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[Display omitted] • In the US, carbon savings are readily achievable by transitioning to heat pump technologies for the vast majority of homes. • The heat pump performance required to achieve carbon and cost neutrality varies by a factor of four across the US. • Energy cost neutrality is much harder to achieve than carbon neutrality. • Achieving carbon and energy costs savings is much easier when replacing older, low efficiency equipment. In order to meet climate goals, it will be necessary to significantly reduce the greenhouse gases emitted by homes. A key factor in the US is to reduce the on-site combustion of fossil fuels for heating end-uses and to replace this with use of electric heat pump technologies connected to a low-carbon grid. The replacement of natural gas furnaces with electric heat pumps is a key home decarbonization strategy. However, the potential for space heating electrification to reduce greenhouse gas emissions depends on the carbon dioxide equivalent (CO 2 e) content of the electricity used by the heat pump. This varies considerably depending on the source of electricity, with large state to state variability. Furthermore, household energy costs are likely to be impacted by the electrification of space heating, because retail energy prices for both natural gas and electricity in each state vary by factors of seven and four, respectively. Contractors, energy programs, government and building code officials, as well as consumers need clear indications of the likely CO 2 e and energy cost impacts of proposed electrification projects, because these will affect decarbonization choices and rationales around scaled heating electrification. Government and utility programs also need to be aware of the likely outcomes of any supported/incentivized measures. In this paper, we investigate these effects by looking at new metrics to analyze the change in CO 2 e emitted and the cost to meet home heating loads when switching from a natural gas furnace to a heat pump for the contiguous 48 states of the mainland US. [ABSTRACT FROM AUTHOR]

• Occupants on-demand heating control behavior in a rural residential building is investigated. • Independently controlled split-type heating equipment were used to elucidate actual demand patterns. • Data collection over three years under an interference avoidance scheme. • Five representative intermittent heating patterns were obtained from a real-world case study. A better understanding of actual heating demands is crucial for optimizing operational heating systems, because disparities between expected load and actual demand are key factors in inefficient heating system design, implementation, and corresponding energy loss. Additionally, the discrete, energy consumption-based billing systems applied to freestanding rural residential buildings encourages reductions in energy waste but produces spatially and temporally distinct heating patterns. Conventional heating systems have only basic controls and slow response times that cannot reflect actual user demand. Hence, this paper presents an experimental scheme for measuring room-wise heating demands, and thus, the actual heating demand patterns of rural residential buildings. A case study was conducted on a typical rural residential building in Beijing to validate the method's feasibility. Real-world usage patterns were obtained using indoor environment sensors and independently-controlled heating devices that collected the operational parameters of each room over three years, in a long-term non-intervention study design. Clustering analysis and various indicators were used to characterize heating demand for each room: heating patterns, usage intensity, and temporal variation. In most case, the occupants heated only a few rooms, rather than the whole building. These results have potential real-word implications for predicting occupant heating behavior and energy conservation. [ABSTRACT FROM AUTHOR]

Abstract: HVAC energy savings have been a key focus of recent building energy management efforts, but the savings typically reduce thermal comfort for building occupants. Established thermal comfort models use complex and person-specific parameters, such as clothing insulation and metabolic rate, to predict individual comfort levels, making the design of automated comfort modelling systems a highly challenging endeavour. In this paper, we investigate the use of humidex, which encapsulates both temperature and humidity, as an easily measurable and highly representative indoor thermal comfort predictor. We verify the feasibility of humidex as an indoor thermal comfort predictor by contrasting its performance to that of the best feature set (the feature set that best predicts the thermal comfort) constructed jointly by recursive sequential forward selection and support vector regression. The analysis using the global datasets, including data from seven climate zones across three continents, shows that humidex is a favourable and easily measurable indoor thermal comfort descriptor when humidity is significant. We take away the message from the analysis and design, develop, and deploy a system that couples a deployment of sensor nodes in an office environment, where each node collects the ambient temperature and humidity at each person's desk, and an automated survey mechanism to record people's thermal sensation votes. We use subjective response through the surveys as ground truth to validate the performance of the thermal comfort prediction using humidex. The results confirm our analysis of global datasets and show that humidex is a good predictor of indoor thermal comfort at high humidity. [Copyright &y& Elsevier]

Abstract: This paper presents a thermal analysis of a building concrete roof with vertical cylindrical holes filled with phase change material (PCM). The objective of incorporating the PCM into the concrete roof is to increase the value of thermal mass of the roof. The PCM absorbs the heat through the melting process before it reaches the indoor space, and thus reducing the heat gain. Numerical method is extensively utilized in this research and it is validated with experimental work. The thermal effectiveness of the proposed concrete roof with PCM is assessed by comparing the heat flux at the indoor surface with that of solid concrete roof during the day. A parametric study is conducted to evaluate the effects of the cylindrical holes dimension, PCM melting temperature, and operating month on the heat gain. The results indicate that heat gain can be reduced significantly with larger PCM holes diameter. The PCM melting temperature of PCM should be selected based on the operating month and working hours for the best performance. For the examine cases in this research, the heat flux at the indoor surface of the roof is reduced between 9% and 17.26%, depending on the selected PCM, working hours, and operating month. [Copyright &y& Elsevier]

Abstract: This paper presents results from a field trial with a hybrid micro-cogeneration system applied to satisfy both thermal and power needs of a typical Canadian detached house. The hybrid system consists of an internal combustion engine integrated with a high efficiency furnace. It was installed, integrated with the rest of the mechanical systems and demonstrated at the Canadian Center for Housing Technology (CCHT). Cost analysis was performed to examine the economics of such systems in relation to different price structures imposed by the electric utilities. The study revealed that the hybrid micro-cogeneration system performed reliably and generated both heat and power with high efficiency during the heating season and was able to satisfy the heating demand under very cold weather conditions. The power generated by the system was first directed to the house satisfying 50% of the electric load with the other 50% being exported to the grid. The project demonstrated that micro-cogeneration systems when sized to meet the base electric load and design thermal load of the residence are a valuable alternative to the central power generation plants and are able to reliably satisfy the house thermal/power demand even under extreme cold conditions. [Copyright &y& Elsevier]

Abstract: An archetypal simulation model of office building representing variability in UK office building stock by parameterising built form, construction elements, occupancy/usage and operational/control strategy has been developed thus enabling detailed energy performance simulation to be used for stock modelling and parametric studies. The paper discusses the building characteristics needed to be considered for energy performance simulation, their values, and how they can be used in parametric studies. These parameters include built forms, fabrics (including thermal mass and insulation positioning), glazing percentages and characteristics, daylight and solar control measures and activity and operational related parameters (heating and cooling set points, ventilation rate, occupancy density and metabolic rate, equipment and lighting gain). The default parameter values suggested for the archetypal simulation model reflect typical existing and currently proposed UK office building stock. An archetypal model, combined with parametric studies, can be used in assessing energy performance of building stock and evaluating adaptation/retrofitting strategies. [Copyright &y& Elsevier]

Abstract: This paper described the development of regression models which are able to predict office building annual heating, cooling and auxiliary energy requirements for different HVAC systems as a function of office building heating and cooling demands. In order to represent the office building stock, a large number of building parameters were explored such as built forms, fabrics, glazing levels and orientation. Selected parameters were combined into a large set of office building models (3840 in total). As different HVAC systems have different energy requirements when responding to same building demands, each of the 3840 models were further coupled with five HVAC systems: VAV, CAV, fan-coil system with dedicated air (FC), and two chilled ceiling systems with dedicated air, radiator heating and either embedded pipes (EMB) or exposed aluminium panels (ALU). In total 23,040 possible scenarios were created and simulated using EnergyPlus software. The annual heating and cooling demands and their HVAC system''s heating, cooling and auxiliary energy requirements were normalised per floor area and fitted to two groups of statistical models. Outputs from the regression analysis were evaluated by inspecting models best fit parameter values and goodness of fit. Based on the described analysis, the specific regression models were recommended. [Copyright &y& Elsevier]

Abstract: Hybrid photovoltaic thermal (or simply PV/T) collectors are devices that simultaneously convert solar energy into electricity and heat. The improving of the electrical efficiency, by reducing the photovoltaic collector''s temperature, as well as taking advantage of the thermal energy produced, constitutes the basic idea in the development of hybrid PV/T collectors. A new design of hybrid collectors for air heating is presented in this paper. The theoretical study is carried out through the numerical modeling, and the results of the simulation are integrally developed; witch a prototype is realized. Experimental validation of the mathematical model as well as the study of the thermal and electric performance is detailed. The application of this new design has given a good thermal and electric performance compared to the traditional hybrid collectors. Its simplicity of implementation and its easy integration in buildings make them more competitive. [Copyright &y& Elsevier]

Abstract: The occupants’ behaviour has a great influence on the energy demand, management and consumption of a building. This paper investigates the influence of three parameters related to human behaviour through their modes of occupations (based on family size, management of the heating system and management of the heated area) on the housing heating loads of a standard dwelling in Belgium. Seven levels of insulation were tested: no insulation, two intermediate levels corresponding to 3 and 6cm of insulation, the current standard for new buildings in Belgium, the low energy standard, the very low energy standard and the passive house standard. Multi-zone simulations were performed with a dynamic thermal simulation software. The impact of occupants’ lifestyle and the interactions between occupation modes and insulation levels are highlighted. These results prove that the more the building is insulated, the more the lifestyle proportionally influences the heating loads. One important strategy for reducing heating consumption during the whole life cycle of the building is adapting the size of the house and its occupation modes to the evolution of family size. However, insulation is paramount, and increasing the insulation of the house provides generally better results than merely adapting the occupation mode. [Copyright &y& Elsevier]

Abstract: In this paper, the electricity, heating and cooling demands of a Southern Ontario residence are assessed and compared. Five specific systems are analyzed: ground and air source heat pumps, stand-alone PV, PV/fuel cell hybrid and a wind turbine/fuel cell hybrid system. Actual monitored data from a residence using a ground source heat pump is taken as a reference and compared with the others. Average weather conditions, electricity prices and average electricity loads in Toronto, Ontario, are used as reference data. Thermodynamic, economic and environmental comparisons are performed. It is found that heat pump systems offer significant advantages over the other systems. [Copyright &y& Elsevier]

Abstract: Radiant floor is a low temperature heating and high temperature cooling system. Three parameters, cooling/heating capacity of radiant floor, uniformity of surface temperature distribution, and the lowest temperature in surface, are concerned most by designers and users of radiant floor. A simplified calculation of these parameters is presented in this paper. The error between experiment results in literature and calculation of cooling capacity and mean surface temperature is within 8% and 0.5°C respectively. A simulation model is established to verify simplified calculation on surface temperature distribution. The absolute error between simulation value and calculation is within 0.2°C. From the perspective of heat resistance, the most important limitation of cooling/heating capacity of radiant floor is heat transfer between floor surface and indoor environment. The thickness and heat conductivity of each layer has important influence on performance of radiant floor. The influence of water pipes should not be ignored. [Copyright &y& Elsevier]

Abstract: Micro Combined Heat and Power (μCHP) technologies are usually operated according to a predetermined conventional heat or electricity led operation strategy (HLOS, ELOS) [1]. μCHP systems can contribute to the transition to a low carbon economy through their relative efficient operation, their ability to use renewable fuels and reduce electrical distribution network losses. Previously, an online linear programming optimiser (LPO) for operating a μCHP system has been developed with the ability to significantly reduce operation costs when compared with HLOS and ELOS [2]. However, the online LPO depends on historical demands. In order to deal with the complexities inherent in the operation of μCHP systems, such as uncertainties in energy demands and performance, a fuzzy logic (FL) approach is required. In this paper, a real time fuzzy logic operation strategy (FLOS) has been developed and evaluated, which aims to minimise operation costs and CO2 emissions of a μCHP system. Three simulation scenarios have been investigated for the real time FLOS: the feed-in tariff (FIT) scheme; the trade of electricity; the introduction of a carbon tax. In all three scenarios investigated. Results show that the real time FLOS significantly reduces operation costs and CO2 emissions when compared with HLOS and ELOS. [Copyright &y& Elsevier]

Abstract: Energy performance of air conditioned buildings and summer comfort can be improved with high solar reflectance and high emittance of building envelopes. Widely used for roofs, this technique known as cool roof, has a direct impact on the external surface temperatures peaks which reduces both heat transfer to the building and to the environment. In this paper, this technique used with façades is experimented in a confined environment similar to a typical urban scene. This reduced-scale of 4 street canyon rows is designed in order to give realistic measurements of thermal confinement. Then, the temperatures of a street canyon with brown cool selective paint façades are compared with a standard brown coating on another street façades, and with an asymmetrical configuration. The analysis of thermal effects on both buildings and outdoor environments gives interesting prospects for urban heat island mitigation. [Copyright &y& Elsevier]

Abstract: Iran is a country with five different climates and 50°C temperature difference between its warmest and coldest regions. In the present paper, the prime-mover capacity of a CCHP system for the same building in five different climates is determined. For this purpose, five cities from these climates are chosen and their weather information for the last five years is gathered from the Iran Metrological Organization. The hourly load of the five cities for the whole year is calculated and the maximum rectangle method is used to determine the size of the prime mover and the recommended full load operation time. The results show that the CCHP system saves energy during the whole year for all the climates. The yearly average fuel energy saving ratio of 37.85%, 33.16%, 30.75%, 29.60% and 25.30% are achieved for Chabahar, Ahwaz, Kamyaran, Tehran and Bandar Anzali, respectively. Furthermore, the analyses show that no heating system is needed for the cities of Chabahar and Ahwaz, but an auxiliary boiler is needed for all the climates to compensate the lack of heating or to support the absorption chiller. The sensitivity analysis shows that the hourly load of building is least sensitive to the minimum wet bulb temperature. [Copyright &y& Elsevier]

Abstract: This paper examines the efficiency (in terms of energy use and carbon emissions) with which 5 different types of domestic water heating systems employed in the UK are able to produce hot water for sanitary use. A method of normalisation is employed allowing results from case studies with different systems and usage levels to be compared. Water heating appliances studied include gas boilers, a micro CHP, heat pumps, an immersion heater, and a solar thermal system. It is found that instantaneous production of hot water is much more efficient than delivery via tank storage for gas-fuelled systems. For electrical systems, an immersion heater is found to perform better in some circumstances than heat pumps and also has advantages when combined with a solar thermal system leading to the proposal that this combination offers the most potential as a low carbon method for domestic hot water provision in the long term. Opportunities are identified to improve the performance of all systems with storage through better control of heat inputs. Inconsistencies in, and problems of compliance with, established standards for mitigation of Legionella in hot water systems are also identified. [Copyright &y& Elsevier]

Abstract: The Low Carbon Futures project, funded by the Adaptation and Resilience in a Changing Climate (ARCC) Programme, has the objective of using the latest UK climate projections (UKCP’09) to assess overheating in a range of domestic and non-domestic buildings. As these climate projections are probabilistic in nature, and dynamic building simulation is being used by the project to assess building performance, the information produced is vast. To understand how to filter this data into a useable tool that can interact with current building practices, the project has commissioned a range of focus groups to obtain practitioner feedback. These focus groups provide guidance on how buildings are currently designed with respect to overheating but also how future overheating risk assessments, incorporating probabilistic climate projections, might be carried out. This paper describes the assimilation of all this research into a coherent building simulation methodology that could be used by building practitioners to assess future overheating risks of a range of buildings, and provide guidance for applying adaptation solutions to prevent defined comfort thresholds being exceeded. [Copyright &y& Elsevier]

Abstract: An economic analysis comparing four different boiler systems running on olive husks, liquefied petroleum gas (LPG), diesel and electricity used to provide both space and water heating in a standard size apartment located in Lebanon''s high mountain area is presented in this study. The results show that the electric boiler system is the most polluting and cost ineffective system with an average energy price of 0.31 $/kWh over its life time, compared to only 0.13 $/kWh for the olive husk or LPG powered boiler systems, and to 0.14 $/kWh for the diesel powered system. Moreover, the current subsidy on diesel oil constitutes a substantial barrier against the deployment of renewable energy as well as other systems running on much cleaner fuels. This paper further presents a financial analysis ranking the different systems in terms of their net present values and suggests measures such as an import tax break and the redirection of the currently existing diesel subsidy towards the olive husk powered system in order to increase the attractiveness of the latter. [Copyright &y& Elsevier]

Abstract: Our paper proposes to present the static heat balance of the human body and the sensitivity range of the comfort equation through average skin temperature and heat loss by sweating, based on Fanger''s work. We will investigate which measurement methods he used to develop the two heat balance equations. In addition a comfort diagram will be used to illustrate its sensitivity at various thermal load levels. [Copyright &y& Elsevier]

Abstract: The paper presents a study of solar electricity generation and energy demand for heating and cooling of housing units’ assemblages. Two-story single family housing units, located in northern mid-latitude climate are considered in the study. Parameters studied include geometric shapes of individual units, their density in a neighborhood, and the site layout. The plan shapes of the housing units included in this study are rectangles and several variants of L shape. Site layouts studied are characterized by a straight road, a south-facing or a north-facing semi-circular road. Rectangular units and a site layout with straight road serve as reference for evaluating the effect of shape and site parameters. Results indicate that a significant increase in total electricity generation (up to 33%) can be achieved by the building integrated photovoltaic (BIPV) systems of housing units of certain shape-site configurations, as compared to the reference. The energy load of a building is affected by its orientation and shape. Increased heating demand by L variants (by up to 8%) is more than offset by annual electricity production of their BIPV systems (by up to 35%). Heating and cooling loads depend significantly on unit density in a site; Attached units require up to 30% less cooling and 50% less heating than detached configurations of the same site. Variation of surface orientation, particularly in curved site layouts, enables the spread of peak electricity generation over up to 6h. This effect may be beneficial to grid supply efficiency. Energy balance assessment indicates that some unit shapes generate up to 96% of their total energy use. Neighborhood configurations studied generate between 65% and 85% of their total energy demand. [Copyright &y& Elsevier]

Abstract: Integrating passive systems such as cross and stack ventilation, a solar chimney, a wind tower or an earth-air tunnel into a building envelope has the potential to significantly reduce the ventilation and air-conditioning demand on buildings. However the application of combination of these features in low rise contemporary buildings is limited. Among the major reasons, is the lack of simple building modelling techniques preventing effective integrated passive systems. Existing coupled multi-zone airflow and thermal modelling software such as COMIS-TRNSYS, CONTAM-TRNSYS or TRNFLOW do not include the passive airflow components which require simultaneous prediction of temperature and airflow rate in the components such as solar chimneys and wind-induced earth-air tunnels. This paper develops an integrated model incorporating these passive airflow components into a coupled multi-zone ventilation and building thermal model. The model is validated against COMIS-TRNSYS software for a lightweight building with large openings. The prediction of each passive airflow component is validated with available published analytical and experimental findings. The solar chimney model is able to predict reverse flow and accurately predicts the air temperature in the chimney. The earth air tunnel (EAT) considers the transient heating up effect of the soil during operation and predicts the outlet air temperature. [Copyright &y& Elsevier]

Abstract: Thermal mass can be effectively used for controlling temperature in buildings. Based on its location and function, building thermal mass can be classified as interior thermal mass and exterior (envelope) thermal mass. In this paper, the dynamic heat transfer performance of exterior Planar Thermal Mass (ePTM) subject to sinusoidal heating and cooling is investigated. When the mean value of outdoor air temperature is equal to indoor air temperature, solutions of temperature distribution and heat flux in ePTM are deduced analytically. Using the analytical solutions, heat exchange and thermal storage of ePTM are attained. Correspondingly, the time lag and the decrement factor are obtained; they show similarity characteristics—independent of environment temperatures. When the two temperatures are not equal, an approximated temperature distribution solution is developed based on the principle of superposition, which has been validated by numerical solutions. The approximated solution is then used to investigate the heat exchange between the ePTM and the environment. In contrast to the common belief that a large thermal mass has an apparent insulating effect, no “insulating effect of mass” under sinusoidal heating and cooling is found in this investigation. Another two rules of thumb based on common belief are corrected: a wood wall is better than a concrete wall of same thickness as exterior walls in terms of the time-lag effect and the decrement factor. The effect of the time lag is not the longer the time lag is the better its contribution to thermal comfort becomes. [Copyright &y& Elsevier]

Abstract: In this paper we undertake a comprehensive study to meet the building heating/cooling and power demand through a sustainable operation. We integrated polymer electrolyte membrane fuel cell (PEMFC) system and triple effect absorption refrigeration system (TEARS) for space cooling/heating and water heating applications in buildings. The analysis is carried out to observe the effects of different operating conditions on the efficiency of the fuel cell, output of the fuel cell and TEARS, and the utilization factor of the system. It is found that the efficiency, the utilization factor, and change in temperature of hot water increases from 36% to 48.8%, 49% to 86%, and 14K to 23K, respectively when the temperature of the cell is increased for different cooling loads and membrane thicknesses. In addition, the increase in membrane thickness affected the efficiency, the utilization factor, and change in temperature of hot water in a negative way and they were found to be decreasing from 47.3% to 42%, 85% to 49%, and 23K to 12K, respectively for different cooling loads. The water supplied to the house is obtained from a geothermal water source which makes the system more sustainable. [Copyright &y& Elsevier]

Abstract: Exergy represents the ability of an energy carrier to perform work and can be seen as a core indicator for measuring its quality. In this article we postulate that energy prices reflect the exergy content of the underlying energy carrier and that capital expenditures can substitute for exergy to some degree. We draw our line of argumentation from cost and technology data for heating systems of four European countries: Austria, Finland, The Netherlands, and Sweden. Firstly, this paper shows that the overall consumer costs for different heating options, widely installed in those countries, are in the same range. In this analysis we derived an overall standard deviation of about 8%. Secondly, additional analysis demonstrates that the share of capital costs on total heating cost increases with lower exergy input. Based on the data used in this analysis, we conclude that for the case of modern cost effective heating systems the substitution rate between exergy and capital is in the vicinity of 2/3. This means that by reducing the average specific exergy input of the applied energy carriers by one unit, the share of capital costs on the total costs increases by 2/3 of a unit. [Copyright &y& Elsevier]

Abstract: Greening the building envelope focusing on green façades with vegetation is a good example of a new construction practice. Plants and partly growing materials in case of living wall systems (LWS) have a number of functions that are beneficial, for example: increasing the biodiversity and ecological value, mitigation of urban heat island effect, outdoor and indoor comfort, insulating properties, improvement of air quality and of the social and psychological well being of city dwellers. This paper discusses a comparative life cycle analysis (LCA) situated in The Netherlands for: a conventional built up European brick façade, a façade greened directly, a façade greened indirectly (supported by a steel mesh), a façade covered with a living wall system based on planter boxes and a façade covered with a living wall system based on felt layers. Beside the environmental benefits of the above described greening systems, it is eventually not clear if these systems are sustainable, due to the materials used, maintenance, nutrients and water needed. A LCA is used to analyze the similarity and differences in the environmental impacts in relation with benefits estimated for two climate types for building energy saving (reduction of electrical energy used for building cooling and heating). [Copyright &y& Elsevier]

Abstract: The use of groundwater for cooling and heating purposes is of interest from both the economical and the ecological perspective. The groundwater heat pump (GWHP) system utilizes groundwater as alternative renewable and clean energy source for space heating and/or cooling, withdraws water from a production well, passes it through a heat exchanger and discharges the water into an injection well. By utilizing the relatively stable temperature of groundwater, GWHP system can achieve a higher coefficient of performance. Due to the utilization of groundwater stored in the aquifer, the assessment of the hydraulic capacity of the aquifer based on numerical groundwater models is always needed for the optimum design and the efficient performance of GWHP. In this paper, numerical methods of underground heat-water transfer, energy balance method and thermal storage method were presented to calculate the capacity of unit area of shallow groundwater aquifer. The model results indicate that the numerical method, which is based on performance efficiency of GWHP, represents the behaviour of groundwater pumping/recharging processes, and serves better than energy balance method and thermal storage method, in addition it has been proven itself that this method has the advantages of energy saving and environmental protection. The calculated capacity is positively related to aquifer thickness. It is found that it is easy for ground water recharge in alluvial and pluvial fan located at the piedmont, while the calculated capacity is relatively smaller compared with that of south-east plain where it is not easy for groundwater recharge. [Copyright &y& Elsevier]

Abstract: A retrofit study was conducted in an unoccupied manufactured house to investigate the impacts of airtightening on ventilation rates and energy consumption. This paper describes the retrofits and the results of the pre- and post-retrofit assessment of building airtightness, ventilation, and energy use. Building envelope and air distribution systems airtightness were measured using fan pressurization. Air change rates were measured continuously using the tracer gas decay technique. Energy consumption associated with heating and cooling was monitored through measurement of gas consumption by the forced-air furnace for heating and electricity use by the air-conditioning system for cooling. The results of the study show that the retrofits reduced building envelope leakage by about 18% and duct leakage by about 80%. The reduction in the house infiltration rates depended on weather conditions and the manner in which the heating and cooling system was controlled, but in general these rates were reduced by about one third. The energy consumption of the house for heating and cooling was reduced by only about 10%, which is relatively small but not totally unexpected given that infiltration only accounts for a portion of the heating and cooling load. [Copyright &y& Elsevier]

Abstract: This paper explores the current state-of-the-art in performance indicators and use of probabilistic approaches used in climate change impact studies. It presents a critical review of recent publications in this field, focussing on (1) metrics for energy use for heating and cooling, emissions, overheating and high-level performance aspects, and (2) uptake of uncertainty and risk analysis. This is followed by a case study, which is used to explore some of the contextual issues around the broader uptake of climate change impact studies in practice. The work concludes that probabilistic predictions of the impact of climate change are feasible, but only based on strict and explicitly stated assumptions. [Copyright &y& Elsevier]

Abstract: Solar energy is considered one of the most prospective sources of renewable energy for greenhouse heating in cold period for Mediterranean climate. In this paper, the thermal performance of a north wall made with phase change material (PCM) as a storage medium in east–west oriented greenhouse is analyzed and discussed. CaCl2·6H2O was used as a PCM. A numerical thermal model taken into account the different components of the greenhouse (cover, plants, inside air and north wall PCM) and based on the greenhouse heat and mass balance, has been developed to investigate the impact of the PCM on greenhouse temperature and humidity. Calculations were done for typical decade climate of January in Marrakesh (31.62°N, 8.03°W). Results shows that with an equivalent to 32.4kg of PCM per square meter of the greenhouse ground surface area, temperature of plants and inside air were found to be 6–12°C more at night time in winter period with less fluctuations. Relative humidity was found to be on average 10–15% lower at night time. [Copyright &y& Elsevier]

Abstract: Energy use in the built environment represents a large part of total energy use in Sweden and is one important sector where energy conservation needs to be significantly improved in order to meet the national implementation of the European goals. One key question that needs to be investigated in relation to these goals is the performance and implementation of passive or low-energy houses. This paper presents results and an evaluation of a newly built house in an area with passive houses in Linköping, Sweden. Nine passive houses were built with the aim to be energy efficient, with an annual space heating demand of 21kWh/m2, and at the same time to have the same visual appearance as any other building in the surrounding area. This study evaluates the energy performance of a residential area with low-energy buildings based on Building Energy Simulation (BES) (IDA ICE 4), and measurements from the real object. Both annual and hourly validation is performed using room by room modeling and internal heat gains. A novel approach to internal heat gain modeling is presented using time-use data (TUD). The results show possible improvements in the design, the building envelope and in the heating control. [Copyright &y& Elsevier]

Abstract: This paper introduces a comparison of different measuring methods of buildings fabric thermal resistance, including the test wall measuring points arrangements and measurement results, conducted in a test chamber in Cagliari (Italy) in summer 2009. Two methods and their measurement uncertainties are presented and compared by the compatibility of measurement study. The non-destructive method involves the heat-flow rate measurement through the test wall and its surface temperatures. The reliability of this method depends on the temperatures difference between the two environments separated by the building envelope. Thus two measurement series with different temperatures were carried out on the test wall. The destructive method instead foresees the acquisition of a sample by the use of a hollow drill, the building envelope layers thickness measurement and the thermal properties assignment to each different material. The wall R-value is the sum of each layer thermal resistance. The comparison shows that the R-values measured by the non-destructive method with a temperature difference of 10°C and 7°C and the one calculated from the destructive method obey the compatibility of measurement principle. [Copyright &y& Elsevier]

Abstract: This paper introduces a solar-assisted ground-coupled heat pump (SAGCHP) system with heat storage for space heating and domestic hot water (DHW) supply. The simulation results of the system''s detailed operating performance are presented. The optimization of the system design is carried out by the TRNSYS and a numerical simulation is performed for continuous operation of 20 years under the meteorological conditions of Beijing. Different control strategies are considered and the operational characteristics of each working mode are studied. The simulating results show that the long term yearly average space heating efficiency is improved by 26.3% compared to a traditional ground coupled heat pump (GCHP) system because the solar thermal collecting system is used to elevate the thermal energy in the soil and to provide direct space heating with heat storage. At the same time, the underground heat load imbalance problem for a heating load dominated GCHP is solved by soil recharging during non-heating periods, while extra solar energy is utilized to supply DHW. The flexibility and high efficiency of the SAGCHP system could offer an alternative for space heating and DHW supply by heat pump technology and solar energy in cold winters of northern China. [Copyright &y& Elsevier]

Abstract: New Zealand has a temperate maritime climate. Despite mild winters compared to nations with continental climates, New Zealand houses have been reported to often be at temperatures below internationally recommended levels. Sources of additional heating are therefore of interest to many New Zealand home occupants. Roof space solar gains have been identified as one possible source of heating. This paper investigates the energy gains available in New Zealand homes from ventilation systems drawing air from the roof cavity. Three New Zealand houses were monitored and a computer-based thermal building simulation developed to quantify the heating and cooling energy that might be transferred by home ventilation systems. The computer model simulating the temperature in the roof space and occupied spaces was constructed using MATLAB, and used publicly available weather station data as the inputs. A good match between measured and modelled results was obtained. Small heating and cooling benefits are possible at certain times from pumping roof space air into the living areas of some New Zealand houses. The magnitude of these benefits, however, is not significant compared with the space heating required to maintain reasonable indoor temperatures over the New Zealand winter. [Copyright &y& Elsevier]

Abstract: Ground coupled heat pump systems can offer high energy efficiency for heating and cooling of buildings. The coupling of the ground loop with system and building represents a complex system and system performances can vary over long periods, in the range of 10–15 years due to the charge or discharge of the ground loop. In order to correctly concept, size and optimise these systems, numerical simulation is a perfect tool. The assessment of the global performance of such systems through simulation relies on several parameters, from the physical model validity to the operating conditions and control of the system. Typically, a GCHP system is simulated with a 1-h step. Transient phenomena inside the borehole are often neglected since ground models are mainly developed to characterise long term phenomena. However, detailed system simulations considering a realistic control of the system require much smaller time steps. In these cases, the validity of simulation models has to be verified. This paper proposes a hybrid approach combining experiments and simulation to highlight and quantify the impact of borehole short-time response on the system efficiency and system operation. First, a comparison between steady state and transient models as well as measurement is carried out. It reveals significant influence of dynamic effects inside the borehole. The comparison is then extended a parametric study with annual simulations for different European climates. [Copyright &y& Elsevier]

Abstract: According to the Energy Performance of Buildings Directive (EPBD) all new European buildings (residential, commercial, industrial, etc.) must since 2006 have an energy declaration based on the calculated energy performance of the building, including heating, ventilating, cooling and lighting systems. This energy declaration must refer to the primary energy or CO2 emissions. The European Organization for Standardization (CEN) has prepared a series of standards for energy performance calculations for buildings and systems. This paper presents related standards for heating systems. The relevant CEN-standards are presented and a sample calculation of energy performance is made for a small single family house, an office building and an industrial building in three different geographical locations: Stockholm, Brussels, and Venice. The additional heat losses from heating systems can be 10–20% of the building energy demand. The additional loss depends on the type of heat emitter, type of control, pump and boiler. [Copyright &y& Elsevier]

Abstract: From energy statistics (primary energy consumption) and a few Census data (residential buildings floor area) the average specific primary energy use (kWh/m2) of a territorial (Regional or National) building stock may be easily evaluated. However, can we achieve a deeper insight on this building stock using basically the same data bases? This is the question which this paper is aiming at, and the results is an analytical methodology to determine the Statistical Distribution Of residential Buildings according to primary Energy consumption for heating purposes (E-SDOB) at a Regional or National scale. This tool may allow the legislator to define a performance scale for building energy certification, to introduce mandatory measures and incentives for building energy retrofits, to evaluate the potential of new technologies, etc. The main source of data required for determining E-SDOB is still the National Census, but it has to be integrated by energy standards and laws, literature and a few data taken from the authors’ experience and in situ analysis. The results obtained have been compared with those derived from two Italian Regional (Piedmont and Lombardy) energy statistics, with excellent agreement. [Copyright &y& Elsevier]

Abstract: HVAC (Heating, Ventilation and Air Conditioning) systems used for heating or cooling buildings, consume a considerable amount of energy. To optimize the energy consumption, the behavior of occupants must be changed. This can be achieved by providing information and suggestions to occupants. A first step is developing of a less expensive and non-invasive measurement system and metering of the electricity and heat consumed. Based on collected experimental data, it can identify the parameters of a thermal model of the house. The model obtained will be used to simulate different aspects that can help to reduce the energy consumption. This paper presents a simple solution for thermal modeling of a house which includes experimental identification of the model''s parameters. Such data are used to simulate the thermal behavior of the house and to obtain solutions to reduce energy consumption. In simulation, the control of the thermal system is performed using a model based predictive control algorithm. [Copyright &y& Elsevier]

Abstract: This paper presents an experimental study on the impact of reflective coatings on indoor environment and building energy consumption. Three types of coatings were applied on identical buildings and their performance was compared with three sets of experiments in both summer and winter. The first experiment considers the impact of coatings on exterior and interior surface temperatures, indoor air temperatures, globe temperature, thermal stratification and mean radiant temperatures for non-conditioned buildings (free-floating case); the second one focused on the impact of coatings on reduction of electricity consumption in conditioned spaces; in the third experiment, the impact of different envelope material properties equipped with different coatings was investigated. The results showed that, depending on location, season and orientation, exterior and interior surface temperatures can be reduced by up to 20°C and 4.7°C respectively using different coatings. The maximum reduction in globe temperature and mean radiant temperature was 2.3°C and 3.7°C in that order. For the conditioned case, the annual reduction in electricity consumption for electricity reached 116kWh. Nevertheless, the penalty in increased heating demand can result in a negative all-year effect in Shanghai, which is characterized by hot summers and cold winters. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents model predictive controller (MPC) applied to the temperature control of real building. Conventional control strategies of a building heating system such as weather-compensated control cannot make use of the energy supplied to a building (e.g. solar gain in case of sunny day). Moreover dropout of outside temperature can lead to underheating of a building. Presented predictive controller uses both weather forecast and thermal model of a building to inside temperature control. By this, it can utilize thermal capacity of a building and minimize energy consumption. It can also maintain inside temperature at desired level independent of outside weather conditions. Nevertheless, proper identification of the building model is crucial. The models of multiple input multiple output systems (MIMO) can be identified by means of subspace methods. Oftentimes, the measured data used for identification are not satisfactory and need special treatment. During the 2009/2010 heating season, the controller was tested on a large university building and achieved savings of 17–24% compared to the present controller. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an evaluation of energy-related and economic aspects of production of thermal energy to heat a family house with wood briquette. The object of the study was a detached house with an area of 247m2, situated in Olsztyn, in the north-east of Poland. The study lasted three years, from October 2006 to September 2009. The highest monthly consumption of wood briquette for thermal energy production: heating water for the central heating system and hot utility water production were recorded in January (1052–1333kg/month). The average annual briquette consumption ranged from 6.36 to 6.72t/year. With the mean lower heating value of briquette of 17.99GJ/t, the mean consumption of energy in the fuel ranged from 114 to 121GJ/year. The annual cost of heat production for a family house with briquette as fuel ranged from €572 to €651, during the 2006/2007 and 2008/2009 seasons, respectively. It would have been cheaper by €187–228year−1 to heat the house with seasoned willow chips, whereas using alternative fuels, such as hard coal (fraction 0.5–2.5cm) oak pellets, natural gas and heating oil would have increased the cost of heat production. If the last of those fuels had been used, it would have increased the cost 3.5-fold as compared with wood briquette. [ABSTRACT FROM AUTHOR]

Abstract: This paper identifies the impact of thermostat strategies on heating and cooling energy consumptions in buildings, thus suggesting the importance of a database for understanding the effect of thermostat settings and for deciding energy-conscious strategies. Using computer simulation, diverse thermostat strategies – change of setback period, change of set-point temperature, and change of setback temperature – were tested parametrically in a typical USA single-family homes, located in two climate zones, namely cold (Detroit, Michigan) and hot-humid (Miami, Florida). Analysis revealed that heating and cooling systems were significant energy-consuming components in each climate zone. Accordingly, heating energy in cold climate zones and cooling energy in hot-humid climate zones have potential for matchingly significant saving. Diverse thermostat strategies (changes of setback period, of set-point, of setback temperature) demonstrated their obvious impacts on such saving. In the cold climate in particular, the heating system showed the most significant energy-saving effect via proper thermostat strategies. Proper setback period, set-point and setback temperature need to be established to achieve energy efficiency in residential buildings. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we propose a vision-based system for human detection and activity analysis in indoor environment. The developed presence sensor is based on video analysis, using a static camera. Composed of three main steps, the first one consists in change detection using a background model updated at different levels to manage the most common variations of the environment. Second, a moving objects tracking, based on interest points, is performed. Third, in order to know the nature of the various objects that could be present in the scene, multiple cascades of boosted classifiers are used. The validation protocol, defined by the industrial partners involved in the CAPTHOM project focusing among other things on “Energy Management in Building”, is then detailed. Three applications integrated into the CAPTHOM project illustrate how the developed system can help in collecting useful information for the building management system. Occupancy detection and people counting as well as activity characterization and 3D location extend to a wide variety of buildings technology research areas such as human-centered environmental control including heating adjustment and demand-controlled ventilation, but also security and energy efficient buildings. [ABSTRACT FROM AUTHOR]

Abstract: In this paper numerical transient simulations were used to investigate the air flow patterns, distribution and velocity, and the particulate dispersion inside an existing typical hospitalization room equipped with an advanced Heating Ventilation Air Conditioning (HVAC), with Variable Air Volume (VAV) primary air system designed for immune-suppressed patients never modelled before. The three-dimensional models of the room consider different, most typical, positions of the patients. Results indicate the best conditions for the high induction air inlet diffuser and the scheme of pressures imposed in the room to provide the effective means of controlling flows containing virus droplets. We believe that our work exemplifies the usefulness of numerical investigations of HVAC performances in real situations and provides important recommendations towards disease control and careful design and optimization of ventilation in hospital settings. [ABSTRACT FROM AUTHOR]

Abstract: A traditional Chinese heating system, the Chinese Kang, is used by 175 million people in detached houses in the rural regions of China, especially in Northeast China. This system utilizes biomass such as corn stalks, straw, corncob and energy plants as the heat sources. The objective of this paper is to establish a set of models to simulate the energy performance of the Kang heating system in one Chinese detached house. An experimental field study was carried out to collect practical parameters in a newly constructed Chinese detached house. The dynamic performance of the Kang heating system was simulated by using IDA-ICE 4.0 embedded with an empirical model built in the field study. The results show that the simulation can obtain good overall agreement with the field measurement results. It was confirmed that the Kang model created by IDA-ICE 4.0 is capable of simulating the performance of the Kang system and of calculating energy consumption in the detached house. Moreover, the result reveals that the thermal environment in the present Chinese detached house is still poor during the severe cold season if only the Kang system is used to heat the whole house. [ABSTRACT FROM AUTHOR]

Abstract: This paper reviews the annual energy and water performance of an aspiring low energy/carbon affordable housing development in southern UK, comprising 25 houses heated by a biomass fueled district heating network. Electrical, heat and water consumption data was collected for all dwellings and more detailed data logging was conducted on a sample of four. The data was analysed to benchmark the overall site performance and compare the individual dwellings. The individual dwellings performed efficiently in terms of electricity, heat and water consumption. Significant variation was identified between maximum and minimum consumers, even when typical performance correlates (i.e. number of occupants, floor area) were accounted for. Water consumption varies by a factor of > 7 and heat and electrical consumption by > 3 which, given the homogeneous design and specification of the buildings, suggested that occupant behaviour was important. Site-wide energy consumption and losses (over and above individual dwelling use) reduced energy and carbon emissions performance by 85% and 70% respectively. Although energy consumption in UK homes can be substantially reduced, the challenge for zero-carbon design is to address issues of total system performance, occupant behaviour and whole-building energy performance. [ABSTRACT FROM AUTHOR]

Abstract: This paper is concerned with the development of a mathematical model, capable of describing the quasi-steady state performance of an integrated ground source heat pump, which is used for heating and cooling of an institutional building located in a Mediterranean climate. The model is structured on functional basis according to the heat pump vapour compression or primary circuit, a secondary ground loop circuit and a secondary building loop circuit. Heat pump heating and cooling capacities, as well as COP, are considered to be dependent variables and are estimated in the model using performance fitted maps. Independent variables include: compressor speed, circulation pump speeds, ground loop return temperature and building circuit return temperature. The model is validated using data from a full-scale ground source heat pump installation. The validated model is used to examine system capacity and performance sensitivity to different control optimisation strategies, including set-point control of room air temperature, room air bandwidth temperature, building loop return water temperature and building loop return bandwidth temperature. [ABSTRACT FROM AUTHOR]

Abstract: In heating mode, fresh air is still essential for a chilled panel system in order to ensure the indoor air quality. In this paper, a chilled ceiling panel system was designed and built in a typical office room. The thermal environment and thermal comfort in the room were fully measured and evaluated by using the Fanger''s PMV–PPD model and the standard of ISO 7730 respectively, when room was heated in two modes, one of which is the chilled panel heating mode and the other of which is the combined heating mode of chilled panel and supply air. The research results indicate that in the combined mode, ceiling ventilation improves the general thermal comfort and reduces the risk of local discomfort. Under the condition of same general thermal comfort, the heating supply upper limit of chilled panel can be increased by 12.3% because of air mixing effect caused by introduction of air ventilation. [Copyright &y& Elsevier]

Abstract: The significant and continuous increment in the global electricity consumption is asking for energy saving strategies. Efficient control for heating, ventilation and air-conditioning systems (HVAC) is the most cost-effective way to minimize the use of energy in buildings. In this framework, an energy management and control system (EMCS) has been developed to schedule electricity end-uses in the campus of the Universidad Politécnica de Valencia (UPV), Spain. This paper presents an evaluation performed by using the EMCS of different control strategies for HVAC split systems. It analyzed the effect of different schedules for a common air-conditioning device and demand response strategies are tested in several situations. The economic saving is calculated taking into account the electricity contract clauses. Finally, a test is made for the control of a group of similar devices in order to reduce the maximum peak power in consumption and to obtain a flexible load shape with the HVAC loads. The studies are then extrapolated to a larger system, the whole University campus, for which energy and economic savings are quantified. [ABSTRACT FROM AUTHOR]

Abstract: Green roofs are a passive cooling technique that stop incoming solar radiation from reaching the building structure below. Many studies have been conducted over the past 10 years to consider the potential building energy benefits of green roofs and shown that they can offer benefits in winter heating reduction as well as summer cooling. This paper reviews the current literature and highlights the situations in which the greatest building energy savings can be made. Older buildings with poor existing insulation are deemed to benefit most from a green roof as current building regulations require such high levels of insulation that green roofs are seen to hardly affect annual building energy consumption. As over half of the existing UK building stock was built before any roof insulation was required, it is older buildings that will benefit most from green roofs. The case for retrofitting existing buildings is therefore reviewed and it is found there is strong potential for green roof retrofit in the UK. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a predictive control structure for thermal regulation in buildings. The proposed method exploits the intermittently operating mode of almost all types of buildings. Usually the occupation profile can be known in advance and this fact will be used to reduce the energy consumption without decreasing the thermal comfort during the occupation. For that purpose, the predictive control strategy is first presented for a single zone building then extended to a multizone building example. Two opposite control strategies commonly exists: the decentralized control structure, which does not offer good performances especially when the thermal coupling among adjacent rooms is not negligible, and on the other hand, the centralized control for which the computational demand grows exponentially with the size of the system, being very expensive for large scale buildings. Our solution is based on a distributed approach which takes the advantages of both methods mentioned above. A distributed MPC algorithm with one information exchange per time step is proposed with good control performances and low computational requirements. Simulations and a comparison performance table end the article. [Copyright &y& Elsevier]

Abstract: To achieve high heat pump efficiency, groundwater heat pump (GWHP) system uses groundwater, which is relatively stable AT temperature compared with outdoor air, as a heat source. However, it is difficult to meet annual heating and cooling loads using only groundwater as a heat source. In order to optimize the operation method of GWHP systems, it is necessary to develop a system utilizing both groundwater and air sources according to the building load conditions. Furthermore, during intermediate seasons (such as spring and autumn) with reduced heating and cooling loads, GWHP system is less efficient than air source heat pump (ASHP) system according to temperature conditions. In order to more efficiently use GWHP systems, it is necessary to develop a system which utilizes both groundwater and air sources according to temperature conditions and building loads. This research has developed a GWHP system that employs a hybrid heat pump system with groundwater wells using dual groundwater and air heat sources. In this paper, the annual performance of the developed system has been calculated, and several case studies have been conducted on the effect of introduction location, refrigerant and pumping rate. Furthermore, the coefficient of system performance and the effects on underground environments have been evaluated by real-scale experiment using two wells. [Copyright &y& Elsevier]