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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]

Abstract: It is well known that it is necessary to insulate the buildings to decrease the thermal demand and to decrease the use of heating and cooling. Due to the high cost of fossil fuels and to the necessity to reduce CO2 emissions, and also due to the new building regulations more attention is paid to the insulation of buildings. Different insulation materials are available in the market. Usually, they are compared by their thermal conductivity and with theoretical calculations, but there are no experimental comparisons available, where the behavior of such insulation materials in a building is compared over time. This is why the authors started a comparison of three typical insulation materials, polyurethane, polystyrene, and mineral wool. For this purpose, four house-like cubicles were constructed (with a size of 2.4m×2.4m×2.4m) and their thermal performance throughout the time was measured. The cubicles were built under a conventional Mediterranean construction system, differing only in the insulation material used. During 2008 and the first months of 2009 the performance of these cubicles was evaluated, and the results are presented in this paper. [Copyright &y& Elsevier]

Abstract: The paper presents an extended method for exergy analysis of buildings and Heating Ventilation Air Conditioning (HVAC) systems, according to an energy demand build-up model from the building side to the energy supply side. The HVAC systems comprise a thermal energy emission and control system, a thermal distribution system, an electricity distribution system and an energy conversion system. Energy and exergy that are required by a building and a HVAC system are posed into the external part and classified by different forms of energy carriers. The external part is out of the boundary of the study. The method is illustrated with an office building equipped with low-temperature heating and high-temperature cooling systems situated in the Netherlands. Thermal exergy and thermal energy demands of the building and thermal energy and thermal exergy losses occurring in the HVAC systems are discussed. The building and the HVAC systems to be considered meet standard Dutch energy performance regulations. Nevertheless their overall exergy efficiencies are low in both cases (17.15% and 6.81% subsequently). The exergy analysis also pinpoints that the thermal energy emission and control system and the energy conversion system are the main causes of the exergy inefficiencies in the heating and cooling cases, respectively. [Copyright &y& Elsevier]

Abstract: Complex, inconvenient and badly arranged push buttons and menus on domestic heating controls often cause users to enter unsuitable settings that result in impaired comfort and poor operating efficiency. This paper proposes a novel approach to the human interface of home heating systems that greatly simplifies the input required from the user. Time settings are derived automatically from electricity consumption and hot water use, also a temperature set point is provided that adapts to user activity levels and external temperature. Practical results from a prototype control system incorporating these methods are reported, showing useful energy savings. It is argued that this increased automation of control allows the benefits of low carbon technologies such as micro-combined heat and power, and solar hot water heating, to be fully exploited. [Copyright &y& Elsevier]

Abstract: Possible solutions for zero energy building design in UK are discussed in this paper. Simulation software (EnergyPlus and TRNSYS 16) are employed in this study, where EnergyPlus simulations are applied to enable facade design studies considering building materials, window sizes and orientations and TRNSYS is used for the investigation of the feasibility of zero energy houses with renewable electricity, solar hot water system and energy efficient heating systems under Cardiff weather conditions. Various design methods are compared and optimal design strategies for typical homes and energy systems are provided. [Copyright &y& Elsevier]

Abstract: The paper concerns thermal energy consumption in residential buildings. Heat consumption data of 2280 buildings are compared. Special attention is given to compare heat consumption in identical buildings. Heat consumption variability analysis enables to evaluate inherent heat consumption for space heating dissipation which exists even if design and construction requirements are met. The attempt is made to find the numeral value of heat consumption dissipation caused by design and construction allowances. The analysis of multiflat panel sister-buildings annual heat consumption reveals that minimal value of maximal and minimal heat consumption ratio in identical panel buildings reaches 1.22 (95% confidence level). Data scatter testify erratic quality of construction works, in other words, maximal and minimal heat consumption ratio trend reflects quality of construction works as a whole. On the other hand awareness of inherent unavoidable heat consumption difference in similar houses may strengthen residents’ and policy makers’ confidence in energy saving tools and enhance thermal renovation of residential buildings. [Copyright &y& Elsevier]

Abstract: Earth–pipe–air heat exchanger (EPAHE) systems can be used to reduce the heating load of buildings in winter. A transient and implicit model based on computational fluid dynamics is developed to predict the thermal performance and heating capacity of earth–air–pipe heat exchanger systems. The model is developed inside the FLUENT simulation program. The model developed is validated against experimental investigations on an experimental set-up in Ajmer (Western India). Good agreement between simulated results and experimental data is obtained. Effects of the operating parameters (i.e. the pipe material, air velocity) on the thermal performance of earth–air–pipe heat exchanger systems are studied. The 23.42m long EPAHE system discussed in this paper gives heating in the range of 4.1–4.8°C for the flow velocities 2–5m/s. Investigations on steel and PVC pipes have shown that performance of the EPAHE system is not significantly affected by the material of the buried pipe. Velocity of air through the pipe is found to greatly affect the performance of EPAHE system. [Copyright &y& Elsevier]

Abstract: Trigeneration systems, also known as Combined Heat, Cooling and Power (CHCP) systems, are interesting alternatives to supply different energy services in urban districts and in large buildings, particularly in warm areas such as Mediterranean countries. These systems can provide substantial benefits from economic, energetic, and environmental viewpoints, since the cogenerated heat can be used for heating in winter as well as cooling in summer with an absorption refrigerator. This paper develops an optimization model using Mixed Integer Linear Programming (MILP) to determine the type, number and capacity of equipment in CHCP systems installed in the tertiary sector as well as to establish the optimal operation mode for the different plant components on an hour-by-hour basis throughout the year. The objective function to be minimized is the annual total cost. The optimization model considers the legal constraints imposed to feed the surplus autogenerated electricity into the grid at a regulated feed-in tariff. The optimization model is applied to design a system providing energy services for a hospital located in the city of Zaragoza (Spain). The effects of the financial market conditions and energy prices in the optimal structure of the system are analyzed. [Copyright &y& Elsevier]

Abstract: This paper presents a detailed meta-analysis of end and primary energy use for heating, cooling and ventilation of 11 low-energy non-residential buildings and one residential building in Germany that belong to the EnOB research program launched by the German Federal Ministry for Economy. In particular, the analysis emphasizes the substantial impact of auxiliary energy use on the efficiency of heating and cooling performance. The investigated buildings employ environmental energy sources and sinks – such as the ground, ground water, rainwater and the ambient air – in combination with thermo-active building systems. These concepts are promising approaches for slashing the primary energy use of buildings without violating occupant thermal comfort. A limited primary energy use of about 100kWhprim/(m2 neta) as a target for the complete building service technology (HVAC and lighting) was postulated for all buildings presented. With respect to this premise, a comprehensive long-term monitoring in high time resolution was carried out over the course of two to five years, with an accompanying commissioning of the building performance. Measurements include the energy use for heating, cooling, and ventilation, as well as the auxiliary equipment, the performance of the environmental heat source and sink, and local climatic site conditions. [Copyright &y& Elsevier]

Abstract: The large thermal time constant of thermally activated building systems (TABS) hampers communication between the system''s production and emission. Therefore, conventional building control strategies, typically using room temperature feedback, are unadapted to control thermal comfort efficiently. In this paper, measurement data and simulation results reveal that unadapted TABS control has a dramatic impact on overall energy performance. Measurements in a TABS building with room temperature feedback show the HVAC system switching between heating and cooling in a very short time frame. A simplified, generic room model is used to simulate, understand and evaluate this behaviour. For room temperature feedback control, only 45% of the cold and 15% of the heat produced actually controls room temperature. The remainder is stored in the TABS and exchanged between the heating and cooling system. Enlarging the heating-to-cooling set point band improves this ratio, while maintaining thermal comfort. On the other hand, night time operation control of the circulation pump, adapted to the TABS thermal time constant, eliminates this ‘unused’ energy completely. In this case, however, even with perfect heat gain forecasts, it is difficult to avoid room temperatures dropping below thermal comfort limits during initial office hours. Hence, a supplementary air-conditioning system seems inevitable. [Copyright &y& Elsevier]

Abstract: The Kyoto protocol binded the developed countries to reduce the greenhouse gas emissions at least by 5% by 2008–2012 in order to tackle global warming and climate change. Some of the measures of the governments to achieve this goal are to promote new buildings construction and to retrofit existing buildings while satisfying low energy criteria. This means improving energy efficiency of buildings and energy systems, developing sustainable building concepts and promoting renewable energy sources. The design of a low energy building requires parametric studies via simulation tools in order to optimize the design of the building envelope and HVAC systems. These studies are often complex and time consuming due to a large number of parameters to consider. Hence, this paper aims to set up a methodology that simplifies parametrical studies during the design process of a low energy building. The methodology is based on the Design of Experiments (DOE) method which is a statistical method widely used in industry to perform parametric studies that reduces the required number of experiments. [Copyright &y& Elsevier]

Abstract: Exergy is naturally related to the concept of quality of energy. Therefore, exergy analysis has been widely applied in parallel with energy analysis in order to find the most rational use of energy. Within the built environment a wide margin for exergy saving may be found. Actually, buildings require mostly low quality energy for thermal uses at low temperatures and nowadays their energy demand is mainly satisfied with high quality sources. Exergy analysis of renewable energy-based climatisation systems may be considered an emerging field, where different and often contrasting approaches are followed. Then, in this paper a comprehensive and critical view on the most recent studies on this topic is presented. Special attention is paid to the methodological aspects specifically related to climatisation systems and renewables, and to the comparison of the results. Main renewable energy-based heating and cooling systems are considered in detail. Finally, conclusions regarding the state of the art and possible trends on this field are derived, with the aim to highlight future research issues and promote further developments of this method. Furthermore, conclusions regarding the usability of the exergy method as a tool to promote a more efficient use of available energy sources are also derived. [Copyright &y& Elsevier]

Abstract: Axiomatic design (AD) is a theory that helps to develop new design objects and allows one to evaluate the quality of designs. The aim of this paper is to apply this theory to the design of heat ventilation and air-conditioning (HVAC) systems and to come to conclusions about the design quality of some specific applications. The focus is the comfort and energy consumption in commercial buildings in South European climates. The discussion contains a brief description of variable air volume (VAV) systems and dedicated outdoor air systems (DOAS) with terminal units, such as fan-coils, induction units and chilled ceilings. Occasionally, the DOAS design should include over-cooled outdoor air in order to ensure an extra cooling means. According to the AD''s first axiom, ideal systems are independent or decoupled. Our conclusion is that VAV and DOAS with induction units are coupled designs, and on the other end, DOAS with fan-coils or chilled ceilings are decoupled designs. In addition, over-cooling outdoor air (OA) flow couples the OA flow with the indoor heat removable needs. [Copyright &y& Elsevier]

Abstract: The Chinese kang is an ancient integrated home system for cooking, sleeping, domestic heating and ventilation. It is still widely used today in nearly 85% of rural homes in northern China. In 2004, there were 67 million kangs used by 175 million people. Existing kang designs are mostly based on the intuition and accumulation of craftsman experience. There is a trend that Chinese kang is gradually replaced by bed and coal-burning radiators, domestic heating stoves, etc. using commercial energy. As rural building heating constitutes 25% of total building energy consumption in China, we consider that the transition and new technologies for rural home heating in northern China is crucial for managing future building energy consumption in China. This paper reviews the basic heat transfer and airflow principles of Chinese kang, as well as describing the traditional grounded kang and the relatively new elevated kang. The thermal performance of the kang is shown by data from literature and field surveys. The future of Chinese kang and research needs is also briefly discussed. There is also a need for scientific study in addition to experience accumulation, to form basis for engineering design. [Copyright &y& Elsevier]

• The cascaded PCMs charge–discharge processes and cycle entransy models are studied. • To run stably and efficiently, the charge–discharge cycle model is recommended. • The thermal performance of cascaded PCMs may be worse than that of single PCM. • The cascaded PCMs is suitable for scenes with large temperature differences. • In heating systems, the total NTU of cascaded PCMs is recommended between 4.5 and 6. Thermodynamic analysis can guide the application of the cascaded latent heat storage system (CLHSS) for space heating. However, in previous studies, the CLHSS charge–discharge process and the cycle are not distinguished, and the applicability of the corresponding models is not analyzed. In addition, the technical advantages of CLHSS in heat utilization are still unclear. This paper solved the above three problems to provide theoretical guidance of the CLHSS integrated into heating systems. First, the CLHSS charge–discharge cycle is the special charge–discharge processes in which the initial and final states of each PCM are consistent. The CLHSS charge–discharge processes and cycle models are established and optimized. Second, the optimization results of charge–discharge processes model cannot ensure the same initial and final states of each PCM, which leads to unstable operation and performance degradation of the CLHSS. Thus, the CLHSS charge–discharge cycle model is recommended. Third, when the total number of heat transfer unit (NTU) of CLHSS is less than that of single-stage latent heat storage system (SLHSS), the thermal performance of CLHSS may be worse than that of SLHSS. Besides, the use of CLHSS instead of SLHSS is suitable for scenes with large temperature differences between heating equipment and heating terminals. Finally, parameters effects on optimization results are analyzed. From the perspective of improving entransy efficiency, it is recommended that the total NTU of CLHSS during charge process and discharge process are between 4.5 and 6, and as close as possible. [ABSTRACT FROM AUTHOR]

• Sleeping thermal comfort using a bed-based ASHP was numerically studied. • A digital thermal manikin (DTM) was used to simulate a sleeping person. • The PTS - WPD model was used to evaluate sleeping thermal comfort. • Four factors affecting sleeping thermal comfort were numerically analyzed. Sleeping is an important human activity and heating system is needed for a comfort sleeping thermal environment in winter. By combining the merits from both an air source heat pump (ASHP) and a Chinese-Kang heating system, a prototype bed-based ASHP (B-ASHP) system has been proposed, and several design/operating parameters were experimentally and numerically studied previously. A numerical study using a digital thermal manikin (DTM) on the impacts of four influencing factors, i.e., operating mode, bed surface temperature (t bed), thermal resistance of mattress (R mat), and thermal resistance of quilt (R q) on sleeping thermal comfort was carried out, and the study results are reported in this paper. The numerical study results suggested that firstly, to maintain a suitable sleeping thermal environment, the use of only the Horizontal section (H-Section) of the bed-based heating terminal of the B-ASHP system was adequate; however using the Horizontal and Vertical section (H + V-Section) could minimize the temperature difference between the micro-climate close to the bed and outside environment, although with a higher energy consumption. Secondly, t bed of the bed-based terminal should be carefully selected, and a t bed of 44 °C could both meet the requirement of thermal comfort and acceptable operating efficiency of the B-ASHP system. Thirdly, the use of a mattress would reduce the heat transfer from the bed-based terminal to a sleeping person and indoor space, however an excessively higher R mat of mattress would reduce the heating capacity and operating efficiency, leading to a cold sleeping environment. Finally, the use of a quilt would help prevent the heat loss from a sleeping person, thereby maintaining a warmer sleeping thermal environment, however a higher-than-necessary R q of quilt would decrease the sleeping thermal comfort. [ABSTRACT FROM AUTHOR]

• The comprehensive survey on individual household heating in Serbia. • Results reveal barriers and opportunities for the successful energy transition. • The obsolescence of HSs, low efficiency, and lack of funds are evident. • Noticeable potential for achieving energy and GHG savings. • Subsidies and raising environmental awareness are recognized as policy measures. This paper presents the results of the household survey on individual household heating systems in Serbia. The survey was conducted in the period October to December 2020 with the participation of 1100 households with individual household heating systems. The information collected in the questionnaire can be separated into three main parts: basic household data, current heating system characteristics, and households' perceptions and attitudes. The survey results provide unique and comprehensive information concerning individual household heating systems and the main barriers and drivers for a successful energy transition in the future. The results show the obsolescence of household heating systems, low efficiency, insufficient investment in thermal insulation in the past, and lack of financial resources for investing in sustainable heating. On the other hand, this survey highlights the positive attitude of about half of households towards potential subsidizing of the cost of new heating systems. This survey presents a valid starting point for defining instruments aimed to improve energy efficiency in the household sector, diminish its influence on climate change, and secure energy transition towards sustainable heating systems. The obtained results should be indicative for middle-income developing countries at the beginning of the energy transition process. [ABSTRACT FROM AUTHOR]

• A comprehensive overview of various modeling methods for BTES is presented. • Validated against the TRNSYS DST model and real-life monitoring data. • Three operation strategies of BTES in DH system are investigated. • Six building insulation and weather scenarios to increase the results' robustness. • The time-scheduled combined control strategy is more beneficial among all scenarios. This paper presents a modeling and simulation method that supports energy performance assessment and operation strategy investigation of borehole thermal energy storage in the Chifeng district heating (DH) system. A living laboratory in Chifeng, China that integrates a 0.5 million m3 borehole thermal energy storage system, an on-site solar thermal plant and excess heat from a copper plant is presented. The research adopts Modelica models from open source libraries to evaluate the system. The validity of the borehole thermal energy storage model is evaluated through an inter-model comparison study and an empirical validation test. We used the validated model to investigate three operation strategies. We conclude that the time-scheduled combined operation strategy is more beneficial for the studied system regarding CO 2 emission reduction. [ABSTRACT FROM AUTHOR]

In the current economic situation in Ukraine, the operation of heat supply systems occurs at a reduced temperature of circuit water. The increased temperature graph of 95/70 °C due to the high cost of fuel is impractical. The experience of such countries as Denmark, Germany, Finland, Sweden and Holland with developed centralized heat supply indicates the need for the first-class equipment of an individual heating point (IHP) of a building with an automatic control system, and then the transition to technology with a reduced temperature graph is carried out. Therefore, the modernization of heat supply systems in Ukraine aimed at the use of a reduced temperature graph will require a transition to closed independent heating systems, to qualitative and quantitative regulation and to automation of consumer IHP systems. A lot of district heating systems in Poland also require modernization to meet the requirements of the European Directive EED 2018/2002. This paper presents the results of numerical study of the influence of design and operating parameters of the heat supply network on the choice of the optimal temperature and flow- rate of circuit water of a distric heating system (DHS). [ABSTRACT FROM AUTHOR]

• Novel energy conservation measure yields up to 12% of energy savings. • Grey-box data-driven model efficiently models monozone building. • Building energy consumption optimized while satisfying thermal comfort constraints. • Energy consumption of a commercial building is optimized during winter and summer. This paper proposes a novel energy conservation measure that optimizes the planning of heating and cooling systems for tertiary sector buildings. It consists of a model-based predictive control approach that employs a grey-box model built from the building and weather data that predicts the building heat load and indoor temperature. Different from classical optimization approaches where the discretized differential algebraic equations are integrated into the optimization formulation, our model is calibrated using black-box multiobjective optimization, which allows for decoupling the predictive model from the optimization problem, thus having more flexibility and reducing the total computational time. Moreover, rather than requiring the angle of solar radiation, solar orientation and solar masks to calculate the radiation data, our approach requires only a simple model of the solar irradiance. The calibrated model is then used by heating and cooling optimization strategies that aim at reducing the energy consumption of the building in the next day while satisfying the indoor thermal constraints. The proposed approach was applied in a case study of a commercial building during heating and cooling seasons and the results show that it was able to yield up to 12% of energy savings while having a mean power forecast error of 8%. [ABSTRACT FROM AUTHOR]

Abstract: A hybrid ground-coupled heat pump (HGCHP) with domestic hot water (DHW) supply system has been proposed in this paper for space cooling/heating and DHW supply for residential buildings in hot-climate areas. A simulation model for this hybrid system is established within the HVACSIM+ environment. A sample system, applied for a small residential apartment located in Hong Kong, is hourly simulated in a typical meteorological year. The conventional GCHP system and an electric heater for DHW supply are also modeled and simulated on an hourly basis within the HVACSIM+ for comparison purpose. The results obtained from this case study show that the HGCHP system can effectively alleviate the imbalanced loads of the ground heat exchanger (GHE) and can offer almost 95% DHW demand. The energy saving for DHW heating is about 70% compared with an electric heater. This proposed scheme, i.e. the HGCHP with DHW supply, is suitable to residential buildings in hot-climate areas, such as in Hong Kong. [Copyright &y& Elsevier]

Abstract: The objective of this paper is to develop a model for simulating the thermal and hydraulic behavior of space heating systems with radiators controlled by thermostat valves (TRVs) in multi-family buildings. This is done by treating the building and the heating system as a complete entity. Sub-models for rooms, radiators, TRVs, and the hydraulic network are derived. Then the suggested sub-models are combined to form an integrated model by considering interactions between them. The proposed model takes into account the heat transfer between neighboring rooms, the transport delay in the radiator, the self-adjusting function of the TRV, and the consumer''s regulation behavior, as well as the hydraulic interactions between consumers. To test the model, two space heating systems in Beijing and Tianjin were investigated, and the model was validated under three operation modes. There was good agreement between the measured and simulated values for room temperature, return water temperature, and flow rate. A modeling analysis case was given based on an existing building and heating system. It was found that when the set value of the TRVs were kept on 2–3, about 12.4% reduction of heat consumption could be gained, compared with the situation in which the TRVs were kept fully open. The water flow rate was an important index that truly reflected the heat load change. It was also noted that if the flow rate or supply water temperature changed much during the transport delay time in the radiator, ignoring the transport delay would introduce an obvious deviation of the simulation results. Additionally, when an apartment stopped using the heating system during a heating season, the heat consumption of its neighboring apartments would be increased about 6–14%. [Copyright &y& Elsevier]

Abstract: This paper investigates energy conservation, mitigation of CO2 emissions and economics of retrofitting for a honey storage building with Trombe wall for winter heating application. The passive heating potential of Trombe wall for a honey storage building was estimated using TRNSYS building simulation software. This honey storage building is located at Gwalior (latitude: 26°14′N) in India. During winter months, the room air temperature of building falls below the required temperature range of 18–27°C which is suitable for honey storage. So, the room air temperature range is maintained in the building using a 2.3kW capacity electrical oil filled radiator (or room air heater) which accounts for the major energy consumption of the building on an annual basis. On account of which there are significant CO2 emissions into the atmosphere from the honey storage building. Hence, this case study was conducted to recommend the passive heating concept to the stakeholders of the building so as to conserve the energy requirement for room air heating. The investigation showed that the room air temperature can be easily maintained in the range suitable for honey storage using a vented Trombe wall. The experimental work was carried out for the existing building on a typical clear day of harsh winter month of January to validate the results of TRNSYS model of the present building. The statistical error analysis showed a good agreement between model and experimental results. This investigation concludes that there is potential of energy conservation up to 3312kWh/year and associated reduction in CO2 emissions (∼33tonne/year) using a Trombe wall. Also, the retrofitting of building is economically viable as the simple payback period is only about 7 months. [Copyright &y& Elsevier]

Abstract: Energy performances and building quality can be achieved by high performance envelopes. In this paper the thermal and mechanical performances of external cladding, applied to a traditional wall, largely used in existing buildings, were investigated by a transient simulation. Result comparison with the thermal performances obtained by simulating the wall without the insulation system showed that external insulation is particularly effective in reducing cooling and heating loads and can also guarantee indoor thermal comfort. Fatigue stresses of the external cladding, investigated by ANSYS simulation, showed that continuous change of the loads over time with limited cyclic stress can cause deterioration of materials. [Copyright &y& Elsevier]

Abstract: This paper analyses the ventilation airflow pattern in a two-bedded hospital room. The whole space of the room is divided in modules by means of curtains and internal partition walls. This configuration has many advantages from the point of view of comfort and medical assistance, but it implies an important restriction as far as ventilation is concerned. The ventilation system consists of an induction unit placed inside the hall ceiling blowing into the room and an exhaust fan in the bathroom. Numerical model solves mass, momentum and mean age of air equations assuming isothermal and stationary flow. Ventilation is evaluated analysing the age of air and the velocity fields inside the room. The results with the initial architectural design of the room show a very deficient ventilation at the patients site. Alternative configurations have been studied, allowing for correct ventilation without renouncing to the assistance advantages. Finally, the optimum configuration of the room is provided, regarding both the comfort of the patients and the cost of execution. [Copyright &y& Elsevier]

Abstract: In the last decade a lot of research effort has been spent on identifying the effect of the urban climate on the energy performance of buildings and HVAC (heating ventilation and air conditioning) systems. In this paper a methodology is proposed to assess that effect by the exclusive use of modeled data. Particularly, by using a downscaling modeling procedure a process for the generation of weather files for energy calculations is achieved. From a non-hydrostatic weather model the urban climate of the city of Lisbon is simulated and via a weather generator climatic data files for the buildings’ simulation software are derived. The results on the energy behavior of a reference test cell for different sites inside the city of Lisbon are presented. [Copyright &y& Elsevier]

Abstract: This paper reports on an analytical investigation into the energy saving potential associated with modified comfort limits in transitional spaces in buildings. Such spaces may not require the same high level and close environmental control of more fully occupied spaces and thus a wider variation in conditions and interpretation of thermal comfort may be permitted. Estimations are made of energy saving potential based upon typical floor area proportions utilised for transition spaces of various types in office/commercial buildings. The data are combined with suggested norms for comfort expectation that have wider temperature limits than for normally occupied office zones. The method has been applied to a series of building types situated in the climate of the East Pennines area of the UK using a thermal analysis tool. The results show that useful energy savings (particularly for heating) are possible by allowing for a modest (and realistic) relaxation of prescribed comfort standards in transition spaces. Further work is now required to confirm the limits and assess energy saving in practice. [Copyright &y& Elsevier]

Abstract: As a high-efficiency air-conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way in office buildings. However, there is no well-known energy simulation software available so far which can be used for the energy analysis of VRF. Based on the generic dynamic building energy simulation environment, EnergyPlus, a new VRF module is developed and the energy usage of the VRF system is investigated. This paper compares the energy consumption of the VRF system with that of two conventional air-conditioning systems, namely, variable air volume (VAV) system as well as fan-coil plus fresh air (FPFA) system. A generic office building is used to accommodate the different types of heating, ventilating, and air-conditioning (HVAC) systems. The work focuses on the energy consumption of the VRF system in the office buildings and helps the designer''s evaluation and decision-making on the HVAC systems in the early stages of building design. Simulation results show that the energy-saving potentials of the VRF system are expected to achieve 22.2% and 11.7%, compared with the VAV system and the FPFA system, respectively. Energy-usage breakdown for the end-users in various systems is also presented. [Copyright &y& Elsevier]

Abstract: Among the different existing methods to characterise the aerodynamic sealing effect provided by an air curtain device placed over the opening between two contiguous compartments, infrared thermography has revealed to be a very useful tool. Besides allowing the capture, in an expedite way, of instantaneous images of the temperature field in the neighbourhood of the door, the technique hereon described has other advantages, in terms of quick and easy setup, low intrusive character and liability of obtained results. To apply this method, a large sheet of paper was stretched in the direction perpendicular to the opening where the air curtain device has placed to allow the registration of pictures or video sequences with an infrared camera setup in its maximum sensitivity. Good concordance between the thermographs obtained with this technique and the temperature fields measured for the same plane with a rack of 16 low velocity omni-directional thermal anemometer probes allowed its validation. Various elucidative examples of the use of this technique as a complementary tool for analysis and visualization of the complex physical phenomena occurring for the studied flow are presented in this article. [Copyright &y& Elsevier]

Abstract: An energy cost allocation system records the energy consumption of a building and divides the overall energy costs between the flats. Because the indoor temperatures of rooms are usually not equal, static heat flows between flats cannot be avoided. Hence, in order to ensure fair energy costs per flat the system should be able to determine the static heat flows, preferably without utilising in situ measurements. This paper presents a new method for estimating static heat flows between neighbouring rooms. The approach is theoretical, focusing only on heat transfer issues. Energy cost allocation is not considered. The approach is based on the parametric model describing thermal behaviour of an occupied space. The model is created for each room of a building. Parameter values are identified using real-time measurements collected by a building automation system from each room and its environment. The tuning of parameters takes a few days using a 15-min sampling time. A prerequisite for successful system identification is the overall control of the room temperatures. All test runs are performed in a simulated office hotel using the TRNSYS simulation program. The results are encouraging, but further research is needed, especially in a real building environment. [Copyright &y& Elsevier]

Abstract: Ground heat exchanger (GHE) coupled heat pumps constitute an alternative system for the air conditioning of buildings, with the vertical U-tube type being the most popular. The installation cost and the overall performance of the system strongly depends on the designing and dimensioning, which however present significant difficulties. The critical parameter in designing vertical systems is the thermal power per meter of borehole that the GHE can handle. This paper presents a calculation algorithm, which aims to redefine the maximum thermal load allowable in vertical ground heat exchangers. [Copyright &y& Elsevier]

Abstract: There are varieties of physical and behavioral factors to determine energy demand load profile. The attainment of the optimum mix of measures and renewable energy system deployment requires a simple method suitable for using at the early design stage. A simple method of formulating load profile (SMLP) for UK domestic buildings has been presented in this paper. Domestic space heating load profile for different types of houses have been produced using thermal dynamic model which has been developed using thermal resistant network method. The daily breakdown energy demand load profile of appliance, domestic hot water and space heating can be predicted using this method. The method can produce daily load profile from individual house to urban community. It is suitable to be used at Renewable energy system strategic design stage. [Copyright &y& Elsevier]

Abstract: Solar air collectors are important components for solar energy utilization in green houses. In this paper, experimental studies were carried out regarding to a solar air collector (SAC), for which the length of air channel is 1500mm, the width is 500mm, and a variable air channel gap ranges from 100 to 500mm. In the experiment, the uniform heat flux along the air channel is effected by three electric heating plates, which play a role as solar radiation. It is found that the temperature distribution of air and the induced natural air-flow rate are highly dependent on heat input, inclination angle, channel gap, etc. Experimental results indicate that the optimum inclination angle for the SAC is 45°, under which a maximum natural ventilation rate can be created. Also found is that there exists an appropriate channel length, about 1m in this study, beyond which the obtained heat and the natural ventilation rate cannot be increased drastically. Higher the volume of air-flow rate through the SAC, lower the temperature difference between inlet and outlet, consequently, it should be balanced between the air temperature rise and a suitable mechanical air-flow rate in order to obtain maximum heat. Additionally, theoretical analysis based on heat balance equations is testified to agree well with experimental results. [Copyright &y& Elsevier]

Abstract: This paper put forward a new kind of under-floor electric heating system with shape-stabilized phase change material (PCM) plates. Different from conventional PCM, shape-stabilized PCM can keep the shape unchanged during phase change process. Therefore, the PCM leakage danger can be avoided. This system can charge heat by using cheap nighttime electricity and discharge the heat stored at daytime. In the present work, the thermal physical properties of shape-stabilized PCM developed by us were measured. A prototype room with this system was set up in Beijing to testify its thermal performance and feasibility of this heating mode. The results show that temperature of the PCM plates upper surface can be kept near the phase transition temperature in whole day and a lot of off-peak period electricity can be used for space heating in stead of using peak period electricity, which obviously lowers the electricity tariff. [Copyright &y& Elsevier]

An experiment was carried out over two heating seasons to test the performance of an inferential control scheme (ICS), which was designed to optimise the control of boilers in multi-zone heating systems [Building Services Engineering Research and Technology 4 (2003) 245], in a real installation. This paper presents the development of the prototype controller, method and result of the experimental testing. The experimental results show that the ICS can significantly improve the long-term performance, i.e. energy efficiency and thermal comfort, of the multi-zone heating system compared with conventional control schemes. It also demonstrates that the ICS can be implemented in a microprocessor-based controller and be commissioned using short-term monitoring data, which makes it a practical control technique. [Copyright &y& Elsevier]

Due to limited availability of natural resources exploited for heating and in order to reduce the environmental impact, people should strive to use renewable energy sources. Heat pumps allow the conversion of ambient heat, available in almost unlimited quantities, to heating energy. The paper describes an energy-saving house provided with good thermal insulation and heated by an air-to-water split-type heat pump. The condenser is located in the attic and the evaporator in the boiler room of the house. The house heating up to the ambient temperature of 0 °C was provided by an air-to-water heat pump and a condensing oil heating furnace if the ambient temperature dropped to below 0 °C. The results of the nine-year testing showed that the heat pump was used during most of the heating season. The average coefficient of performance (COP) of the air-to-water heat pump in nine heating seasons was 3.16, indicating that over 68% of the heat was obtained from the ambient air. The comparison between COP of air-to-water heat pumps in energy-saving house and of water-to-water heat pumps fitted in houses dealt with under other projects indicates that water-to-water heat pumps have higher COPs. The heat pumps obtain heat from groundwater, hence they are capable of operating throughout the heating season, and possess the highest COP. The advantage of an air-to-water heat pump, however, lies in its simple design and a wide range of applications.In comparison to the furnace the heat pump yielded considerable saving in fuel and money, which justifies its home heating application in the Central European climatic area. The analysis conducted by the Austrian company Energie Ag/Obero¨stereich showed that heating with heat pumps was the highest and heating with liquid gas was the least cost efficient. [Copyright &y& Elsevier]

This paper studies the influence of two admixtures on expanded perlite aggregate concrete. Both silica fume and fly ash were added as replacement for cement by decreasing the cement weights in the ratios of 10, 20 and 30% by weight. The binder dosage was kept constant at 200 kg/m3 throughout this study. Superplasticizer was used 1.5% by weight of Portland cement to reduce w/c ratios.The obtained results showed that: the thermal conductivity decreased with the increase of silica fume and fly ash as replacement for portland cement up to 14 and 18%, respectively. Densities of all samples decreased from 522 to 483 kg/m3 with the increase of both admixtures. Silica fume and fly ash decreased the density of samples. The compressive strengths decreased 12, 19, 29 for 7 days, and increased 9, 13%, 4%, for 28 days due to 10, 20 and 30% silica fume, respectively. Fly ash induced to reductions in the compressive strength up to 36% at 7 days and 27% at 28 days. [Copyright &y& Elsevier]

The evaluation of renewable energy used to increase the environmental friendliness of passive houses (PH) is the topic of this paper. A time-dependent model of passive house thermal behavior is developed. The heat-transfer through the high thermal inertia elements is analyzed by using a 1D time-dependent conduction heat-transfer equation that is solved numerically by using a standard Netlib solver (PDECHEB). Appropriate models for the conduction through the low thermal inertia elements are used, as well as a simple approach of the solar radiation transmission through the windows. The model takes into account in a detailed fashion the internal heat sources. Also, the operation of ventilation/heating system is described and common practice control strategies are implemented. Three renewable energy sources are considered. First, there is the passive solar heating due to the large window on the fac¸ade oriented south. Second, the active solar collectors system provides thermal energy for space heating or hot domestic water preparation. Third, a ground heat exchanger (GHE) increases the fresh air temperature during the cold season. The model was applied to the Pirmasens Passive House (Rhineland Palatinate, Germany). The passive solar heating system provides most part of the heating energy during November, December, February and March while in January the ground heat exchanger is the most important renewable energy source. January and February require use of additional conventional energy sources. A clever use of the active solar heating system could avoid consuming classical fuels during November, December and March. The ground heat exchanger is a reliable renewable source of energy. It provides heat during all the day and its (rather small) heat flux is increasing when the weather becomes colder. The air temperature at heater exit is normally lower than 46 °C. This is a good reason for the use of renewable energy to replace the classical fuel or the wood to be burn in the heater. [Copyright &y& Elsevier]

A passive house is a cost-efficient building that can manage throughout the heating period, due to its specific construction design, with more than 10 times less heat energy than the same building designed to standards presently applicable across Europe. Its extended thermal insulation and enhanced air-tightness removes the need for temperatures higher than 50 °C. This makes renewable energy sources particularly suitable for heating, cooling and domestic hot water production. Modeling of renewable energy usage for space heating requires as a preliminary stage the detailed description of the building structure, of the HVAC equipment and of the internal heat sources. This paper shows the main data used to model the thermal behavior of a passive house. Details about Pirmasens Passive House (Rhineland Palatinate, Germany) are given, as for example, the internal heat sources, including electric appliances, heat and humidity released by human bodies, thermal internal facilities as hot and cold water pipes. All these are quantified by using statistically derived data. A detailed time schedule for a standard German family with two adults and two children was prepared. It takes into account the national celebrations, vacation and weekends among others. [Copyright &y& Elsevier]

The residential heating method in Korea underwent various phases of development to reach the current system. The first phase was the traditional Ondol (the traditional under floor heating system in Korea), where the floor was heated by the circulation of hot gas produced by a fire furnace (before the 1950s). The second phase involved the use of the modified anthracite coal Ondol, for which the fire furnace was modified for briquette use (from the early 1950s to the late 1970s). The third phase involved the use of hot water radiant floor heating with embedded tubes (from the late 1970s). This paper presents insights into the problem of current residential heating in Korea and the general aspects of heating energy savings by tracing the history of residential heating in Korea and analyzing related data. The results show that modern apartment buildings with hot water radiant floor heating (the third phase) yield less heat loss due to the tighter envelope, but also yield higher energy consumption than the traditional Ondol heating housing (the first phase). Because of an inefficient system and lack of thermal insulation of the traditional Ondol heating housing, Ondol heating was used to heat occupants sitting directly on the floor, keeping lower room temperature and higher floor surface temperature. So the range of comfortable floor temperature for Korean people is higher and this unique comfort sense is related to energy consumption in modern apartment housing. As a result, several energy saving methods were found such as reducing the total floor heating area or zoning the floor area, receiving continuous heat supply, and installing a delicate control system and metering devices. [Copyright &y& Elsevier]

[Display omitted] • Waste heat seasonally stored in the subsurface provides a source of renewable energy. • Borehole thermal energy storage (BTES) can reduce space heating GHG emissions. • BTES integrated with heat pumps has a potential to deliver building heat economically. On average, fossil fuel space heating constitutes 56% of a building's total energy usage in Upstate New York due to the cold winter climate. Similar levels of fossil fuel heating pertain in at least 15 states in the U.S. northern tier. To meet aggressive carbon reduction goals in this tier, decarbonizing the heat supply in the residential and commercial sector must be pursued. Using Borehole Thermal Energy Storage (BTES) to seasonally store excess thermal energy in the subsurface for later heating use is an innovative way to increase heating efficiency and lower carbon emissions. This paper investigates the technical and economic feasibility of heating Snee Hall on Cornell campus with unused summer steam from Cornell's Combined Heat and Power Plant stored in an optimized BTES array. Snee Hall is a 6855 m2 building with an annual total heating load of 3040 GJ. A standard 2-D transient subsurface conductive heat transfer model is coupled to a high temperature heat pump (delivering > 60 °C) that can supply Snee Hall's existing radiators with 70 °C water. For local geological parameters, 94% of Snee Hall's winter space heating demand can be supplied by a 37-borehole array (90 m depth, 3 m spacing) and a 250-kW high temperature heat pump capacity with average coefficient of performance of 3.85. The calculated storage efficiency is 68.7% and the system has a 30-year net present value of about $526,400, an internal rate of return of 13%, and a payback period of 10 to 11 years. The system offsets about 6900 MMBTU (7280 GJ) of natural gas combustion and saves 250 MT CO 2 emissions annually. The results of the single building analysis can be applied to other buildings on campus or in similar geologic settings in the U.S northern tier. [ABSTRACT FROM AUTHOR]

• Three inverse modelling approaches are used to create radiant heater virtual meters. • Zone models using steady-state and transient greybox approaches are developed. • Zone models using water side load disaggregation approach are developed. • Virtual meters accuracy is used to evaluate the performance of the models. • Modelling approaches' data requirements, data processing, and accuracy are compared. Virtual metering at the equipment level provides a non-intrusive tool to understand energy flows in commercial buildings and monitor building energy performance. The accuracy of virtual meters depends on the modelling approach and its ability to capture the underlying physical processes. This paper presents a novel comparison and provides guidance for the selection of inverse modelling approaches used to create virtual meters to estimate the heat supplied by zone-level hydronic perimeter heaters. The approaches investigated are: steady-state inverse greybox modelling, transient inverse greybox modelling, and water-side load disaggregation. Models that represent these three approaches are trained using data from a highly instrumented academic building in Ottawa, Canada. Model parameters are identified using the genetic algorithm and used in creating virtual meters that can estimate the heat added by perimeter heaters into building variable air volume zones. The accuracy of these virtual meters is assessed by comparing them to physical meters installed in these zones. The results indicate that the three modelling approaches can estimate the daily heating energy supplied by perimeter heaters at a normalized root-mean-square error between 16% and 18%. However, the accuracy of the virtual meters declines as the number of zones increases. The performance of the three modelling approaches is evaluated through illustrative examples that compare modelling assumptions, data requirements, data processing, and model prediction accuracy. [ABSTRACT FROM AUTHOR]

• A hybrid optimization algorithm in online optimization of MPC is proposed. • A distributed MPC for multi-zone buildings existing input coupling is studied. • Nash-optimization acts on enhancing the control performance in distributed MPC. • The redefined global performance index provides the possibility to save energy. To meet demands of smart heating development, the novel dynamic regulation methods of heating systems need to be pursued. This paper presents a model predictive control (MPC) approach for room temperature regulation in multi-zone buildings. Among them, a) For heating systems with nonlinearity and large time delay, a hybrid optimization algorithm consisting of the improved particle swarm optimization (IPSO) algorithm and Newton-Raphson (NR) method in online optimization of MPC for a single zone building is proposed. Compared with the quadratic programming method, it can identify successfully the optimal control vector. b) A distributed MPC approach is presented for multi-zone buildings existing hydraulic coupling. Firstly, Nash-optimization acts on searching the global equilibrium point in the distributed structure, then the hybrid optimization algorithm works in the online optimization of these local MPCs. Compared with the decentralized MPC, the control performance is improved through co-operating and communicating between subsystems via network to share information related to their future behavior. Besides, the global performance index in the distributed MPC is redefined as the weighted sum of energy consumption and thermal comfort, which provides the possibility to eliminate quickly the most unfavorable thermodynamic loop in heating systems and reduce energy consumption. [ABSTRACT FROM AUTHOR]

• Control strategy of the heating of an all-air system in an educational building is optimized. • A nearly zero energy educational building in Belgium is used as case study. • Winter monitoring campaign is analysed and a building energy simulation is calibrated. • Climatic control of the boiler causes a decrease of comfort hours up to 23%. • Climatic control of the storage tank determines energy saving until up to 47%. The optimal control of the HVAC system in the nearly zero energy buildings (nZEBs) can be considered as a challenge. Indeed, the lack of data given by monitored data does not allow understanding what are the implications of different strategies on thermal comfort and energy consumptions. This paper determines an approach for the evaluation of the management of the heating system in an existing educational nZEB. The aim is to understand how the energy efficiency of the heating system is sensitive to controls strategies and the important role played by the control systems. The test lecture rooms on KU Leuven Ghent Technology Campus (Belgium) have been chosen as case study. A deep analysis, starting from an in-field monitoring, was carried out during the winter period of 2019, in order to assess the actual operation and the energy use of building systems under real conditions. Then, a building energy simulation (BES) model of the building and its systems was developed and calibrated against the real monitoring data. Control strategies of the heating system are simulated and compared to the current configuration. The simulation results show that strategies based on a definition of a heating curve for the boiler can reduce the comfortable time (−23%). Controlling the temperature inside the storage tank as a function of the outdoor temperature together with the control on the activation of the air handling unit result in an energy savings from 32% to 46%, with a correspondent increase of comfort time in the period from 0.6% to 3.4% compared to the baseline scenario, depending to the relationship between the external temperature and water temperature inside the water storage tank. [ABSTRACT FROM AUTHOR]

• Listed dwellings of southern Spain were monitored in winter to evaluate IEQ and EP. • Lengthy high rates of IRH were observed. • High levels of CO 2 concentration were recorded in bedrooms at night. • Thermal comfort is only achieved through a constant use of the heating systems. • Heat losses are entirely building-driven. Although European heritage buildings are excluded from energy efficiency targets, it would be beneficial to include the largest group, that of listed housing, in energy retrofit plans, in order to encourage its occupation and contributing to the sustainable maintenance of historic cities. This requires reliable experimental studies, which have been rare so far, in order to establish energy rehabilitation plans that do not jeopardize the conservation of their values. This paper aims to contribute to addressing this gap. It evaluates the energy performance and indoor environmental quality of dwellings within listed buildings of the conservation area of Seville, Spain, in the Mediterranean climate zone, under actual winter use and occupation conditions. An experimental campaign was conducted, generating energy models and measuring rates of indoor air temperature to validate them. The findings highlight important health and environmental issues: despite the mild winters of southern Spain, intensive use of the heating system is needed to maintain thermal comfort indoors, increasing polluting emissions; CO 2 concentration in bedrooms is usually excessive overnight and, regularly, indoor relative humidity remains too high; heat losses depend entirely on the physical condition of the constructive elements (walls, roofs, air leakage and glazing) which occupants cannot easily improve. [ABSTRACT FROM AUTHOR]

• Wall-type heat recovery units are solution for improving ventilation in refurbishment. • Assessment of air stream mixing by visualization and CO 2 measurements was conducted. • The risk of air mixing when using wall-type heat recovery units is low. • The analysis of the annual energy demand for residential buildings was conducted. • Wall-type heat recovery units are helpful in achieving low energy buildings. In the cold and moderate climates the energy demand for heating of fresh ventilation air is crucial. The mechanical ventilation systems with heat recovery are used to decrease the peak power of the heating system and to save the energy. In a case of wall-type heat recovery units there is a doubt about the possibility of mixing fresh and exhausted air in the combined intake-outtake device. In this paper experimental investigations were conducted to assess their hygienic safety. The original set-up containing test chamber and the equipment for CO 2 concentration measuring has been used. Visualization of airflows mixing with the usage of smoke is presented. The results show that the risk of the exhausted air return to the building is low. At the same time the ventilating efficiency of such systems is high. The analysis of the annual energy demand for the sample single-family and multi-family buildings has been conducted to present the possible energy benefits of usage such devices. Concluding, the wall-type heat recovery units should be considered as hygienic safe and helpful devices in achieving the standard of low energy buildings in a case of existing and refurbished ones. [ABSTRACT FROM AUTHOR]

• Solar assisted heat pump coupled to a seasonal storage allows heating production. • Seasonal storage of thermal energy is technical and economically feasible. • Seasonal storage is able to be implemented in middle latitude. • PVT panels performance increase with the inclusion of a seasonal storage tank. • Key sizing factors are solar field area, volume of storage and capacity of heat pump. A water-water solar-assisted heat pump (SAHP) is projected on an under construction academic building at the University of Zaragoza (Spain). It integrates a heat pump heating system with photovoltaic/thermal collectors and seasonal storage. Because of its innovative design, considerably higher performances than a conventional type air-source heat pump are expected. This paper shows the simulation of the system performed in TRNSYS, a graphically based software used to simulate the behavior of transient systems. In addition, starting from the current design of the energy system, different sensibility analysis are simulated in order to study alternative configurations of the heating system. The solar coverage of the current installation design is about 60% and the expected savings yield to a payback period of 15,4 years. Three alternative configurations are proposed in this work, reaching up to around 98% of solar coverage. The study results show the technical and economic feasibility of the heating installation based on a solar assisted heat pump with implementation of seasonal storage in an educational building located in a middle latitude. [ABSTRACT FROM AUTHOR]

• Demand-Side-Management with air-to-water heat pump in a Nearly-Zero-Energy-Building. • Model Predictive Control with Artificial Neural Network for heat demand prediction. • Variation of storage capacity and heat pump power shows cost savings up to 24.3% • Market based concepts need further incentives to exploit the flexibility potential of heat pumps. The rollout of the supply dependent generators wind turbines and photovoltaics leads to a flexibility demand that can be adressed from the consumer side, via Demand-Side-Management, as well. In single family houses, the heat pump, in combination with thermal energy storage, can shift their energy comsumption according to price signals in order to reduce consumer costs. This paper analyses the impact of different heat storage sizes and heat pump powers on cost savings and shifting potential, focussing on the Luxembourgish context, when variable electricity prices based on the electricity market are applied. A model predictive controller determines the cost-optimal operating cycles of the heat pump. The building's heat demand is predicted with the help of a neural network. The results of the parametric study show significant differences in energy efficiency and cost savings. Furthermore limitations of taking advantage of variable electicity prices due to the price structure are disclosed. The cost savings however do not give a sufficient incentive for the consumer to invest in optimizing the heating system for Demand-Side-Management purposes. By consequence, the potential and the efficiency of Demand-Side-Management are limited and further incentives are necessary. [ABSTRACT FROM AUTHOR]