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In hot and humid climate such as in Japan and south east Asia, dehumidification in summer is really important for air conditioning. Temperature and humidity independent control (THIC) of air conditioning system can handle sensible heat and latent heat separately, and provide good indoor environment and achieve energy conservation. Desiccant air handling unit is one of the major solution for THIC of air conditioning system. It needs hot water to regenerate sorbent which absorbs moist in the air. Combined heat and power can supply hot water at almost constant temperature for desiccant air handling system and also contribute to the business continuity plan of commercial buildings. However, there are still uncertainties about the factors which affect energy performance of desiccant air handling unit and the optimum design and operations in hot and humid climate. The objectives of this paper are to prove factors which affect energy performance of desiccant air handling unit by measurement analysis and show optimum condition of the desiccant air handling unit under various room conditions by simulation. Measurement analysis shows that energy performance of desiccant air handling unit depends not only on the inlet air condition to dehumidification wheel but also on designed supply air humidity. Furthermore, simulation results show the optimum inlet air condition entering dehumidification wheel under various supply air absolute humidity which is determined by design room conditions. These results provide useful information of desiccant air handling unit during design and operation phase of buildings in hot and humid climate. [ABSTRACT FROM AUTHOR]

The paper is an addendum to the paper entitled “Ancient vernacular architecture: characteristics categorization and energy” that was published at “Energy and Buildings” in 2010 [1] . This addendum provides an explicit list of 114 codes representing vernacular architectural regions across the whole globe defined by climate, culture and continent. Codes are intended to support work in analyzing and memorializing vernacular building characteristics that otherwise may be lost. This addendum will be an important and useful resource for analyzing and studying vernacular architecture. [ABSTRACT FROM AUTHOR]

The increase in global environmental concerns as well as the advancement of computational tools and methods have had significant impacts on the way in which buildings are being designed. Building professionals are increasingly expected to improve energy performance of their design. To achieve a high level of energy performance, multidisciplinary simulation-based optimization can be utilized to help designers in exploring more design alternatives and making informed decisions. Because of the high complexity in setting up a building model for multi-objective design optimization, there is a great demand of utilizing and integrating the advanced modeling and simulation technologies, including BIM, parametric modeling, cloud-based simulation, and optimization algorithms, as well as a new user interface that facilitates the setup of building parameters (decision variables) and performance fitness functions (design objectives) for automatically generating, evaluating, and optimizing multiple design options. This paper presents an integrated framework for building information modeling (BIM)-based performance optimization, BPOpt. This framework enables designers to explore design alternatives using an open-source, visual programming user interface on the top of a widely used BIM platform, to generate models of building design options, assess the environmental performance of the models through cloud-based simulation, and search for the most appropriate design alternatives. This paper details the process of the development of BPOpt and also provides a case study to show its application. The case study demonstrates the use of BPOpt in minimizing the energy consumption while maximizing the appropriate daylighting level for a residential building. Finally, strengths, limitations, current adoption by academia and industry, and future improvements of BPOpt for high-performance building design are discussed. [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]

This paper presents the development of a symbolic transformation based strategy with interpretability and visualisation for building energy performance assessment. The strategy was developed using shape definition language based symbolic transformation and hierarchical clustering. Advanced visualisation techniques including dendrogram, heatmap and calendar view were used to assist in understanding building energy usage behaviours. A comparison of this proposed strategy with a Symbolic Aggregate approXimation (SAX) based strategy was also performed. The performance of the proposed strategy was tested and evaluated using the three-year hourly heating energy and electricity usage data of a higher education building. The result demonstrated that the proposed strategy can identify distinct building energy usage behaviours. The visualisation techniques used also assisted the information discovery process. The discovered information helped to understand building energy usage patterns. The comparison of the proposed strategy with the SAX based strategy showed that the proposed strategy outperformed the SAX based strategy for the case building tested in terms of the variations in building energy usage. This proposed strategy can also be potentially used to evaluate the operational performance of building heating, ventilation and air-conditioning (HVAC) systems. [ABSTRACT FROM AUTHOR]

The present paper describes a holistic energy efficient retrofit of low income multiple social housing located in Athens, Greece. A holistic analysis was conducted in order to determine the optimum retrofit plan that includes innovative and state of the art commercially available technologies, passive techniques as well as renewable energy sources, aiming to reduce its energy consumption and carbon footprint, improve indoor environmental conditions and be cost effective at the same time. An extensive experimental campaign including air leakage measurements, thermal imaging, energy consumption and indoor environmental quality measurements was conducted before and after the implementation of the retrofit. In addition, advanced building simulation, occupant surveys and socioeconomic analyses were performed in order to evaluate the impact of the retrofit and estimate specific performance indicators. [ABSTRACT FROM AUTHOR]

Abstract: This paper analyzes the operating principle and the advantages of the parallel-type hybrid-power gas engine-driven heat pump system (PHGHP) and builds test systems to test the performance of the system in the heating conditions and cooling conditions. PHGHP used heat pump system's cooling capacity, heat capacity, fuel-consumed flow, fuel consumed-rate, thermal efficiency and reclaimed heat as the economic analysis parameters. In addition, this paper puts forward the concept of the equivalent fuel-consumed flow and the equivalent output power of engine. The test results show, the speed and torque of gas engine which used the baseline control strategy and combined with a gas engine optimization curve control strategy are always in the designated economic. Fuel-consumed flow changes in 280–340g(kWh)−1. With compressor speed increasing, the drive system thermal efficiency is maintained between 0.23 and 0.28. [Copyright &y& Elsevier]

Abstract: In the last years many studies concerning the evaluation of the thermal conductance of building elements via measurements have been carried out; this value has to be ensued from the analysis of recorded temperature and heat flux profiles. The determination of this property in situ would allow a more accurate a more accurate evaluation of the real heating energy demand of a building. Papers discussing different data analysis methods are present in literature and measurements on test components under real conditions and evaluations on different theoretical aspects by means of numerical simulations have been already developed. This paper aims at widening the existent literature of the in situ evaluation of the thermal conductance, through the discussion of the results of a measuring campaign which lasted four years on real buildings, and by comparing the reference specific thermal conductance (C) values with those computed on the basis of the measurements. Various tests on the same elements are discussed. Finally an analysis on the influence of the C value on the evaluation of the net heating energy demand of a building in different climates is presented. [Copyright &y& Elsevier]

Abstract: Recent results show that a predictive building automation can be used to operate buildings in an energy and cost effective manner with only a small retrofitting requirements. In this approach, the dynamic models are of crucial importance. As industrial experience has shown, modeling is the most time-demanding and costly part of the automation process. Many papers devoted to this topic actually deal with modeling of building subsystems. Although some papers identify a building as a complex system, the provided models are usually simple two-zones models, or extremely detailed models resulting from the use of building simulation software packages. These are, however, not suitable for predictive control. The objective of this paper is to share the years-long experience of the authors in building modeling intended for predictive control of the building''s climate. We provide an overview of identification methods for buildings and analyze their applicability for subsequent predictive control. Moreover, we propose a new methodology to obtain a model suitable for the use in a predictive control framework combining the building energy performance simulation tools and statistical identification. The procedure is based on the so-called co-simulation that has appeared recently as a feature of various building simulation software packages. [Copyright &y& Elsevier]

Abstract: Although absorption cooling has been available for many years, the technology has typically been viewed as a poorly performing alternative to vapour compression refrigeration. However, rising energy prices and the requirement to improve energy-efficiency is driving renewed interest in the technology, particularly within the context of combined cooling, heat and power systems (CCHP) for buildings. In order to understand the performance of absorption cooling, numerous models are available in the literature. The complexities involved in the thermodynamics of absorption chillers have, however, so far restricted researchers to creating steady-state or dynamic models reliant on data measurements of the internal chiller state, which require difficult-to-obtain, intrusive measurements. The pragmatic, yet fully dynamic model described in this paper is designed to be easily calibrated using data obtained from the measurements of inflows and outflows to a chiller, without resorting to intrusive measurements. The model comprises a series of linked control volumes featuring both performance maps and lumped mass volumes, which reflect the underlying physical structure of the device. The paper describes the modelling approach, theory and limitations, along with an example of the implementation of the model in the ESP-r code complete with calibration and an application to a specific example. [Copyright &y& Elsevier]

Abstract: This paper compares several different simplified methodologies for building energy performance assessment during winter time selected based on its large application and/or its user friendly characteristics. Hourly values for energy demand are calculated by a detailed comparison tool based on hourly weather data. A simplified building procedure spreadsheet to evaluate energy demand is also presented. It gives reliable results, needs only a little input data to describe the building design and low time consumption. The spreadsheet is therefore useful for preliminary design tasks in the early design stages where rough estimates of the building design and preliminary energy use are needed for primary decision support. The method is based on a seasonal heating calculation of heat losses and usable heat gains for the building, where the heat-accumulating capacity of the building is considered. The seasonal mean values of the solar radiation and degree days are applied. This paper describes the applied calculation technique and the assumptions made to carry out heating calculation. [Copyright &y& Elsevier]

Abstract: Photovoltaic (PV) connected systems are experiencing rapid market growth. This is due to the continually downward trend in PV cost together with government support programs. A scenario has been assumed to analyse the geographical market of PVs. The results provide clear evidence of the influence that some variables have on the profitability of PV investments. This study presents a model for minimising investment risk and maximising the return of a renewable energy portfolio in Italy. The value of the paper is in showing that the energy and CO2 reduction potential that can be reached through consumer-oriented policy measures, but the paper also looks at the effectiveness and social implications of such measures. Private households possess immense unused potential for energy reductions (and climate protection) that could be realised through gains in energy efficiency, behavioural changes, and extended use of low-emission energy. The focus of energy policy has been on businesses rather than on private households, which are only partly captured by direct policy measures. To achieve the goals of climate policies, the current political and scientific discussion increasingly considers measures that aim to reduce energy consumption in the private sector. Quantitative estimates are presented for economic indicators and will show the various effects of policy measures on the implemented household types. [Copyright &y& Elsevier]

Abstract: The microclimate around a building, establishing through the interaction with other buildings or the natural environment, is a significant factor in the building energy consumption. This paper presents a method for the quantitative analysis of building energy performance under any given urban contexts by linking the microclimate model ENVI-met to the building energy simulation (BES) program EnergyPlus. The full microclimatic factors such as solar radiation, long wave radiation, air temperature, air humidity, and wind speed have been considered in the proposed scheme. A case study has been conducted to analyze the effects of different microclimatic factors on the energy balance of an individual building. The method outlined in this paper could be useful for urban planning and building design. [Copyright &y& Elsevier]

The area of projected shadow on building facades may play a role of paramount importance in the prediction of solar energy conversion and building thermal and energy performance. Algorithms for solar shading calculations may directly affect the accuracy of results obtained by building energy simulation tools. In addition, the consideration of uncertain design parameters imply an estimative of a confidence interval of solar fraction results that determine the reliability as well as the improvement of shading calculation models. In this way, this paper presents a methodology for uncertainty and sensitivity analysis applied to the prediction of sunlit area on building exterior surfaces with shading devices. From a single building model, the solar fraction was investigated for two cities and four typical days. According to the obtained results, more than 20% of all simulation time steps have uncertainties equal or higher than 5% on the solar fraction calculation at 95% confidence level. The maximum values of the uncertainties occur in warmer months, which could significantly impact the building energy balance. Three inputs have higher influence on the uncertainties on solar fraction results: (1) latitude, (2) orientation and (3) width of overhang fins. Perturbation of only 5° on the building orientation may imply important uncertainties on solar fraction, which is normally neglected by designers. The results highlight the importance of assessing the uncertainty of inputs in algorithms such as the one to calculate the surface solar fraction that is an important prerequisite of the final building energy balance. [ABSTRACT FROM AUTHOR]

Energy-efficient buildings, made of ecologically acceptable materials, are result of a worldwide ecological awareness induced by ever growing concern in regard to climate changes and economic aspects of long term energy savings. Complexities regarding energy-efficiency, economy and traditional construction of residential family homes led to acceptance of new building materials and forming of several typical wall types in south-eastern European region. This paper offers an energy performance analysis and a life cycle assessment of three common outer wall types: prefabricated timber-frame, an aerated autoclaved concrete and a solid brick wall with two model heating regimes. In order to verify energy and environmental performance of each wall type in a complete building, a detached house model was determined with the same parameters used for comparison. Model performances were determined for the selected life cycle stages and system boundaries during an eighty year period taken as a service life of family houses and compared to conventional and passive houses performances found in literature. Analysis results show that the model with aerated autoclaved concrete wall has the best environmental performance and that model with masonry brick walls has the best thermal performance in discontinuous heating mode of the three analysed walls. [ABSTRACT FROM AUTHOR]

Evaluation methods can be used to determine what constitutes good energy performance in a building. With an increasing focus on energy use of buildings worldwide, this evaluation assumes a fundamental importance. This paper provides a comprehensive review of the available methods for analysing, classifying, benchmarking, rating and evaluating energy performance in non-domestic buildings. Methodologies are grouped in five categories: engineering calculations, simulation, statistical methods, machine learning and other methods. Techniques for evaluating buildings are described, their principal applications are shown and limitations are identified. The use of performance evaluation in energy efficiency programmes and standards is mapped. There is a need to further develop interactions between the main modelling techniques to produce simple, robust and validated models. Also, evaluation techniques must be developed to consider comfort or service provision in the buildings as a factor in energy performance. [ABSTRACT FROM AUTHOR]

The paper describes a study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. To evaluate thermal performance and energy consumption, simulations were carried out using FLUENT and EnergyPlus software, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building using a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a Dedicated Outside Air System (DOAS) was used as an alternative to Fan Coil Unit (FCU) that was installed in conjunction with the radiant cooling system. A comparison of energy consumption calculated that the radiant system was 17.5% more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. The Computational Fluid Dynamics (CFD) simulation showed that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. [ABSTRACT FROM AUTHOR]

Highlights: [•] The paper proposes an approach which is easier to implement. [•] The model based on fuzzy ANP is under linguistic variables. [•] Seven criteria are used to evaluate and label buildings. [•] These criteria are location and climate data, geometrical shape, building envelope, mechanical systems, lighting system, hot water system, renewable energy and cogeneration. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a theoretical model of a concentrating photovoltaic thermal (CPV/T) system is presented in order to size it and to evaluate its thermal and electrical performance when it is used to satisfy the electric, heating and cooling loads referring to a domestic application. First of all choice and sizing of the CPV/T system components are considered. The reflective optics with parabolic mirror concentrators of point-focus type and the triple-junction cells (InGaP/InGas/Ge) assembled with a dual axis tracker are used to obtain a high concentration system. An active cooling system of the photovoltaic cells is considered. In order to satisfy the cooling load, the CPV/T system allows to recover thermal energy at high temperature for the absorption heat pump working. The model analyzes the CPV/T system working for different time levels (yearly, monthly, daily, hourly) in terms of direct normal irradiance, cell efficiency, module electric and thermal efficiency, thermal and electric energy provided by cell and module, cell and cooling fluid temperatures. The simulation process has allowed to define the best configuration of the CPV/T system under different working conditions and to evaluate the energy and economic convenience of the CPV/T system in comparison with a traditional system. [Copyright &y& Elsevier]

Abstract: This paper aims to validate and improve three cross and single-sided natural ventilation models implemented in a whole-building hygrothermal and energy simulation program. The tested models are the British Standard for cross ventilation, the de Gids and Phaff's and Larsen's for single-sided ventilation. Airflow rates obtained by those models have been compared to the measurements performed in two full-scale buildings: one single room house located in a wind tunnel facility and one real three-storey building. Results show a large variation of airflow rates provided by the different models. The Larsen's model can be improved if coupled to the CPCALC algorithm, providing better results for both wind tunnel and on-site experiments. [Copyright &y& Elsevier]

Abstract: Building managers have specific duties and certain outputs that are required of them. Without the necessary data, information, tools, and time, they are unable to adequately meet their organisational goals. Scenario modelling enables explicit and unambiguous coupling of building functions with other pivotal aspects of building operation in a method that specifically considers the education and technical expertise of building managers. This new method captures, transforms, and communicates the complex interdependencies of environmental and energy management in buildings through an easily navigable, holistic, and reproducible checking mechanism that compares actual performance with predicted performance and completes the “plan-do-check-act” cycle for building managers. Most important, the structured nature of this method caters to the diverse profile of building managers, making it applicable for widespread deployment. This paper demonstrates the benefit of using the new method by examining its application to a performance analysis of two existing buildings. [Copyright &y& Elsevier]

Abstract: In the tropics, daylighting from a side window requires shading to intercept direct sunlight from the window whilst allowing penetration of daylight from sky. In this paper, daylighting from a double-pane glazed window with enclosed horizontal slats (slat window) was investigated for which it is situated on either north or south wall of a room. Full-scale experiments and simulations were conducted to characterize distribution of the interior daylight from the slat window under a real tropical climate. Performance of the slat window was evaluated in terms of the “useful daylight illuminance” (UDI), interior daylight availability and light power density (LPD) of an integrated dimmable lighting system. Empirical formulas were developed for determining annual average LPD values of the dimmable lighting system over its served area. The LPD value can be used with a reduced form of the energy equation of Thailand's building energy code to evaluate the reduced annual electrical energy consumption for accreditation of the daylight use in a building. The analysis of life cycle cost proved that the daylighting from the slat window integrated with the dimmable lighting system is cost effective. [Copyright &y& Elsevier]

Highlights: [•] This paper reviews available hybrid liquid desiccant air conditioning system technologies. [•] We cover relevant information such as configurations, and the performances. [•] We focus on the hybrid liquid desiccant with vapor compression system. [•] Conclusions and some important suggestions are presented. [Copyright &y& Elsevier]

Abstract: This paper presents a novel thermoelectric radiant air-conditioning (TE-RAC) system, which employs the thermoelectric modules as radiant panels instead of conventional hydronic panels. The novel radiant system brings a lot of benefits including Freon free, convenient installation, no complex water distribution pipes, quiet and reliable operation, etc. Switching between cooling and heating modes can be easily achieved by reversing the input current. The purpose of this study is to investigate the feasibility and performance of the novel TE-RAC system, including its cooling and heating performances, condensation risk, dynamic thermal response and inertia, and cost-effectiveness. A case study of the TE-RAC system is presented to compare the TE-RAC system with conventional air-conditioning (AC) systems and radiant air-conditioning (RAC) systems in terms of cooling and heating capacities, energy consumption and operation reliability. It is found that the COP of the TE-RAC system could be comparable to conventional RAC systems and AC systems, besides many other benefits in life-cycle performances. [Copyright &y& Elsevier]

Abstract: The possibility of storing thermal energy within the building structure to reduce building energy consumption has been studied. Hollow core panels used for a building structure are able to pass air through core cavities and be utilized as thermal storage. Previously, thermal storage models for ventilated slab system using the panels have been developed but it has typically focused on the system development and performance evaluation under particular conditions. As a result, it has been difficult to understand the effect of the system on whole building energy performance. This study develops a computational model for a ventilated slab system and investigates its implementation in a whole building energy simulation program, EnergyPlus. The system has two major components: an auxiliary air handling unit (AHU) and a radiant slab with hollow core panels. The auxiliary AHU includes an outside air mixer, coils, and a fan to produce either conditioned or unconditioned air depending on the user''s input. The air is then controlled by a defined delivery method, after passing through the cavity of the panel. This paper illustrates the new model development for the building energy simulation program and provides some evaluation with an existing model from another study. [Copyright &y& Elsevier]

Abstract: Nowadays, dynamic analysis of air-conditioner units is essential to achieve satisfactory comfort conditions in buildings with low energy consumption and operation cost. In this paper, a nonlinear multi input–multi output model (MIMO) of an air-handling unit (AHU) is considered. In the presence of realistic harmonic disturbances, nonlinear dynamics of AHU is investigated. The effect of various thermodynamics and geometrical parameters on limit cycles behaviour of the indoor temperature is investigated. It is observed that the indoor space volume plays as the bifurcation parameter of the system. Decreasing the indoor space volume leads to the occurrence of secondary Hopf (Neimark) bifurcation and consequently the unstable quasi-periodic solution of the indoor temperature. To overcome this problem, a multivariable control strategy based on feedback linearization approach is implemented, in which the air and cold water flow rates are the control inputs while the indoor temperature and relative humidity are the control outputs. It is shown that the designed controller guarantees the comfort indoor conditions by preventing the unstable quasi-periodic responses and improving the limit cycles behaviour. [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: Energy and comfort management is the major task for a building automation system. As a trend of next-generation''s commercial buildings, intelligent buildings are capable of facilitating intelligent control of the building to fulfill occupants’ needs. Since occupants’ behaviors have a direct impact on the system performance, the building should be able to interact with occupants by responding to their requests and obtaining feedbacks based on their behaviors. In this paper, a multi-agent based intelligent control system is developed for achieving effective energy and comfort management in a building environment. The developed multi-agent system turns out to be capable of facilitating the building to interact with its occupants for realizing user-centered control of buildings. [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: Building energy performance assessment is crucial to ascertain the efficiency of energy use in buildings and is the basis to make any decision for enhancing energy efficiency. In order to assess the energy performance of existing buildings quantitatively, the energy use of the assessed buildings should be quantified first. The quantified energy use will be then used to compare with the assessment criteria to determine the energy performance quantitatively. This paper presents an overall review on the state of the art of the research and applications of quantitative energy performance assessment. A framework is proposed for categorizing the energy quantification methods and performance benchmarking methods for energy performance assessment for existing buildings. Energy quantification methods are classified into three categories, i.e. the calculation-based, measurement-based and hybrid methods, according to the energy data acquisition approaches. Energy performance assessment methods are classified according to the assessment scope and depth of assessment, i.e. whole-building benchmarking method at building level and multi-level assessment method. [Copyright &y& Elsevier]

Abstract: The commercial building sector has become the focus of many governmental energy reduction initiatives to achieve more sustainable development. Reducing building energy use starts by improving the design of buildings. To this end, energy modeling and simulation tools are used during the design phase to predict energy use and help designers choose and size the different building systems. Large discrepancies are however being observed between predicted and actual building energy performances. In order to determine the sources of errors and improve these predictions, the sensitivity of energy models to different input parameters needs to be evaluated. Studies in literature have extensively evaluated the sensitivity of models to the buildings’ technical design parameters. However, none considered the parameters related to the energy consumption behavior of occupants, leaving their impact on energy modeling unknown. This paper presents a comprehensive sensitivity analysis study performed on the occupancy behavioral parameters of typical office buildings of different size and in different weather zones. Significant sensitivity levels were observed, varying according to both building size and weather conditions. The highest sensitivity was obtained when varying the ‘heating temperature set point’ parameter in small-size buildings located in US weather zone 2 Dry. [Copyright &y& Elsevier]

Abstract: This paper presents a simplified energy performance assessment method for existing buildings in cooling season, which is based on energy bill disaggregation and energy performance analysis. This method requests very limited building energy data and can effectively assess the energy performance at building and system levels, and disaggregate the whole-building consumption into consumptions of three groups of end-uses. This method is based on two basic energy balance principles, i.e., the electricity consumption balances at building level and the cooling energy balances between demand side and supply side of HVAC systems. An optimization algorithm is developed to establish best possible cooling energy balances by minimizing the balance residuals and therefore to disaggregate the energy consumption of different users. The performance of the proposed method was validated in two existing buildings in Hong Kong and Beijing. The results, including the disaggregated energy consumptions and the key energy performance indicators of HVAC system, agreed well with the “measured” data in mechanical cooling months. [Copyright &y& Elsevier]

Abstract: In-home displays (IHDs) have the potential to change the way energy use feedback is communicated to householders and to induce behavioural change by providing real-time information on energy consumption. How feedback is presented to users and how users understand the meaning of such feedback depends on the design of the display interface. This paper presents a laboratory study to investigate how the user interface of energy displays might be best designed. The work studied people''s ability to spot changes in smart meters by comparing three different types of display design to see which was most effective in attracting attention to changing information, and whether the use of colour would also facilitate detecting changes. A computerised spot-the-difference task was undertaken; accuracy rates and response times were the key dependent variables, and qualitative information on participant preferences was gathered in interviews after the computerised task. Results showed that there was a difference between design types presenting the same information: simple numerical displays were superior to pictographic or analogue scale designs in both response time and accuracy. They also showed that the use of colour did not significantly affect performance. In general, participants also subjectively preferred numerical design for their in-home energy displays. [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: This paper presents an investigation into the use of occupancy space electrical power demand to mimic occupants’ activities in building cooling load prediction by intelligent approach. The occupancy space electrical power demand is obtained from an intelligent networked building power monitoring system. It works as a prototype advanced metering infrastructure – a key feature in smart grid technology. The artificial neural network model adopted is the Levenberg–Marquardt algorithm. The input parameters include the usual external climatic data, hour-type/day-type and pretreated air unit operation schedule, and the occupancy space electrical power demand. The output is the electrical power demand of the building cooling system. Simulation studies are conducted for a university building in Hong Kong. The 2010 and 2011 yearly data is used to conduct simulations. The performance indices used in evaluating the prediction performance are the coefficient of correlation (R), coefficient of variation (CV) and mean absolute percentage error (MAPE). It is demonstrated that with the use of occupancy space electrical power demand as one of the model input parameters, the prediction accuracy of the building cooling load model can be improved. In summer season, the best MAPE and CV is 4.494% and 5.808% respectively for hourly prediction, and is 1.935% and 2.345% respectively for daily prediction. On daily peak cooling load prediction in summer season, the best MAPE and CV is 2.313% and 2.862% respectively. It is found that the variability in the prediction is modest in summer season. [Copyright &y& Elsevier]

Abstract: A building integrated cooling facade is proposed in this paper. It is a fan-assisted system that consists of two vertical plenums. The first plenum was made of black aluminium transpired plate and a sandtile wall, while the second plenum is formed by the sandtile wall and the building wall. The aluminium plate served as a solar collector and the sandtile wall was an evaporative pad. The reverse side of the sandtile wall that contacted with the air in the second plenum was coated with a water-resistant layer, hence the air was cooled without adding any moisture into it. The facade cooling performance under various operating conditions is investigated through experiment and theoretical analyses. It is found that inlet water temperature is the key factor affecting the cooling performance. In terms of cooling efficiency, the energy consumption to generate 1kW of cooling that cooling the air to 293K is only 0.52W, which is similar to the amount of energy required by some of the solar indirect evaporative cooling and desiccant cooling systems. [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 this paper, design and experimental analysis of glaze photovoltaic thermal (PVT) tile air collector has been discussed. Fabricated glazed PVT tile consists of a single solar cell, duct and fan for extraction of heat associated with the bottom of solar cell. Observations taken at glazed hybrid PVT tile 1 and tile 2 have been considered as case-I and case-II, respectively. Experimental validation has also been performed and it has been observed that that there is a good agreement between theoretical and experimental results with correlation coefficient and root mean square percentage deviation of 0.96 and 7.9, respectively. The performance evaluation in terms of electrical efficiency, overall thermal energy and exergy gain of both the cases has been carried out in indoor conditions at various intensities. It has been found that the electrical efficiency is higher in case-I as compared to case-II. On the contrary the thermal output of case-II is higher than case-I on same intensity and mass flow rate. It has been found that the average electrical and thermal efficiency of newly designed and fabricated glaze PVT tile is 12.4% and 35.7%, respectively. This economical solar simulator can be used by manufactures for testing of different type of photovoltaic tiles as well as photovoltaic modules. [Copyright &y& Elsevier]

Abstract: The renewed Energy Performance of Building Directive and European regulations for buildings energy efficiency are becoming increasingly restrictive and moving towards near zero energy buildings. To achieve this goal, amongst others measures, a building utility system has to be carefully designed and optimized to perform efficiently and to utilize renewable energy source to greater extent. This paper is focused on the multi-objective performance optimization of buildings free cooling systems. The optimization was twofold: firstly, the energy consumption and available free cooling potential were estimated using weather forecasts, and secondly, the free cooling system operation regime was optimized to meet the required energy consumption using variable air distribution and flow control. The results of the optimization show the significant influence of such system operation control on system performance indicators. [Copyright &y& Elsevier]

Abstract: This paper deals with determine the energy and exergy efficiencies and exergy destructions for thermal optimization of a geothermal district heating system by using artificial neural network (ANN) technique. As a comprehensive case study, the Afyonkarahisar geothermal district heating system (AGDHS) in Afyonkarahisar/Turkey is considered and its actual thermal data as of average weekly data are collected in heating seasons during the period 2006–2010 for ANN based monitoring and thermal optimization. The measured data and calculated values are used at the design of Levenberg-Marquardt (LM) based multi-layer perceptron (MLP) in Matlab program. The results of the study are described graphically. The results show that the developed model is found to quickly predict the thermal performance and exergy destructions of the AGDHS with good accuracy. In addition, two main factors play important roles in the thermal optimization: (i) ambient temperature and (ii) flow rates in energy distribution cycle of the AGDHS. Various cases are investigated to determine how to change the energy and exergy efficiencies of the AGDHS for the temperature and flow rate. Finally, a monitoring and performance evaluation of a geothermal district heating system and its components by ANN will reduce the losses and human involvement and make the system more effective and efficient. [Copyright &y& Elsevier]

Abstract: Many parameters have been used to evaluate the thermal performance of envelope wall/roofs, most of them for air-conditioned buildings. In this paper, the interest is focused on parameters to assess the thermal performance of envelope wall/roofs for non air-conditioned buildings. Five groups of parameters, some previously used and some newly proposed, have been analyzed. To test the evaluation parameters, numerical simulations of the periodic heat transfer through five different roof configurations have been carried out. This research shows the suitability of the energy transferred through the wall/roof during a day, the decrement factor, the discomfort degree hours, and the hot (or cold) thermal performance index to be used for thermal evaluation of wall/roofs in non air-conditioned buildings. The sensitivity of these parameters with climatic conditions and with the outdoor surface solar absorptance is analyzed. Additionally, it has been shown that the steady-state thermal transmittance, the thermal admittance modulus, the periodic thermal transmittance modulus, and the surface decrement factor, calculated with surface temperatures, are not suitable parameters to evaluate wall/roofs in non air-conditioned buildings. [Copyright &y& Elsevier]

Abstract: This paper presented a novel hybrid solar GSHPS (HSGSHPS) composed of a GSHPS and a solar assisted GSHPS (SAGSHPS) used in an office building for heating and cooling. The key issues of designing the HSGSHPS were introduced and a simulation model was developed in TRNSYS to predict the multi-year performance of this system. The simulated results showed that the proposed HSGSHPS was reasonably designed to resolve the ground temperature imbalance problem on an annual basis. The suitable control strategy for the solar collection and storage was found according to the coefficient of performance (COP) of SAGSHPS. The first-operation time has impact on the operation of SAGSHP and GSHPS. Injection of thermal energy into the borehole heat exchanger (BHE) or borehole thermal energy storage (BTES) before the heat extraction from BHE/BTES was favourable to the overall COP of system. It is very important to SAGSHPS to store sufficient solar thermal energy in the BTES because of its small spacing between boreholes. 32% of the electrical energy consumption in the HSGSHPS could be saved if the load circulation pump was turned off when no fan-coil was running, rather than always keeping it running at all times. [Copyright &y& Elsevier]

Abstract: Emphasizing that sustainable development, health, social security and renewable energy sources implementation are inextricably linked, paper examines the state of the art of building''s health and sustainability relevant technologies. Sustainability definitions, relevant criteria and indicators related to healthy buildings have been searched and studied. Reviewed is the wide range of physically sound interdisciplinary research, results of which are new knowledge and developed synergetic analytical/experimental methods that lead to a sustainable, healthy, comfortable/productive indoor and outdoor environment. Research and knowledge based building intelligence and e-automation are elucidated as crucial technologies and techniques for design, construction and operation of sustainable buildings. Study shows, that qualitative relations and relevant comparative evaluation methods between indoor environmental quality and work performance or health, and further relation of both to the energy and energy efficiency, are not enough neither known nor searched. Initiated research is devoted to the healthy and sustainable buildings relevant performance modeling, evaluation methods and metrics investigation, and determination of all relevant interdependent relations, as well as determination of the relevant synergetic sustainability criteria and indicators. Initial results of related research are presented. Further research needs are outlined, drawing the attention on the role of harmony and interdisciplinarity in synergetic buildings health/sustainability study. [Copyright &y& Elsevier]

Abstract: Primary–secondary chilled water systems with decoupled bypass in building air-conditioning often cannot work in healthy condition as desired in practical operation, due to excess secondary flow demand resulting in deficit flow in the bypass line. This paper presents a fault-tolerant and energy efficient control strategy for secondary chilled water pump systems to solve this operation and control problem providing enhanced operation performance and energy efficiency of chilled water systems. The strategy employs the flow-limiting technique that ensures the water flow of secondary loop not exceed that of the primary loop while still maintaining highest possible delivery capacity of cooling to terminals. The strategy is also integrated with a differential pressure set-point optimizer to determine the optimal set-point. The performance of this strategy is evaluated in a simulated real-life environment representing the chilled water system in a super high-rise building by comparing it with two conventional control strategies. Results show that the proposed strategy can effectively eliminate the deficit flow at both starting and normal operation periods. The energy saving in the secondary chilled water pumps can be up to over 70% and 50% at system starting and normal operation periods respectively compared with the other strategies. [Copyright &y& Elsevier]