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Abstract: The success of modeling the sustainable performance of the residential building envelope will be to a great extent associated to the sustainable energy performance indicators used. The sustainable energy performance indicators that these building assessment models are developed around should be chosen by taking into account the targeted objectives. However, it is very common to find building performance assessment models that do not take into account these considerations and therefore have a limited capability and scope. This leads to inadequate aggregate indicators for the actual assessment of the sustainable performance of the building envelope for a sustainable energy efficient building. The focus of this paper is to investigate the principal sustainable energy performance indicators for modeling the sustainable performance of the residential building envelope and develop an approach for determining the most appropriate sustainable energy performance indicators. In doing that, this paper provides an overview of previous research on sustainable energy performance indicators and discusses conceptual framework for developing sustainable energy performance indicators. In order to identify these indicators that influence the capability of building performance assessment models, a comprehensive survey of construction industry professionals was conducted using questionnaire survey technique while the data was analyzed using correlation analysis techniques. [Copyright &y& Elsevier]

Abstract: Building designers are often limited in their ability to reduce the environmental impact of buildings, due to a lack of information on the environmental performance of building components as well as inconsistencies in the way in which this information is derived. Whilst numerous tools exist to help facilitate the low-energy building design process, these typically require large investments of time and money that are often beyond those available within any particular project. This paper describes an approach for streamlining the design process to reduce building life cycle energy consumption. Building assemblies are ranked based on an assessment of the life cycle energy requirements associated with their use within a building. This facilitates early stage assessment, negating the need for a resolved design before the relative energy requirements of alternate design solutions are known. Previous work assessed the initial and recurring embodied energy as well as the operational energy requirements for heating and cooling associated with the use of a range of building assemblies, using a simplified house model. This paper presents a sensitivity analysis of variations to the floor area, shape and orientation of this model, to test the reliability and applicability of the ranking approach across a broad range of circumstances. It was found that these variations did not influence the ranked order of the assemblies in terms of their life cycle energy requirements. Thus, the ranking of assemblies appears to provide an appropriate approach for streamlining the selection of construction elements during the building design process. [Copyright &y& Elsevier]

Abstract A critical decision to be made once a building project is defined is the selection of a convenient construction method (CM) for various building elements. To deal with varied decision criteria and the classified nature of building elements, this paper implements the decision-making process in an object-oriented model, in which each building element is modeled as a class with various possible alternative construction methods as subclasses. Although the subclasses inherit all the main class attributes, each subclass is specified by additional attributes. The uncertainty and vagueness of expert knowledge on the performance of each construction method regarding the attributes are mapped with fuzzy numbers in this multi-criteria-decision-making problem to deal with the inherent imprecision of subjective judgment. To demonstrate the use and capability of the model, a case study is presented. [ABSTRACT FROM AUTHOR]

Highlights • This study presents a detailed review on IRT for the investigation of building envelope defects. • The literature survey is conducted regarding existing IRT methodologies for building envelopes. • The previous studies with measurement methods, analysis schemes and analysis types are categorized in the literature matrix. • Recent advances and future trends on IRT methods are presented. Abstract Thermal radiation generated by limited resources is emitted from the surfaces and interpreted as temperature. On the other hand, the limited resources necessitate prevention of energy leakages causing noticeable temperature differences on surfaces. Providing sensitive information on temperature contrast, infrared thermography (IRT) is a prominent tool for detecting infrared energy on the surfaces of the objects. IRT is also very promising method for detecting thermal irregularities, air leakages and even moisture abnormalities on building envelopes. Since the concept of nearly zero energy buildings is to be the main target of energy policies in European Union published by European Commission, improving thermal performance of buildings becomes crucial in the last decade. Therefore, implementation of IRT for visualizing and analyzing concealed defects on building envelopes is very promising for improving the energy efficiency of buildings. Given recent regulations and benefits of emerging thermogram technologies mentioned above, a detailed review of the previous studies investigating the abnormalities of building envelopes by IRT is presented in this paper. Furthermore, the applications with measurement methods, analysis schemes and analysis types are classified to highlight the potential of IRT in inspection of building envelopes for providing energy efficient solutions. Finally, recent advances and practical future opportunities are presented for additional contribution of the IRT methods previously employed. [ABSTRACT FROM AUTHOR]

Abstract The actual thermal behaviour of façades is important to identify suitable energy-saving measures and increase the energy performance of existing buildings. However, the accuracy of in situ measurements of façades’ U-values varies widely, mostly due to inadequate test durations. The aim of this paper was to evaluate the minimum duration of in situ experimental campaigns to measure the thermal transmittance of existing buildings’ façades using the heat flow meter method, and to analyse the thermal performance of the façade during the test. Minimum test duration was determined according to data quality criteria, variability of results criteria, and standardized criteria for different ranges of theoretical thermal transmittance and for the same range of average temperature difference. Then, the minimum test duration results were compared. The findings show that ISO criteria are more sensitive and provide more accurate results, requiring a longer test duration. However, when certification is not required, the duration of the test could be reduced by applying data quality and variability of results criteria. The minimum duration of experimental campaigns depends on the theoretical thermal transmittance and the stability of climatic conditions. Moreover, results are more accurate when the dynamic method is used. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents the evaluation of the current HVAC components and indoor climate of a high tech Naval Depot when the system fails. The methodology of the research was: first, implementation of the heat, air & moisture models of the building and HVAC components. Second, validation of the models using measured data from the existing building control system. Third, simulation of the current and new HVAC systems designs. Fourth, discussion of the usability of the approach. For this specific case, we concluded that the current system design performs well if, in case of a fault, the air supply to the depots is switched off automatically. The construction of the depots has sufficient thermal inertia to maintain a stable indoor climate for a period long enough to allow it to be repaired. The design could be further improved by controlling the indoor climate surrounding the depots instead of inside the depots itself. In such a case, even if the system did not detect a fault and continued supplying uncontrolled air to the surroundings of the depot, the indoor climate in the depot would remain stable. We conclude that the approach presented in this paper has a wider application than this single case study. [ABSTRACT FROM AUTHOR]

Abstract: This paper aims to study the various parameters that affect the energy performance of commercial buildings in Singapore. The parameters are diverse, ranging from characteristics of construction of the walls and windows, to the various system settings and types within the building. Building energy performance is measured via two key indexes, namely, the Envelope Thermal Transfer Value (ETTV) and the annual cooling energy requirement (E c). Parameters related to these two indexes are identified. An additional parameter, the solar absorptance of the wall, is further incorporated to calibrate the ETTV equation. A relative ranking on the functional parameters of ETTV has been performed to evaluate their effectiveness in lowering the ETTV of buildings. In addition, the impact of using cladding on ETTV is also studied. A correlation for E c, expressed in the form of a simple linear equation, has been developed. This correlation accounts for the internal building loads, envelope loads, operating schedules and efficiency of the cooling equipment. Finally, ETTV and E c have been employed to study the effects of chiller over-sizing and ventilation rates on building cooling energy. In the pursuit for better energy-efficient buildings, the approach presented in this paper contributes to the construct of sustainable energy-efficient built-environment. [Copyright &y& Elsevier]

[Display omitted] • The application of OB models in the building design process is reviewed. • The role of OB models for a robust and resilient built environment is highlighted. • The gap between the occupant behaviour research field and the end-users is mapped. • A simulation framework for integrating OB models in the design practice is proposed. • Criteria for evaluating, choosing, and adapting OB models are given. Occupant behaviour is an important source of uncertainty in building energy performance simulations. This has led to the development and integration of different modelling approaches that represent the complex, stochastic nature of human-building interaction. Yet, several barriers prevent their wide use in simulation-aided building design. The procedures and practical solutions for integrating occupant behaviour models are segmented through the literature. Accordingly, this paper examines the state-of-the-art in the application of occupant behaviour models. Based on the PRISMA methodology, the literature is critically analysed to: i) identify and map the barriers between theory and application; ii) propose a simulation framework establishing the steps for integrating occupant behaviour models into building performance simulations; iii) synthetise practical solutions and highlight remaining challenges towards a simulation framework adequately integrating occupant behaviour. The paper stresses the added value within the decision-making process at different building design stages. Furthermore, key elements for identifying the appropriated modelling approach for each occupant behaviour aspect are presented considering factors such as type of behaviour, building type, and spatial and temporal scale. Ultimately, this critical review establishes guidelines for the integration of occupant behaviour into building design practice and defines a research pathway for bridging the gap between the OB research field and the simulation-aided building design practice. [ABSTRACT FROM AUTHOR]

[Display omitted] The hot box test method has been applied to evaluate both the steady-state (U-value) and dynamic thermal properties of building envelopes. However, the high construction cost of full-scale hot box apparatus and the testing time required (usually several days) may prevent its wider adoption. To overcome the limitations of full-scale hot box tests, this paper proposes a novel method to evaluate the dynamic thermal performance of building envelope components using a small-scale calibrated hot box and scaled-down specimen. In this paper, the scaling relationships of thermal properties evaluated using a full-size specimen and a scaled-down specimen are established based on the Laplace transform of the heat transfer equations. In addition, dynamic thermal properties obtained from scaled-down experimental tests are compared to the values calculated by the EN ISO13768 (ISO) method. A small-scale hot box with a 355 mm × 355 mm metering area was constructed and calibrated to validate the correlations. Three scaled-down concrete sandwich wall panels were then tested and the scaling relationship was cross-validated using the experimental results, finite difference (FD) simulations, and the ISO method. The results indicate that the dynamic thermal properties obtained from a scaled-down hot box test can be correlated to its full-size counterpart when certain conditions are met. The scaled-down hot box test is demonstrated to be an effective yet economical alternative to a full-scale test with significantly reduced experimentation cost and turn-around time. [ABSTRACT FROM AUTHOR]

An industry foundation class based building product model of University College Cork’s “to be constructed” Environmental Research Institute will be developed. This paper discusses combining such a building product model with a building management system and other tools and technologies to create a framework for monitoring, analysing and controlling a building throughout its building lifecycle based on a set of performance metrics. The framework will be known as the building energy monitoring, analysing and controlling (BEMAC) framework. Current building performance assessment practices lack standardisation/continuity throughout the building lifecycle. An environment such as the BEMAC framework described in this paper offers a means to achieving such standardisation/continuity by documenting and communicating performance metrics data such that these data can provide value across the complete lifecycle of a building project, from planning through design and construction into occupancy and operation. [Copyright &y& Elsevier]

• Bottom-up archetype model for space heating demand of Swiss office building stock. • Archetypes characteristics derived from energy certificates database. • Estimation of current thermal performance and energy retrofit's potential. • Calculation of national heating demand and distribution among archetypes. • Influence of design characteristics and buildings properties on heating demand. Energy efficiency in buildings is a key objective of the European energy strategy. To address the limited knowledge of the thermal performance of the non-domestic building stocks, this paper presents a bottom-up, physics-based, archetypal model derived from a large building stock database and physical characteristics from 2170 building energy performance certificates in Switzerland. The model was validated by measured energy consumption data and national statistics. Results highlight the potential for energy retrofit: most of the stock is still heated with fossil fuels (67% of the total heated area) and 40% of the total envelope surface has a poor thermal performance associated with the period before 1980. We estimate national final energy demand for heating of the office building stock (11.3 PJ/year) and present detailed breakdown of energy by thermal loss element. Significant differences were found between archetypes related to urban settings (specific demand 50% higher in rural than in urban contexts) and age of the buildings (56% of the total demand is due to buildings constructed before 1970). The physical model highlights the impact of architectural design characteristics such as building compactness and glazed surface ratios on thermal performance. The model represents an important step for studies on optimal thermal retrofit pathways. [ABSTRACT FROM AUTHOR]

In recent years, measurement protocols for the estimation of the total aggregate building heat transfer coefficient (HTC) have provided sufficient empirical evidence to indicate that buildings often do not perform as intended. However, little research has been carried out into the associated uncertainties. Within this context, this paper reviews sources of uncertainty associated with co-heating tests; characterises these uncertainties and their impact on HTC estimates; and devises a method for the calculation of HTC uncertainty. The method proposed was applied to 14 co-heating tests, showing estimated total uncertainty ranging between 2.2-21.1 ▪ (or 4.6-26.7% of the measured value) with a mean of 10.1 ▪ (or 8.7%). The natural variation of HTC and often-observed inaccuracy of design calculations (the 'prediction gap') suggest that more accurate measurements may be of little benefit. Additionally, results suggest that weather conditions, challenging building design and poor experimental technique can all significantly contribute to HTC uncertainty. However, when suitable buildings are tested by experienced technicians and under suitable weather conditions, HTC estimates from the co-heating protocol are likely to provide a useful tool to assess and understand real-world building fabric performance. • Uncertainties in steady state co-heating measurements are reviewed. • Uncertainties are characterised by their nature and impact upon HTC estimates. • A framework for estimating uncertainty in HTC estimates if given. • Range of estimated uncertainty on 14 tests is 5-27%. • Cases with poor experimental control and problematic test buildings result in higher uncertainty. [ABSTRACT FROM AUTHOR]

An excellent way to obtain a detailed description of the air flows and temperature field in a zone is to perform accurate Computational Fluid Dynamics (CFD) simulations. Unfortunately, this is often prohibitive due to the powerful resources that are required, and the large computational times. As a consequence, several intermediate models between CFD and the standard well-mixed models have been proposed over the years. These are known as zonal models, and they aim at delivering sufficiently accurate predictions of the thermal comfort in a room, for long periods (months or even years), and with substantially shorter computational times. However, none of these models has yet been implemented in a building performance simulation (BPS) tool. In this work, we have developed and implemented a BLOCK zonal model [1,2] within the IDA ICE (BPS) software. A multi-node 1D model for the prediction of vertical temperature gradients is used, together with flow element theory and an appropriate algorithm for the estimation of view-factors in non-convex geometries with obstacles. The paper presents the theoretical background of the model along with advice on its range of applicability. Finally, the model is validated against several test cases, showing its suitability in predicting the thermal stratification. [ABSTRACT FROM AUTHOR]

• Incidence of windows design on energy and visual comfort is studied under climate change. • The case study is an office building located in representative European climates. • Triple low-emissive windows, in oceanic and continental climates achieves energy saving of −35 %. • Double selective windows assures savings from −27 % to −57 % in the warm and oceanic climate. • The primary energy will increase until 27 % in for warn climates considering the 2080 scenario. The design of the glazed elements of the building envelope is a critical issue for both new and refurbished building when the effect of climate changes and expected overheating conditions are considered. Indeed, the windows affect the building energy balance and also the natural lighting that impacts both on visual comfort and illuminance consumptions. This paper develops a methodological approach for performing a parametric analysis aimed at quantifying the effects of different window's designs on the total primary energy and visual comfort of an office in the most representative European climatic zones. The considered parameters are: windows' orientation, window to wall ratio, glass and frame type and the installation of shading system. A new approach for evaluating the resilience of the optimal solution selected for the current climates is introduced by taking into account medium and long-term emissions scenarios. This analysis suggests that in the warm-summer humid continental climate, a double selective window may be resilient. Indeed, in the worst emission scenario, the achievable annual energy saving will be around −26 % if compared with a clear double window. Meanwhile it will be lower than −10 % if compared with the same optimal solution but simulated in the short-term emission scenario. For the humid subtropical climates and hot-summer Mediterranean climates, the scientific community should be focused the development of new solutions because also a dynamic system as the electrochromic one, is not able to guaranteed energy saving in the future scenario. Indeed, also the optimal configuration selected under the current conditions would be characterized by higher primary energy request (between 16 % and 27 %) under the future emissions scenarios. [ABSTRACT FROM AUTHOR]

[Display omitted] • The leaf area index for urban farming crops. • The life cycle growing of urban farming crops. • The lack of the discussion about the method to simulate urban farming crops. • Approaches suggestion in order to simulate the urban farming performance. • The urban farming crop rotation. This paper presents an exploratory research about the possibilities to simulate the thermal performance of buildings with green roofs, or in this case rooftop farming. Different from the green roofs, a rooftop farming has a leaf area index (LAI) variable during all the year because the vegetable crops growing cycle repeats sometimes along the year. The contribution of this paper is to bring this discussion to the art state. The method uses computer simulation as a research strategy using the software Energy Plus. The research method was developed in 3 steps. In the first one, a literature review was performed in order to search data from 18 vegetable crops and 3 substrates. One of these data was the LAI, which in the second research step was simulated considering 5 different possibilities (LAI constant all the year; LAI observing monthly the growing cycle; Average LAI considering the growing cycle; crop rotation with average monthly LAI; and LAI defined each ten days considering the crop growing cycle). The results demonstrated that: a) the simplified LAI found in the literature considering the rooftop farming simulations are defined as constant; b) using LAI constant all the year can overestimate until 7% the energy use intensity (EUI) in buildings for the climate in the South of Brazil. c) Thus, in order to simulate the performance of buildings with rooftop farming it is important to develop a data base of the vegetable crop considering the LAI variation along the cycles, and also the number of cycles during the year. [ABSTRACT FROM AUTHOR]

Buildings consume a significant amount of energy worldwide in maintaining comfort for occupants. Building energy management systems (BEMS) are employed to ensure that the energy consumed is used efficiently. However these systems often do not adequately perform in minimising energy use. This is due to a number of reasons, including poor configuration or a lack of information such as being able to anticipate changes in weather conditions. We are now at the stage that building behaviour can be simulated, whereby computer programs can be used to predict building conditions, and therefore enable buildings to use energy more efficiently, when integrated with BEMS (i.e. simulation assisted control [1]). In this paper we demonstrate a low cost BEMS that uses building simulation to predict optimised electrical heating startup control points. Those that use electricity for heating in Scotland, where this study was based, tend to be fuel-poor, hence there is a strong case for optimisation, particularly when electricity costs nearly three times as much as the equivalent unit of gas for heating applications. The proposed system demonstrated a 50% energy saving in the reduced heating time compared to scheduling when retrospectively evaluated. [ABSTRACT FROM AUTHOR]

Occupant behaviour has a direct impact on building energy consumption. A better understanding of human-building interactions enables to describe with higher accuracy the occupant behaviour. This paper addresses occupant behaviour in residential buildings, providing a review of current methods in (1) monitoring occupant behaviour, (2) developing occupant behaviour models, and (3) applying occupant behaviour models in building performance simulations. Occupant behaviour studies with focus on residential buildings are presented including both challenges and potential for improving building energy performance. [ABSTRACT FROM AUTHOR]

A pronounced gap often exists between expected and actual building performance. The multi-faceted and cross lifecycle causes of this performance gap are found in design assumptions, construction issues and commissioning and operational compromises. Some important factors are firmly rooted in the lack of interoperability around building information. New solutions to the interoperability challenge offer the potential to leverage and reuse available heterogeneous data in a manner that can significantly assist building performance assessment. Linked data provides an open, modular and extensible solution for the challenge. However, in the buildings domain, the integration of rule-based performance metrics and contextual information has yet to be formally established. This paper describes an approach to the provision of in-depth building performance assessment through the integration of OpenMath and linked data. An ontology describing performance metrics in RDF is presented, together with an automated metric evaluation solution using multi-silo queries and computer algebra systems, providing a flexible, automated and extensible mechanism for the assessment of building performance. Building managers and engineers can simultaneously analyse time-series building performance at a range of levels, without burdensome manual intervention such as is the case with traditional solutions. A test implementation on a large university building highlights the potential of this solution. [ABSTRACT FROM AUTHOR]

This paper empirically investigates the influence of building fabric, services and occupant related factors on actual energy use of six case study dwellings, located in three new low energy social housing developments in UK, covering a variety of built forms and construction systems (timber frame, hempcrete, steel-frame). Physical monitoring of indoor environment and window-opening is cross-related with building fabric and systems’ performance, and qualitative data gathered through occupant surveys, review of control interfaces and handover guidance, to understand the causes of the gap between modelled and measured energy use. Actual energy use is found to exceed design expectations by a factor of three, questioning the need for whole-house mechanical ventilation heat recovery (MVHR) systems at measured air permeability rates of 6 m³/(h.m²) against the design target of 3 m³/(h.m²). Lack of proper commissioning of MVHR and heating systems, combined with inadequate user comprehension about their operation and control leads to occupant ‘misuse’ wherein systems are de-activated, thereby negatively affecting indoor air quality. This is confounded by occupant factors related to higher demand temperatures, unexpected opening of windows during winters due to under-performance of MVHR combined with habitual behaviours, and over-use of heating systems to compensate for higher than expected air permeability. [ABSTRACT FROM AUTHOR]

This study investigates an energy-inefficient council housing tower block in London, due for retrofit, by exploring the correlations between occupancy and energy consumption patterns, thermal comfort and building energy performance in the winter. The aim of this study is to evaluate the building performance and develop a reliable building simulation model to be employed in the second phase of the study for developing an energy-efficient and cost-effective retrofit strategy to support the council's plans. The research seeks to demonstrate the significance of using dominant occupancy and energy use profiles as opposed to relying on standardised profiles when calculating building energy consumption using building simulation software. The paper reports on the results from the first phase of the study where a quantitative methodology; including a questionnaire, structured interviews, indoor monitoring, and building simulation modelling was adopted. The results provide evidence that occupants’ socio-demographic characteristics have a considerable impact on household energy consumption and fuel bills. The results also show that indoor environmental issues experienced in many flats are partly attributed to the thermally inefficient building envelope and partly due to occupants’ patterns of operating their homes with evidence of excessive heating energy use in attempts to alleviate the indoor issues experienced. [ABSTRACT FROM AUTHOR]

An investigation of building performance through a comfort and operational quality standpoint is not too often discussed for Net-Zero Energy Buildings (NZEB). It would seem important that predications and claims for reducing energy-use in buildings and the move towards NZEB does not compromise comfort in buildings. A high school in Essendon, Victoria (near Melbourne) Australia undertook a retrofitting process to improve its existing library from a functional as well as an environmental standpoint. In the process, several pre- and post-measurements were made of building performance. An advanced packaged unit mechanical system applies a demand control ventilation system with a specialised control that promises uniform air temperature throughout the volume of the conditioned space. This system utilises staged compressors with variable speed drive fans and results in minimal background noise. For the mechanical system to deliver as promised, the building envelope was air pressure sealed to an international standard and double glazed (from single glass) and zoned according to orientation and spatial function. Efficient LED lighting was also applied to a dimming control responsive to occupancy and daylight. This level of building improvement requires before and after measurement procedures to assure and prove a quality performance for a near NZEB. Various measurements of pressurisation, air exchange rates through tracer gas, air temperature stratification, IAQ, as well as a continuous and localised comfort survey measurement all contribute to a pre and post assessment of building performance. This paper discusses several measurement processes considered useful to characterize the performance of an HVAC system in a retrofitted library space. As a result of the building envelope quality, subsequent monitoring of the mechanical conditioning system showed that it could have been reduced to half its specified size. Furthermore, sub-metering of the space indicates that the attention given to the lighting and conditioning systems has reduced their impact, so that plug loads are beginning to dominate and require attention if net zero energy building is to be targeted. [ABSTRACT FROM AUTHOR]

In this study, the objective is to redesign a previous concept for a single-family Zero greenhouse gas Emission Building (ZEB). The concept is redesigned based on comparing greenhouse gas (GHG) emission loads and compensation from different design solutions applied in Norwegian single-family ZEB pilot buildings and selected sensitivity studies. The objective is to see if a previously developed ZEB model (2011) can be redesigned to achieve a life cycle energy and material emission balance (ZEB-OM), which previously was not achieved. Five different design parameters are evaluated: area efficiency, embodied emissions in the envelope, insulation thickness, heating systems and different roof forms with respect to the photovoltaic area. Embodied emissions reductions were possible in the ground foundation, from around 1 kg CO 2 /m 2 to 0.6 kg CO 2 /m 2 per year. Both models are able to compensate for all operational emissions. The new model is in addition able to compensate for 60% of embodied emissions, whereas the previous model only could compensate for 5%. The new model does not reach the life cycle energy and material balance. The paper presents and discusses different approaches for achieving the ZEB-OM balance. Further concept model optimization is needed. [ABSTRACT FROM AUTHOR]

As one of the latest emerging HVAC technologies, the Variable Refrigerant Flow (VRF) system with heat recovery (HR) configurations has obtained extensive attention from both the academia and industry. Compared with the conventional VRF systems with heat pump (HP) configurations, VRF-HR is capable of recovering heat from cooling zones to heating zones and providing simultaneous cooling and heating operations. This can further lead to substantial energy saving potential and more flexible zonal control. In this paper, a novel model is developed to simulate the energy performance of VRF-HR systems. It adheres to a more physics-based development with the ability to simulate the refrigerant loop performance and consider the dynamics of more operational parameters, which is essential for representing more advanced control logics. Another key feature of the model is the introduction of component-level curves for indoor units and outdoor units instead of overall performance curves for the entire system, and thus it requires much fewer user-specified performance curves as model inputs. The validation study shows good agreements between the simulated energy use from the new VRF-HR model and the laboratory measurement data across all operational modes at sub-hourly time steps. The model has been adopted in the official release of the EnergyPlus simulation program since Version 8.6, which enables more accurate and robust assessments of VRF-HR systems to support their applications in energy retrofit of existing buildings or design of zero-net-energy buildings. [ABSTRACT FROM AUTHOR]

To better address energy and indoor air quality issues, ventilation needs to become smarter. A key smart ventilation concept is to use controls to ventilate more at times it provides either an energy or indoor air quality (IAQ) advantage (or both) and less when it provides a disadvantage. A favorable context exists in many countries to include some of the existing smart ventilation strategies in codes and standards. As a result, demand-controlled ventilation (DCV) systems are widely and easily available on the market, with more than 20 DCV systems approved and available in countries such as Belgium, France and the Netherlands. This paper provides a literature review on smart ventilation used in residential buildings, based on energy and indoor air quality performance. This meta-analysis includes 38 studies of various smart ventilation systems with control based on CO 2 , humidity, combined CO 2 and total volatile organic compounds (TVOC), occupancy, or outdoor temperature. These studies show that ventilation energy savings up to 60% can be obtained without compromising IAQ, even sometimes improving it. However, the meta-analysis included some less than favorable results, with 26% energy overconsumption in some cases. [ABSTRACT FROM AUTHOR]

Buildings are a significant contributor to the rapidly increasing electricity demand in Egypt which is straining the existing supply network causing economic and social impacts. There are current initiatives aimed at improved building performance including adoption of international standards. The performance of existing Egyptian buildings is not well understood making the impact of these international standards uncertain. This paper provides insight into performance of current Egyptian office buildings through a multi-building energy survey and a detailed case study. The most common office type in the survey has natural ventilation and local cooling. A process to capture observed performance in a representative model and input parameter set is presented. The model is used to investigate performance impacts of parameters including: location, weather, building envelope, intensity of occupancy, behaviour, and installed systems including the HVAC strategy. HVAC strategy was identified as the most significant factor. Typical Egyptian offices with natural ventilation and local cooling systems under personal control have electricity demand less than 50% of centrally serviced buildings. System efficiencies (HVAC, lights, equipment) and occupant behaviour (e.g. use of systems, temperatures) were also identified as significant factors, each with potential of around 30% saving compared to current typical offices. Possible policy measures to promote energy efficient systems and energy conscious behaviour are proposed which together can reduce the energy demand of typical offices by 50%. Trade-offs between energy use and indoor environmental quality (IEQ) are discussed. [ABSTRACT FROM AUTHOR]

More than 30% of the total primary energy in the world is consumed in buildings. It is crucial to reduce building energy consumption in order to preserve energy resources and mitigate global climate change. Building performance simulations have been widely used for the estimation and optimization of building performance, providing reference values for the assessment of building energy consumption and the effects of energy-saving technologies. Among the various factors influencing building energy consumption, occupant behavior has drawn increasing attention. Occupant behavior includes occupant presence, movement, and interaction with building energy devices and systems. However, there are gaps in occupant behavior modeling as different energy modelers have employed varied data and tools to simulate occupant behavior, therefore producing different and incomparable results. Aiming to address these gaps, the International Energy Agency (IEA) Energy in Buildings and Community (EBC) Programme Annex 66 has established a scientific methodological framework for occupant behavior research, including data collection, behavior model representation, modeling and evaluation approaches, and the integration of behavior modeling tools with building performance simulation programs. Annex 66 also includes case studies and application guidelines to assist in building design, operation, and policymaking, using interdisciplinary approaches to reduce energy use in buildings and improve occupant comfort and productivity. This paper highlights the key research issues, methods, and outcomes pertaining to Annex 66, and offers perspectives on future research needs to integrate occupant behavior with the building life cycle. [ABSTRACT FROM AUTHOR]

Buildings accounted for half of global electricity consumption in recent years. Accurate occupancy information could improve the energy efficiency and reduce the energy consumption in built environment. Although prior studies have explored various sensing techniques for occupancy sensing, these solutions still suffer from serious drawbacks, e.g. their estimated occupancy information is coarse, extra infrastructure is required, and the privacy of occupants is exposed. In this paper, we present the design and implementation of a novel and practical occupancy sensing system, WinOSS, which is able to provide fine-grained occupancy information thoroughly by leveraging existing commodity WiFi infrastructure along with the WiFi-enabled mobile devices carried by occupants. We have implemented WinOSS in a 1500 m 2 built environment for four weeks to validate its performance. Extensive experimental results demonstrate that WinOSS outperforms existing occupancy sensing techniques, and provides comprehensive fine-grained occupancy information (including occupancy detection, counting and tracking) in an accurate, reliable, cost-effective and non-intrusive manner. [ABSTRACT FROM AUTHOR]

Energy demand reduction from buildings is widely recognised as a key component of greenhouse gas abatement strategies. As governments shift towards large-scale sectoral interventions, a far more robust research and evidence base is needed to support the development, implementation, and on-going evaluation of energy demand policy. The shift to a low carbon built environment will require both a step change in the energy performance of buildings alongside more efficient provision of energy services, and an aggressive decarbonisation of the energy used. Yet the prerequisite data of building stocks needed to support this essential shift in energy performance of buildings are not necessarily available or are inaccessible or incomplete. As more information on building energy use is collected through high frequency sensors and building form analytics become more sophisticated, the analysis methods applied to the myriad and diverse sub-sectors of the building stock ‘population’ need to be commensurate with the heterogeneity of the building stock. This paper describes and illustrates the basis of the IEA EBC Annex 70: Building Energy Epidemiology, which draws on the health sciences to posit ‘energy epidemiology’ as a whole-system approach for empirical research that provides a methodological framework for building physicists, engineers, social scientists, and economists to engage in cross-disciplinary studies. It makes the case that the development and application of an epidemiological approach to investigating energy demand can advance understanding of the inter-related factors for policy guidance and evaluation and provide insights on the mechanisms that influence energy demand. The aim of the IEA EBC Annex 70 is to work in an international collaboration to identify user needs around energy demand in buildings and to establish best practice methods and harmonized formats for data collection, analysis and modelling. To illustrate this process, we present an example from the UK on the application of energy epidemiological methods to building energy performance in the residential sector. The case study investigates the potential effectiveness of the policy and technical measures proposed by the UK Government. Policy implementation for broad, deep, and urgent reductions in energy demand from the building sector requires a far better understanding of the underlying relationships between people, energy use, buildings and the environment. [ABSTRACT FROM AUTHOR]

Aerogel was one of the most promising nano-materials for use in buildings and its thermal performance was widely discussed in the literature while an accurate study of acoustic properties was never provided. The aim of the paper is to investigate experimentally the influence of granules size on both thermal and acoustic properties of granular aerogels and aerogel-based solutions (a plaster and a translucent polycarbonate panel) for energy saving in buildings. Several kinds of aerogels were investigated, ranging from small granules (0.01–1.2 mm) to large granules (1–4 mm). For each kind of aerogel, the absorption coefficient (α) and Transmission Loss (TL) were measured at normal incidence in a traditional impedance tube, taking into account 5 thicknesses (15, 20, 25, 30 e 40 mm) and thermal conductivity (λ) was evaluated by the Heat Flux Meter, setting up an appropriate methodology because of the sample nature. The aerogel granules outperformed the conventional insulating materials: depending on the particle sizes, λ varies in 19–23 × 10^(-3) W/(mK) range at 10 °C. The smallest granules (highest density) had the best performance, both in terms of thermal and acoustic insulation: α-values and TL better than the ones of rock wool were achieved (α = 0.95 and TL = 15 dB at about 1700 Hz). The good acoustic behaviour was confirmed also considering the two aerogel-based solutions for buildings: the peak of the absorption coefficient of the aerogel-based plaster was 0.29 at about 1050 Hz, compared to a value of about 0.1 of conventional plasters; simultaneously, λ diminished from 0.7 W/mK to 0.05 W/mK. [ABSTRACT FROM AUTHOR]

This study is focused on the evaluation of the effectiveness of vacuum insulation panel (VIP) for typical Mediterranean climate. The interest for this material is due to indisputable advantages in term of insulation performance both for new and refurbished buildings; mainly in retrofit design, adoption of lower thickness assure same results with less invasive interventions. The problem is the behavior during the summer period, not investigated in the available scientific literature. Numerical and experimental approaches are used in this paper to compare the performance of several wall packages integrating VIP with constructive technologies that result in different stationary and dynamic parameters. More in detail the results of a yearly measurement campaign in three real building of south Italy are presented; recorded data of the surface and the mean air temperatures as well as of the heat flux are commented. Data for one typical week of each season are evaluated to compare the wall made of concrete block and vacuum insulation material with a massive structure and also with a concrete wall with expanded polystyrene as insulation material. Furthermore, simulation results (by means of EnergyPlus) are presented to study, mainly during the summer, the effect of integration of vacuum insulation panel in multi-layered wall made of concrete blocks with different values of density and thermal conductivity; moreover these configurations are compared with a wall made of innovative insulated interlocking brick and with the wall types considered in the experimental phase. Using a typical office building as case study, energy consumptions and environmental and economic indexes are valuated. Experimental and numerical results show the effectiveness of solution with VIPs also for Mediterranean climate. [ABSTRACT FROM AUTHOR]

• Investigated climate change impacts on office building performance in Brussels. • Applied a long-term climate change sensitive system sizing and design approach. • Time-integrated discomfort analysis showed a major surge in overheating by 2100. • Long-term climate change resistivity is ensured in reference building until 2100. • Primary energy use and GHG emission findings are useful in mixed humid climates. As climate change continues, it is expected that the risk of overheating will rise in both new and existing buildings in mixed humid climate zones in Europe. This study introduced a novel climate change sensitive sizing and design approach for cooling and heating systems in nearly zero-energy office buildings in Brussels, Belgium, for different weather scenarios. This approach considered the long-term effects of climate change on building performance. The climate change effects were assessed using current and future climate data from the regional atmospheric model, MAR. To demonstrate the approach, a case study of a nearly zero-energy office building in Brussels was conducted. The reference building model was first calibrated using monthly energy use data from the year 2019 using ASHRAE Guideline 14. Then, the building was evaluated with different HVAC strategies and their performances were quantified. The results indicated an increase in overheating as high as 1.2 °C and cooling energy use as high as 13.5 kWh/m2 and a decrease in overcooling as low as 0.3 °C and heating energy use as low as 10.9 kWh/m2 in the reference building by the end of the century. In addition, due to climate change sensitive sizing and design approach coupled with optimal sizing, the reference building was climate change resistant towards the worst-case scenario by end of the century with up to 3.7 for climate change overheating resistivity and 20.2 for climate change overcooling resistivity. Finally, the paper provided recommendations for future practice and research based on the study findings. [ABSTRACT FROM AUTHOR]

• Spent coffee ground can efficiently be reused in GP-products manufacture. • Novel GP-products are suitable for innovative architectural applications. • Spent coffee ground based-GP products show superior energy saving behaviour. • The cost associated with GP-products production is lower to traditional ones. • A 19% energy improvement per year is achieved for the building envelope. This study investigates a possible alternative reuse of spent coffee grounds (SCG), the major residue of the brewing process, to manufacture green geopolymeric materials for innovative building applications in energy-saving construction, in line with the European Green Deal towards zero-energy building. Specimens were prepared by a combination of biomass fly ash from the Kraft paper-pulp process, as raw material (70 wt%), and SCG (up to 17.5 %), as filler. The high amount of reused bio-wastes makes the material fit the requirements for the Minimum Environmental Criteria (MEC) certification, in light of the Circular Economy (CE) approach. Sustainability is also boosted by the manufacturing process that completely occurred at ambient conditions (20 °C, 65 % RH). Materials engineering performance is evaluated to predict possible applications in construction and promote an integrated architectural design process to propose a "coffee-house" equipped with an innovative energy structure and envelope. For the scope, different technological solutions are designed and virtual energy modelling is implemented to simulate the performance of a building model in different climatic conditions and estimate the possible real efficacy of the proposed solutions in relation to building efficiency and cost management, as envisaged by the EU 2018/844 on the buildings' energy performance. The major result is that the developed material represents an optimum candidate to substitute traditional construction and building materials with a great manufacturing financial saving, up to 37 % for the 17.5 % SCG, and an energy improvement up to about 19 % per year, leading further saving in the yearly building management. [ABSTRACT FROM AUTHOR]

• Building performance simulation is powerful but computationally expensive. • Machine Learning (ML) surrogate models can reduce simulation times significantly. • Building energy and peak loads are predicted under different operational settings. • Extreme gradient boosting outperformed other methods. • Linear regression showed the lowest training time with competitive predictive power. Building Performance Simulation (BPS) is a powerful and widely used technique to evaluate building design and operation strategies prior to construction or retrofitting. However, BPS models often have high computational costs, which is particularly limiting for applications that require a significantly large number of simulations, such as building design optimization or uncertainty analyses. To overcome this gap, researchers have turned to surrogate modeling, where a mathematical model, such as a machine learning algorithm, is trained to mimic the performance of a BPS, allowing to test numerous building design/operation configurations at low computational costs. Past studies have applied surrogate BPS modeling to predict the impact of building design parameters on energy performance. However, few have considered building operational parameters, such as occupancy, equipment and lighting usage, and thermostat setpoints, which significantly impact energy consumption and peak loads, especially in harsh climate conditions. This paper presents a unique evaluation and comparison of machine learning algorithms as surrogates to BPS predictions of building performance (energy consumption and peak loads) under different operational settings. Results indicate that Extreme Gradient Boosting outperformed all other methods in predictive accuracy, with R2 values reaching as high as 0.99 for some models. In contrast, linear regression models were the fastest to train and easiest to interpret while still achieving competitive prediction accuracies (R2 values > 0.9). This work provides direct evidence of the machine learning surrogate models' ability to accurately predict building performance under different operational settings. It also offers unique insights into the strengths and weaknesses of white-box and black-box predictive modeling approaches and the effect of dataset size on the results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Real-time identification of occupancy and window opening using AI-powered cameras. • Occupant-centric control strategy for better thermal comfort, energy efficiency and air quality. • The heating energy consumption was reduced by between 0.6 % and 29.0 %. • The level of indoor thermal comfort increased by up to 58.8 %. • Indoor CO 2 concentrations below 1000 ppm for 89.2 % of the time being occupied. Recently, Occupant-Centric Control (OCC) strategies have gained mounting interest. Previous studies made use of OCC strategies for adjusting the operation of heating/cooling systems, improving indoor thermal comfort and governing mechanical ventilation systems. However, a very limited number of studies have applied OCC strategies to natural ventilation systems. Further, the feasibility of establishing OCC strategies for controlling indoor thermal comfort, energy use and specifically air quality has received much less attention and investigation. This paper presented an Occupant-Centric Heating and Natural Ventilation Control (OCHNVC) strategy for enhancing indoor thermal comfort, building energy performance and indoor air quality. Firstly, real-time profiles of occupant behavior and window opening in a case study building were collected using artificial intelligence (AI)-powered cameras and deep vision algorithms. Secondly, shallow artificial-neural-networks predictive models were established for forecasting the responses of the studied building to different levels of occupant behavior and window opening behavior. Thirdly, an OCHNVC strategy tailored to the studied room was proposed and applied to the studied room. The strategy could lower heating energy consumption by between 0.6 % and 29.0 % and improve the level of indoor thermal comfort by between 0 % and 58.8 %, relative to a conventional control strategy. Moreover, the conventional window control strategy only maintained indoor CO 2 concentrations below 1000 ppm for 59.7 % of the period that occupants were within the studied room, while the proposed controller could do so for 89.2 % of the period. Future works shall focus on experimentally deploying the strategy to real buildings and evaluating its performance. [ABSTRACT FROM AUTHOR]

• Energy performance certificate (EPC) to c contribute in defining a energy poverty index. • Mapping building energy poverty risks to support policy actions for tackling energy poverty. • Merging GIS tool and EPC database to obtain city energy poverty maps at city (Bologna) level. Energy poverty is defined as the condition in which low-income people is no more able to face the costs of energy bills and consequently accept to live in cold and uncomfortable houses. In recent years the scientific literature about this specific issue has registered a significant growth, despite the problem is mainly approached from an econometric point of view to which instead medical, social and energy aspects have to be coupled. Recent EU policies like the Clean Energy Package and the Energy Building Performance Directive Recast III encourage to increase the efforts to tackle and eradicate the energy poverty. The paper approaches the problem focusing on one of its complementary causes: the building energy performance. The adopted methodology includes the calculation of the energy costs for each household, the definition of the energy poverty threshold, the calculation of the related building energy performance limit, otherwise leading to the energy poverty condition. These data, associated with the energy performance certificates, are used to create a GIS based mapping of the buildings potentially affected by energy poverty. Maps can be used to support decision making process in addressing appropriate strategies at urban level to tackle the energy poverty risk. The paper includes a case study in the city of Bologna where the proposed methodology is tested. [ABSTRACT FROM AUTHOR]

• EU policy efforts on energy efficiency in buildings stared in the 1970s in response to the oil crisis. • The first comprehensive EU policy was the SAVE directive in 1992, introducing policy actions still relevant today. • A major step forward was the Energy Performance of Buildings Directive in 2002 and its subsequent amendments. • Mandatory energy performance standards are progressively converging towards near zero energy buildings. • Additional policies and financing are needed for the full decarbonisation of the building stock. The reduction of energy demand in buildings through the adoption of energy efficiency policy is a key pillar of the European Union (EU) climate and energy strategy. Energy efficiency first emerged in the EU energy policy agenda in the 1970s and was progressively transformed with shifting global and EU energy and climate policies and priorities. The paper offers a review of EU energy policies spanning over the last half century with a focus on policy instruments to encourage measures on energy efficiency in new and existing buildings. Starting from early policies set by the EU in response to the Oil Embargo in the 1973, the paper discusses the impact of EU policies in stimulating energy efficiency improvements in the building sector ranging from the SAVE Directive to the recently 2018 updated Energy Performance of Buildings Directive and Energy Efficiency Directive. The review explores the progress made over the last 50 years in addressing energy efficiency in buildings and highlights successes as well as remaining challenges. It discusses the impact of political priorities in reshaping how energy efficiency is addressed by EU policymakers, leading to a holistic approach to buildings, and provides insights and suggestions on how to further exploit the EU potential to save energy from buildings. [ABSTRACT FROM AUTHOR]

The European SHERPA project aims to share knowledge for energy renovation in buildings by public administrations. The EU Energy Performance in Buildings Directive (EPBD) recast, indicates the necessity of transforming EU buildings into Nearly Zero Energy Buildings (nZEB). Each Member State transposes differently the EPBD, usually based on European norms like Spain did. The generated knowledge about improving performance and transforming public buildings into nZEBs, is applied here to schools, according to the Spanish transposition. SHERPA, among other buildings, has audited four schools sited in the Valencia Region (Spain, Southern European Country). The paper starts describing, briefly, the general auditing protocol devised by SHERPA. Particularly, one school was chosen out of the four to illustrate the protocol and was converted into a nZEB. This school led to the most unexpected and outstanding results, although the trends were shared among all the audited schools. Finally, based on the results, the paper suggests some recommendations to the policy makers about the practical definition of nZEB and financial instruments to engage this nZEB challenge for schools. [ABSTRACT FROM AUTHOR]

• A review of simulation-aided occupant-centric building design studies is presented. • Covered themes include occupant-centric metrics, models and design practices. • Most studies focus on energy-related metrics with a lack of implementation. • Metrics related to occupant comfort, wellbeing and space planning are understudied. • Improved data collection, modeling and communication methods are recommended. Occupants are active participants in their built environment, affecting its performance while simultaneously being affected by its design and indoor environmental conditions. With recent advances in computer modeling, simulation tools, and analysis techniques, topics such as human-building interactions and occupant behavior have gained significant interest in the literature given their premise of improving building design processes and operating strategies. In practice, the focus of occupant-centric literature has been mostly geared towards the latter (i.e., operation), leaving the implications on building design practices underexplored. This paper fills the gap by providing a critical review of existing studies applying computer-based modeling and simulation to guide occupant-centric building design. The reviewed papers are organized along four main themes, namely occupant-centric: (i) metrics of building performance, (ii) modeling and simulation approaches, (iii) design methods and applications, and (iv) supporting practices and mechanisms. Important barriers are identified for a more effective application of occupant-centric building design practices, including the limited consideration of metrics beyond energy efficiency (e.g., occupant well-being and space planning), the limited implementation and validation of the proposed methods, and the lack of integration of occupant behavior modeling in existing building performance simulation tools. Future research directions are discussed, covering large-scale international data collection efforts to move from generic assumptions about occupant behavior to specific/localized knowledge, improved metrics of measuring building performance, and improved industry practices, such as building codes, to promote an occupant-in-the-loop approach to the building design process. [ABSTRACT FROM AUTHOR]

• An overall panorama of the school buildings in Brazil was presented. • Energy billed data and survey evidence were used to build a statistical stock model. • The Weibull distribution was the most adequate to represent the continuous variables. • kWh/student·year was more suitable than kWh/m2·year to model Brazilian school buildings stock. • Thermal performance is an issue to be greatly improved in schools in Brazil. Understanding the actual conditions in school buildings regarding energy usage and environmental satisfaction gives way to the development of consistent building stock modelling. In the Brazilian context, a deep-rooted inefficient structure of energy management implies a lack of mapping the actual conditions of the public schools. Therefore, this paper aimed to assess the actual energy performance of school buildings in Brazil. This paper innovates by integrating questionnaire responses and billed energy data to allow the construction of an evidence-based stock model through a statistical approach, which was never performed for the Brazilian building stock. Moreover, the association of energy use intensity (EUI) with the core aspects of building characteristics, occupancy, environmental satisfaction and necessary improvements mapped the relevance of such aspects in energy usage patterns. Additionally, a discussion of the EUI indicators was addressed. Results showed an unprecedented broad panorama of the school building stock in Brazil and its main features. In terms of statistical analysis, the Weibull distribution was appropriate for representing the continuous variables of the stock. The EUI as a function of the number of students was more suitable than the floor-plan area to achieve a reliable energy performance analysis. Several tests were performed to assess if the energy management, environmental satisfaction and maintenance practices impacted the EUI or not. Finally, the main conclusion was that the stock model obtained was simple and fit the energy management structure in the Brazilian scenario. [ABSTRACT FROM AUTHOR]

This paper reports the investigation of the correlation of building energy use intensities, estimated by six building performance simulation programs and, based on findings, establishes formulas for conversion of each program to another in selected simulation tools. The data used for the analyses was collected from 15 residential projects and 180 simulation runs in two construction modes: as-built and code compliance (California's Title 24 Standard), using six different simulation tools. The data set included heating and cooling energy use intensities, multiple building attributes, and climate conditions. The results were compared by various program combination sets to analyze and determine the correlation of estimated energy use intensities (EUIs). The statistical analysis of the collected data revealed that heating EUI conversion formulas were more robust than those of cooling EUIs, and a project case generating moderate or high EUIs generated lower error rates than that with low EUIs. Since building energy performance always generates significant discrepancies, depending on the simulation tools adopted, the outcome of this study will help building performance stakeholders understand the estimated energy performance of one tool as compared to that of another. The result will also be helpful for designing a high performance building without a technical mishap. [ABSTRACT FROM AUTHOR]

This paper evaluates the potential for use of building information modelling (BIM) as a tool to support the visualisation and management of a building's performance; demonstrating a method for the capture, collation and linking of data stored across the currently disparate BIM and building management system (BMS) data environments. Its intention is to identify the barriers facing implementation of BIM for building designers and operators as a performance optimisation tool. The method developed links design documentation and metered building performance to identify the technological requirements for BIM and building performance connection in a real-world example. This is supplemented by interviews with designers and operators identifying associated behavioural and methodological challenges. The practicality of implementing BIM as a performance management tool using conventional technologies is established, and recognises the need for more effective data management in both design and operation to support interlinking of these data-rich environments. Requirements for linking these environments are proposed in conjunction with feedback from building designers and operators, providing guidance for the production and sourcing of data to support building performance management using BIM. [ABSTRACT FROM AUTHOR]

According to the Directive (2010/31/EU), the main goal in the energy performance of buildings, especially for achieving longer-term objectives in the energy saving, is achieving Nearly Zero-Energy Buildings (NZEBs). Thus, this plan can be achieved by refurbishing of existing or by constructing new buildings to satisfy NZEB requirements. Nowadays, refurbishment of existing buildings to satisfy NZEB requirements becomes one of the major aim in construction. In solving this refurbishment problem, Multi-Attribute Decision Making (MADM) methods help here to evaluate existing state of buildings and to compare them with optimal alternative, which equals to NZEB. This comparison allows selecting optimal refurbishment methods to achieve NZEB requirements. However, existing MADM methods do not applied to compare existing alternatives (i.e. buildings) with the optimal alternative (i.e. NZEB), which is based on standards and laws. Usually existing researches present comparison of selected alternatives among each other or with the best alternative from compared, like in the TOPSIS or ARAS methods. Therefore, in this paper, we analyse the concept of a Passive house and NZEB and its applicability in Lithuanian standards and, respectively, define the optimal alternative (i.e. an optimal building). Second, we analyse possibility of extending existing MADM methods to be MADM optimal (MADM-opt). Moreover, we present several modifications how to transform WASPAS, ARAS and TOPSIS by adding optimal alternative. The modified methods were applied for evaluation of 13 apartments. The results show that MADM-opt is useful for the assessment of alternatives and their evaluation according to the optimal alternative. Moreover, it allows determining difference between the assessed alternatives and the optimal alternative. [ABSTRACT FROM AUTHOR]

This is the second part of the paper “Simplified method for shading-loss analysis in BIPV systems”. The objective of Part 2 is to apply the simplified method described in Part 1 in order to estimate the influence of partial shadings on the performance of four installed and in operation BIPV systems. The method consists in identifying and quantifying the shading on a surface, relating the fraction of shaded area with the percentage of incident irradiation reduction during the same period, in order to propose a shading index (SI) that represents the energy losses on partially shaded PV systems. SI was validated through the analysed case studies and it was proved to be a convenient way of estimating the PV generation of partially shaded PV systems. This method is independent from the electric configuration and can be used for already installed PV systems, or surfaces under investigation for PV installations, both through manual calculations and also through calculations using dedicated software packages. [ABSTRACT FROM AUTHOR]

Lighting energy savings, as well as visual and non-visual user benefits have been widely attributed to daylighting. This paper explores daylight design strategy, visual appraisal, Daylight Factor (DF), lighting energy usage and discomfort glare using two green building offices in Malaysia, which have incorporated daylighting into both façade and interior design. Visual appraisal surveys were collected from 39 and 145 subjects in the open plan working space of the Energy Commission Building (ECB) and Public Works Department Block G (PWD), respectively. The survey focused on task brightness, colour appearance, uniformity and lighting preference. Discomfort glare assessed via occupant point-of-view luminance maps was juxtaposed here from a glare study involving the same buildings. Illuminance loggers were used to monitor artificial lighting usage as well as the DF on a selected floor of each building. There were no significant differences in occupant responses to the visual appraisal survey for both office spaces. Using MS1525:2014 and Green Building Index (GBI NRNC) tool as baselines, the DF performance of both offices differs significantly: PWD had a 45.5% daylit area, with ECB a 14.8% daylit area for DF >1%. However, lighting energy usage results show substantial savings of 53% and 41% occurred from daylighting. These findings of visual appraisal, DF, lighting energy savings and discomfort glare show a discrepancy in using only the DF to justify the daylight performance of an office space in a tropical climate such as Malaysia. The findings suggest that equivalent consideration should be given to interior design to facilitate daylighting, which is often beyond the control of designer, but in the hands of office end users. [ABSTRACT FROM AUTHOR]

Integration of CCHP systems into large buildings provides considerable advantages, as far as the economy, energy consumption and environment related issues are concerned. In this paper, the integration of a hybrid CCHP system into a commercial building is studied. The hybrid CCHP system consists of a renewable and a non-renewable CHP component, photovoltaic/thermal (PV/T) panels and internal combustion engine (ICE). Three objective functions are considered based on cost saving, energy saving and emission reduction goals where are determined as annual operating cost ratio (AOCR), primary energy saving ratio (PESR) and carbon emission reduction ratio (CERR). Considering each objective function, the GA optimization is applied in three different approaches as a single objective optimization problem to find the best size of the system components. Then, using Analytic Hierarchy Process (AHP), which is one of the most used Multi-Criteria Decision Making (MCDM) procedures, the most profitable answer is determined from the three answers achieved in the optimization process. The results showed a good performance of the system. In PESR optimization, which is selected as the best system size, values of 32.96%, 17.25% and 14.79% was achieved for AOCR, PESR and CERR, respectively. [ABSTRACT FROM AUTHOR]

Ultra-lightweight concrete (ULWC) was recently introduced as a novel building material that combines moderate thermal insulation properties with load-bearing capacity. Its intended use as monolithic building envelope brings new opportunities in building physics, by merging characteristics of both heavyweight and lightweight construction types. This paper investigates the potential of ULWC building envelopes in terms of energy efficiency and thermal comfort. The dynamic thermal characteristics of a monolithic structure of ULWC were first compared to more conventional constructions using EN-ISO-13786 calculation methods. The main contribution of this article lies in the subsequent development and application of a simulation strategy for predicting the energy and comfort performance of ULWC on the whole-building level. The quality of the simulations in EnergyPlus was first ensured in an analytical validation study, and then applied to assess the performance of ULWC for commercial and residential case studies in the Netherlands. Results show that ULWC constructions are comparable to heavyweight buildings in long-term behaviour, whereas they resemble the performance of lightweight building envelopes for short-term heating periods. ULWC can therefore be a suitable construction type in buildings with intermittent operation, but in other cases it can get outperformed by conventional constructions with low or high thermal mass. [ABSTRACT FROM AUTHOR]

Egyptian electricity demands have increased in recent years and are projected to grow further with significant economic and social impacts. Recently, mandatory and voluntary building codes based on international standards have been increasingly adopted. The performance of existing Egyptian buildings is not well understood making the impact of these new codes uncertain. This paper aims to provide insights into existing Egyptian building performance, and elaborate a process for developing a representative model to assist in future policy. The work presented is for office buildings but intended to be widely replicable. An energy survey was carried out for 59 Egyptian offices, categorised by building service type, it was observed that energy use increases as building services increase, and existing Egyptian offices use less energy than benchmarks. A more detailed investigation for a case study office was carried out, to inform detailed model calibration. This provided insight into energy use, thermal comfort and environmental conditions, and revealed high variability in behaviours. A calibrated model was created for the case study office, then a baseline model and input parameter sets created to represent generalised performance. Future uses including assessment of the impact of codes are discussed, and further replication potentials highlighted. [ABSTRACT FROM AUTHOR]

In this paper, we present a hierarchical Bayesian approach to model human interactions with motorized roller shades and dimmable electric lights. At the top level of hierarchy, Bayesian multivariate binary-choice logit models predict the probability of shade raising/lowering actions as well as the actions to increase the level of electric light. At the bottom level, Bayesian regression models with built-in physical constraints estimate the magnitude of actions, and hence the corresponding operating states of shading and electric lighting systems. The models are based on a dataset from a field study conducted in private offices designed to facilitate a large number of participants and to collect data on environmental parameters as well as individual characteristics and human attributes governing human-shading and – electric lighting interactions. In this study, models were developed only for arrival periods due to the low frequency of actions during intermediate time intervals with continuous occupation. Our modeling framework demonstrates the advantages of the Bayesian approach that captures the epistemic uncertainty in the model parameters, which is important when dealing with small-sized datasets, a ubiquitous issue in human data collection in actual buildings; it also enables the incorporation of prior beliefs about the systems; and offers a systematic way to select amongst different models using the Bayes factor and the evidence for each model. Our findings reveal that besides environmental variables, human attributes are significant predictors of human interactions, and improve the predictive performance when incorporated as features in shading action models. [ABSTRACT FROM AUTHOR]

The hollow block ventilated wall is a new kind of ventilated wall, the exhaust air of HVAC system is used as the supply air to flow through the cavity of this wall in this paper. The heat or cool storage in the wall is reduced by using the heat recovery technology; the temperature of internal surface is lowered in summer and increased in winter, and the human thermal comfort is enhanced. A semi-dynamic heat transfer model of the ventilated wall is presented for thermal performance prediction. The dynamic optimized resistance-capacitance (ORC) model and the number of transfer units (NTU) model are joined together to develop the semi-dynamic heat transfer model of this ventilated wall. The experimental study is carried out for validating the semi-dynamic heat transfer model. The maximum relative error is 4.3% for mean internal and external surface temperatures, and it is 2.6% for the outlet air temperature of the cavity. The heat transfer model established for hollow block ventilated wall is fairly reasonable and possesses high accuracy. This model can be used to predict the surface temperature of the hollow block ventilated wall and the heat flux removed by the airflow in the cavity for performance evaluation. [ABSTRACT FROM AUTHOR]

With the growing concern of global climate change in the future, how building energy use pattern would change in response is of great interest and importance in drafting future building performance regulations and codes. In this paper, the outputs from global climate model (GCM) are integrated to typical meteorological year weather file to downscale and predict local hourly weather data in the context of U.S. climate regions using a “morphing” methodology. The “morphed” future hourly weather data is then used by EnergyPlus to predict future energy use pattern for residential building in the United States. Case studies in four representative cities in the U.S. show that climate change is to have great impacts on residential and office building energy use during the year of 2040–2069. The change of annual energy use is predicted to range from −1.64% to 14.07% for residential building and from −3.27% to −0.12% for office building under A2 scenario (a carbon emission scenarios defined by IPCC) in different regions. The research results suggest that the climate change will narrow the gap of energy use for residential buildings located in cold and hot climate regions in the U.S. and generally reduce office building energy use in the future. It is also found that the energy use of lightings and fans will slightly decrease in the future. Moreover, the growing peak electricity load during cooling seasons is going to exert greater pressure for the future grid. [ABSTRACT FROM AUTHOR]