificial neural networks (ANN) and case-based reasoning (CBR), which mimic the way the human brain processes information and reasons, were used to develop the predictive models. Principal component analysis (PCA) was used to reduce the number of inputs without lowering the model accuracy, by identifying significant variables that contain most of the overall variability present in the dataset. A building operation mode corresponding to office working hours was identified, and ANN and CBR models using these measurements were developed. The prediction was carried out on an hourly basis, with a horizon of 1 to 6 h. The predictive performances of the models were compared, and the results revealed that there was no accuracy loss when only the PCA-selected inputs are used. The ANN models consistently outperform the CBR models, achieving errors as low as 7.3%. However, the error of both CBR and ANN models is within the recommended ASHRAE limits. [ABSTRACT FROM AUTHOR]

Sport centers and more specifically swimming pools are regarded as high energy consuming installations and also major air pollutants, contributing to Green House Gas (GHG) emissions as their demand in energy is extremely large. Taking into consideration EU mandating directives and policies in accordance with this high energy consumption, it is obvious that establishing guidelines for swimming pools in order to improve their energy performance by implementing energy conservation actions and increasing their energy efficiency will consequently result to significant energy savings. The aim of this paper is to assess energy performance of outdoor swimming pools operating in Greece. The approach followed is a bottom-up approach as it first analyses the characteristics of all operating swimming pools based on data retrieved from General Secretary of Sports, questionnaires and specific energy audits and surveys, with the aim of quantifying their energy performance. Examining the performance of swimming pools, which mainly use conventional oil or gas fired boilers to cover their thermal needs, it is made clear that there is a broad field to apply energy conservation measures and achieve financial and environmental benefits. [ABSTRACT FROM AUTHOR]

This paper discusses the performance of CO 2 adsorption device and its utilization to save energy in buildings. This new device adsorbs CO 2 and a small amount of moisture in the CO 2 capture process, and it evaporates pure CO 2 by thermal energy in the desorption process. This study shows the possibility of implementing a CO 2 capture device in the operation of an air ventilation system for high performance air cooling and heating of buildings. This innovative strategy provides a means to recirculate indoor air to save energy for a certain period of time and the potential for an energy-efficient operation of buildings. This study presents the analysis of CO 2 adsorption performance measurements and evaluates the application of the device by numerical calculations. The results of simulations for the tropical summer and Central European winter season show that 30–60% of air ventilation energy for cooling and heating can be saved competed to conventional systems. Based on these results, this study describes the possibility of using this system to recirculate indoor air using the CO 2 capture device to save energy and minimize air cooling and heating loads. This novel strategy introduces a new paradigm of air ventilation and can replace conventional air ventilation systems for certain period of time. [ABSTRACT FROM AUTHOR]

In previous literature, it has been reported that over 50% of all energy consumed in buildings occurs during non-working hours. Unfortunately, to the best of the authors’ knowledge, studies to date using field-collected data have only investigated energy consumed during periods of non-occupancy in non-domestic buildings and little is known regarding this quantity of energy in households. The work presented in this paper bridges this information gap and contributes to the literature by presenting a first look into this quantity in households. In a yearlong investigation of seven dormitories, hourly occupancy data and electricity consumption is combined and analyzed using numerous statistical methods to discover the amount of energy that is expended in unoccupied households. Across the seasons, the average household consumed between 27.5% and 31.5% of all energy while unoccupied. This quantity in individual rooms fluctuated from under 4% to over 80%. Differences in occupant behavior, along with time spent unoccupied, can explain the differences in this quantity among the households. Further, no meaningful relationship was found between total energy consumption and percentage of energy spent in empty rooms for individuals. High and low energy users both spent electricity while away from home in proportion to his/her consumption. [ABSTRACT FROM AUTHOR]

High performance simulation of low energy building requires ever more accurate descriptions of the systems under study to improve the building's performance. This paper describes a numerical model to simulate a single room, using a three-dimensional description of heat conduction in the envelope with environmental conditions that vary over short time-steps are described. The simulation considers the projection of solar radiation through a window onto interior walls. The indoor air temperature is assumed to be uniform. The temperature of the inner and outer surface of the walls are calculated at each time step using a variable-step solver. Validation of the model was carried out using experimental data from a low energy cell operating in a natural climate. A set of well-calibrated temperature sensors and an infrared camera have been used to accurately measure the cell's thermal behavior. Comparison between experimental data and numerical results for free varying conditions shows good agreement and the reliability of the model is proven. These validated results were found for a highly insulated cell. Future studies for different thermal mass cells, with new materials, will be realized to show the contribution of this model. Thermal comfort will also be studied. [ABSTRACT FROM AUTHOR]

The dynamic thermal behaviour of opaque building components can be studied through the well-known dynamic thermal properties, i.e. thermal admittance, decrement factor and surface factor. These parameters, firstly introduced in the 70s, make it possible to quantify the response of the building fabric to sinusoidal temperature swings; their use has been recently recommended in some international Standards, such as the ISO 13786:2007. This paper shows that, based on the previously mentioned properties, it is possible to build up a general analytical model for the simulation of the dynamic response of a whole room. In comparison with other similar approaches available in the literature, the proposed model is more rigorous and comprehensive. Indeed, thanks to the use of the Fourier analysis, one can tackle any periodic driving force, and not only sinusoidal ones. Moreover, the model facilitates the identification of each single heat flux released by the opaque envelope as a response to each different forcing condition. The reliability of the model is checked against the procedure outlined in the Standard ISO 13792:2012. The results also clarify to which extent a higher order of harmonics may affect the shape of the indoor air temperature profile and the reliability of the model. [ABSTRACT FROM AUTHOR]

In this paper, a fractional-order (FO) adaptive minimum energy cognitive lighting control strategy is developed to minimize the energy usage in a hybrid lighting system. A hardware-in-the-loop prototype of a cognitive hybrid lighting control plant is designed and built. The FO lighting control strategy is the combination between an FO extremum seeking controller (ESC) and a proportional integral derivative (PID) controller. The FO ESC guarantees the minimized energy usage, while the PID controller is applied to achieve a comfortable light level. The FO ESC demonstrates an improved convergence speed and accuracy. The experimental results are presented to demonstrate the practicality and effectiveness of the proposed FO minimum energy cognitive lighting control scheme. [ABSTRACT FROM AUTHOR]

Radiant panels are known to be energy efficient sensible heating systems and a suitable fit for low-energy buildings. The main goal of this paper is to optimize the thermal insulation layers of house heated by using the radiant heating systems. This work is conducted to study four radiant systems: floor-heating system, wall-heating system, ceiling-heating system and newly developed floor-ceiling heating system located in a net-zero-energy house in Kragujevac, Serbia. The operation of these panels is simulated by software EnergyPlus. For the optimization of the optimal length of the thermal insulation software GenOpt is used. [ABSTRACT FROM AUTHOR]

Underfloor air distribution (UFAD) system, which is a relative new method of providing conditioned air and ventilation to the commercial buildings and data centers, is focused by researchers and designers for its potential advantages of better indoor thermal comfort (ITC) and indoor air quality (IAQ), layout flexibility, reduced life cycle costs, and energy saving. However, the application of UFAD system are still obstructed by the gap in the fundamental understanding of some new elements, such as the cooling load calculation, control of the thermal stratification, and evaluation of energy consumption. This paper reviews the current situation of UFAD technology, and the existing problems in recent researches are summarized. To improve the performance of UFAD system, several possible directions for the further studies are suggested. [ABSTRACT FROM AUTHOR]

Modeling of energy consumption in buildings is essential for different applications such as building energy management and establishing baselines. This makes building energy consumption estimation as a key tool to reduce energy consumption and emissions. Energy performance of building is complex, since it depends on several parameters related to the building characteristics, equipment and systems, weather, occupants, and sociological influences. This paper presents a new model to predict and quantify energy consumption in commercial buildings in the early stages of building design. Building simulation software including eQUEST and DOE-2 was used to build and simulate individual building configuration that were generated using Monte Carlo simulation techniques. Ten thousands simulations for seven building shapes were performed to create a comprehensive dataset covering the full ranges of design parameters. The present study considered building materials, their thickness, building shape, and occupant schedule as design variables since building energy performance is sensitive to these variables. Then, the results of the energy simulations were implemented into a set of regression equation to predict the energy consumption in each design scenario. A good agreement was seen between the predicted data based on the developed regression model and DOE simulation and the maximum error was less than 5%. It is envisioned that the developed regression models can be used to estimate the total energy consumption in the early stages of the design when different building schemes and design concepts are being considered. [ABSTRACT FROM AUTHOR]

This paper will discuss the feasibility of a net zero energy house design targeting for energy balance, financial and environmental sustainability from the initial planning to the final construction for Northern China. A residential house as an experimental objective, which could satisfy an average family's daily needs are in Datong, Shanxi Province in China. Dynamic thermal simulation of the indoor environment, house geometries, solar electric and hot-water collectors, appliances are set in the house. After analysis of the integrated performance of the house, a net zero energy building with the best system configuration predicted by hardware and software simulation are validated. Furthermore, the house is precisely energy monitored and energy controlled after construction. The case study shows that the innovation of a net zero building should be considered as a technological improvement and with a social approval by the occupants of the house. [ABSTRACT FROM AUTHOR]

As one form of passive cooling, night ventilation (NV) has been proven effective to improve the building energy performance. In previous studies, however, fixed NV operating strategies were usually pre-defined, ignoring the weather condition variations over the whole operation process, the influence of outdoor humidity on NV's efficiency, and NV's integrated performance with active air conditioning systems. Such strategies may have potentials for further improvements. This paper presents a systematic approach to address the dynamic optimization of integrated operation of NV and active building air conditioning using typical variable–air–volume (VAV) systems as the case. In the optimization scheme, the physical model is developed per differential algebraic equations (DAEs). The simultaneous collocation method is introduced to translate the dynamic optimization into a nonlinear program, which is then implemented in the GAMS platform and handled by IPOPT solver. The study results indicate that the optimized strategies lead to a remarkable energy saving of 23.19–49.31% in different climate conditions compared to the traditional local control scheme without NV, and a saving of 14.97–39.70% compared to that with pre-defined NV. [ABSTRACT FROM AUTHOR]

This paper provides a comparative study of the energy efficiency of a conventional ventilating and air conditioning (VAC) system with three configurations. This system was used to cool an experimental room in an office building in more control scenarios realised by adopting different cooled water temperatures and chiller cooling systems. In this purpose, an air–water mist cooled system for an air-cooled chiller is proposed. Depending on the components, the analysed VAC system has the following configurations: (1) air handling unit (AHU) and fan-coil units (FCUs); (2) air handling unit (AHU); and (3) heat recovery unit (HRU) and fan-coil units (FCUs). The electricity consumption weight of the equipment of each VAC system, the total energy consumption and the influence of control parameters on this consumption are analysed. The results of the experiments indicate that the optimal efficiency VAC system in office buildings includes an AHU and FCUs with an air–water mist cooled chiller and a cooled water temperature of 8 °C. For this system, a mathematical model is developed to minimise the electricity consumption by optimal control, where the consumption depends only on non-controlled parameters (solar radiation intensity and outdoor air temperature). This model is verified with actual measurements to confirm its accuracy, and a good agreement between the prediction and measurement is achieved. Additionally, the assessment of thermal comfort in the experimental office is performed based on the PMV-PPD model using the ASHRAE Thermal Comfort programme. The obtained results demonstrate that the AHU&FCUs system assures an increase in thermal comfort. Finally, a TRNSYS simulation model of energy consumption and PMV-PPD indices for the AHU&FCUs system is developed and experimentally validated. [ABSTRACT FROM AUTHOR]

The increase of complexity in school buildings to ensure for users comfort and social and functional demands are changing energy consumption patterns. In the Portuguese context, a recent rise in energy consumption, after a major national refurbishment programme, confirms the need to improve energy management in schools in order to reduce their environmental impact. Besides building design and systems, users are also a determining factor impacting energy consumption in buildings. However, behavioural issues are still among the areas least covered by scientific literature. The present paper analyses the energy consumption patterns of eight Portuguese case-study schools, with a methodological approach that integrates quantitative and qualitative data analysis. The approach made it possible to link the energy consumption patterns of the schools (selected as Key Performance Indicators) with the user behaviour and management strategies. As a result, six Key Performance Strategies (KPS) were identified so as potentially to enhance the energy performance of school buildings through use and management. Some of the identified KPS can be implemented directly through school management policies to reduce energy use and enhance efficiency. Others can be incorporated in future building design strategies. Some have the potential for being hereafter integrated into the simulation models of buildings’ energy performance. [ABSTRACT FROM AUTHOR]

Model predictive control (MPC) is an advanced control that can be used for dynamic optimization of HVAC equipment. Although the benefits of this technology have been shown in numerous research papers, currently there is no commercially or publicly available software that allows the analysis of building systems that employ MPC. The lack of detailed and robust tools is preventing more accurate analysis of this technology and the identification of factors that influence its energy saving potential. The modeling environment (ME) presented here is a simulation tool for buildings that employ MPC. It enables a systematic study of primary factors influencing dynamic controls and the savings potential for a given building. The ME is highly modular to enable easy future expansion, and sufficiently fast and robust for implementation in a real building. It uses two commercially available computer programs, with no need for source code modifications or complex connections between programs. A simplified building model is used during the optimization, whereas a more complex building model is used after the optimization. It is shown that a simplified building model can adequately replace a more complex model, resulting in significantly shorter computational times for optimization than those found in the literature. [ABSTRACT FROM AUTHOR]

Light pipes transmit daylight into building interiors. Their installation into thermally insulated roofs of low energy buildings can be a problem because of thermal bridges and condensation problems. This article is focused on a CFD simulation thermal analysis that includes four variations of light pipes with a segment of a flat roof. Common light pipes with a hollow light guiding tube were compared to special light pipes containing an additional glass unit located inside the tube. The additional glass units increase thermal resistance and reduce condensation risks of the light guiding systems. The light pipes were compared in two different simulation models run in ANSYS Fluent software and the CalA program. Temperature profiles and air flow patterns of the cross sectional profiles of the light pipes served to determine the total heat transmittance and heat losses of the studied light pipes installed in a segment of a thermally insulated flat roof. The paper compares simplified 2D rotational–symmetrical numerical model based on the thermal diffusion equation with the complex 3D CFD numerical simulation. The results confirm that the simplified 2D numerical model is suitable for the thermal evaluation of the light pipes containing an additional glass unit, too. The additional glass unit with the triple glass improves thermal resistance up to 88% in case of light pipe with diameter 600 mm and reduces optical transmittance to 28%. [ABSTRACT FROM AUTHOR]

The paper presents the results of 1-year measurement of indoor environment parameters (temperature, relative humidity, CO 2 concentration) in exhibition rooms of one Polish museum in various periods of the year, and the results of simulation on thermal model of this building. The influence of a temperature control scheme in museum rooms on heating and cooling demand was analysed. The actual state (poor control of internal temperature) and ideal control of internal temperature were analysed – two cases in the winter and two cases in the summer. Simulations were performed by ESP-r program. The multi-zone model of the building was validated based on measurement data. Measurements and simulations revealed significant variations in the temperature in the rooms of the museum. The analysis showed that the maintaining internal temperature at constant level of 20 °C in winter reduces monthly heat demand in most of the exhibition rooms. Obtained effect is 5–16% depending on the premises. Provision the raise of a temperature by 1 K results in the increase of heat consumption by 6%. Maintenance of a desired internal temperature, which does not exceed 24 °C in the summer, requires the provision of coolness to the museum premises. [ABSTRACT FROM AUTHOR]

This review paper gives the latest state of the art communicated during the 11th International Vacuum Insulation Symposium IVIS2013 and beyond. Although the largest application of the Vacuum insulation panels (VIPs) concerns the refrigeration industry (60%) and transport boxes (30%) and only a tiny amount is used in the building industry (10%), the number of scientific publications dealing with VIPs with regard to the latter dominate since more than a decade. The main topics addressed therein are the aging of the VIP as a whole as well as the role of the components, under different long term hygrothermal stress conditions. There is a clear expansion of VIP applications in buildings from primarily German speaking countries, toward Europe, and then to overseas. Recent years have witnessed an increasing confidence in this product among researchers and practitioners interested in energy efficient buildings worldwide. [ABSTRACT FROM AUTHOR]

Obtained as a research result of conducted project, this paper presents an innovative, energy efficient multipurpose system for a sustainable globally cost-effective building's solar energy use and developed methodology for its dynamic analysis and optimization. The initial research and development goal was to create a cost-effective technical solution for replacing fossil fuel and electricity with solar energy for water heating for different purposes (for pools, sanitary water, washing) in one SPA. After successful realization of the initial goal, the study was proceeded and as a result, the created advanced system has been enriched with AC performance. The study success was based on understanding and combined measurements and by BPS made predictions of AC loads and solar radiation dynamics as well as on the determination of the synergetic relations between all relevant quantities. Further, by the performed BPS dynamic simulations for geographically spread buildings locations, it has been shown that the final result of the conducted scientific engineering R&D work has been the created system of confirmed prestigious to the sustainability relevant performance – globally cost-effective building integrated photovoltaic powered heat pump (HP), assisted by waste water heat recovery, for solar AC, water heating and saving. [ABSTRACT FROM AUTHOR]

In this paper is presented methodological approach to the energy efficiency optimization of high density data centre, in a synergy with relevant performance analysis of corresponding case study. Related case study goal—to optimize energy efficiency to the level characterized by the power usage effectiveness nearly equal 1 (PUE ≈ 1), has been successfully realized, tracing an energy efficiency optimization road to a hyper energy efficient data centre of the superb IT and energy performance. In addition to the corresponding energy densities, and energy efficient removal of extremely high heat dissipation, to reach superb IT performance very special focus is to be devoted to finally controlling indoor air temperature and humidity conditions. It has been shown that, by an integrated approach to the optimization of building construction, data centre's intrinsic IT systems and equipment selection is to be done also with the reference to its specific energy efficiency and the most recent breakthroughs in IT infrastructure fields, as well as in data centre's high performance air-conditioning and infrastructure's high precision cooling. Finally, data centre greening, implementing renewable energy sources has been analysed. [ABSTRACT FROM AUTHOR]

Liquid desiccant dehumidification system has received much attention in recent years for its important economic benefits in energy saving of buildings. Furthermore, the specific surface area of desiccant solution can be expanded dramatically by the ultrasonic atomization technology, which generates numerous tiny droplets with diameter about 50 μm. However, the tiny atomized droplets are found to be easily captured by the wall of dehumidifier chamber, resulting in the poor performance of this type of system. In this paper, a new criterion called “droplets suspension rate” together with an optimized design method was proposed to improve the performance of ultrasonic atomization liquid desiccant dehumidification system via optimizing its dehumidifier chamber. Experiments were carried out to verify the improvement, where the dehumidification effectiveness, desiccant consumption rate and the air temperature rise were adopted as indicators to evaluate the performance of the system. The results showed that the performance of ultrasonic atomization liquid desiccant dehumidification system was enhanced significantly and the desiccant consumption was reduced markedly after the improvement. Moreover, the improved system was found to be able to utilize lower-grade desiccant solution. The criterion and the method proposed may build a foundation for the better design of ultrasonic atomization liquid desiccant dehumidification system. [ABSTRACT FROM AUTHOR]

A distributed energy system (DES) is recognized as a local energy system. Over the past decade, number of studies in technological fields, economizing and its regulatory aspects corroborated that an increasing attention has been paid toward the planning of these systems. However, lack of a proper planning because of simplifications in the assumptions may overshadow the potentials of the DESs hitherto. Disregarding some intrinsic characteristics of a real world like uncertainties and noises may distort results and consequently undermine its efficiency. This paper mainly focused on designing a building's energy system under demand, costs (like carbon emission cost, primary energy saving…) and prices (like fuel tariff and electricity prices…) uncertainties concerning data insufficiency by means of robust optimization. Various sustainable technologies such as photovoltaic arrays were also considered as an alternative. In order to study the probable consequences, the proposed robust model was applied to a real-world problem and the outcomes were presented, analyzed and compared to the deterministic model's results. [ABSTRACT FROM AUTHOR]

The aim of this paper is to show the environmental benefits provided by the Multilayer Structural Panels technology when applied to construct low rise residential buildings. This is a holistic approach that takes into account the structural aspects and the environmental issues involved. Conclusions are based on the assessment of a broad set of cases and a procedure is provided to compare the environmental impact of each one. The design space was composed of single-family houses with three different building technologies: Reinforced Concrete Multilayer Structural Panels solving, at the same time and with high level of efficiency, structural and thermal insulation requirements; Reinforced Concrete Frame structures combined with insulated cavity walls; and Steel Frames structures plus insulated cavity walls. An optimized structural analysis was applied to fulfil the load transfer requirements. On each case were evaluated the economic cost, the embodied energy and the amount of CO 2 emissions during the construction phase and also the energy savings obtained along the use phase of the building due to the reduction in heat losses. The conclusions show that the more substantial improvements can be achieved when buildings are located on intense seismic activity areas or places with poor bearing capacity soils. [ABSTRACT FROM AUTHOR]

Vacuum insulation panels (VIPs) have thermal resistance values, at the center of the panel, up to 10 times or more than those of conventional thermal insulation materials. In Canada, known for its predominantly extreme cold climate, the potential to apply VIPs in the building construction industry is estimated to be enormous, particularly with the introduction of the new 2011 National Energy Code of Canada for Buildings (NECB 2011). VIPs can play a major role in Canadian buildings to meet energy requirements of the NECB 2011. However, the lack of long-term performance credentials and various constructability issues are among the major barriers for mass application of VIPs in the Canadian construction industry. This paper presents the design strategy, construction details, instrumentation and thermal performance monitoring observations of a VIP retrofitted wall system in Yukon, located in Northern Canada. Experience gained from the construction process and available thermal performance data over a period of three years provide encouraging indicators for the constructability and long-term thermal performance of VIPs in Canadian subarctic weather. [ABSTRACT FROM AUTHOR]

This paper provides a comparative study of state-of-the-art means of predicting occupancy for smart heating control applications. We focus on approaches that predict the occupancy state of a home using occupancy schedules – that is, past records of the occupancy state. We ran our analysis on actual occupancy schedules covering several months for 45 homes. Our results show that state-of-the-art, schedule-based occupancy prediction algorithms achieve an overall prediction accuracy of over 80%. We also show that the performance of these algorithms is close to the theoretical upper bound expressed by the predictability of the input schedules. Building upon these results, we used ISO 13790-standard modelling techniques to analyse the energy savings that can be achieved by smart heating controllers that use occupancy predictors. Furthermore, we investigated the trade-off between achievable savings (typically 6–17% on average) and the risk of comfort loss for household residents. [ABSTRACT FROM AUTHOR]

The global trend toward a low carbon, sustainable economy is widely acknowledged to create a large number of jobs across many sectors of the economy. The deployment of renewable and energy efficiency projects represent a large share of the so called green jobs and help retain current levels of employment especially in countries facing the socio-economic threat of increasing unemployment rates. These effects should be taken into account during the process of energy planning, but due to difficulties in their quantification this is not always feasible. This paper utilizes the input–output analysis and the adjusted earnings gain approach for assessing the employment effects associated with the implementation of energy saving interventions in the building sector, with a view to produce results that can be easily incorporated into cost–benefit analyses. The proposed framework, which comprises four basic steps, namely identification of all the potential changes in employment due to energy efficiency interventions, quantification of these employment effects in physical terms, calculation of the net present value of the estimated employment effects and monetization, has been implemented for three energy efficiency interventions widely implemented in Greek buildings. The results of the analysis clearly show that the exploitation of energy saving technologies in the Greek building stock generates significant employment benefits, ranging between €0.11 and 0.23 million per €1 million of investment in the base case scenario and reaching the 10–24% of the energy costs savings attributed to the implementation of these interventions throughout their entire lifetime. [ABSTRACT FROM AUTHOR]

Several studies have shown that the actual energy performance of buildings can differ significantly from its designed value. An important part of this performance is constituted by the building fabric's thermal performance. A common method to evaluate the latter for an actual building is the co-heating test. The co-heating test comprises a quasi-stationary heating experiment followed by linear regression analysis of aggregated building performance data. This paper reviews related research work and cristallises the current state-of-the-art. The physical phenomena working behind the scenes of the generally assumed simplified heat balance are discussed. Statistical constraints generally prevent these from being uncovered fully during the analysis. Multiple linear regression is proposed as the most sensible method to analyse co-heating measurement data. A novel way to visualise such analysis, deduce building performance data graphically and compare different co-heating test results is presented. [ABSTRACT FROM AUTHOR]

It is possible to reshape the building's post-control electricity consumption by introducing an electrical storage element. This paper presents a parametric stochastic optimization model, that combined with a heuristic decision-making method, allows to determine the most suitable electrical battery capacity to be installed in a Low Exergy (LowEx) multi-family house located in the temperate climate zone of Middle Europe. In contrast to most common battery models, this optimization is not formulated in terms of the battery payback period. This model does not explicitly consider the battery cost, but aims instead at a twofold objective, namely to minimize the normalized annual electricity cost and simultaneously peak-shave the 15-minute average electrical power. The sensitivity of the model to uncertainties is accounted for by introducing stochastic elements in several model components. The natural variability in the solar electricity production is modeled by using a historical 12-year-data period, and the estimated electricity consumption by occupants is formulated as a probability distribution. Multiple scenarios are hypothesized in order to evaluate the model performance under different conditions. This model assumes a market-based dynamic electricity-pricing scheme. The effect of the dynamic electricity prices is examined by evaluating the model's behavior when subjected to spot market prices from three different geographically close locations. [ABSTRACT FROM AUTHOR]

Abstract: One of the primary reasons for the application of cool materials is their energy and associated environmental impact on the built environment. Cool materials are usually applied on the roof of buildings to reduce cooling energy demand. The relative benefits of this reduction depend on the construction of the building, external weather conditions and use of the building. This paper examines the impact from the application of a reflective paint on a flat roof in a naturally ventilated office building in the area of London, UK where the climate is moderate with high heating demand by buildings. The environmental conditions (internal/external air and surface temperatures) of the building were monitored before and after the application of the cool roof during the summer. It was found that internal temperatures were reduced after the application of the cool roof. The building was modelled using TRNSYS and the model was calibrated successfully using the measurements. A parametric analysis was carried out by varying the reflectivity and insulation of the roof and ventilation rate; the heating and cooling demand for a year was calculated using the Summer Design Year for London as the weather file. It was found that cooling demand is significantly reduced, heating demand is increased and the total energy savings vary between 1 and 8.5% relative to an albedo of 0.1 for the same conditions. In free floating (naturally ventilated) buildings summer comfort is improved but there is a penalty of increased heating energy during the winter. Thermal comfort can be improved by an average of 2.5°C (operative temperature difference for a change of 0.5 in albedo) but heating demand could be increased by 10% for a ventilation rate of 2 air changes per hour. The results indicate that in the case of temperate climates the type, operation and thermal characteristics of the building should be considered carefully to determine potential benefits of the application of cool roof technology. For the examined case-study, it was found that a roof reflectivity of 0.6–0.7 is the optimum value to achieve energy savings in a cooled office, improve summer internal thermal conditions in a non-cooled office (albeit with some heating energy penalty). It indicates that it is a suitable strategy for refurbishment of existing offices to improve energy efficiency or internal environmental conditions in the summer and should be considered in the design of new offices together with other passive energy efficient strategies. [Copyright &y& Elsevier]

Abstract: Fault detection and diagnosis (FDD) is an important issue in building energy conservation. This paper proposes a new option for solving this problem at the building level by using a recursive deterministic perceptron (RDP) neural network. Results show a higher than 97% level of generalization in all the designed experiments. Based on this high detection ability of RDP model, a new diagnostic architecture is proposed. Our experiments demonstrate that it is able to not only report correct source of faults but also sort sources in the order of degradation likelihood. [Copyright &y& Elsevier]

Abstract: This paper describes a small-scale experimental direct-expansion ground source heat pump system in typical clay soils for space heating of a building in Jinzhou, China. It uses R22 as the refrigerant, consisting of four single U-shaped copper ground heat exchangers with a uniform depth of 20m. A special circular bend is designed on the copper tube to enhance the lubricant oil return of the scroll compressor. The operation performance and energy efficiency of the DX-GSHP system is tested in the heating mode. Results show that the present DX-GSHP system is reliable and effective. During the heating period, when the heating capacity of the indoor fan coil is 6.41kW, the room temperature varies from 18 to 20°C even if the door is opened or closed frequently. The average COP of the heat pump unit and the whole DX-GSHP system are 3.12 and 2.88, respectively, and the average heat-transfer rate of GHEs per depth is 54.4W/m. In addition, the influence of the opening of the electronic expansion valve on the operation performance is analyzed. The present results can provide useful guides for the design and further improvement of DX-GSHP systems under similar geological conditions. [Copyright &y& Elsevier]

Abstract: Chiller sequencing control plays an important role in achieving air-conditioning system energy efficiency since chillers usually account for major part of system overall energy consumption in commercial buildings. This paper compares and evaluates the in situ performances of three commonly used chiller sequencing control strategies. These three control strategies are operating online in parallel on a management and communication platform in a super high-rise building in Hong Kong. The comparison and evaluation focus on the perspectives of chiller switch number, electrical peak demand and overall energy consumption in one week. Meanwhile, the different impacts of two systematic errors (i.e. positive errors which cause direct measurement larger than true value and negative errors which cause measurement smaller than true value) on each control strategy are also analyzed. The performance comparison demonstrates that the strategy, using fused cooling load measurement, achieved the best performance. The applications of the online computed chiller maximum cooling capacity and the advanced data fusion technique, which removes the negative impacts of sensor measurement uncertainties, can significantly improve the performance of chiller sequencing control. [Copyright &y& Elsevier]

Abstract: A major focus of existing literature on energy conservation is the modelling and quantification of energy savings and the corresponding carbon dioxide emissions from lightings. While many studies have established theoretical frameworks concerning these issues, very little documentation exists relating to energy savings and emission levels in students’ hostels. This paper considers the lighting efficiency improvement of four University of Lagos halls of residence for the purpose of quantifying energy saving and the minimization of carbon dioxide that can be made. Compact fluorescent lamps are considered alternatives to the current primary usage of conventional fluorescent and incandescent bulbs. The existing electricity consumption data obtained from energy audit are used in combination with conversion factors to estimate the annual CO2 contributed to the atmosphere by lighting in each of the buildings. The result of the study shows that over 45% reduction in carbon dioxide emission can be achieved. There is a lot individuals can do to reduce the emissions, for example, using energy saving appliances, turning off appliances when not in use, less use of fossil fuels, are simple measures that can be adopted to reduce annual carbon footprint, improve economic growth, enhance environment, health and save the planet. [Copyright &y& Elsevier]

Abstract: This paper reports investigations of energy, environmental, and economic performances of floor, wall, ceiling, and floor–ceiling heating. It is found that the floor–ceiling heating has the best performances: the lowest energy and exergy consumption, exergy destruction, CO2 emissions (compound, direct, and avoidable), and operation costs. In addition, it uses boiler of the lowest power. The worst system by all these parameters is the classical ceiling heating. The comparison of the room operative air temperatures and the operative air temperatures set by thermostats shows that all systems give satisfactory results without significant deviations. The largest deviation and the lowest values of the surrounding inner surfaces of the exterior walls are found for the floor–ceiling ceiling panel system. [Copyright &y& Elsevier]

Abstract: The increasing attention to energy saving in buildings has led to more accurate analysis of the thermal performance of windows. In particular, the use of aluminum frames has known a rapid development; thanks to the installation of thermal break systems, the performance of aluminum frames is nowadays comparable to the one wooden frames. The numerous air cavities inside aluminum frames suggest a deep investigation of the heat exchange process; the paper, therefore, analyzes the effect of the geometric and surface characteristics of the cavities on the overall performance of the profile. The attention was focused on the emissivity properties of the cavity inner surfaces, since they play a fundamental role on radiation heat transfer; furthermore, the frame thermal performance was evaluated when the geometries of some cavities are changed with the insertion of rubber gaskets. All the analysis were conducted with two different approaches: numerical and experimental, obtaining a good match between the methods; the validation of the CFD model makes it a quick and user-friendly tool for the preliminary design and optimization of aluminum window frames with a high thermal resistance. [Copyright &y& Elsevier]

Abstract: Designing low-energy buildings has become a necessity, encouraged by thermal regulations, the need for energy savings and environmental awareness. Computer-aided thermal design of building walls is currently investigated using the latest optimization algorithms. This paper studies building multilayer walls by coupling a direct thermal model with a specific optimization algorithm. The direct problem solution is based on the Laplace transform of the quadrupole method, and then translated by numerical inversion into the time domain by the Fourier series method. The optimization model minimizes a least squares criterion between intended indoor temperatures and a direct response model. The work aims to optimize the thermal insulation and the heat capacity of wall layers and further building heating loads. An indoor temperature evolution is specified under fixed outdoor conditions in order to identify the composition of the building walls using an inverse resolution based on a reflective Newton algorithm applied to a direct quadrupole model. [Copyright &y& Elsevier]

Abstract: Energy efficiency in buildings is essential for economic, social, and environmental reasons. Under current European legislation, buildings have to be certified with an energy efficiency index. To provide a fair comparison of the energy performance in buildings we need a global and unified representation. In this paper we propose the Energy Efficiency Ontology (EEOnt) to provide a foundation upon which this requirement can be built. EEOnt extends the applicability of other ontological models of buildings incorporating energy efficiency data and knowledge that can be calculated with high spatial and temporal resolution in what we call an Energy Efficiency Landscape (EELB). These EELB''s provide significant information which allows a detailed diagnosis of the energy efficiency within the building. Consequently, EEOnt is capable of representing buildings and energy efficiency in a unified way. Furthermore, it supplies a tool for managing the energy efficiency in buildings and constructing national inventories. These two features link the global and particular needs of governments and users, thus becoming key to both improve the energy efficiency in buildings and to implement viable certification schemes. [Copyright &y& Elsevier]

Abstract: Shop window lighting usually represents a meaningful quantity in the lighting consumption of a shop because the large amount of installed power and its high number of running hours. Dimming of lighting can improve its energy efficiency, however, conventional systems, as photocell detectors, are difficult to be used. Besides, the usual control objective of daylight harvesting cannot be applied in this context because here the main objective is to maintain the attractiveness on shop window. In this paper, a control system for shop window lighting is proposed. In this system, a digital camera as a luminance meter has been used. Furthermore, the main objective of the controller is to keep constant the contrast of the shop window interior with respect to its surroundings. The proposed control has been tested in a shop window prototype where real working conditions have been simulated. [Copyright &y& Elsevier]

Abstract: The age of European existing building stock and the very low growth rate make energy retrofit a critical issue at the moment. The spreading of good practices is strongly hampered by their cost effectiveness. National legislation thermal requirements for retrofitting works play a fundamental role. If they are too strict, the initial economic investment could be too high if compared with energy savings achievable. The paper refers to a case study of improving fabric thermal performance of stone masonry buildings located in Cagliari – Italy. They were built in 1950s. The economic feasibility of different energy efficiency retrofits is evaluated. Two different scenarios are analyzed: the former according to the earlier Italian legislation (valid from 2006 to 2008), the latter according to the latest and strictest measures (valid from 2010). The results show that heavy thermal performance upgrades, even though compulsory, are not completely cost-effective in a mild Mediterranean climate area as far as payback time is concerned. National subsidy policies can improve the economic return on the investment. The impact of present Italian incentives has also been evaluated. [Copyright &y& Elsevier]

Abstract: Energy efficiency and energy saving are important concepts bearing in mind by governments and population during the last years. There exist a widespread concern about fossil fuel depletions and the consequent sharp rise in their value. In particular, building is an area highly influenced by those issues. Studies indicate that 40% of the energy generated worldwide is consumed inside buildings, and then, measures to reduce energy consumption are required. In this work, an optimal controller for distributing the energy consumption rate inside a building and preserving, at the same time, the user welfare is proposed. More precisely, the paper presents a predictive control approach that obtains a high thermal comfort level optimizing the use of an HVAC (Heating, Ventilation and Air Conditioning) system by means of a cost function. The optimization procedure is based on the Lagrangian dual method, which allows the use of parallel programming paradigms in an easy way. This may reduce the computational effort proportionally to the number of processing elements when the problem to solve is large. [Copyright &y& Elsevier]

Abstract: This paper presents the Energy, Carbon and Cost Assessment for Building Stocks (ECCABS) model, which is a bottom-up model to assess energy-saving measures (ESM) and carbon dioxide (CO2) mitigation strategies in building stocks. The model is based on a one-zone hourly heat balance that calculates the net energy demand for a number of buildings representative of the building stock and an additional code for the input and output data. The model generates results in terms of net and delivered energy, associated CO2 emissions, and the costs of implementing different ESM. The results are extended to the entire building stock by means of weighting factors. Empirical and comparative validations of the heat-balance modelling of single buildings are presented. The building stock modelling is validated against the current Swedish residential stock, for which the results of the modelling are in agreement with the statistical data. Using the model to assess a number of ESM reveals that the energy usage of the Swedish residential sector can be reduced by 55% and the associated CO2 emissions can be reduced by 63%, with most of the ESM being cost–effective. The applicability of the model to countries other than Sweden is under investigation. [Copyright &y& Elsevier]

Abstract: The building sector is an energy intensive sector, with great potential to reduce energy needs and environmental pollution. Several measures are being taken to increase the energy efficiency and avoid energy consumption in this sector. A recent trend is the nearly zero energy buildings, which was already adopted by some of the latest regulations, such as the 2010 recast of the European Performance of Buildings Directive (EPBD). However, to reach these goals, especially considering the existing building stock, new retrofit solutions are required, which must be well adapted to the specific building stock needs, and ensure that the building retrofit can achieve the nearly zero energy buildings standards. This paper presents a new prefabricated retrofit module solution for the facades of existing buildings, and also the steps taken to optimise its performance, which includes a judicious choice of materials, 3D modelling, cost–benefit analysis, use of different simulation tools for performance optimisation and prototyping. It is also shown the implementation of the retrofit module within an integrated retrofit approach, whose final goal was to obtain a building with the minimum possible energy consumption and greenhouse gas emissions. [Copyright &y& Elsevier]

Abstract: The building sector consumes, even today, about one third of primary energy used in countries like Germany, which, in addition to tons of CO2 and depletion of energy sources, involves a cost of millions of Euros. This paper shows how, only through the optimization of the system technique regulations, energy savings by a margin of 30% can be achieved in offices and administrative buildings. This potential reduction or even elimination of expenses is possible with the use of the automation system that is proposed in this article. It is important to emphasize that simulation models of HVAC systems and rooms are very often used during the planning phase of a project for a proper system design. However, these simulation tools offer additional possibilities for control algorithm development and performance observation which are not used in practice so far. This article demonstrates that simulation based predictive control, using a system operation that is not depending on a main computer but on the components of an intelligent bus, offers the opportunity of a better utilization of the buildings and their thermal mass. [Copyright &y& Elsevier]

Abstract: Retrofitting of existing buildings offers significant opportunities for reducing global energy consumption and greenhouse gas emissions. This is being considered as one of main approaches to achieving sustainability in the built environment at relatively low cost and high uptake rates. Although there are a wide range of retrofit technologies readily available, methods to identify the most cost-effective retrofit measures for particular projects is still a major technical challenge. This paper provides a systematic approach to proper selection and identification of the best retrofit options for existing buildings. The generic building retrofit problem and key issues that are involved in building retrofit investment decisions are presented. Major retrofit activities are also briefly discussed, such as energy auditing, building performance assessment, quantification of energy benefits, economic analysis, risk assessment, and measurement and verification (M&V) of energy savings, all of which are essential to the success of a building retrofit project. An overview of the research and development as well as application of the retrofit technologies in existing buildings is also provided. The aim of this work is to provide building researchers and practitioners with a better understanding of how to effectively conduct a building retrofit to promote energy conservation and sustainability. [Copyright &y& Elsevier]

Abstract: In general, a proper balance of temperature and humidity control is essential for efficient datacenter operation and is integral to protecting the significant investment in computer and network technology in datacenter facilities. However, the rising costs of energy and the drive to be green are resulting in a greater demand to conserve energy. One method of reducing facility costs for a chilled water plant is by adding an economizer. The purpose of this study is to develop energy models of the most common economizer systems. A normal chiller plant with an air-side economizer and a water-side economizer are compared. Results show that outdoor conditions influence facility energy consumption. This paper provides terminology and definitions for the two different types of economizer modes and compares their energy performance against key datacenter attributes in temperate or subtropical regions. The electrical end use breakdown and the Power Usage Effectiveness (PUE) value for a typical year were estimated. The water-side economizer made it possible to achieve a maximum energy performance improvement of about 16.6% over the reference base cooling system, whereas the air-side economizer made it possible to achieve about 42.4% improvement. [Copyright &y& Elsevier]

Abstract: The purpose of the research described in this paper was to demonstrate that an old Danish multi-family building built in 1896 could be retrofitted to a “nearly-zero” energy building. Three types of retrofit measures were implemented in a “test” apartment to obtain practical experiences. The first measure was the installation of two different types of interior insulation, specifically, an insulation component consisting of an aerogel–stone wool mixture or vacuum insulation panels. The second measure related to the retrofit of windows in which five measures were completed that consisted of applying a secondary frame, a sash mounted on the frame or to coupled frames. The third measure consisted of installing a decentralised mechanical ventilation system with heat recovery. The results showed that following the retrofit the building''s theoretical energy use diminished from 162.5kWh/(m2 year) to 51.5kWh/(m2 year), corresponding to a reduction in energy use of 68%. The theoretical energy use after retrofitting fulfilled the requirements for new buildings in Denmark. The practical experiences that were retained following the retrofit were that the ventilation system ought to be installed with low noise components, insulation materials must be sized and cut to fit on site, and that new windows were selected. [Copyright &y& Elsevier]

Abstract: The paper presents life cycle energy (LCE) analysis of different types of residential buildings (one storey, two storey, and duplex and multi storey) in Indian context. A total of 10 houses’ designs were examined with energy saving features, e.g. thermal insulation on wall and roof, double pane glass for windows. One of these buildings was further examined to assess LCE performance with on-site power generation. Dynamic energy simulation tools DesignBuilder, e-Quest and EnergyPlus were used to assess energy performance of the buildings. LCE of the buildings is varying from 240 to 380kWh/m2 year depending on the type (envelope) of the building and climatic conditions. LCE savings of about 5–30% are observed with thermal insulation on wall and roof along with double pane glass for windows. It is found that net zero operating energy building can be achieved by on-site power generation from PV and wind turbine. LCE of the building for net zero operating energy is evaluated to be 71.24kWh/m2 year. [Copyright &y& Elsevier]

Abstract: In consideration of the climatic characteristics of different climatic zones, the annual energy consumption of existing buildings before and after reconstruction in hot summer and warm winter regions of South China and cold regions of North China is analyzed in this paper using DOE-2 dynamic cold and heat load simulation software. For cold regions of North China, the annual comprehensive energy saving benefits of existing buildings reconstruction in summer and winter should be analyzed, and the cost savings in the initial investment for heat resource and electricity construction should also be included at the same time. While for hot summer and warm winter regions of South China, the building energy saving should focus on new buildings. The building energy saving reconstruction and the feasibility in the two regions is also compared and analyzed. [Copyright &y& Elsevier]

Abstract: The diversity of non-domestic buildings at urban scale poses a number of difficulties to develop models for large scale analysis of the stock. This research proposes a probabilistic, engineering-based, bottom-up model to address these issues. In a recent study we classified London''s non-domestic buildings based on the service they provide, such as offices, retail premise, and schools, and proposed the creation of one probabilistic representational model per building type. This paper investigates techniques for the development of such models. The representational model is a statistical surrogate of a dynamic energy simulation (ES) model. We first identify the main parameters affecting energy consumption in a particular building sector/type by using sampling-based global sensitivity analysis methods, and then generate statistical surrogate models of the dynamic ES model within the dominant model parameters. Given a sample of actual energy consumption for that sector, we use the surrogate model to infer the distribution of model parameters by inverse analysis. The inferred distributions of input parameters are able to quantify the relative benefits of alternative energy saving measures on an entire building sector with requisite quantification of uncertainties. Secondary school buildings are used for illustrating the application of this probabilistic method. [Copyright &y& Elsevier]