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A building-integrated photovoltaic (BIPV) system produces power using photovoltaic (PV) modules as building exterior materials, whose architectural performance serves the same functions as those of existing building materials. Most relevant studies targeted general PV modules used in the building-mounted and -attached types. This study aims to integrate the building elevation-type BIPV system and exterior materials to secure both exterior material performance and PV electrical performance by embedding a power optimization device in an integrated system of BIPV modules and exterior materials. Thus, the advantages of economy, safety, aesthetics, and ease of maintenance can be achieved. In this study, experiments were conducted on elevation-type BIPV modules with and without a power optimizer, that is, a DC/DC converter, under various shade conditions, and the power loss rate of the BIPV system was analyzed. The power optimizer-equipped BIPV system was experimentally observed to have a PV power-loss rate approximately 2–3 times lower than that of the BIPV system without a power optimizer when the shade ratio of one module was approximately 10–75%. This exterior material-integrated BIPV-specific power optimization device reduces dependence on fossil fuels for power production and improves energy sustainability, contributing to the spread of zero-energy buildings and carbon neutrality. [ABSTRACT FROM AUTHOR]

In this study, energy, exergy and exergy-economic analyses of a novel system that simultaneously generates cooling effect, heat, electricity, hot water and desalinated water for a zero-energy building are presented. It is aimed to evaluate the feasibility of using a solar-geothermal system to meet the energy and water demands of a residential building using exergy-economic indexes. The multi-generation system operates based on solar and geothermal energies, and it consists of proton exchange membrane (PEM) electrolyser, PEM fuel cell, photovoltaic system, and a desalination system with a pressure exchanger. Results indicate that energy and exergy efficiencies in cooling mode are 13.27% and 32.44%, respectively, and in heating mode are 17.25% and 42.4%, respectively. The largest exergy destruction occurs in the photovoltaics and organic Rankine cycle. It is observed that the turbine and boiler have the highest portion in the exergy destruction of the organic Rankine cycle. The capital investment and operating and maintenance cost rate, and the cost of produced distilled water are 4.288 ($/h), 67.63 (c$/m3), respectively. Moreover, the unit exergy costs of power, heating and cooling effect are investigated. The exergy-economic factor and the cost of exergy destruction for the entire system are 57.38% and 4.288 ($ h) , respectively. • A novel multigeneration system for zero-energy building is proposed. • The exergy unit cost of generated power, heating and cooling are calculated. • The energy and exergy efficiencies of the system is higher in heating mode. • The exergetic performance of the system deteriorates at higher solar irradiation. [ABSTRACT FROM AUTHOR]

Zero-energy buildings (ZEBs) can contribute to decarbonizing building energy systems, while the energy mismatch between energy demand and on-site stochastic generation in ZEBs increases the need for energy flexibility. This study proposed mixed-integer linear programming energy management schemes for optimizing the flexible scheduling of distributed energy resources, including battery energy storage, heat pump, and building thermal mass as a passive thermal energy storage system. With optimally designed objectives, this study used case studies to evaluate the flexibility potential provided by the demand-side management, considering dynamic characteristics of the process. The results showed that the proposed demand-side management for battery storage offers significant potential in increasing photovoltaic (PV) self-consumption and reducing operational costs. Cost reduction ratios of flexible dispatch of combined PV and battery storage systems exceed 15%. Flexible coupling of PV and heat pump systems for meeting hot water demand can reduce energy cost by more than 20%. The flexible coupling of the heat pump and PV system also had a significant impact on the power consumption pattern of domestic heat pumps, the load-shifting potential highly depends on the available PV generation and hot water demand. The optimal trade-off between thermal energy use and thermal comfort violation may not reduce the total energy used for space heating, the increased PV consumption helped reduce grid imports. The study provides insights into the energy flexibility behavior and efficiency of the proposed demand-side management for ZEBs, which is expected to provide guidelines for exploring demand-side flexibility. [ABSTRACT FROM AUTHOR]

The transition to a net-zero energy system is being promoted in the energy sector, which has led to the creation of energy prosumers. These produce, consume, and trade energy using renewable energy systems installed in buildings or complexes. Here, a community was set as the target to apply the concept of an energy prosumer at the individual building and regional levels. Energy-sharing systems were divided into three categories: energy production, energy storage, and energy management. Energy-sharing systems centered on electrical energy—photovoltaic, battery energy storage, and energy management systems—were installed in two communities located in South Korea, and the energy-sharing effects of the system operation were reported. Monthly power consumption in spring and fall exhibited significant savings of approximately three times that of winter consumption, owing to the energy-sharing systems. Daily hourly power-consumption patterns differed on weekdays and weekends because of the weekday working and building-use hours of the communities. Energy could be shared between communities and buildings because of surplus energy. More surplus power was available for energy sharing on weekends because power consumption was lower. Because energy trading and sharing are restricted, the related laws are being revised. Therefore, a low-carbon community can be realized through surplus energy trading and sharing technology between communities and buildings as renewable energy systems spread owing to low carbonization. [ABSTRACT FROM AUTHOR]

The search for opportunities to save and use energy efficiently should primarily focus on sectors of the economy with the highest energy consumption. One such sector is construction. Buildings built in Poland in different periods according to the introduced and successively tightened thermal protection requirements have different energy characteristics, which differ from contemporary standards and future expectations in this respect. This article presents guidelines for the energy transformation of building resources towards climate neutrality and the condition of these resources in Poland to an extent relevant for estimating the energy savings potential as a result of their thermal modernization. The economic aspect relating to the implementation of the energy policy is also presented. Over the last twenty years, there has been a nearly 37% increase in final energy consumption and a close to 34% decrease in final energy intensity of gross domestic product (GDP) recorded in Poland, which proves that energy efficiency is growing virtually without increasing energy demand. Significant potential for rationalizing energy consumption is found, as well as the need to incur high costs relating to the construction sector transformation. The problem is the lack of databases on the technical condition, age, and energy performance of various groups of buildings, which means it is difficult to determine the thermal modernization needs and the achievable effects of energy savings for the entire building stock. Some inconveniences relating to the implementation of zero-emission guidelines are also pointed out due to the fact that the Polish energy system is largely based on fossil fuels. [ABSTRACT FROM AUTHOR]

Solar power systems, such as photovoltaic (PV) systems, have become a necessary feature of zero-energy buildings because efficient building design and construction materials alone are not sufficient to meet the building's energy consumption needs. However, solar power generation is subject to fluctuations based on weather conditions, and these fluctuations are higher than other renewable energy sources. This phenomenon has emphasized the importance of predicting solar power generation through weather forecasting. In this paper, an Automatic Machine Learning (AML)-based method is proposed to create multiple prediction models based on solar power generation and weather data. Then, the best model to predict daily solar power generation is selected from these models. The solar power generation data used in this study was obtained from an actual solar system installed in a zero-energy building, while the weather data was obtained from open data provided by the Korea Meteorological Administration. In addition, To verify the validity of the proposed method, an ideal data model with high accuracy but difficult to apply to the actual system and a comparison model with a relatively low accuracy but suitable for application to the actual system were created. The performance was compared with the model created by the proposed method. Based on the validation process, the proposed approach shows 5–10% higher prediction accuracies compared to the comparison model. [ABSTRACT FROM AUTHOR]

Toward net zero emissions by 2050, efficient renewable energy systems and various energy interactions are increasingly proposed to improve energy matching and flexibility capacities. The existing studies primarily focused on onshore solar and wind energy sources, which can interact with electric vehicles or static batteries to improve the economic performance by the energy flexibility control. However, the hybrid system of ocean energy interacting with buildings and electric boats is rarely discussed. This study proposes an innovative integrated energy flexibility control to improve the techno-economic performance of a hybrid wave energy converter (WEC) and floating photovoltaic panel (FPV) energy system supporting a coastal hotel building and eight electric boats. We propose five control strategies, guaranteeing the normal excursion function of the boats while supporting enough energy for the building. In addition, two new indicators are presented to investigate the peak-shaving (PSI) and valley-filling (VFI) capabilities. A weighted matching index (WMI) is provided to investigate the overall energy matching capability. Annual electricity fees and relative net present value (NPVrel) are introduced to analyse the economy. To analyse the environmental aspect, we use the annual operational equivalent CO2 emissions (CEa) to track the emissions of the hybrid system. We observe that strategy E, integrated with the non-dominated solutions from the other four strategies, shows a significant profitable economic performance The annual electricity fee is reduced by 12.22%, and the NPVrelis improved by around 16.62%. PSI and VFI can reach 98.01% and 17.05% for a 100 kW line.

Nearly zero-energy-consumption buildings are the inevitable trend of future buildings. There have been a large number of studies on nearly zero building technology issues. However, there is no detailed study on how to effectively promote the development of nearly zero-energy consumption buildings according to China's national conditions. Here, by establishing an evolutionary game model, this paper discusses the dynamic game scheme selection and stability strategy of three stakeholders, namely local government, real estate companies, and construction consumers, related to the development of nearly zero-energy-consumption buildings in the development process. The conditions required for evolutionary stabilization strategies were identified. Finally, Matlab data simulation analysis is used to further illustrate the stability and equilibrium strategies of each subject and the sensitivity analysis of the main influencing factors at various stages in the development process of nearly zero-energy-consuming buildings. The research results show that the government plays a leading role in the early stage of the development of nearly zero-energy consumption buildings, and as the market matures, government intervention gradually withdraws from the market; furthermore, if the cost of supervision is prohibitively high, the government's willingness to supervise the market will be reduced. This will hinder consumers and developers from choosing nearly zero-energy-consuming buildings and if the penalties and subsidies are too low, it will be meaningless to the evolution of the optimal solution of the three parties. On this basis, targeted promotion programs are established to realize the rapid development of China's nearly zero-energy-consumption building sector. Our research results can provide important scientific basis for the development of the nearly zero-energy building industry in China. [ABSTRACT FROM AUTHOR]

A building-integrated photovoltaic (BIPV) system produces power using photovoltaic (PV) modules as building exterior materials, whose architectural performance serves the same functions as those of existing building materials. Most relevant studies targeted general PV modules used in the building-mounted and -attached types. This study aims to integrate the building elevation-type BIPV system and exterior materials to secure both exterior material performance and PV electrical performance by embedding a power optimization device in an integrated system of BIPV modules and exterior materials. Thus, the advantages of economy, safety, aesthetics, and ease of maintenance can be achieved. In this study, experiments were conducted on elevation-type BIPV modules with and without a power optimizer, that is, a DC/DC converter, under various shade conditions, and the power loss rate of the BIPV system was analyzed. The power optimizer-equipped BIPV system was experimentally observed to have a PV power-loss rate approximately 2–3 times lower than that of the BIPV system without a power optimizer when the shade ratio of one module was approximately 10–75%. This exterior material-integrated BIPV-specific power optimization device reduces dependence on fossil fuels for power production and improves energy sustainability, contributing to the spread of zero-energy buildings and carbon neutrality.

With the development of a low-carbon economy, zero-energy structures will become prevalent and take center stage in the construction industry. This paper uses the CiteSpace software to create knowledge maps of authors, institutions and keywords, and then examined and commented on research publications regarding zero-energy buildings in order to understand the research state and development trends of zero-energy buildings. The findings demonstrate that: (1) Since its inception in 2000, research on zero-energy buildings has advanced significantly; (2) A subject analysis approach is used to identify development trends and research emphasis, and the four research areas with the most papers published are energy fuels, construction building technology, civil engineering and green sustainable science technology; (3) China, the United States and Italy are the countries with the most activity in zero-energy building research; (4) Out of the eight most prominent keywords for the study subjects, the design of zero-energy buildings, the estimation of the carbon emissions of zero-energy buildings, the technical challenges of zero-energy buildings and the follow-up energy-saving measures of zero-energy buildings are the four fundamental topics covered in the most cited papers; (5) There are three obstacles to the development of zero-carbon buildings: unclear standards, immature technology and insufficient development momentum. The following three problems should receive more attention in the future: how to develop a widely accepted zero-carbon building standard; how to coordinate national support to achieve technological breakthroughs; and the establishment of an effective incentive mechanism at the international and national levels to promote the development of zero-carbon buildings. [ABSTRACT FROM AUTHOR]

This study analyzes the optimal sizing design of a stand-alone solar hydrogen hybrid energy system for a house in Afyon, Turkey. The house is not connected to the grid, and the proposed hybrid system meets all its energy demands; therefore, it is considered a zero-energy building. The designed system guarantees uninterrupted and reliable power throughout the year. Since the reliability of the power supply is crucial for the house, optimal sizing of the components, photovoltaic (PV) panels, electrolyzer, storage tank, and fuel cell stack is critical. Determining the sufficient number of PV panels, suitable electrolyzer model and size, number of fuel cell stacks, and the minimum storage tank volume to use in the proposed system can guarantee an uninterrupted energy supply to the house. In this study, a stand-alone hybrid energy system is proposed. The system consists of PV panels, a proton exchange membrane (PEM) electrolyzer, a storage tank, and a PEM fuel cell stack. It can meet the continuous energy demand of the house is sized by using 10 min of averaged solar irradiation and temperature data of the site and consumption data of the house. Present results show that the size of each component in a solar hydrogen hybrid energy system in terms of power depends on the size of each other components to meet the efficiency requirement of the whole system. Choosing the nominal electrolyzer power is critical in such energy systems. • A stand-alone hybrid solar-hydrogen energy system is designed and investigated. • The system is proposed for a zero-energy building with no connection to the grid. • The hybrid system has PV panels, electrolyzer, and fuel cell. • The selection of the components is dictated by the actual solar and weather data at the site. • The consumption profile at the house is based on actual data. [ABSTRACT FROM AUTHOR]

This study aims to institutionalize an evaluation methodology to assess water-source heat pumps (WSHPs) when designing a zero-energy building. Thus, regions where zero-energy buildings were designed were subdivided into 66 sub-regions, thereby standardizing the temperatures on the source side of WSHPs using river water and pipeline water. Based on these data, ground-source and water-source heat pump system-based simulation (new and renewable energy self-sufficiency rate compared to building energy consumption) values were derived for cases whose condition (region or heat source) was different among the buildings certified as zero-energy buildings. The application of the standard meteorological data and reference hydrothermal data to the ECO2 program and outcome evaluation led to the following findings: in all cases (reference: Seoul), ground-source heat pumps (GSHPs) showed a higher self-sufficiency rate than WSHPs (ground source > pipeline water > river water). The self-sufficiency rate of GSHPs was 11–33% higher than that of WSHPs. In a regional comparison among the cold (Jeongseon), central (Seoul), and southern (Jeju Island) regions, WSHPs exhibited higher energy self-sufficiency rates than GSHPs under the conditions of higher water temperatures in winter and lower water temperatures in summer, as in the southern region. [ABSTRACT FROM AUTHOR]

The transition to a net-zero energy system is being promoted in the energy sector, which has led to the creation of energy prosumers. These produce, consume, and trade energy using renewable energy systems installed in buildings or complexes. Here, a community was set as the target to apply the concept of an energy prosumer at the individual building and regional levels. Energy-sharing systems were divided into three categories: energy production, energy storage, and energy management. Energy-sharing systems centered on electrical energy—photovoltaic, battery energy storage, and energy management systems—were installed in two communities located in South Korea, and the energy-sharing effects of the system operation were reported. Monthly power consumption in spring and fall exhibited significant savings of approximately three times that of winter consumption, owing to the energy-sharing systems. Daily hourly power-consumption patterns differed on weekdays and weekends because of the weekday working and building-use hours of the communities. Energy could be shared between communities and buildings because of surplus energy. More surplus power was available for energy sharing on weekends because power consumption was lower. Because energy trading and sharing are restricted, the related laws are being revised. Therefore, a low-carbon community can be realized through surplus energy trading and sharing technology between communities and buildings as renewable energy systems spread owing to low carbonization.

The energy consumption in buildings is increasing, then, a new global multiple-objective optimization method for zero-energy buildings with the comprehensive assessment method is used in this study. The applied optimization design methods for renewable energy systems are the multiple-objective optimization by Enhanced Archimedes Optimization Algorithm (EAOA) on the original design for energy costs and energy optimal models. The Hybrid Gray Multiple-Level Comprehensive Assessment Method (HGMLCAM) is utilized to the optimal model including the solar energy use efficacy, energy conservation, economic and social factors. By the selected decision based on the global optimal model, the best solution is presented. For designing the practical building, the defined solution can be useful for the architects and decision-makers. Consequently, a multiple-objective design for a building located in Shanghai, in China, is studied. Based on the results, it can be concluded that the presented method is efficient to make decisions.

Solar power systems, such as photovoltaic (PV) systems, have become a necessary feature of zero-energy buildings because efficient building design and construction materials alone are not sufficient to meet the building’s energy consumption needs. However, solar power generation is subject to fluctuations based on weather conditions, and these fluctuations are higher than other renewable energy sources. This phenomenon has emphasized the importance of predicting solar power generation through weather forecasting. In this paper, an Automatic Machine Learning (AML)-based method is proposed to create multiple prediction models based on solar power generation and weather data. Then, the best model to predict daily solar power generation is selected from these models. The solar power generation data used in this study was obtained from an actual solar system installed in a zero-energy building, while the weather data was obtained from open data provided by the Korea Meteorological Administration. In addition, To verify the validity of the proposed method, an ideal data model with high accuracy but difficult to apply to the actual system and a comparison model with a relatively low accuracy but suitable for application to the actual system were created. The performance was compared with the model created by the proposed method. Based on the validation process, the proposed approach shows 5–10% higher prediction accuracies compared to the comparison model.

The exploitation of renewable energy sources in the building sector is a challenging aspect of achieving sustainability. The incorporation of a proper storage unit is a vital issue for managing properly renewable electricity production and so to avoid the use of grid electricity. The present investigation examines a zero-energy residential building that uses photovoltaics for covering all its energy needs (heating, cooling, domestic hot water, and appliances-lighting needs). The building uses a reversible heat pump and an electrical heater, so there is not any need for fuel. The novel aspect of the present analysis lies in the utilization of hydrogen as the storage technology in a power-to-hydrogen-to-power design. The residual electricity production from the photovoltaics feeds an electrolyzer for hydrogen production which is stored in the proper tank under high pressure. When there is a need for electricity, and the photovoltaics are not enough, the hydrogen is used in a fuel cell for producing the needed electricity. The present work examines a building of 400 m2 floor area in Athens with total yearly electrical demand of 23,656 kWh. It was found that the use of 203 m2 of photovoltaics with a hydrogen storage capacity of 34 m3 can make the building autonomous for the year period.

Nearly zero-energy-consumption buildings are the inevitable trend of future buildings. There have been a large number of studies on nearly zero building technology issues. However, there is no detailed study on how to effectively promote the development of nearly zero-energy consumption buildings according to China’s national conditions. Here, by establishing an evolutionary game model, this paper discusses the dynamic game scheme selection and stability strategy of three stakeholders, namely local government, real estate companies, and construction consumers, related to the development of nearly zero-energy-consumption buildings in the development process. The conditions required for evolutionary stabilization strategies were identified. Finally, Matlab data simulation analysis is used to further illustrate the stability and equilibrium strategies of each subject and the sensitivity analysis of the main influencing factors at various stages in the development process of nearly zero-energy-consuming buildings. The research results show that the government plays a leading role in the early stage of the development of nearly zero-energy consumption buildings, and as the market matures, government intervention gradually withdraws from the market; furthermore, if the cost of supervision is prohibitively high, the government’s willingness to supervise the market will be reduced. This will hinder consumers and developers from choosing nearly zero-energy-consuming buildings and if the penalties and subsidies are too low, it will be meaningless to the evolution of the optimal solution of the three parties. On this basis, targeted promotion programs are established to realize the rapid development of China’s nearly zero-energy-consumption building sector. Our research results can provide important scientific basis for the development of the nearly zero-energy building industry in China.

Following the Paris Agreement in 2015, the worldwide focus on global warming countermeasures has intensified. The Japanese government has declared its aim at achieving carbon neutrality by 2050. The concept of zero-energy buildings (ZEBs) is based on measures to reduce energy consumption in buildings, the prospects of which are gradually increasing. This study investigated the annual primary energy consumption; as well as evaluated, renewed, and renovated buildings that had a solar power generation system, and utilized solar and geothermal heat. It further examines the prospects of hydrogen production from on-site surplus electricity and the use of hydrogen fuel cells. A considerable difference was observed between the actual energy consumption (213 MJ/m2), and the energy consumption estimated using an energy simulation program (386 MJ/m2). Considerable savings of energy were achieved when evaluated based on the actual annual primary energy consumption of a building. The building attained a near net zero-energy consumption considering the power generated from the photovoltaic system. The study showed potential energy savings in the building by producing hydrogen, using surplus electricity from on-site power generation, and introducing hydrogen fuel cells. It is projected that a building's energy consumption will be lowered by employing the electricity generated by the hydrogen fuel cell for standby power, water heating, and regenerating heat from the desiccant system. [ABSTRACT FROM AUTHOR]

With the development of a low-carbon economy, zero-energy structures will become prevalent and take center stage in the construction industry. This paper uses the CiteSpace software to create knowledge maps of authors, institutions and keywords, and then examined and commented on research publications regarding zero-energy buildings in order to understand the research state and development trends of zero-energy buildings. The findings demonstrate that: (1) Since its inception in 2000, research on zero-energy buildings has advanced significantly; (2) A subject analysis approach is used to identify development trends and research emphasis, and the four research areas with the most papers published are energy fuels, construction building technology, civil engineering and green sustainable science technology; (3) China, the United States and Italy are the countries with the most activity in zero-energy building research; (4) Out of the eight most prominent keywords for the study subjects, the design of zero-energy buildings, the estimation of the carbon emissions of zero-energy buildings, the technical challenges of zero-energy buildings and the follow-up energy-saving measures of zero-energy buildings are the four fundamental topics covered in the most cited papers; (5) There are three obstacles to the development of zero-carbon buildings: unclear standards, immature technology and insufficient development momentum. The following three problems should receive more attention in the future: how to develop a widely accepted zero-carbon building standard; how to coordinate national support to achieve technological breakthroughs; and the establishment of an effective incentive mechanism at the international and national levels to promote the development of zero-carbon buildings.

This study aims to institutionalize an evaluation methodology to assess water-source heat pumps (WSHPs) when designing a zero-energy building. Thus, regions where zero-energy buildings were designed were subdivided into 66 sub-regions, thereby standardizing the temperatures on the source side of WSHPs using river water and pipeline water. Based on these data, ground-source and water-source heat pump system-based simulation (new and renewable energy self-sufficiency rate compared to building energy consumption) values were derived for cases whose condition (region or heat source) was different among the buildings certified as zero-energy buildings. The application of the standard meteorological data and reference hydrothermal data to the ECO2 program and outcome evaluation led to the following findings: in all cases (reference: Seoul), ground-source heat pumps (GSHPs) showed a higher self-sufficiency rate than WSHPs (ground source > pipeline water > river water). The self-sufficiency rate of GSHPs was 11–33% higher than that of WSHPs. In a regional comparison among the cold (Jeongseon), central (Seoul), and southern (Jeju Island) regions, WSHPs exhibited higher energy self-sufficiency rates than GSHPs under the conditions of higher water temperatures in winter and lower water temperatures in summer, as in the southern region.

Energy sharing is critical for zero-energy buildings on the community level. However, most existing works studied the energy sharing problems without considering the physical energy sharing circuit. In this paper, we provide a new perspective to explore the energy sharing among building with a specific energy sharing circuit, and then, the modeling, control, and verification of the energy sharing system are presented. The energy sharing system is modeled as a cyber-physical system, where the physical layer characterizes the physical energy sharing circuit, and the cyber layer represents the communication topology among buildings. In the control layer, an average state-of-charge (SoC) estimator is designed for energy storage systems (ESSs) of each building using the dynamic consensus protocol, and a cooperative SoC tracking law is designed to achieve the SoC balancing of ESSs. The closed-loop model of the energy sharing system is developed using the block diagram. A laboratory prototype is built to verify the effectiveness of the proposed energy sharing method. The experimental results verify that the proposed energy sharing system can achieve energy sharing among ESSs effectively and efficiently.

The objective of this study is to derive a design methodology for a zero-energy building considering the energy production and consumption of the building. In order to establish the design methodology, various factors affecting the energy production and consumption of the building are derived, and the effect of the heat transmission rate, the surface to volume ratio (S/V ratio), the location and the orientation of the building are analyzed by simulation method. As a result, the S/V ratio and the heat transmission rate are the most important factors in the central region of Korea where consumes large amounts of heating and cooling energy. This is because the final energy consumption varies depending on the heat loss through the envelope. It was confirmed that solar power generation is the most important factor in the southern regions of Korea where the energy consumption is relatively small. The final energy consumption varies depending on the solar power generation in these areas. Therefore, when designing a zero-energy building, the zero-energy of the building can be achieved by using the design methodology established in this study. [ABSTRACT FROM AUTHOR]

Following the Paris Agreement in 2015, the worldwide focus on global warming countermeasures has intensified. The Japanese government has declared its aim at achieving carbon neutrality by 2050. The concept of zero-energy buildings (ZEBs) is based on measures to reduce energy consumption in buildings, the prospects of which are gradually increasing. This study investigated the annual primary energy consumption; as well as evaluated, renewed, and renovated buildings that had a solar power generation system, and utilized solar and geothermal heat. It further examines the prospects of hydrogen production from on-site surplus electricity and the use of hydrogen fuel cells. A considerable difference was observed between the actual energy consumption (213 MJ/m2), and the energy consumption estimated using an energy simulation program (386 MJ/m2). Considerable savings of energy were achieved when evaluated based on the actual annual primary energy consumption of a building. The building attained a near net zero-energy consumption considering the power generated from the photovoltaic system. The study showed potential energy savings in the building by producing hydrogen, using surplus electricity from on-site power generation, and introducing hydrogen fuel cells. It is projected that a building’s energy consumption will be lowered by employing the electricity generated by the hydrogen fuel cell for standby power, water heating, and regenerating heat from the desiccant system.

According to the previous pieces of research, the building sector consumes about 40 % of total yield energy and produce one-third of GHG pollution emission. This point shows the significant potential in two aspects of energy optimization and pollution reduction in this field. The purpose of this research as a case study is to construct a residential building and develop the paths for reaching a zero-energy building, considering GHG emissions in the climate of Tehran, Iran. In thirty scenarios of this study, solar panels, solar water heaters, ground source heat pumps, and combined heat and power generators were selected to provide the required power and energy in the building. All three passive, single active, and hybrid active scenarios were defined and analyzed with respect to technical and economic factors. In all of the defined scenarios, the conditions are two-folded: (a) considering the effect of national profits, fuel saving, and pollution reduction and (b) without considering them so that the results would become more realistic. In the end, three different types of conclusions were made with respect to macro-engineering, energy, and economic perspectives. Statistical conclusions based on a questionnaire filled by 50 people and the perspective of achieving NZEB definition are presented.

• A new concept of photovoltaic-driven liquid air energy storage (PV-LAES) is explored. • A dynamic PV-LAES model is built to match building energy requirements. • Poly-generation of combined cooling, heating and power (CCHP) is achieved. • Technical, economic and environmental merits of the PV-LAES are clarified. • The multi-functional PV-LAES provides solutions for future zero-energy buildings. Renewable energy and energy storage technologies are expected to promote the goal of net zero-energy buildings. This article presents a new sustainable energy solution using photovoltaic-driven liquid air energy storage (PV-LAES) for achieving the combined cooling, heating and power (CCHP) supply. Liquid air is used to store and generate power to smooth the supply-load fluctuations, and the residual heat from hot oil in the LAES system is used for the cooling and heating supplements. Taking an actual building as the research object, the dynamic PV-LAES system model is built to optimize the power/cooling/heating supplies, and then evaluate the economic and environmental performances. In a single year, the PV-LAES system can produce 523.93 MWh of electricity, 57.75 GJ of cold energy, and 119.24 GJ of heat energy, resulting in an improved round-trip efficiency of 67.05 % and a carbon emission reduction of 368.35 tons. The dynamic payback period is 6.45 years and the cumulative net present value (NPV) reaches 515 k$ throughout the life cycle. Overall, this article provides a new solution using the PV-LAES system to obtain high energy efficiency, good economic benefits, and high environmental performance for future zero-energy buildings. [ABSTRACT FROM AUTHOR]

Renewable energy is becoming increasingly popular in the development of low-carbon societies. Radiative sky cooling (RSC) technology utilizes long waves in the atmospheric window to radiate heat into outer space; it promises a good cooling effect and wide applicability. This paper reviews RSC technology in terms of its background, materials, heat transfer and influences, and applications in buildings. High-performance radiative cooling materials have been proposed to realize RSC during both the day and night. Using these materials, sky radiative coolers and cooling systems have been fabricated for different scenarios. Radiative and non-radiative heat transfer and cooling performances can be calculated or measured using the radiation law. The correlations between the sky effective radiative temperature and effective emissivity are summarized. Environment conditions affect the RSC performance, and the influences are systematically analyzed. Owing to its advantages of cleanliness, accessibility, and extensive resources, RSC technology can be applied to building envelopes and heating, ventilation, and air conditioning systems, to develop low-carbon and zero-energy buildings. Passive and active applications are also discussed. Finally, challenges of applying RSC technology to building systems are briefly discussed. This review should help promote the practice and implementation of RSC technology. • Spectrally selective radiative cooling materials and cooler forms are reviewed. • Heat-transfer parameters, performances and influences of RSC are summarized and analyzed. • Applications of RSC in building envelopes and HVAC systems are presented. • Challenges on RSC applied to buildings are discussed. [ABSTRACT FROM AUTHOR]

Achieving the best energy performance has become an important goal. The European Union has consequently developed legislative measures that introduce the concepts of nearly zero-energy buildings and cost-effectiveness during life-cycle. We use these concepts, looking for the design of energy-efficient wineries, while reducing wine production costs. The research method is based on the monitoring of temperature and humidity of 12 red wine aging rooms of representative construction designs with almost zero energy consumption that together with the economic data obtained from construction cost update, determine a parameter that has been called “construction effectiveness”. This parameter allows the evaluation of the cost–benefit ratio of each of the analyzed constructions. The results obtained demonstrate that adequate conditions can be achieved for the wine aging with zero-energy buildings, although there are notable differences in cost, damping effectiveness, and resulting hygrothermal environment depending on the type of building. The correlation between performance and construction costs shows large differences in cost per unit of damping achieved: 0.5–2.7 €/m2 for temperature and 0.6–5 €/m2 for relative humidity. With a correct design, the differences between typologies can be reduced or even non-existent. The results obtained can be a valuable tool to promote the design of zero-energy warehouses.

The objective of this study is to derive a design methodology for a zero-energy building considering the energy production and consumption of the building. In order to establish the design methodology, various factors affecting the energy production and consumption of the building are derived, and the effect of the heat transmission rate, the surface to volume ratio (S/V ratio), the location and the orientation of the building are analyzed by simulation method. As a result, the S/V ratio and the heat transmission rate are the most important factors in the central region of Korea where consumes large amounts of heating and cooling energy. This is because the final energy consumption varies depending on the heat loss through the envelope. It was confirmed that solar power generation is the most important factor in the southern regions of Korea where the energy consumption is relatively small. The final energy consumption varies depending on the solar power generation in these areas. Therefore, when designing a zero-energy building, the zero-energy of the building can be achieved by using the design methodology established in this study.

In Oman, like in all countries of the Gulf region, the building culture is in a crisis. The challenge to balance between a harsh outdoor climate and raised expectations for indoor comfort is not solved in a sustainable way, yet. Due to the availability of fossil fuel at very low costs, energy for cooling buildings is not used efficiently. This is not only wasteful, but also takes away the incentive to innovate. Consequently, the region’s building boom of the past decades was a growth without progress. Neither has significant new knowledge been generated locally, nor has external knowledge been transferred to build local capacity in the field of sustainable buildings. To break up this stagnation, The Research Council of the Sultanate of Oman (TRC) started in 2011 to fund a project in which the German University of Technology in Oman (GUtech) designed, planned, built, and currently operates and monitors a net-zero-energy residential building on its campus. This paper shows that GUtech’s EcoHaus is not only in a building as a product, but also a process of generating and transferring knowledge by combining teaching, research and practice within one university project. [ABSTRACT FROM AUTHOR]

The continuous growth of population in sub-urban areas leads to increasing demand for mid-rise housing. Recent studies found that greenhouse gas emission in Indonesia continues to escalate at an alarming rate, and housing development is considered as one of the greenhouse gas contributors. Zero-Energy Residential Building, a highly energy efficient and low carbon housing design concept, is regarded as the answer for this environmental issue. Application of Zero-Energy Residential Building concept can reach almost zero sites electrical consumption and reduce greenhouse gas emission since this concept utilizes clean and renewable energy sources, e.g. solar cell, to generate electricity independently. However, this design concept has not been implemented widely since the utilization of solar panels, and other energy conservation components are still too expensive. This study is proposed to find out an optimum combination of design parameters that contribute to cost optimization housing design using sequential search algorithm. Comprehensive study literature and experiment using software are applied in this research. Hence, using the parameter combination in designing a mid-rise dense housing and Zero-Energy Building concept can generate optimum life cycle cost performance. As a result, the study concludes that the life cycle cost of optimized mid-rise Zero-Energy Building is better than the conventional mid-rise housing with annual electrical cost saving up to 98 percent. [ABSTRACT FROM AUTHOR]

Buildings that are designed with aggressive energy performance targets are defined broadly in this study as high-performance buildings. As the technology advances, some of these buildings have the potential to become zero-energy ready through the adoption of cost-effective measures, such as retro-commissioning and occupant behavior techniques. This study demonstrated the viability of an office building to achieve the zero-energy goal and intended to engage the owners of similar facilities. The case building was designed as a very low-energy building with an energy use intensity (EUI) goal of 42 kWh/(m2 a), and the actual EUI was 23.9 kWh/(m2 a). The calibrated simulation approach was employed in the study, and the results indicated that the case building can achieve the zero-energy goal by optimizing the controls of the HVAC (Heating, Ventilation and Air Conditioning) system, changing the occupant behavior and improving the performance of the photovoltaic system. [ABSTRACT FROM AUTHOR]

• An integrated air conditioning system (IACS) is proposed for a passive house. • A machine learning model is developed to quantify thermal comfort. • Multi-objective optimization of operating conditions for the IACS is presented. • The IACS consumes less energy under optimal operating conditions. • The IACS is economical, particularly in a passive house. Appropriate dehumidification systems are essential for passive houses to prevent thermal discomfort under high dehumidification loads. In this study, an integrated air conditioning system (IACS) consisting of a dedicated outdoor air system and sensible cooling unit is developed to manage dehumidification loads in passive houses. Multi-objective optimization of the operating conditions of the IACS is performed considering the energy consumption and thermal comfort of a passive house. A thermal comfort model is constructed using a big-data-driven machine learning method to improve prediction accuracy compared to a conventional model. Additionally, an artificial-neural-network-based metamodel is developed to estimate the performance of the IACS. The optimal operating conditions are determined based on the Pareto solution set obtained from multi-objective optimization. The optimized performance and economic feasibility of the IACS are compared to those of a conventional air conditioning system (CACS). For the IACS in a passive house, the optimal indoor set-point temperature and relative humidity were determined to be 27.01 ℃ and 50.35%, respectively. The energy-saving rates of the IACS were 15.96% and 7.53% in passive and normal houses, respectively, compared to the CACS. The IACS is more economical than the CACS based on its energy-saving effects, particularly in passive houses. [ABSTRACT FROM AUTHOR]

The proliferation of grid-dependent, zero-energy buildings in a region will alter the diurnal electric power demand to a U-shaped demand curve that limits the role of base-load power plants and the flexibility of the electric grid to meet the power demand. Zero-energy buildings that are also grid-independent (GIB-ZEBs) ensure that carbon emissions are curtailed and that the electricity grid will retain its flexibility to make appropriate use of large, base-load power production units. Such buildings incorporate a reliable system for energy storage that supplies the needed energy when the renewable energy source does not. This paper offers a detailed analysis of the power needs, the seasonal energy usage, and the seasonal energy storage requirements of two GIB-ZEBs. The first is located in the South-West part of the USA, where the air-conditioning demand is very high and the second in the North, where the heating demand is very high and the irradiance/insolation is less. Hydrogen storage and battery storage systems were considered for the energy storage requirements of the buildings. Calculations for the two buildings include: the hourly electric power and total energy demand of the building throughout the year; the hourly energy production by a system of photovoltaics; the hourly energy storage needed throughout the year; the photovoltaics area requirements; the overall capacity and seasonal use of the energy storage system needed; and the effects of the various components and systems performance on the power production and storage parameters. [ABSTRACT FROM AUTHOR]

This paper presents the results of a demonstration project, including building-integrated photovoltaic (BIPV) solar panels, a residential building and a hydrogen fuel cell electric vehicle (FCEV) for combined mobility and power generation, aiming to achieve a net zero-energy residential building target. The experiment was conducted as part of the Car as Power Plant project at The Green Village in the Netherlands. The main objective was to assess the end-user’s potential of implementing FCEVs in vehicle-to-grid operation (FCEV2G) to act as a local energy source. FCEV2G field test performance with a Hyundai ix35 FCEV are presented. The car was adapted using a power output socket capable of delivering up to 10 kW direct current (DC) to the alternating current (AC) national grid when parked, via an off-board (grid-tie) inverter. A Tank-To-AC-Grid efficiency (analogous to Tank-To-Wheel efficiency when driving) of 44% (measured on a Higher Heating Value basis) was obtained when the car was operating in vehicle-to-grid (V2G) mode at the maximum power output. By collecting and analysing real data on the FCEV power production in V2G mode, and on BIPV production and household consumption, two different operating modes for the FCEV offering balanced services to a residential microgrid were identified, namely fixed power output and load following. Based on the data collected, one-year simulations of a microgrid consisting of 10 all-electric dwellings and 5 cars with the different FCEV2G modes of operation were performed. Simulation results were evaluated on the factors of autonomy, self-consumption of locally produced energy and net-energy consumption by implementing different energy indicators. The results show that utilizing an FCEV working in V2G mode can reduce the annual imported electricity from the grid by approximately 71% over one year, and aiding the buildings in the microgrid to achieve a net zero-energy building target. Furthermore, the simulation results show that utilizing the FCEV2G setup in both modes analysed, could be economically beneficial for the end-user if hydrogen prices at the pump fall below 8.24 €/kg. [ABSTRACT FROM AUTHOR]

The need to improve the energy efficiency of buildings has introduced the concept of nearly zero-energy buildings into European energy policies. Moreover, a percentage of the building stock will have to be renovated annually to attain high energy performance. Conventional passive interventions in buildings are focused on increasing the insulation of the building envelope to increase its energy efficiency during the operating phase. Often, however, intervention practices imply the incorporation of embodied energy into the building materials and increase the associated environmental impacts. This paper presents and evaluates a comparison of two different proposals for a real-world building renovation. The first proposal was a conventional project for energy renovation, while the second was a low-energy building proposal (following the Passivhaus standard). This study analysed the proposals using an integrated life cycle and thermal dynamic simulation assessment to identify the adequacy of each renovation alternative regarding the post-renovation energy performance of the building, including an evaluation of the introduction of a renewable insulation material into the low-energy building proposal, specifically a specific cork solution. The most significant conclusion was the convenience of the renovation, achieving energy savings of 60% and 80% for the conventional and Passivhaus renovations (ENERPHIT), respectively. The former supposed less embodied energy and environmental impacts but also generated less energy savings. The latter increased the embodied impacts in the building, mainly for the large amount of insulation material. The environmental implications of both proposals can be compensated for within a reasonable period of time, over 2 years in the majority of alternatives and impact categories. However, the ENERPHIT project was 30% better than the conventional proposal when the total lifespan of the building was considered. The introduction of cork did not fit the requirements for competing with the common non-renewable insulation materials because it did not imply better environmental performance in buildings, but cork insulation solutions currently present ample room for improvement. [ABSTRACT FROM AUTHOR]

In the current century, a suitable strategy is concerned for optimal consumption of energy, due to limited natural resources and fossil fuels for moving towards sustainable development and environmental protection. Given the rising cost of energy, environmental pollution and the end of fossil fuels, zero-energy buildings became a popular option in today's world. The purpose of this study is to investigate the factors affecting the design of zero-energy buildings, in order to reduce energy consumption and increase productivity, including plan form, climatic characteristics, materials, coverage etc. The present study collects the features of zero-energy building in Isfahan, which is based on the Emberger Climate View in the arid climate, by examining the books and related writings, field observations and using a descriptive method, in the form of qualitative studies. The results of the research showed that some actions are needed to save energy and, in general, less consumption of renewable energy by considering the climate and the use of natural conditions. [ABSTRACT FROM AUTHOR]

Buildings that are designed with aggressive energy performance targets are defined broadly in this study as high-performance buildings. As the technology advances, some of these buildings have the potential to become zero-energy ready through the adoption of cost-effective measures, such as retro-commissioning and occupant behavior techniques. This study demonstrated the viability of an office building to achieve the zero-energy goal and intended to engage the owners of similar facilities. The case building was designed as a very low-energy building with an energy use intensity (EUI) goal of 42 kWh/(m2 a), and the actual EUI was 23.9 kWh/(m2 a). The calibrated simulation approach was employed in the study, and the results indicated that the case building can achieve the zero-energy goal by optimizing the controls of the HVAC (Heating, Ventilation and Air Conditioning) system, changing the occupant behavior and improving the performance of the photovoltaic system.

The building and transportation sectors in the EU are progressing towards the zero-energy/emission levels according to the EU 2050 roadmap while the H 2 vehicles have recently started to be commercialized. Based on these backgrounds, this paper focuses on the investigation of a hybrid zero-energy system which consists of a zero-energy building and a H 2 vehicle integrated H 2 system. The focused aspects in this paper are the impact of the ground source heat pump (GSHP), the Finnish and German climate conditions, and the on-site PV and wind turbine capacities and their mix on system performance. The parametric analyses based on these aspects are conducted in the TRNSYS simulation environment. The results show that the use of a GSHP helps realize the net zero-energy balance with less local generation, while improving the overall matching capability with marginal influence on the utilization of the cogenerated heat. Moreover, the Finnish condition has a clear preference on the wind based net zero-energy system, whereas the German condition has a preference on the solar based system. Correspondingly, the optimal mix of PV and wind turbine for the net zero-energy cases occurs when the PV generation percentage reaches 20% and 60% under Finnish and German conditions, respectively. [ABSTRACT FROM AUTHOR]

Hydrogen economy has become topical due to the rapid development of hydrogen vehicles and national hydrogen roadmaps. The zero-energy concept has been developed to support energy policy making with an aim at designing and building sustainable buildings and communities. In this article we define the concept ‘zero-energy hydrogen economy’ (ZEH 2 E) as such a zero-energy system, where hydrogen is one of the key energy carriers. We review recent research on the integration of zero-energy hydrogen economies at the level of single buildings and communities. We conclude that the energy use of transportation, hydrogen supply from other than renewable energy resources (e.g. as a by-product of industrial processes), and supporting metrics including the grid interactions, energy matching and reliability should be included in the zero-energy definition. We deduce that the research should focus on finding solutions that facilitate the parallel operation of conventional centralized systems and decentralized hydrogen economies. More research is needed to understand the impacts of the exchange of various energy types between vehicles, buildings and/or communities and hybrid smart grids. Innovative sharing economy models, incentives and energy policies are required. The awareness and acceptance of hydrogen technology among occupants and home owners should be surveyed and promoted. [ABSTRACT FROM AUTHOR]

The aim of this paper is to assess the state of the art of the facade building technology, in order to investigate the possibility of future retrofits achieving nearly ‘Zero-Energy Building' in existing non-residential buildings. The assessment was based on the published literature in the field of ‘smart' facade retrofits for energy performance upgrades on existing buildings and the benefits and challenges therein. It also investigates the available technologies, which can increase energy performance efficiency. This can be used as a possible retrofit tool for implementation on existing office buildings, aiming at an increase of the building's energy performance. It was concluded that near ‘Zero-Energy Building' status was not achievable solely through facade retrofits. Retrofit schemes can, however, succeed in the reduction of greenhouse gas emissions, in correlation with environmental goals of many countries worldwide and the European Union. Furthermore, the climate in south-eastern Europe and in the Mediterranean region presents a set of challenges for all forms and types of passive facade technologies, especially during the summer. [ABSTRACT FROM PUBLISHER]

Housing stock is one of the major energy consumers in Europe, or the Czech Republic respectively, and it is not easy to reach European 20/20/20 target with an envelope insulation only. Therefore a deep renovation alternative consisting of prefabricated insulating panels, implementation new smart HVAC systems and use of renewable energy sources is presented. In this article, boundary conditions and limitations of various aspects of such solution are described and the possible use is shown, particularly on a reference building in Milevsko, Czech Republic, representing the most common Czech multi-family housing sample. [ABSTRACT FROM AUTHOR]

• The energy performance of solar signage windows in buildings was simulated. • The study covers various climates, window-to-wall ratios, and solar signage types. • Solar signage windows were found to improve the energy efficiency of buildings. • The use of solar signage windows in specific climate zones is proposed. The applicability of solar signage windows that concurrently generate electricity upon installation in buildings, exhibit display functionality using the generated electricity, and transmit light was evaluated. Four cities representing different US-based climate zones were selected for the analysis: 1A-Miami (Arizona), 2B-Phoenix (Florida), 3C-San Francisco (California), and 5A-Ann Arbor (Michigan). Five types of solar signage windows with different characteristics were designed, and five window-to-wall ratios were considered to analyze the indoor environment and energy consumed by a building by using the DesignBuilder simulation program. The results showed that the solar signage windows were most effective in 3C-San Francisco and least effective in 1A-Miami and 5A-Ann Arbor. According to the amount of electricity generated, an energy-saving rate of up to 17,970 kWh/y (105%) was observed in 3C, highlighting the potential of applying solar signage windows to realize zero-energy buildings in this area. These findings emphasize the remarkable potential of solar signage windows as exterior materials for buildings. [ABSTRACT FROM AUTHOR]

This research focuses on the design phases and economic analysis of a standalone photovoltaic system to electrify a house in the rural fringe of Famagusta, Cyprus. The designed system has the capability to cover residents’ electricity demand (17.23 (kW h/day)) during the winter (with the lowest solar irradiation). Utilizing mathematical model, the PV panels area, PV peak power, the battery capacity, inverter and charge controller sizes were determined to be 46.73 (m 2 ), 7.5 (kW), 44.78 (kW h), 2 (kW) and 350 (A) respectively. Moreover, the life cycle cost analysis was investigated. The life cycle cost of the system was found to be [TRY] 54,560 whereas the annualized life cycle cost and unit price of electricity was calculated to be around [TRY] 2700 and [TRY] 0.43 for each kilowatt-hour. It was concluded that a standalone photovoltaic system is economically and technically feasible and a viable technology for the electrification of a house in Cyprus. [ABSTRACT FROM AUTHOR]

There are over 70 low energy and carbon standards in use around the world. None of these standards have been designed by the clients who pay for and occupy the buildings in question. In this work, the client was asked to define the building code for the construction of a new 2800 m2 building via a structured survey. The resulting zero-energy standard simply required the building to incur no energy utility bill. One year of monitoring of the completed building was used to see if the standard had been met. The result of this work is a new way of thinking about environmental building standards that solves many of the issues of obtaining and maintaining buy-in from the client.Practical application: This is the first time that the client has played a key role in the definition of a low-energy building standard. Measured energy consumption and renewable energy generation data are presented and demonstrate that the zero-energy criteria were successfully met. This work is important as it shows that the client can have a meaningful input into the design of an environmental standard. The paper should be of interest to architects, engineers, building energy researchers and those interested in methods that can be used to reduce the energy demand of buildings. [ABSTRACT FROM AUTHOR]

Proper sizing of energy systems in a zero-energy building is crucial to ensure that the zero-energy building can perform well during its operational process. Meteorological data should be well prepared as they are important inputs for the system design of a zero-energy building. Particularly, the extreme and typical weather data are crucial for the sizing of air-conditioning system and renewable system, respectively. However, the existing weather datasets including typical meteorological year (TMY) and extreme meteorological year (XMY) show limited extreme and typical weather information of multiple years, which would lead to improper system sizes and consequently result in deteriorated building performance. To fill this gap, this study develops a calibrated TMY weather file by applying a quantile mapping method on conventional TMY using multi-year weather data, which can accurately represent both extreme and typical weather information of multiple years, overcoming the limitations of the existing weather datasets. In the validated case, the calibrated TMY is developed using the weather data of 1979–2015 purchased from the Hong Kong Observatory. The results indicate that in comparison with the conventional TMY-based design, the calibrated TMY-based design substantially improves the building performance with reduction of 28 unmet hours, 11% improvement of load match ratio and 10.4% reduction of lifecycle cost. Therefore, the calibrated TMY shows great potentials to replace the conventional TMY for zero-energy building system design in practice. • The calibrated TMY has accurate extreme and typical weather data of multiple years. • Weather data of 1979–2015 is adopted to demonstrate ZEB's performance improvements. • Load match ratio is improved by 11% while lifecycle cost is reduced by 10.4%. • Calibrated TMY shows high robustness despite of different conventional TMY bases. • The calibrated TMY can replace the conventional TMY in ZEB's system design. [ABSTRACT FROM AUTHOR]

Metamodels are developed and used for aerodynamic optimization of a ducted opening integrated into a high-rise building to maximize the amplification factor within the duct. The duct consists of a nozzle, a throat, and a diffuser. 211 high-resolution 3D RANS CFD simulations are performed to generate training and testing datasets. The space-filling design and Genetic algorithm are used for data sampling and optimization, respectively. The performance of five commonly-used metamodels is systematically investigated: Response Surface Methodology (RSM), Kriging (KG), Neural Network (NN), Support Vector Regression (SVR), and Genetic Aggregation Response Surface (GARS). The investigation is based on (i) detailed in-sample and out-of-sample evaluations of the metamodels, (ii) annual available power in the wind (P available), and (iii) annual energy production (AEP) for a 3-bladed horizontal-axis wind turbine (HAWT) installed in the mid-throat for the optimum designs obtained by the metamodels. The results show that converging-diverging ducted openings can magnify the experienced wind speed by the turbine and enhance the available wind power. In addition, the use of different metamodels can lead to a variation of up to 153% in the estimated P available. For a small dataset, crude yet still acceptable accuracy can be achieved for Genetic Aggregation Response Surface and Kriging at a very low computational time. • Metamodels are used for the optimization of building-integrated ducted openings. • The performance of different commonly-used metamodels is systematically assessed. • Converging-diverging ducted openings can magnify the annual available wind power. • The use of different metamodels can significantly impact the predicted wind power. • Kriging and Genetic Aggregation Response Surface are recommended as models of choice. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new polygenerational solar energy system integrated with near-zero energy building is proposed. • The system consists of PVT and PTC collectors, water desalination and hydrogen energy storage cycles. • All demands, and cycle outputs were calculated on an hourly basis for a full year. • A dynamic simulation model based on the energy, exergy, economic and environmental analyses is developed. • By applying the proposed system, 70% of the electricity and 48.1% of the heating loads of building can be covered. The main objective of this study is to propose and analyze a multi-generation system to cover heating, electricity, and water demands of a building in St. Petersburg (Russia). The main energy source of the system is solar energy to integrate with hydrogen energy storage system (HESS), and multi-effect desalination (MED). Hot water storage tank, and hydrogen energy storage system are used to store solar energy as heating and electricity, respectively at peak solar radiation. The stored energy will be used at off-peak hours to supply the demands of the building. Photovoltaic-thermal (PVT) collectors are used to cover heating load of the building and parabolic trough collectors (PTC) are suitable for providing heat demand of MED and HESS. In order to supply whole demands, auxiliary systems such as a heater for heating load and grid for electricity load are used whenever even storing systems are unable to cover them. The tools used for analyzing the proposed system dynamically are a comprehensive approach of energetic, exergetic, and economic-environmental under fixed conditions. Results of the transient analysis show that the proposed system can cover up to 70% and 57.9% of the electricity and heat demands, respectively, without any auxiliary system. At the same time, all the annual demand of the required freshwater of the building and the HESS is supplied by the proposed system. Moreover, the energy and exergy efficiencies of the integrated system with constant input parameters are obtained equal to 20% and 7%, respectively. Finally, by economic analysis, it is found that the net present value (NPV) of the proposed system, assuming an interest rate of 3%, becomes positive after 9 years. [ABSTRACT FROM AUTHOR]

• Building regulation has become key element in low-carbon transition of building sector. • Calculation of building performance opens new spaces for politics. • Policy actors create specific transition pathways of the building sector through specific performance calculations. • New building code in Sweden facilitates a lenient version of low energy buildings with limited climate mitigation impact. New building codes and stricter regulation of energy consumption and CO 2 emissions have become key strategies to support the low-carbon transition of the housing sector. Such regulations rest heavily on setting performance targets for buildings and developing standardized calculation procedures for determining the compliance of new buildings with the building code. While developing such targets, standards and calculation tools are largely presented as a technocratic and expert-driven process; our argument is that these calculations are actually heavily imbued with politics. Empirically, the article analyses the implementation of the European Energy Performance of Buildings Directive (EPBD), which makes nearly zero-energy buildings mandatory, into Swedish law. Studying the negotiations and controversies taking place in adapting the Swedish building code reveals how the power play of resourceful actors, the negotiation of interests and the different visions and valuations of what is regarded important for the future of the housing sector shape calculation procedures and how these are included in the new building code. Unpacking the political decisions and valuations underlying the calculative practices and technical details of the building code can be seen as an important step towards a more transparent public debate about the future of sustainable buildings. [ABSTRACT FROM AUTHOR]