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Massive construction systems have always characterized traditional architecture and are currently the most prevalent, straightforward, and cost-effective in many Mediterranean countries. However, in recent years, the construction industry has gradually shifted towards using lightweight, dry construction techniques. This study aims to assess the effects on energy consumption, comfort levels, and environmental sustainability resulting from the adoption of five high-performance construction systems in a multi-family residential building: (i) reinforced concrete structure with low-transmittance thermal block infill; (ii) reinforced concrete structure with light-clay bricks and outer thermal insulation; (iii) steel frame; (iv) cross-laminated timber (CLT); (v) timber-steel hybrid structure. To achieve this goal, a multidisciplinary approach was employed, including the analysis of thermal parameters, the evaluation of indoor comfort through the adaptive model and Fanger's PMV, and the quantification of environmental and economic impacts through life cycle assessment and life cycle cost applied in a long-term analysis (ranging from 30 to 100 years). The results highlight that heavyweight construction systems are the most effective in terms of comfort, cost, and long-term environmental impact (100 years), while lightweight construction systems generally have higher construction costs, provide lower short-term environmental impacts (30 years), and offer intermediate comfort depending on the thermal mass. [ABSTRACT FROM AUTHOR]

Nowadays, the use of hybrid systems has become very common all over the world. In this study, the aim is to minimize the use of grid energy to provide heating and cooling energy with the help of a hybrid heat pump equipped with a flat solar collector, phase change material (PCM), and photovoltaic (PV) panels. To achieve the best results, a numerical dynamic model consisting of different solar PV panels in three models, batteries, inverters, and hybrid heat pump along with collector and PCM has been modeled by solving Engineering Equation Solver (EES) and TRNSYS software. According to the proposed scenarios, multi‐objective optimization has been done to simultaneously improve the study answers in several sections by multi‐objective particle swarm optimization algorithm with MATLAB software. Also, economic and environmental optimization is also presented separately for comparing and reviewing solutions. The results of multi‐objective optimization show that the amount of lifecycle cost (LCC) when using polycrystalline panel is 21.26% lower than monocrystalline panel and 38.71% higher than thin film panel. As a result, according to the specific conditions and attitude, you can choose the desired system. Also, in the economic optimization, it was found that the best system is related to the polycrystalline panel, the volume of PCM used in the system is equal to 1 m3 , the number of panels used is 18, and the minimum amount of LCC is $3929.08. [ABSTRACT FROM AUTHOR]

Zero-energy building is the main development trend in the current construction field. Reducing the carbon emission of the building, enhancing the indoor comfort of the building, and improving the comprehensive performance of the building are the current research hotspots in the field of construction, and it is necessary to explore the impact of the envelope on the performance of the building as the main medium for the transfer of indoor and outdoor heat in the building. In this paper, zero energy consumption buildings in Northwest China are taken as the study application. Numerical simulation and experimental research are combined to compare and analyze the changes of indoor thermal environment under the conditions of external wall insulation layer thickness of 150 mm, 140 mm, 130 mm and window-wall ratio of 0.36 and 0.5 in the heating season. The results show that the indoor comfort level of 130 mm is lower than that of 140 mm and 150 mm external wall insulation layer thickness, and in winter, the increase of window wall ratio improves indoor thermal comfort. In general, increasing the thickness of external wall insulation layer and window wall ratio can be effective means to improve indoor comfort. However, blindly increasing the thickness of insulation layer and window wall ratio will only cause resource waste and cost increase, affecting the long-term development of zero-energy buildings. [ABSTRACT FROM AUTHOR]

The Integrated Design Process is one of the most recommended methods to deliver Zero-Energy Buildings as it brings together all the stakeholders in the early moments of design, allowing performance optimisation and synergies among the different approaches and expertise. The practice of this design process is complex and difficult because it aims to integrate evolving decisions by all parties. It has been widely studied from the perspective of the process itself and its efficacy. However, the human side or how to manage the collaboration of the different stakeholders in the design development for a Zero Energy Building is unknown. To address this research gap this study is focused on the synergies among the consultants and the purpose behind this kind of building. Through the analysis of the design process and eight interviews with the main stakeholders of a Zero Energy Building at the National University of Singapore, three human factors are identified as critical for the success of an Integrated Design Process: client leadership, acting as the engine of the project; trust among the team, acting as the glue during the process, and focus on the goals that sustains the effort and allows the continuity in time. Although the results are limited to a case study, they can serve as a guide for clients and consultants to implement optimised Integrated Design Processes for future Zero Energy Buildings. [ABSTRACT FROM AUTHOR]

As societies are shifting toward carbon neutral environments, they are beginning to account for their carbon emissions. One of the primary contributors of greenhouse gas emissions and global warming is the building industry; therefore, Life Cycle Assessment (LCA) is one of the instruments that allows an assessment of the energy and the energy-related environmental impacts of the buildings from cradle to grave, according to ISO 14040. In this context, the aim of this research study is to assess the Life Cycle carbon dioxide (LC CO2eq) emissions over a 50-year-lifespan of a zero-carbon solar-powered earth-based building, built with carbon-free adobe bricks, in the hot semi-arid climate of Morocco. While research on the carbon dioxide equivalent (CO2eq) emissions across the life cycle is crucial to determine the energy-intensive stages, this study looks into global tendencies of CO2eq emissions arising during the cradle-to-gate embodied (A1-3) and operational (B6) phases of a Zero Carbon Building (ZCB) case study, and which should be offset by carbon-free energy in order to abide by the ZCB definition. Results show that the LC CO2eq emissions of the eco-friendly zero-carbon residential building falls in 48.62 Kg CO2eq/m2.y., with an operational phase that has a share of around 93 % of global LC CO2eq emissions. In addition, when conventional construction materials such as concrete, bricks, and insulation materials are used as an alternative, embodied carbon emissions accounts for 6.3 kg CO2eq/m2.y. and is 85 % higher than the eco-friendly building, and it constitutes approximately 12.5 % of the overall carbon footprint. Moreover, the annual embodied and operational CO2eq emissions are offset by the 3.3-kWc-building-added-photovoltaic system. Hence, the conducted case study offers valuable insight into the good practices for decarbonization of Morocco's building stock.Through that case study, we aim to generate knowledge of net zero carbon buildings within the African continent, promoting the perks of decentralized solar energy in leaping forward a carbon-free electrified continent and valorizing the local construction techniques and knowhow in the building sector.

Modernization and industrialization have significantly increased energy consumption, causing environmental problems. Given that China is the largest energy user, the rise in building energy consumption necessitates clean energy alternatives. The purpose of this study is to summarize typical building models for primary and secondary schools in Hainan Province, and to use software to simulate and calculate the photovoltaic utilization potential of primary and secondary school buildings. In China, the government is usually the manager of primary and secondary schools, and due to their architectural characteristics, these buildings can be used to assess photovoltaic applications. The aim is to drive the application of photovoltaic systems in all types of buildings and promote urban energy reform. This study summarizes the types of primary and secondary school buildings in Hainan Province and analyzes them. It evaluates rooftop photovoltaic projects at the Second Middle School and the Siyuan School in Wanning City, Hainan Province, and uses PVsyst 7.2 software to assess the photovoltaic utilization potential. The results show that the optimal orientation in Hainan Province is south-facing, and the optimal inclination angle is 10° to 20°. The most favorable orientations of facade photovoltaic systems are 20° southeast or southwest. The longest dynamic investment payback period is approximately 15 years, and the environmental benefits are $0.012/kWh. The findings indicate significant potential for photovoltaic applications in primary and secondary school buildings. A combination of facade and rooftop photovoltaics can result in the zero-energy consumption of these buildings, reducing the pressure on urban power grids and achieving sustainable utilization. [ABSTRACT FROM AUTHOR]

This paper presents a study on solar walls integrated with phase change material (PCM) to enhance energy efficiency in zero-energy buildings. The research focuses on expanding the surface area with PCM-filled compartments to improve thermal performance. The effects of different expanded surface shapes and outlet air distances on the solar wall's temperature and PCM solidification process are investigated through numerical simulations. The findings show that semicircular surfaces with a 30 cm outlet air distance have the highest temperatures, while rectangular surfaces with the same distance have the lowest temperatures. Semicircular surfaces take the longest time to freeze PCM completely, whereas rectangular surfaces with a 30 cm gap achieve the fastest solidification. These insights provide valuable guidance for optimizing solar wall design and energy efficiency in zero-energy buildings. Finally, it was seen that by changing the shape of the extended surfaces and the air gap, the outlet air temperature changes up to 1.15° and the wall temperature changes up to 1.21°.

Existing buildings necessitate conversion to green buildings through remodeling. In early stages of this green remodeling project, it is crucial to establish a clear objective or strategy, because this determines the energy efficiency improvement rate of existing buildings. In this study, a local public nursery school was taken as the case study, where three objectives were determined: zero energy building (ZEB), greenhouse gas emissions (GHG), and energy saving cost (ESC), and an efficient strategy for green remodeling according to each objective was provided. In addition, this study introduced a function called multi-objective energy efficiency ratio (MO-EER) to allow consumers to establish an optimal strategy by setting weights for each objective. The results of the study demostrated that both passive and renewable technologies were important in zero energy buildings. To achieve ZEB, it was advantageous to apply passive and renewable energy technologies that greatly reduces primary energy consumptions. In terms of GHG emissions, the more green remodeling technology, the better the building energy efficiency. In case of ESC, it was advantageous to apply a technology that greatly reduces secondary energy consumptions.

A ground-source heat pump (GSHP) system is a renewable energy technology that effectively reduces greenhouse gas emissions and consequently mitigates the progression of global warming. The thermal efficiency of ground heat exchangers (GHEs) is a critical component in the GSHP system that must be accurately estimated for its long-term operationality. Therefore, in this study, the thermal performance of double-spiral GHEs incorporated within the thermal piles of a zero-energy building in Sapporo, Japan, was investigated using the actual measured data obtained from the site and a novel metric, namely, the coefficient of heat extraction/injection, for a more precise evaluation. Moreover, this study assessed the coefficient of performance (COP) of the GSHP units during various periods of cooling or heating. The temperature of the circulating fluid remained within an ideal operational range over an operational period of 2 years, and the COP calculations indicated a high operational efficiency. The results derived in this study substantially exceeded those of traditional U-tube GHEs, indicating the enhanced efficiency and superior performance of large-diameter thermal piles with augmented thermal capacity. Our findings suggest that GSHP systems with double-spiral-tube GHEs have superior efficiency than conventional GHEs. [ABSTRACT FROM AUTHOR]

In this study, for the first time, an off-grid zero-energy building with hydrogen energy storage integrated with two hydrogen cars is simulated and analyzed transiently. Regarding the novelties, for the first time, two types of wind turbines are compared as an energy supplier of the building, and all human living requirements are considered. Therefore, the study can fill in the gap of a comprehensive analysis of such off-grid hydrogen-integrated zero energy building by considering two types of wind turbines as its energy supplier. The mentioned wind turbines are compared in terms of total capital cost, and the cheapest one is specified. The fuel consumption of two typical hydrogen cars is considered. An occupant's thermal comfort level and domestic hot water usage are considered. Trnsys software is employed to examine the building's annual transient performance. Electrical split heat pumps and humidifiers are used to keep the residents warm. A solar collector heats a hot water storage tank for residential water heating. When renewable energy sources are unavailable, energy is stored and used through a hydrogen energy system. This way, electricity will be transformed by utilizing an alkaline electrolyzer into hydrogen and stored in a tank. Using fuel cells, stored hydrogen converts to electricity. Waste heat from fuel cells and electrolyzers is also an additional heating source for a hot water storage tank. Results demonstrate that five vertical-axis or seven horizontal-axis wind turbines are required to supply the energy needs of a typical 150 m2 building in Boston. Both of them have 2 kW rated power. The cheapest case is horizontal-axis wind turbines. The given number of wind turbines meets the building's energy requirements for two hydrogen cars. The monthly expected discontent percentage is below 9% when using a suitable split electrical heat pump and humidifier, and the predicted mean vote is in the range of − 0.4 and 0.4. An evacuated tube solar collector can meet four building residents' hot water needs. Typical buildings can be transformed into off-grid zero energy for windy cities like Boston by mounting all required energy suppliers, including solar collectors and wind turbines, on the rooftop. [ABSTRACT FROM AUTHOR]

The production and consumption of non-renewable energy resources have disrupted the environment's biodiversity cycle. Global climate change, including worldwide warming, has made human life both now and in the future. The construction industry in the world has a significant share in the demand for energy consumption in these challenges. Therefore, the primary purpose of this paper is to implement standards to save and prevent energy loss to control and limit the demand for energy requested from the power network. Constructing a building with self-sufficient energy production that meets its energy needs by producing clean energy becomes more important. It also sells the excess energy to the grid, known as zero energy buildings. In the present paper, the issue is a constrained optimization problem that aims to minimize the total annual cost, including the initial investment cost for PV and batteries and their maintenance costs, as well as the cost of network exchanges. Among the limitations, the proposed model can mention the restrictions governing the battery, such as the limitations of the battery state of charge (SoC). The problem under optimization is a mixed integers nonlinear programming (MINLP) that will be solved by a particle swarm optimization (PSO) algorithm considering the total cost minimization.

The decarbonisation strategy of the building sector, which accounts for 24% of national greenhouse gas (GHG) emissions, is important to achieve climate neutrality in Korea by 2050. In this study, a bottom-up model and four scenarios were developed for examining scenarios for the decarbonisation of the residential building by 2050. A comparative analysis of energy consumption, GHG emissions, and investment cost was performed. The result showed that building energy performance improvement and heating fuel electrification are key measures for decarbonisation. We concluded that an investment of KRW 6.2 trillion per year would be required to achieve the 2050 decarbonisation scenario. Policy strategies were proposed for increasing investment in accelerating building retrofit, mandating zero-energy building (ZEB), and prohibiting gas boilers.

Currently, there is no official green or sustainable built environment evaluation system in Turkey. When a certification is required for a building or a site, various certification systems are employed. To meet the demand, the Turkish Green Building Council released an evaluation system called B.E.S.T. in 2013. In this paper, the B.E.S.T. evaluation system is introduced as well as a sample application. The evaluation of the Yalova University Engineering Faculty Building using the B.E.S.T. evaluation system is presented. Field research was conducted and evidentiary documents were gathered in preparation. The study employed both analytical and field research methodologies in this regard. As a result of the study, Yalova University Engineering Faculty Building was assessed to be eligible for the lowest level certificate, the ‘Approved’ degree of the B.E.S.T. evaluation system. Furthermore, the results achieved with the B.E.S.T. were compared to those acquired previously with other green or sustainable building evaluation systems. HIGHLIGHTS - An exemplary set of the evaluation was performed for university campus buildings with the B.E.S.T. certification system. - The conducted case study is one of the earliest samples of B.E.S.T. evaluations. - A comparison of B.E.S.T. with LEED and BREAM is provided. - The importance of establishing a local certification system has been discussed.

Trombe wall is a passive strategy that reduces the energy consumption in buildings and helps for sustainable development of the residential sector. Applying these walls is very important in areas that need heating load in winter. This study evaluates a set of Trombe walls for the energy management of a residential building under real conditions in Binalood region with a cold and dry climate. In order to study the potentials of the Trombe wall, four different designs, including cubic Trombe wall with rectangular structure and three-sided glass, Trombe wall with trapezoidal structure and three-sided glass, Trombe wall with trapezoidal structure and four-sided glass, and Trombe wall with thicker storage wall, trapezoidal structure, and three-sided glass, for Trombe wall are considered. Trombe walls of all four suggested designs are exposed to outdoor conditions and installed at 17 places on the southern walls of the residential building. The results show that the most optimal design, i.e., Trombe wall with thicker storage wall, trapezoidal structure, and three-sided glass, leads to the greatest decrease (1637 kWh) in heating load in January. In addition, this design of the Trombe wall has the greatest effect in increasing the indoor air temperature among other Trombe walls investigated in this study. The Trombe wall with thicker storage wall, trapezoidal structure, and three-sided glass with a storage wall thickness of 40 cm is able to reduce the heating load of the building by 5.59 MWh in 5 months. This plan reduces the energy demand of the building by 8% more than the conventional structure of Trombe wall. [ABSTRACT FROM AUTHOR]

Indoor dehumidification is usually achieved by mechanical cooling resulting in significant consumption of high-grade energy resources such as electricity. Conventional rotary dehumidification systems also require the use of high-grade energy to heat the desiccant and regenerate it. Utilization of renewable energy for indoor dehumidification is highly of concern. Ventilated roof desiccant bed system is a novel dehumidification method which can regenerate itself automatically with low-grade energy usage by taking advantage of solar energy and natural ventilation directly. Using renewable energy as an alternative, it can reduce the building energy consumption, which is beneficial to achieve nearly zero energy building (nZEB) target. This study establishes the heat and moisture transfer model of the ventilated roof desiccant bed while the moisture transfer model is validated by using the reference data. The flow-field characteristics in the airflow channels are numerically analyzed, and the regeneration process of the desiccant bed in a typical day is also simulated. Results show that both the temperature and air velocity in the channel are increasing from the inlet to the outlet. The air velocity increment can reach 0.5 m/s, and the temperature can rise about 6 °C under the same boundaries. On a typical day, the regeneration process of the ventilated roof desiccant bed lasts for approximately 3 h, and 80 g of water is desorped per unit. It means that about 18 units are sufficient to remove the moisture produced in 8 h by a man. The research results can provide data reference for the design of the system, and thus facilitates the realization of engineering application. • A ventilated roof desiccant bed system using natural energy for dehumidification is proposed. • A coupled heat and moisture transfer model of the desiccant bed is established and validated. • The flow-field characteristics in the airflow channels are numerically analyzed. • The dehumidification and regeneration characteristics of the desiccant bed are analyzed. [ABSTRACT FROM AUTHOR]

A variety of strategies intended to support environmentally friendly and resource-efficient building processes comprise sustainable construction policies. The limited number of bibliometric analyses in the field may hinder the ability to assess the efficacy and impact of research efforts, impede the potential for collaboration, and even limit the dissemination of best practices. Therefore, the present study aims to analyze the impact of published data on the topic of energy efficiency of buildings using the Web of Science core collection database. We perform a bibliometric analysis and science mapping research that assesses significant parameters for the field. A total of 28,555 papers were analyzed using the VOSviewer program. The data was divided into two periods to determine the evolution of trends in this field. The most prolific countries in this field were China, the United States, and England. Following the analysis of the collaboration maps, it was determined that there is a strong collaborative relationship between these countries in the development of papers. The most prolific papers of the first period were published in Energy Policy and Energy and Buildings, which also ranked first in the second period, followed by Energies. It was observed that the most frequent terms used in literature searches in the field differ according to the periods analyzed. In the beginning, the most frequent term was "energy efficiency and performance", and between 2011 and 2023, the terms "applied energy" and "renewable and sustainable energy" increased considerably with technological development. The results of this research demonstrate the significant and expanding scientific interest in this area and serve as a valuable asset for researchers studying the energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

Modernization and industrialization have significantly increased energy consumption, causing environmental problems. Given that China is the largest energy user, the rise in building energy consumption necessitates clean energy alternatives. The purpose of this study is to summarize typical building models for primary and secondary schools in Hainan Province, and to use software to simulate and calculate the photovoltaic utilization potential of primary and secondary school buildings. In China, the government is usually the manager of primary and secondary schools, and due to their architectural characteristics, these buildings can be used to assess photovoltaic applications. The aim is to drive the application of photovoltaic systems in all types of buildings and promote urban energy reform. This study summarizes the types of primary and secondary school buildings in Hainan Province and analyzes them. It evaluates rooftop photovoltaic projects at the Second Middle School and the Siyuan School in Wanning City, Hainan Province, and uses PVsyst 7.2 software to assess the photovoltaic utilization potential. The results show that the optimal orientation in Hainan Province is south-facing, and the optimal inclination angle is 10° to 20°. The most favorable orientations of facade photovoltaic systems are 20° southeast or southwest. The longest dynamic investment payback period is approximately 15 years, and the environmental benefits are $0.012/kWh. The findings indicate significant potential for photovoltaic applications in primary and secondary school buildings. A combination of facade and rooftop photovoltaics can result in the zero-energy consumption of these buildings, reducing the pressure on urban power grids and achieving sustainable utilization.

The need for efficient buildings to contribute to sustainable development has led to the proposal of goals and regulations in different countries linked to net zero energy objectives, following approaches specific to their regions. Such regulations are not yet developed in a developing country such as Panama. Thus, this study develops the first framework for Zero Energy Districts (ZED) in Panama based on passive and active solutions through dynamic simulation. For this, an existing urbanization area consisting of 34 residential buildings, called the existing case (EC), was studied. After undergoing a design based on the bioclimatic methodology, a redesigned case (RC) is proposed to maintain thermal comfort and reduce energy consumption. Key redesign factors are the buildings' shape, orientation, glazing, the use of shadows, material of the walls, and the air conditioning configuration. Results showed energy consumption decreases by 37.5% when considering all buildings with natural ventilation, reaching ranges of positive net energy (+356.50 kWh/m2y). In the case of nearly ZED in Panama, the ranges could be considered between 14 and 180 kWh/m2y. This balance indicates that there is potential on site to develop zero energy districts. [ABSTRACT FROM AUTHOR]

As a result of economic and political requirements, renewable energy investments are supported with various incentives all over the world, while fossil fuel systems are restricted by regulations. This article aims to make conventional heating, cooling and power systems more efficient or to develop an alternative system based on renewable energy by modeling an office building. Considering three scenarios - classical heating-cooling system, combined cooling-heating-power system and zero energy building, the test building’s energy estimation analysis and life-cycle cost analysis have been conducted and 3 different sub-scenarios for renewable energy scenarios have been generated. As a result of the Hourly Analysis Program (HAP), the building’s cooling design load was found to be 742.7 kW, and the heating design load was 439.8 kW. The required borehole length for ground source heat pump is determined as 20,371 m for cooling and 9,137 m for heating, while the heat is discharged into the borehole with a rate of -44.3 W / m and extracted with a rate of 34 W / m. Annual energy generation of the photovoltaic plant was determined as 607.639 kWh and installed power of for this plant was calculated as 463 kWp. Lifecycle cost analyses were performed by using P1-P2 method and according to the calculations, the payback period for the extra investment cost is 37 months for the combined cooling-heating-power plant, whereas it is 94 months for the improved zero energy building design. Similarly, the payback period for the full investment cost is determined as 58 months for the combined cooling-heating-power plant, and 127 months for the improved zero energy building design. As a result, a hybrid zero energy building (air source condenser + ground source heat pump, photovoltaic panels) is proposed as the best design option for the office building identity.

Given the notable consumption of fossil fuels, buildings prioritize their energy utilization. This paper's aim is to explore the primary strategies in attaining zero-energy and zero-carbon buildings. The investigation employs two specialized software programs: Design Builder, which analyzes energy usage, and PV Syst, which evaluates renewable energy requirements. The study is conducted in Fort Myers, USA, and Dubai, UAE, leveraging diverse regional and climate discrepancies, and real-world data on zero-energy and carbon constructions for comparison and validation. Within the Design Builder software, the research examines four strategies, with the first serving as the realistic baseline. By implementing the second strategy, utilizing internal shading devices such as Shade Roll, a reduction of 376 kWh in Fort Myers and 591 kWh in Dubai is achieved. The third strategy encompasses the deployment of blind-type internal shading systems, resulting in reductions of 212 kWh in Fort Myers and 348 kWh in Dubai. The fourth strategy involves integrating renewable energy via photovoltaic panels, injecting 323.5 kWh in Fort Myers and 2237 kWh in Dubai into the power grid for lighting purposes. Furthermore, 3200.5 kWh and 4722 kWh of energy are respectively injected into the grid for heating in Fort Myers and Dubai. Cooling, however, necessitates additional energy from the grid, amounting to 2243.94 kWh in Fort Myers and 9211.64 kWh in Dubai. In the pursuit of zero-carbon goals, the implementation of suitable low-carbon recycled materials, in place of primary building materials, reduces carbon dioxide emissions from 79 tons to 7.315 tons in Fort Myers and 7.038 tons in Dubai. By employing appropriate materials, the zero-carbon objective is attained. [ABSTRACT FROM AUTHOR]

• Demonstrated the first real-world energy sharing in an energy community. • Fully electrified a community with a 107 MWh scale using high renewable energy. • Achieved 57.6% self-consumption, 38.4% self-sufficiency, 126.3% energy independence. • Used machine learning to uncover complex grid and building energy interactions. • Reduced annual electricity costs by 18.3% through demand side management. Achieving 'carbon neutrality' in the building sector involves high penetration of renewables, electrification of energy use, and improved flexible interactions with the grid to balance energy supply and demand. This study analyzed one year in an urban energy community powered entirely by electricity, using high levels of renewable sources. By facilitating energy sharing between residential and non-residential buildings, the community redirected surplus energy to meet demand, achieving 57.6% self-consumption, 38.4% self-sufficiency, and 126.3% energy independence rate. This achievement involved an annual electricity consumption of 107 MWh, sevenfold that of previous simulation-based studies, marking the first real-world demonstration. Using machine learning clustering with domain-based interpretation, the study unraveled complex interactions between building operations and the power grid, influenced by external factors (weather, occupant behavior), system design, and controls. Managing low-probability high-impact (LPHI) events of severe demand or production peaks, accounting for only 0.5% of the time and 1.8% of net energy annually, was crucial to grid stability and cost reduction. The study confirmed the limitations of increasing battery energy storage capacity in certain environments, highlighting the importance of demand-side management (DSM) with thermal systems. The DSM effectively handled LPHI events, reducing grid stress with an 18.3% decrease in annual electricity cost. [ABSTRACT FROM AUTHOR]

A ground-source heat pump (GSHP) system is a renewable energy technology that effectively reduces greenhouse gas emissions and consequently mitigates the progression of global warming. The thermal efficiency of ground heat exchangers (GHEs) is a critical component in the GSHP system that must be accurately estimated for its long-term operationality. Therefore, in this study, the thermal performance of double-spiral GHEs incorporated within the thermal piles of a zero-energy building in Sapporo, Japan, was investigated using the actual measured data obtained from the site and a novel metric, namely, the coefficient of heat extraction/injection, for a more precise evaluation. Moreover, this study assessed the coefficient of performance (COP) of the GSHP units during various periods of cooling or heating. The temperature of the circulating fluid remained within an ideal operational range over an operational period of 2 years, and the COP calculations indicated a high operational efficiency. The results derived in this study substantially exceeded those of traditional U-tube GHEs, indicating the enhanced efficiency and superior performance of large-diameter thermal piles with augmented thermal capacity. Our findings suggest that GSHP systems with double-spiral-tube GHEs have superior efficiency than conventional GHEs.

The decarbonisation strategy of the building sector, which accounts for 24% of national greenhouse gas (GHG) emissions, is important to achieve climate neutrality in Korea by 2050. In this study, a bottom-up model and four scenarios were developed for examining scenarios for the decarbonisation of the residential building by 2050. A comparative analysis of energy consumption, GHG emissions, and investment cost was performed. The result showed that building energy performance improvement and heating fuel electrification are key measures for decarbonisation. We concluded that an investment of KRW 6.2 trillion per year would be required to achieve the 2050 decarbonisation scenario. Policy strategies were proposed for increasing investment in accelerating building retrofit, mandating zero-energy building (ZEB), and prohibiting gas boilers. [ABSTRACT FROM AUTHOR]

Currently, there is no official green or sustainable built environment evaluation system in Turkey. When a certification is required for a building or a site, various certification systems are employed. To meet the demand, the Turkish Green Building Council released an evaluation system called B.E.S.T. in 2013. In this paper, the B.E.S.T. evaluation system is introduced as well as a sample application. The evaluation of the Yalova University Engineering Faculty Building using the B.E.S.T. evaluation system is presented. Field research was conducted and evidentiary documents were gathered in preparation. The study employed both analytical and field research methodologies in this regard. As a result of the study, Yalova University Engineering Faculty Building was assessed to be eligible for the lowest level certificate, the 'Approved' degree of the B.E.S.T. evaluation system. Furthermore, the results achieved with the B.E.S.T. were compared to those acquired previously with other green or sustainable building evaluation systems. HIGHLIGHTS - An exemplary set of the evaluation was performed for university campus buildings with the B.E.S.T. certification system. - The conducted case study is one of the earliest samples of B.E.S.T. evaluations. - A comparison of B.E.S.T. with LEED and BREAM is provided. - The importance of establishing a local certification system has been discussed. [ABSTRACT FROM AUTHOR]

Copyright of Architectural Journal / Jian Zhu Xue Bao is the property of Architectural Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Architectural Journal / Jian Zhu Xue Bao is the property of Architectural Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: Thermoelectric module (TEM) is a scalable, reliable, and noise‐free solid‐state device that converts thermal energy into electrical energy and vice‐versa. TEM has been explored for cogeneration, electronics cooling, power production, waste heat harnessing, and air‐conditioning. The potential applications of TEM‐based systems are in the building, for heating, ventilation, and air‐conditioning (HVAC), which represents its significant share in the energy consumption in the building sector. A photovoltaic powered thermoelectric system has even a stronger techno‐economical potential. The main objective of the study is to explore the potential of PV‐powered thermoelectric technology as a distributed air‐conditioning system in buildings. In this study, a comprehensive review on PV‐powered thermoelectric technology is presented in addition to several new design concepts for application in future development of sustainable zero energy building technologies in view of sustainability and global climate change concerns. A novel "STEM‐Wall" concept is also discussed concerning future thermoelectric system designs for buildings. Additionally, the thermal comfort aspect of HVAC systems is critically analyzed by reviewing the standard predicted mean vote and predicted percentage of dissatisfied indices. The research outcome, analysis, and potential of TEM applications for future sustainability and thermal comfort in buildings are presented. Further follow‐up research areas are also identified. [ABSTRACT FROM AUTHOR]

Building Information Modeling (BIM), as an auxiliary design platform, is increasingly adopted in construction projects. However, it is not widely applied in the collaborative design of zero energy buildings (ZEBs), due to the cross-discipline and complex features of ZEB projects and lack of research on the procedure and method of collaborative design in this field. This paper introduces a BIM-based collaborative design method for ZEBs. From the perspective of the technical requirements of ZEBs, the study elaborates the application of a BIM-based collaborative design method among specialists from different disciplines in passive design, renewable energy utilization and active design. The feasibility of this method is verified by the actual design and construction of the T&A House in Solar Decathlon China (SDC) competition. The research results show that the BIM-based collaborative design method can facilitate the completion of a construction project and achieve the expected goal of zero energy consumption in ZEBs. [ABSTRACT FROM AUTHOR]

Recent advancements in green building technologies (GBTs) have grown substantially, as an outcome of the environmental, economic and societal benefits. It has the potential to move toward sustainable development, specifically related to climate change. In GBTs, the main objective is to use energy, water and other resources in a balanced way, without using them extensively. This will improve the environmental conditions. Green buildings (GBs) are beneficial when it comes to energy consumption and emissions; low maintenance and operation costs; boosting health and productivity; etc. There is a lack of a critical review of the past or present research work in the area of the Green Building Technology (GBT) sector to identify the future roadmap for sustainable green building technologies. A critical review, with the help of proper research methodology, was identified. The scope of this study is to analyze the existing work on different issues, and find different key issues in green building research, which has minimal use of natural resources, is cost-effective and is designed and constructed for a longer duration, considering future prospects. This paper examines the state of green building construction today and makes recommendations for further study and development which will be necessary for a sustainable future. In order to encourage research, this study also identified a few possible future research directions in sustainable development. [ABSTRACT FROM AUTHOR]

In this study, some locations with different climates, off-grid zero energy buildings with hydrogen energy storage systems are designed, and transient analysis is conducted. These considered buildings supply their electricity consumption without using the electrical grid and PV panels or wind turbines. Also, they supply thermal comfort to occupants by using a vapor compression chiller and humidifier. Domestic hot water of occupants is supplied using solar collectors. For analyzing building's performance and objectives achievement, TRNSYS software is used. Also, for evaluating occupant thermal comfort, the Fanger model is used. The considered building is a one-story building with a 150 m2 area. Four occupants are considered. Both of them are seated at rest, and another is seated with light working such as typing. Using the Fanger model equation and MATLAB software, the thermal comfort of occupants is determined. For domestic hot water consumption, verified profiles that vary during 24 h of the day are considered. Achieved results show that for humid and cold cities, PV panels with an area of 73 and 76 m2 can be supplied the required electricity of considered building with four occupants and battery state of charge is higher than 50% and 10%, respectively. Moreover, with a suitable air conditioner system, the predicted percentage of dissatisfied (PPD) can be lower than 12% and 8% for humid and cold cities. Therefore, the building can be converted to a zero-energy building using its rooftop area. • Analyzing wind and PV panels as renewable energy suppliers for supplying energy. • Storing hydrogen energy system as for off-grid zero energy buildings. • Transient analysis and design of off-grid zero energy buildings. • Evaluating thermal comfort of occupant in zero energy buildings. • Using Fanger model and PPD and PMV parameters. [ABSTRACT FROM AUTHOR]

In this study, zero energy building (ZEB) with four occupants in the capital and most populated city of Iran as one of the biggest greenhouse gas producers is simulated and designed to reduce Iran's greenhouse emissions. Due to the benefits of hydrogen energy and its usages, it is used as the primary energy storage of this building. Also, the thermal comfort of occupants is evaluated using the Fanger model, and domestic hot water consumption is supplied. Using hydrogen energy as energy storage of an off-grid zero energy building in Iran by considering occupant thermal comfort using the fanger model has been presented for the first time in this study. The contribution of electrolyzer and fuel cell in supplying domestic hot water is shown. For this simulation, Trnsys software is used. Using Trnsys software, the transient performance of mentioned ZEB is evaluated in a year. PV panels are used for supplying electricity consumption of the building. Excess produced electricity is converted to hydrogen and stored in the hydrogen tank when a lack of sunrays exists and electricity is required. An evacuated tube solar collector is used to produce hot water. The produced hot water will be stored in the hot water tank. For supplying the cooling load, hot water fired water-cooled absorption chiller is used. Also, a fan coil with hot water circulation and humidifier are used for heating and humidifying the building. Domestic hot water consumption of the occupants is supplied using stored hot water and rejected heat of fuel cell and the electrolyzer. The thermal comfort of occupants is evaluated using the Fanger model with MATLAB software. Results show that using 64 m2 PV panel power consumption of the building is supplied without a power outage, and final hydrogen pressure tank will be higher than its initial and building will be zero energy. Required hot water of the building is provided with 75 m2 evacuated tube solar collector. The HVAC system of the building provided thermal comfort during a year. The monthly average of occupant predicted mean vote (PMV) is between −0.4 and 0.4. Their predicted percentage of dissatisfaction (PPD) is lower than 13%. Also, supplied domestic hot water (DHW) always has a temperature of 50 °C, which is a setpoint temperature of DHW. Finally, it can be concluded that using the building's rooftop area can be transformed to ZEB and reduce a significant amount of greenhouse emissions of Iran. Also, it can be concluded that fuel cell rejected heat, unlike electrolyzer, can significantly contribute to supplying domestic hot water requirements. Rejected heat of electrolyzer for heating domestic water can be ignored. • Off-grid zero energy building with hydrogen energy storage is designed for the capital of Iran as a case study. • Designed building supplies the human living requirement of 4 occupants. • Solar collectors and PV panels are used as energy suppliers. Absorption chiller and fan coils are used. • The thermal comfort of occupants is analyzed using the Fanger model. • For making solar collectors smaller, rejected heat of fuel cell is used for heating domestic water. [ABSTRACT FROM AUTHOR]

This study evaluates the techno‐economic feasibility of a new biomass‐driven cogeneration system designed to fulfill all energy requirements (i.e., electricity, hot water, cooling, and heating) of a grid‐connected building throughout the year. The proposed system is also expected to achieve the goal of zero energy building (ZEB). A 10‐story residential complex is considered as the present case study. The study is carried out for three cities of Iran with different climate conditions (mild, hot, and cold) and with the annual energy requirements of about 104,472 kWh, 128,784 kWh, and 142,518 kWh, respectively. After defining two objective functions ("annual actual benefit" and "loss of building requirements supply probability"), the system is optimized by using the Non‐dominated Sorting Genetic Algorithm (NSGA‐II). The results show that the designed system is economically viable with the levelized cost of energy (LCOE) of about 0.15–0.2 $/kWh. The results also indicate that if the cost of CO2 emission is taken into consideration, the annual benefit of the system is decreased by 16%–25%. Finally, a sensitivity analysis shows that heat generation cost and electricity selling price have the most and the least effect on the system's annual benefit, respectively. [ABSTRACT FROM AUTHOR]

One of the challenges in construction of nearly and net ZEBs is how to truly achieve the nearly and net energy goals after building occupancy. Traditional building design standards and practices are mostly based on design performance evaluation, but practices show that many designed nearly/net ZEBs failed to achieve the energy goals after building occupancy. To facilitate the practical achievement of nearly and net ZEBs, recently most of the newly-released ZEB design standards have turned to post-occupancy performance evaluation, posing great challenges to nearly and net ZEB design. However, the detailed challenges have not be comprehensively investigated, and effective optimal design methods which can facilitate the achievement of nearly and net ZEBs under these standards are still absent. In this study, new challenges of nearly and net ZEB design under the post-occupancy performance-based design standards are fully investigated, and a risk-benefit based optimal design method is proposed to facilitate the achievement of nearly and net ZEBs under these standards. The newly-released ZEB standard in China is taken as an example to investigate the challenges and test the proposed method. Results show that nearly and net ZEBs designed using conventional design method have high risk in achieving energy goals under these standards due to high risk in satisfying the requirement regarding non-renewable primary energy consumption after building occupancy. The proposed design method is effective to facilitate achieving energy goals under these standards based on the risk that decision-makers would like to take. [ABSTRACT FROM AUTHOR]

This article reviews the definitions related to buildings that promote zero energy balance. Besides, this article identifies the main challenges for the dissemination of and overcrowding of these sustainable buildings, which are called Zero Energy Buildings -ZEB. The analyzed literature shows that the main challenges are to include technical, economic, social, and environmental aspects of each territory in the scenarios and proposed incentives since the roadmaps adopted by the countries will depend on their industrial development. In emerging countries, the roadmap development process should be needs-based, not solution-based. This article proposes, as opportunities to disseminate and spread the ZEB in the territories, to contemplate a type of regulatory scenarios that promote the development of passive designs that promote the construction of new buildings based on promoting the use of bioclimatic and advances in new materials that improve comfort according to the needs of each region. On the other hand, the design of direct and indirect incentives focused on research and innovation of own developments related to active designs for the renovation of existing buildings is proposed. [ABSTRACT FROM AUTHOR]

Over the last decades, Australia has taken several measures to tackle the increasing trend of energy use in residential buildings. Recently, the Trajectory for Low Energy Buildings has been endorsed aiming to reduce energy usage in residential buildings. However, the primary focus of this trajectory is on decreasing operational energy without considering the embodied energy of the building and systems. This paper aims to address one primary question; 'can the continued exclusion of embodied energy from the energy efficiency regulations effectively lead to reducing energy consumption in Australian residential buildings?'. The findings indicate that embodied energy becomes a dominating factor as buildings' thermal performances increase according to the Australian energy efficiency regulations. In transitioning from a standard 6.0-star building to a highly energy-efficient 8.7-star building, the proportion of embodied energy significantly increases from 20–40% to 50–75%. This study recommends establishing minimum mandatory requirements for buildings' embodied performance. [ABSTRACT FROM AUTHOR]

In this paper, the development and demonstration of a hybrid solar geothermal heat pump polygeneration system is presented. The poly-generation system has been designed, modeled, and simulated in TRNSYS software environment. Its performance was assessed followed by installation and demonstration at a demo site in Cheongju, Korea. The space heating and cooling load of the building is 13.8 kW in heating mode at an ambient temperature of −10.3°C and 10.6 kW in cooling mode at an ambient temperature of 32.3°C. The simulation data were compared with the field demo data using ISO 13256. The results showed that the model data compare well with the demo data both in heating and cooling modes of operation. At a source temperature of 16.7°C, the heat pump lab performance data-based COPc shows 9.9, while demonstration COPc shows 10.3, thus, representing 4.3% relative error. The heat pump source temperature decreased by 4.0°C from 20.9°C to 16.9°C due to ground heat exchanger coupling and resulted in a COPc increase by 13.3% from 8.5 to 9.8. When compared at the design conditions (outside temperature of 32.3°C), the TRSNYS model overestimated the demonstration site data by 12%, 9.3 vs. 8.1 kW with power consumption of 3.1 vs. 2.2 kW. The hybrid polygeneration system power consumption decreased by 1.2 kW when ambient temperature decreased from 35°C to 25°C.

Energy efficient infrastructure is the need of the hour for sustainable development. Zero energy building (ZEB) is one of the concepts towards sustainability. One of the most effective ways to achieve sustainability is to convert existing buildings to zero energy buildings. In this study concept of zero energy building and various retrofitting techniques for conversion of existing building to zero energy is studied in detail. A case study of residential house in rural area has been done for retrofitting in which Building Envelope and Renewable Energy techniques are used for retrofitting. Cost analysis and recovery period of the retrofitting is carried out. The first 24 years are used to recoup the entire expense of the retrofit. Building is used for the remaining 16 years with the advantage of cost savings from retrofitting of Rs. 2, 87,445/-. From case study it is concluded that both the techniques are suitable and cost effective for conversion of residential house into zero energy building.

The need for efficient buildings to contribute to sustainable development has led to the proposal of goals and regulations in different countries linked to net zero energy objectives, following approaches specific to their regions. Such regulations are not yet developed in a developing country such as Panama. Thus, this study develops the first framework for Zero Energy Districts (ZED) in Panama based on passive and active solutions through dynamic simulation. For this, an existing urbanization area consisting of 34 residential buildings, called the existing case (EC), was studied. After undergoing a design based on the bioclimatic methodology, a redesigned case (RC) is proposed to maintain thermal comfort and reduce energy consumption. Key redesign factors are the buildings’ shape, orientation, glazing, the use of shadows, material of the walls, and the air conditioning configuration. Results showed energy consumption decreases by 37.5% when considering all buildings with natural ventilation, reaching ranges of positive net energy (+356.50 kWh/m2y). In the case of nearly ZED in Panama, the ranges could be considered between 14 and 180 kWh/m2y. This balance indicates that there is potential on site to develop zero energy districts.

Building Information Modeling (BIM), as an auxiliary design platform, is increasingly adopted in construction projects. However, it is not widely applied in the collaborative design of zero energy buildings (ZEBs), due to the cross-discipline and complex features of ZEB projects and lack of research on the procedure and method of collaborative design in this field. This paper introduces a BIM-based collaborative design method for ZEBs. From the perspective of the technical requirements of ZEBs, the study elaborates the application of a BIM-based collaborative design method among specialists from different disciplines in passive design, renewable energy utilization and active design. The feasibility of this method is verified by the actual design and construction of the T&A House in Solar Decathlon China (SDC) competition. The research results show that the BIM-based collaborative design method can facilitate the completion of a construction project and achieve the expected goal of zero energy consumption in ZEBs.

The concept of zero energy buildings (ZEBs) has recently been actively introduced in the building sector, globally, to reduce energy consumption and carbon emissions. For the implementation of ZEBs, renewable energy systems, such as solar collectors, photovoltaic (PV) systems, and ground source heat pump (GSHP) systems, have been used. The system performance of solar collectors and PV systems are dependent on the weather conditions. A GSHP system requires a large area for boring machines and mud pump machines. Therefore, inhabitants of an existing small-scale buildings hesitate to introduce GSHP systems due to the difficulties in installation and limited construction area. This study proposes an integrate photovoltaic-thermal (PVT) and air source heat pump (ASHP) system for realizing ZEB in an existing small-scale building. In order to evaluate the applicability of the integrated PVT-ASHP system, a dynamic simulation model that combines the PVT-ASHP system model and the building load model based on actual building conditions was constructed. The heating and cooling performances of the system for one year were analyzed using the dynamic simulation model. As the simulation analysis results, the average coefficient of performance (COP) for heating season was 5.3, and the average COP for cooling season was 16.3., respectively. From April to June, the electrical produced by the PVT module was higher than the power consumption of the system and could realize ZEB.

This work gives a precise review of the researches completed on the energy conservation characteristics of liquid flow glazing. Its energy saving and environmental benefits under various design and operation conditions, contributions with renewable energy utilization, as well as application in zero energy buildings are timely explored and summarized. Its advantages lie in the reduction of thermal transmission between the indoor and outdoor environments, the beneficial thermal collection, and the tactful utilization of renewable energy. The optical and thermal properties, as well as the energy performance of liquid flow glazing were found much affected by the glazing and fluid properties, the window configuration, and the operating conditions. These are consequently linked to the degree of electricity saving, the decrease in atmospheric CO 2 emission, and the shortened life cycle payback time. The integrated use of solar and geothermal energy in liquid flow glazing systems is also addressed. This leads to more practical studies on the applications in zero energy buildings, such as control, real-time monitoring, and energy management strategies of liquid flow glazing system. In essence, the development of an evaluation platform or database, with systemic classification of liquid flow glazing categories plus the corresponding graded energy saving characteristics, is deemed helpful to the building professionals in meeting the zero energy buildings development targets. [Display omitted] • Liquid flow glazing/window. • Enhanced thermal insulation, thermal collection and thermal comfort. • Energy, environment and economic benefits. • Improved energy efficiency with renewable energy application. • Modularization, Monitor and Control, plus energy management toward ZEB. [ABSTRACT FROM AUTHOR]

This study proposes the novel concept of waste upcycling-driven zero energy building (W-ZEB). W-ZEB aims to accelerate the development of zero-energy buildings by incorporating waste upcycling processes (e.g., waste-to-energy (WtE), insulation material recovery, and biochar used in green roofs), ultimately advancing towards plus-energy building. W-ZEB includes three approaches: (1) generating additional energy through WtE, (2) enhancing building energy efficiency by utilizing advanced building materials recovered from waste, and (3) maintaining all elements and assets of W-ZEB using earnings obtained or saved from waste upcycling and management. To implement W-ZEB effectively, a building energy and waste management system (BEWMS) is suggested to coordinate and optimize energy demand, waste generation, and utilization, contributing to a net zero energy status and zero solid waste to landfills throughout building life cycle. Practical insights and research directions for unlocking the untapped potential of waste upcycling strategies to achieve zero-energy buildings are also provided. [Display omitted] • The concept of waste upcycling-driven zero energy buildings (W-ZEB) is proposed. • W-ZEB includes energy-based and material-based approaches. • A building energy & waste management system (BEWMS) is suggested to implement W-ZEB. • A literature review provides practical insights and research directions. [ABSTRACT FROM AUTHOR]

• The definition of zero energy building needs updating to overcome its limitations. • Boundary, weighting, and timestep are crucial variables for nZEB energy balance. • The zero power building concept is a new method for building performance assessment. • A novel methodology is presented to describe buildings as highly dynamic entities. • Application to a real-world district supports stakeholders in decision making. This research introduces an innovative method aimed at evaluating building energy performance within urban environments and communities, departing from the conventional Zero Energy Building (ZEB) concept and introducing the Zero Power Building (ZPB) framework. This approach, overcoming the limitations of the ZEB concept, offers a holistic definition in line with the goal of achieving a Zero-emission Building stock. By employing a power balance assessment coupled with dynamic Key Performance Indicators (KPIs), this methodology surpasses traditional techniques, providing a more accurate assessment of energy consumption and generation patterns. The method was applied to a district case study encompassing seven nearly Zero Energy Buildings (nZEBs), demonstrating its potential efficacy. Findings indicate how the proposed framework can accurately evaluate the integration of energy storage and sharing strategies, increasing the Zero Power target from 29 % to 51 % of annual hours. KPIs were also dynamically examined at the building and district level, introducing the concept of KPI accuracy and identifying pivotal hourly patterns to guide a sustainable transistion. The adoption of the Zero Power Building framework and the utilization of dynamic KPIs offer viable solutions to address conventional limitations in building energy assessments. This approach aids in guiding targeted energy efficiency measures aimed at fostering sustainable and Zero-emission Communities. [ABSTRACT FROM AUTHOR]

Zero-energy buildings usually achieve annual net-zero energy balance by generating electricity using on-site renewable energies and interconnecting with the power grid. However, the impact of energy mismatch problem in zero-energy buildings design on the grid is often overlooked, which potentially compromises grid's stability. To address this issue, this paper presents an optimization design method based on "grid-friendly interaction" which optimizes the energy system of zero-energy buildings to ensure better alignment between the building's electricity purchase/sale and grid demand. In this study, an indicator of "grid-friendly interaction", which represents the ratio of the net building friendly interaction power to the total annual interaction power, is firstly established to guide buildings in improving their interaction with the grid. Next, the energy supply, demand, and storage schemes of renewable energy systems in the zero-energy building are iteratively adjusted to achieve the best match with grid's expectations. This optimization design method was applied to a practical case in Hong Kong. Results show that, compared to the benchmark building, the optimal system design scheme increases grid friendliness by 83 %, reduces carbon dioxide emissions by 77 %, but also incurs a total cost increase of 180 %. The optimization design method proposed in this paper can effectively mitigate the impact of zero-energy buildings on the power grid, fostering enhanced interplay between the building structures and the grid. The study significantly contributes to the advancement of exploring the potential for energy flexibility in zero-energy buildings, which is of great significance for the safe and stable operation of future grids. The purpose of this study is to explore the energy flexibility potential of zero-energy buildings, which is of great significance for the safe and stable operation of future grids. • A novel indicator that reflects the degree of friendly interaction is proposed. • An optimization design method based on "grid-friendly interaction" is presented. • Single-objective and multi-objective optimization are applied respectively to ZCB. • It is of great significance for the safe and stable operation of future grids. [ABSTRACT FROM AUTHOR]

To realize zero energy buildings, photovoltaic-thermal (PVT)–ground source heat pump (GSHP) systems are being developed. However, the PVT–GSHP system faces challenges in urban areas or in existing buildings owing to the complicated installation process and high initial cost. To address this problem, this study devised an integrated PVT–air source heat pump (ASHP) system that allows installation in a limited space and reduces the initial cost. Particularly, a real-scale experimental plant was constructed based on a small-scale building to evaluate the performance of the PVT–ASHP system. The measurement data of the PVT–ASHP system was collected using a monitoring system, and the heating and cooling coefficients of performance (COPs) were evaluated. The average heating and cooling COPs of the PVT–ASHP system were 3.54 and 3.31, respectively. The COP of the system improved by approximately 52% compared to the ASHP. The PVT–ASHP system indicated a performance difference of approximately 9% compared to the PVT-GSHP system. Moreover, the initial cost of the PVT–ASHP system was reduced by 44% compared to the PVT–GSHP system. PVT–ASHP systems have economic benefits and are a suitable alternative to PVT–GSHP systems. • The COP of PVT–ASHP improves by up to 52% compared to ASHP. • PVT–ASHP can realize zero energy buildings in summer. • The heating COP of PVT–ASHP differs from PVT–GSHP by less than 9%. • PVT–ASHP reduces initial investment cost by 44% compared to PVT–GSHP. [ABSTRACT FROM AUTHOR]

In order to move toward net zero energy buildings, use of new and renewable energy resources parallel with development of high performance energy storage systems is necessary to maximize energy absorption and reduce energy losses with subsequent improvement in the energy performance of systems. In this research, two separate energy storage systems for supplying electricity and hot water for 500 residential buildings in Beijing have been designed and compared based on their performance. 1500 solar panels provide the required power for buildings. The first system is compressed air energy storage (CAES), while the second system is hydrogen energy storage (HES). Simulation has been done in TRNSYS and EES software. Energy and exergy analyses have been done for both systems. In case of the loss of hot water produced by the systems, the annual average energy efficiency of CAES and HES is about 44 % and 42 %, respectively. The energy efficiency of the first system decreases in the hot months of the year and reaches about 42 %, but the efficiency of the HES system is constant throughout the year. If the hot water produced by the systems is used for consumption in residential buildings, the energy efficiency of CAES and HES reaches 93 % and 64 %, respectively. The most exergy destruction in the CAES is related to combustion chambers (41 % of the total exergy destruction) and in the HES, it is related to electrolyzers (71 % of the total exergy destruction). The exergy efficiency of the first system is about 56 %, while for the second system this value is about 34 %. • Compressed air energy storage (CAES) and hydrogen energy storage (HES) are used. • Energy storage systems are used in parallel to provide electricity and water for buildings. • TRNSYS and EES used to perform energy and exergy analyses. • Energy efficiency of CAES and HES reaches 93 % and 64 % when using hot water in buildings. • Highest exergy destruction of CAES & HES are in combustion chambers (41 %) & electrolyzers (71 %). [ABSTRACT FROM AUTHOR]