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Domestic electricity consumption in the Kingdom of Bahrain accounts for 48% of total national electricity consumption, increasing between 1.5 and 3.5% annually. This increase is due to indoor cooling electricity accounting for up to 80% of domestic electricity consumption. The Kingdom is aiming for a reduction in carbon emissions of 30% by 2035 and to achieve carbon neutrality by 2060. Hence, reducing electricity consumption is necessary. Recently, the Kingdom's Electricity and Water Authority has issued updated building regulations regarding the maximum thermal transmittance allowed for residential buildings. This study employed a quantitative simulation of a typical housing unit (T8) in the Kingdom of Bahrain, assessing building envelope materials and air conditioning efficacy following the updated building regulations via DesignBuilder V. 7.0.2.006 software. Additionally, this study examined the potential of building regulations to facilitate the transition to net-zero energy buildings by comparing electricity consumption with renewable energy generated from rooftop photovoltaic panels. It was determined that electricity consumption could be reduced by up to 52% by following building regulations and relying on current materials in the residential sector. Furthermore, this reduction may facilitate the Kingdom's attainment of net-zero energy status through onsite power generation of 12,500 kWh/year. This study concluded that achieving net-zero energy status is possible by following building regulations and relying on commercially accessible construction materials; however, guidelines for energy storage or a feed-in tariff for the residential sector must be established. [ABSTRACT FROM AUTHOR]

The three categories of energy scarcity, population growth and environmental concerns explain the need for new energy sources. Saudi Arabia has become one of the regions capable of using solar energy, particularly through the use of photovoltaic systems, thanks to Saudi Arabia's excellent ability to effectively utilize the sunlight. This study examines the performance of photovoltaic-integrated shading systems (PVIS) in enhancing energy efficiency for residential buildings under the extreme climatic conditions of Riyadh and Abha in Saudi Arabia. The study advances the knowledge of PVIS applications by addressing the dual challenges of energy efficiency and sustainability in urban residential settings. Leveraging numerical simulations conducted with EnergyPlus, the research evaluates various shading configurations, including louvers, horizontal and sidefin canopies, to quantify their impact on cooling, heating, lighting demands and energy production. The annual efficiency of the proposed integrated systems to achieve sustainable and net-zero energy buildings (NZEBs) is a key metric evaluated in this study. The key findings highlight the effectiveness of horizontal PVIS in achieving the highest energy efficiency, with up to 27.19% in Abha and 24.72% in Riyadh, based on the ratio of annual available solar energy to PV energy production. The integration of PVIS not only reduces the cooling loads by optimizing shading but also contributes significantly to renewable energy production toward NZEBs. The lifecycle cost analysis (LCCA) identifies horizontal canopies as the most cost-effective configuration, with a payback period of 8.6 years in Abha and 10.2 years in Riyadh. [ABSTRACT FROM AUTHOR]

Zero-emission buildings, which do not emit CO2 or other greenhouse gases throughout their entire life cycle, play a crucial role in sustainable development and the fight against climate change. Achieving carbon neutrality in construction requires considering emissions associated with material production, construction, operation, as well as demolition and disposal. These buildings utilize energy-efficient technologies, renewable energy sources, and low-carbon materials, minimizing their environmental impact. The building sector accounts for a significant percentage of global greenhouse gas emissions, making it a key area for climate action. In Poland, where aging and energy-inefficient buildings prevail, the need for a transition towards zero-emission buildings is particularly urgent. This paper assesses the feasibility and hurdles of retrofitting existing buildings to achieve zero emissions by utilizing renewable energy systems like solar photovoltaic and heat pump technologies. The publication discusses the technical, economic, and legal aspects of this transformation, with particular emphasis on the Polish context and available support programs. The purpose of this publication is to disseminate practical knowledge and foster innovation among architects, investors, and decision-makers engaged in the development of a sustainable built environment. A key example is Net Zero Energy Buildings (NZEBs), which generate as much energy as they consume over a year through technologies such as photovoltaic panels, solar collectors, and heat pumps. NZEBs combine effective insulation, energy-efficient systems, and smart energy management to minimize consumption, and may even produce excess energy that feeds back into the grid. Despite challenges in construction and maintenance, the increasing adoption of zero-emission and NZEBs worldwide reflects their long-term ecological, economic, and health benefits. The focus of this publication is to analyze the potential for transforming standard buildings, as defined by current regulations, into zero-emission buildings powered entirely by renewable energy sources. This case study analyzes the energy potential of a residential building located in Krakow, Poland. The building's energy efficiency potential was assessed through computer simulations using Audytor OZC software (version 7.0 Pro, Sankom), taking into account local climate conditions and building standards. The study analyzed the impact of various strategies, such as upgrading thermal insulation, using energy-efficient windows, and installing photovoltaic panels, on energy consumption and CO2 emissions. [ABSTRACT FROM AUTHOR]

With the continuous rise in the energy consumption of buildings, the study and integration of net-zero energy buildings (NZEBs) are essential for mitigating the harmful effects associated with this trend. However, developing an energy management system for such buildings is challenging due to uncertainties surrounding NZEBs. This paper introduces an optimization framework comprising two major stages: (i) renewable energy prediction and (ii) multi-objective optimization. A prediction model is developed to accurately forecast photovoltaic (PV) system output, while a multi-objective optimization model is designed to identify the most efficient ways to produce cooling, heating, and electricity at minimal operational costs. These two stages not only help mitigate uncertainties in NZEBs but also reduce dependence on imported power from the utility grid. Finally, to facilitate the deployment of the proposed framework, a graphical user interface (GUI) has been developed, providing a user-friendly environment for building operators to determine optimal scheduling and oversee the entire system. [ABSTRACT FROM AUTHOR]

The article examines the feasibility of implementing standalone hydrogen-based renewable energy systems in Spanish residential buildings, specifically analyzing the optimization of a solar-battery and solar-hydrogen system for a building with 20 dwellings in Spain. The study initially assesses two standalone setups: solar-battery and solar-hydrogen. Subsequently, it explores scenarios where these systems are connected to the grid to only generate and sell surplus energy. A scenario involving grid connection for self-consumption without storage serves as a benchmark for comparison. All system optimizations are designed to meet energy demands without interruptions while minimizing costs, as determined by a techno-economic analysis. The systems are sized using custom software that incorporates an energy management system and employs the Jaya algorithm for optimization. The findings indicate that selling surplus energy can be economically competitive and enhance the efficiency of grid-connected self-consumption systems, representing the study's main innovation. The conclusion highlights the economic and technical potential of an autonomous hybrid energy system that includes hydrogen, with the significant remaining challenge being the development of a regulatory framework to support its technical feasibility in Spain. • PV-battery and PV-H2 self-sufficient stand-alone systems for a 20-dwelling building. • Residential energy demand based on actual annual four-dwelling metering data. • Sale of surplus generation to the grid from a renewable stand-alone system. • Custom-made software and Jaya algorithm for system simulation and cost optimization. • PV-H2 integration in residential buildings leads to a reduction in grid dependency. [ABSTRACT FROM AUTHOR]

The three categories of energy scarcity, population growth and environmental concerns explain the need for new energy sources. Saudi Arabia has become one of the regions capable of using solar energy, particularly through the use of photovoltaic systems, thanks to Saudi Arabia’s excellent ability to effectively utilize the sunlight. This study examines the performance of photovoltaic-integrated shading systems (PVIS) in enhancing energy efficiency for residential buildings under the extreme climatic conditions of Riyadh and Abha in Saudi Arabia. The study advances the knowledge of PVIS applications by addressing the dual challenges of energy efficiency and sustainability in urban residential settings. Leveraging numerical simulations conducted with EnergyPlus, the research evaluates various shading configurations, including louvers, horizontal and sidefin canopies, to quantify their impact on cooling, heating, lighting demands and energy production. The annual efficiency of the proposed integrated systems to achieve sustainable and net-zero energy buildings (NZEBs) is a key metric evaluated in this study. The key findings highlight the effectiveness of horizontal PVIS in achieving the highest energy efficiency, with up to 27.19% in Abha and 24.72% in Riyadh, based on the ratio of annual available solar energy to PV energy production. The integration of PVIS not only reduces the cooling loads by optimizing shading but also contributes significantly to renewable energy production toward NZEBs. The lifecycle cost analysis (LCCA) identifies horizontal canopies as the most cost-effective configuration, with a payback period of 8.6 years in Abha and 10.2 years in Riyadh.

Cities have a high environmental impact on boththe site and the surrounding area due to their energy requirements. In this article, we analyze the implementation of photovoltaic (PV) solar technology as a clean energy self-supply alternative in a mixedresidential sector in the Andean equatorial city of Cuenca, Ecuador. Based on the energy demands of the buildings in the selected area, LiDAR is used to identify rooftops that, due to their geometry, orientation, or location, are suitable for PV panel installation. Real energy consumption data are collected, and using SAM software with local climate data, the self-sufficiency capacity is simulated with the integration of PVs to achieve energy neutrality in each property. The combined electrical generation is determined and it is established that the energy demand can be met by 94.88%, with the installation of 427 PV panels of 335 Wp distributed across 29 properties and with a spatial occupation requirement of 11.95% of the available roofs. It is concluded that the entire electrical demand can be self-supplied through rooftop space, and this could even serve as an alternative to meet other demands such as cooking and transportation that are currently met with fossil fuels. [ABSTRACT FROM AUTHOR]

High performance of HVAC connected Building Integrated Photovoltaic/Thermal (BIPV/T) systems relies on appropriate control. However, optimal control is often overlooked, resulting in systems that operate inefficiently. This paper investigates how model predictive control (MPC) can improve the operation of open loop air-based BIPV/T systems connected to multiple thermal applications. The BIPV/T system at the first institutional net-zero energy building in Canada, the Varennes library, is used as an archetype. The BIPV/T covers 16% of the south-facing roof and operates under a simple rule-based control strategy. The developed control and design strategies consider variations of this system, to achieve higher thermal utilization efficiency. A control-oriented BIPV/T model is developed and calibrated using monitored data. The BIPV/T airflow is regulated through MPC for simultaneous heat supply to an Energy Recovery Ventilator and air-to-water heat pump. The BIPV/T air flow is efficiently controlled, considering the connected thermal applications, environmental conditions, and PV temperature. Model-based control for BIPV/T systems can increase the amount of useful heat and reduce PV overheating. The MPC controller for the examined system reduced the building energy consumption compared to the business-as-usual operation by 40% and together with increased BIPV/T area can supply excess heat to adjacent buildings. [ABSTRACT FROM AUTHOR]

We may lessen the detrimental effects of global warming on human thought processes by reducing greenhouse gas emissions, encouraging sustainability, and giving adaption measures top priority. The purpose of the letter is to draw attention to the necessity of net-zero energy buildings (NZEB) in academic institutions in order to reduce academic stress, promote well-being, and improve cognitive functions. While some levels of stress might be advantageous, excessive and mismanaged stress can be detrimental to students' well-being. To foster a healthy academic atmosphere, it is essential to offer resources, support networks, and stress-reduction techniques. As human authors, we thoroughly edited ChatGPT's responses to create this letter. [ABSTRACT FROM AUTHOR]

Building integrated photovoltaic (BIPV) is a promising solution for providing building energy and realizing net-zero energy buildings. Based on the developed mathematical model, this paper assesses the solar irradiation resources and BIPV potential of residential buildings in different climate zones of China. It is found that roofs are the first choice for BIPV installation, followed by south façades, especially in high-latitude cities, and then east and west facades. North façades could be recommended in some cities with frequent clouds. The photovoltaic (PV) contribution of a combined rooftop and south façade BIPV system to building energy is highlighted, where the PV covers 50 % of the roof and 40 % of the south façade area. The system can meet the net load of a 4, 8, 7, 6, 4, and 4-storey building in Harbin, Urumqi, Beijing, Shanghai, Chengdu, and Guangzhou, respectively. In areas with sufficient irradiation and low demand, such as Lhasa and Kunming, the proposed system is most likely to achieve net-zero energy consumption in high-rise residential buildings. Different from previous study, this study proposes a comprehensive research framework for assessing the potential of residential BIPV system in various regions of China, considering partial shading effects. Since many provinces have issued relevant policies to promote distributed PVs, the findings can provide guidance for BIPV deployment in China. [Display omitted] • The solar irradiation resources of building façades including the north façade are examined. • The photovoltaic contributions to net zero energy residential buildings are assessed in China. • Partial shading is considered for modeling the building integrated photovoltaic (BIPV) system. • A research framework for assessing the potential of residential BIPV system is proposed. [ABSTRACT FROM AUTHOR]

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Iran's energy sector, which includes power generation, transportation, industry, buildings, and homes, is a significant source of greenhouse gas emissions. Plans for efficient design and development of maximum power control systems aim to increase the share of renewable energy in electricity usage. Floating photovoltaic systems combine existing photovoltaic systems with a floating structure to generate clean energy and integrate existing dams to enhance power sources. The results indicate that installing a hybrid floating solar power plant at a level of more than 1 km2 over the dam reservoir's surface provides 194 GWh to 257 GWh of electricity per year. Installation floating photovoltaic plant would supply electricity for 2260 green cottages while also improving the environment and reducing water evaporation. Adding a floating solar power plant with 10% of the lake reservoir cover of six dams saves 70.7 million cubic meters of water per year which is enough to meet the annual needs of one million people. This study fills a research gap in the energy sector by studying the economics of hybrid renewable energy systems in Net-zero energy buildings. [ABSTRACT FROM AUTHOR]

Building operations use 45% of the total energy in Australia, and Net-Zero Energy Buildings (NZEBs) are instrumental in achieving net zero emissions by 2050. However, research reveals that various factors hinder NZEB adoption in Australia, and it is imperative to contextualise the barriers, thereby highlighting clear gaps that can be addressed to enhance the implementation of NZEB in Australia. This study presents a systematic literature review and bibliometric analysis to examine the barriers that hinder the implementation of NZEB contextualised within the Australian building industry. The paper's novelty resides in its contextualisation of barriers to NZEB thereby highlighting clear gaps that can be addressed to enhance the implementation of NZEB in Australia. Emergent results reveal the most impactful barriers experienced and the inter-relatedness between barriers and their effects on each other. These identified barriers are also compared with comparable countries, including the UK, China, Italy and the US. New insight and knowledge acquired provide a basis for assessing potential solutions to the main barriers. Findings show that a lack of knowledge, climate issues, and cost issues, in addition to government policy factors, are considered primary barriers encountered by the industry, hindering the achievement of NZEBs. It is imperative that future studies and initiatives counteract these impacts to realise a better implementation of NZEB in the Australian context. [ABSTRACT FROM AUTHOR]

The high energy consumption by buildings has called for a need to use energy-efficient material for future construction applications. Cementitious composites in various forms are the most used building material for the construction of buildings. Therefore, in order to ensure these buildings made with cementitious composites are energy-efficient, it is imperative to find innovative and sustainable ways to improve the thermal properties of these cementitious composites. One of the sustainable and effective ways to improve the thermal properties of cementitious composites is with the incorporation of various waste. Therefore, this paper aims to discuss different types of wastes that can be recycled into cementitious composites to improve the thermal properties (i.e. reduce thermal conductivity) based on existing experimental studies. Discussion from this paper showed that recycled materials such as rubber and plastics can be used to reduce the thermal conductivity of cementitious composites when used as a replacement of up to 50% of natural aggregates. It was also concluded that there is a good relationship between density and thermal conductivity of cementitious composites and waste/recycled materials can be incorporated as aggregate/filler in cementitious composites to improve the thermal performance. However, there is a need for the limitations associated with the use of these waste/recycled materials to be resolved before they are incorporated into cementitious composites.

Residential and commercial buildings consume approximately 60% of the world's electricity. It is almost impossible to provide a general definition of thermal comfort, because the feeling of thermal comfort is affected by varying preferences and specific traits of the population living in different climate zones. A few studies have been conducted on thermal satisfaction of net-zero energy buildings prior to this date; one of the objectives of the present study is to draw a comparison between the thermal parameters for evaluation of thermal comfort of a net-zero energy building occupant. The building in this study was first optimized for the target parameters of thermal comfort and energy consumption, and hence, a net-zero energy building was formed. Subsequent to obtaining the acceptable thermal comfort range, the computational analyses required to determine the temperature for thermal comfort are carried out using the computational fluid dynamics model. The findings of this study demonstrate that for reaching net-zero energy buildings, solar energy alone is not able to supply the energy consumption of buildings and other types of energy should also be used. Furthermore, it is observed that optimum thermal comfort is achieved in moderate seasons. [ABSTRACT FROM AUTHOR]

Summary: Global warming is caused by greenhouse gas (GHG) emissions produced from the use of fossil fuel–based energy sources. Buildings consume about 30% to 35% of the global energy use, which makes buildings a major contributor to the global warming problem. A long‐term plan has been established at the Thermal Processing Laboratory (TPL) at McMaster University to investigate the use of various renewable energy–based technologies to achieve net‐zero energy buildings (NZEB) in Canada. This paper presents results of an investigation of the effectiveness of using a thermal buffer zone (TBZ) in real‐size buildings. A TBZ is a closed passage built around the building that allows air to passively redistribute heat energy from solar radiation received on the south side throughout the building. A TBZ offers an effective solution of the overheating problem usually experienced on the south side of the building, and at the same time, it helps in reducing the heating load of the north side of the building. An experimental setup employing TBZ in a lab‐scale model of a typical building floor has been built. An analytical model of the TBZ has been developed. The experimental data has been used to validate the developed analytical model, which then was used to predict the performance of the TBZ implemented in a real‐size building floor, considering four cases. Results of the first three case studies considering the use of TBZ in cold and hot climates, with and without thermal insulation, show that the predicted effectiveness of TBZ could reach 117% and 72.5% in the winter and summer, respectively. Results of the fourth case study considering the effect of integrating a fan with the TBZ show that a fan is beneficial up to a certain fan power, beyond which the use of the fan would not be feasible. Results presented herein confirm that the TBZ is an effective means of integrating solar energy into buildings, thereby reducing buildings' fossil fuel–based energy consumption. [ABSTRACT FROM AUTHOR]

Net-zero energy buildings produce enough renewable energy to meet their own annual energy requirements and have been proposed as an important method of reducing operational greenhouse gas emissions in the building sector. However, self-generation via building-integrated solar PV in cold and temperate climates is anti-correlated with increasingly-electrified heating demand and could increase seasonal variability in net electricity demand to the point that it poses challenges for future electricity systems. In this paper we explore scenarios of future large-scale uptake of electrically-heated, solar-PV net-zero energy residential buildings in New Zealand and quantify the seasonal variation of the resulting net electricity demand. A scenario of large-scale uptake of very high efficiency buildings leads to reductions in annual demand of −30% and seasonal variation of −50% in 2050 compared to a base case of current building standards. In comparison, a scenario with self-generation via solar PV without changes to the building standard reduces annual demand by −30% but increases seasonal variation by +40%. In a scenario where very high building standards are combined with solar PV, annual demand decreases by −65% and seasonal variation by only −4%. From a policy perspective, whether large-scale solar PV self-generation should be supported (in addition to very-high efficiency buildings) depends on an economic trade-off between the value of distributed solar generation (including any carbon emission reductions) vs the electricity system cost of seasonal variation. For New Zealand, given the low cost of renewable electricity from a variety of alternative sources, scenarios of large-scale uptake of solar-powered net-zero energy buildings are not favourable from an electricity system perspective. [ABSTRACT FROM AUTHOR]

[Display omitted] • Design management and optimization framework for advancing net-zero energy buildings. • A grid-protective energy management strategy with novel assessment indicators. • Multi-objective optimizations identify optimal system sizing and interactive impact. • EV interaction improves grid flexibility by 29.63 % and electricity bill by 18.70 %. • Optimum net-zero energy building with good techno-economic-environmental feasibility. This study proposes a design management and optimization framework of renewable energy systems for advancing net-zero energy buildings integrated with electric vehicles and battery storage. A building load data augmentation model is developed to obtain the annual hourly load profile of a campus building based on the on-site collected data adopting the Gate Recurrent Unit neural network. A grid-protective energy management strategy of the solar photovoltaic (PV) power and storage system is proposed with novel assessment indicators including PV utilization ratio, load match ratio and grid flexibility factor. Multi-objective optimizations are conducted to identify optimal sizing of the renewable energy system and its interactive impact on balanced techno-economic performance. The research results indicate that the net-zero energy building achieves optimum performance with the sizing configuration of 1050 kW rooftop PV power, 300 electric vehicles and 450 kWh batteries. The vehicle-to-building interaction introducing vehicle discharge improves the load coverage (+12.08 %), grid flexibility (−29.63 %), annual electricity bill (−18.70 %) and levelized cost of energy (−6.24 %). The optimum net-zero energy building achieves good techno-economic-environmental feasibility regarding the load coverage (+16.22 %), grid flexibility performance (−58.48 %), annual electricity bill (−27.86 %), decarbonisation benefits (−34 times) and vehicle degradation. The developed design management and optimization framework of the renewable energy system provides a possible pathway for the typical campus building towards zero-carbon operations, and it also offers guidance and reference for stakeholders to develop similar carbon–neutral buildings. [ABSTRACT FROM AUTHOR]

This paper proposes an analysis methodology that can be applied by governments and local administrations to evaluate energy retrofit programs that involve entire building categories. Through a simulation based approach, that combines detailed energy modelling and algorithmic optimization, the analysis methodology is aimed to assess the magnitude of achievable energy savings for various retrofit levels along a cost-optimal path towards achieving net zero energy operation conditions. The proposed approach allows to identify the most cost-effective energy efficiency measures (EEMs) for building retrofits and their required investment costs. The retrofit potential benefits of the Italian office buildings stock is used as a case study to illustrate the application of the proposed analysis methodology. The results of the evaluation analysis for the Italian office building stock indicated a potential primary energy savings of 54% (i.e., 8000 GWh), when retrofitted through optimal combinations of EEMs and rooftop integrated photovoltaics. The optimal set of EEMs showed strong dependency on building typology and climate. In general, the cost-optimal combinations of EEMs and rooftop PV systems did not allow to reach net-zero energy operation conditions for any Italian office building type and climatic zone. [ABSTRACT FROM AUTHOR]

Recent global developments in awareness and concerns about environmental problems have led to reconsidering built environment approaches and construction techniques. One of the alternatives is the principle of low/zero-energy buildings. This study investigates the potentials of energy savings in an existing multi-story building in the Mediterranean region in order to achieve net-zero energy as a solution to increasing fossil fuel prices. The Colored building at the Faculty of Architecture, Eastern Mediterranean University, Cyprus was chosen as a target of this study to be investigated and analyzed in order to know how energy efficiency strategies could be applied to the building to reduce annual energy consumption. Since this research objective is to develop a strategy to achieve net-zero energy in existing buildings, case study and problem solving methodologies were applied in this research in order to evaluate the building design in a qualitative manner through observations, in addition to a quantitative method through an energy modeling simulation to achieve desirable results which address the problems. After optimizing the building energy performance, an alternative energy simulation was made of the building in order to make an energy comparison analysis, which leads to reliable conclusions. These methodologies and the strategies used in this research can be applied to similar buildings in order to achieve net-zero energy goals. [ABSTRACT FROM AUTHOR]

Many scientific evidences have shown that Earth's climate is rapidly changing. By 2050, European Union is aiming to significantly reduce greenhouse gas emissions (GHG) in the building sector. Achieving this target might help the mitigation of global warming, but the climate change seems inevitable. This means that both new and refurbished buildings should be able to face those conditions that they are going to experience during their lifetime. Therefore, any building design should be checked both for current and future climate scenarios. This study describes the use of a downscaling method named morphing to generate future weather scenarios and intends to support the design process of a deep energy retrofit of a day care center in order to improve the energy and thermal comfort performance of the building under the current and future weather scenarios. The retrofit concept of the building also includes hybrid ventilation, automated solar shading, lighting controls and renewable energy generation systems. [ABSTRACT FROM AUTHOR]

The aim of this paper is to develop an optimal scheduling strategy model for a grid-tied photovoltaic (PV) system to power a heat pump water heater (HPWH). The system is composed of PV modules that are grid-tied and a backup battery. The PV is capable of supplying power simultaneously to the HPWH and domestic load, whilst the grid and the battery are complementary sources. The objective function of this model is energy cost. The time-of-use (TOU) electricity tariff is taken into account in the optimal scheduling model. The control variables are the power flows within the branches of the system. The optimal control strategy of this grid-tied PV system can be implemented to reduce the energy cost while meeting the technical and operational constraints. This model has shown to have more economic benefits than solar thermal heaters, because of the possibility to turn the dwelling into net-zero energy or positive-energy buildings with the attractiveness of the feed-in tariff. A case study is done based on 3 × 16 kW HPWH installed at a Pretoria hotel in South Africa. Simulations are run for a year on selected seasonal date using the actual HPWH demand. The optimal control results show how the battery status of charge and TOU affect the power scheduling strategy of the HPWH. The energy and cost savings are presented in this paper as well. [ABSTRACT FROM AUTHOR]

A Net-Zero Energy Residential Test Facility has been constructed at the National Institute of Standards and Technology to demonstrate that a home similar in size, aesthetics, and amenities to those in the surrounding communities can achieve net-zero while meeting the needs of a four member family. The home incorporates a vast array of renewable energy and energy efficient technologies, a subset of which was used during the first year of operation, including an air-to-air heat pump system, a solar photovoltaic system, a solar thermal hot water system, and a heat recovery ventilation system (HRV). The solar photovoltaic system generated 13,523 kW h of energy, exceeding the home's annual energy consumption by 484 kW h during the 12-month test interval. The solar thermal hot water system provided 54% of the energy required to meet the hot water load. Use of the heat recovery ventilator, used to provide ventilation air to the home, resulted in 1965 kW h of energy consumption, 514 kW h to power the HRV and 1451 of energy used by the heat pump system to meet the additional sensible and thermal loads. This paper describes the facility and presents performance data for the first year of operation. [ABSTRACT FROM AUTHOR]

This paper presents grid impact indicators, developed to evaluate the performance of local control mechanisms, affecting the impact of a net-zero energy building on the electricity grid, without the need to simulate the grid itself. The capacity factor, loss-of-load probability, cover factor for supply and demand, load match index, power exchange variability, one-percent peak power, peaks above limit, dimensioning rate, and kVA credit are proposed and applied to example single-building simulations. These simulations include control mechanisms affecting the power exchange of the building with the grid by adjusting the set-point temperature of the thermal energy storage tank of the heat pump, shifting local consumption to better coincide with local photovoltaic generation, or by directly limiting the power supplied to the grid. The simulations focus on a single net-zero energy building and use one such building as a reference and others for comparison of trends in simulation results. All modeling is done in the equation-based object-oriented modeling language Modelica. Simulations are performed using the Dymola environment. [ABSTRACT FROM PUBLISHER]

Building energy management systems (BEMS) must consider energy utilization efficiency improvement, energy cost reduction, and renewable energy technology utilization in order to serve local energy loads in building structures with dispersed resources. The distributed management of building energy system proposed in this paper utilizes a semi-centralized decision-making methodology using multi-agent systems for BEMS for electrical, heating, and cooling energy zones with combined heat and power system optimizations aimed at improving energy efficiency and reducing energy costs. A case study is presented to demonstrate the validity of the proposed energy management scheme. [ABSTRACT FROM AUTHOR]

Abstract: Traditional building energy consumption calculation methods are characterised by rough approaches providing approximate figures with high and unknown levels of uncertainty. Lack of reliable energy resources and increasing concerns about climate change call for improved predictive tools. A new approach for the prediction of building energy consumption is presented. The approach quantifies the uncertainty of building energy consumption by means of stochastic differential equations. The approach is applied to a general heat balance for an arbitrary number of loads and zones in a building to determine the dynamic thermal response under random conditions. Two test cases are presented. The approach is found to work well, although computation time may be rather high. The results indicate that the impact of a stochastic description compared with a deterministic description may be modest for the dynamic thermal behaviour of buildings. However, for air flow and energy consumption it is found to be much more significant due to less “damping”. Probabilistic methods establish a new approach to the prediction of building energy consumption, enabling designers to include stochastic parameters like inhabitant behaviour, operation and maintenance to predict the performance of the systems and the level of certainty for fulfiling design requirements under random conditions. [Copyright &y& Elsevier]

Abstract: Net-zero energy buildings (NZEBs) are expected to play an important role in fighting climate change and reducing the energy use of the built environment. But even if the best design practices are widely adopted and implemented, this will only mitigate global warming. It is too late to prevent it. Yet buildings – including net-zero energy buildings – are often designed using historical data representing the average climate between 1961 and 1990, or between 1976 and 2005 at best. This paper investigates the use of the downscaling method known as “morphing”, proposed by Belcher et al. (2005), to generate weather data files. The impact of using these weather files on the energy performance of an actual NZEB is then assessed. Morphing is applied to typical “horizon years” representative of future climate and also on a month-by-month and year-by-year basis using raw data from a selected GCM. A 50-year series of hourly weather data is obtained and analyzed for two different locations, Montréal (QC) and Massena (NY). The data are then used to simulate the performance of a net-zero energy home as it was designed using historical data. The results show that the building misses the net-zero energy target for most years. The year-to-year variability of the total energy use is relatively small but the impact on the energy excess or shortage in relation to the net-zero target is significant. climate-sensitive buildings such as NZEBs should always be designed using multi-year simulations with weather data that take climate change into account. [Copyright &y& Elsevier]

[Display omitted] • High resolution data from a Dutch net zero energy neighborhood is analysed. • Most buildings are positive energy, emit less carbon than they offset. • Large occupant differences in energy demand are visible across the households. • Occupant preferences and weather conditions greatly influence thermal energy demand. • Due to the high thermal efficiency, there is a high risk for summer overheating. Decarbonizing the building stock is a central component of global climate change mitigation efforts. In practice, this decarbonization can be achieved by a variety of different measures, including improvements in building energy efficiency, electrification of energy demand to reduce reliance on fossil fuels, and installation of distributed (renewable) generation in conjunction with flexible storage. However, these large-scale, often disruptive changes to the built environment also raise a number of concerns, such as loss of occupant comfort exacerbated by climate change, and introduction of additional stressors on the distribution grid. In this paper, we demonstrate several conclusions using detailed sub-hourly data of two years (2019–2020) collected from 40 homes in a recently refurbished net-zero energy neighborhood in the Netherlands. This paper shows that, in renovation projects like the case study, net-zero energy balances should be considered on a neighborhood, rather than building level to minimize worst case planning by accounting for occupant influences and seasonal effects. Furthermore, the energy flexibility and climate resilience in the buildings seems to be rather limited, as a result of energy efficiency improvements. While helpful in climate change mitigation efforts, the large seasonal differences in energy demand and generation imply that this evolution is perhaps sub-optimal from the grid perspective. The results illustrate that all homes in the study were net-zero energy over the two year period, sometimes net positive by up to a factor of three. This led to considerable excess generation especially during the summer months. In addition, it was found that indoor air temperature sensors in a number of buildings showed overheating beyond guideline thermal comfort temperature of 25°C, showing potential thermal comfort and heat stress for vulnerable occupants. These results motivate energy storage or modifications of the installed heat pumps to leverage summer excess generation while reducing the impact of summer heat waves. These findings should enable the Netherlands and other countries aiming to fully decarbonize the building stock formulate better, future-proof policies. [ABSTRACT FROM AUTHOR]

[Display omitted] • A comprehensive overview of NZEBs is conducted by using bibliometric techniques. • Hot research topics of NZEBs are identified through keyword co-occurrence analysis. • The research trend, key journals, publications, authors, and countries are analyzed by co-citation analysis. • The thematic evolutionary analysis of NZEBs was investigated using SciMAT tool. This study aims to provide a comprehensive overview of three-decade research developments in the field of Net-Zero Energy Buildings (NZEBs) by using bibliometric analysis techniques. The specific objectives of this paper are to: (1) identify the most influential researchers, sources, and countries in this field; (2) identify the main thematic research focus areas and hot topics in the field; and (3) analyze the thematic evolution of NZEBs. VOSviewer software was used to realize the first two objectives while to meet the third objective, the SciMAT tool was employed to examine the thematic evolution of the field within three sub-periods (1995–2005; 2006–2015; 2016–2022). The results indicate that the main thematic areas of the field were initially limited to a few themes including 'environmental impact', 'green buildings', 'building materials', and 'fuel cells', and it expanded in the next periods by encompassing more themes. The results also showed that the field has now reached a certain level of consolidation by acknowledging the significance of three major themes: (1) buildings' energy conservation, (2) energy production and energy storage, and (3) methodological approach. Nevertheless, the evolutionary analysis points out that the field is still expanding with several themes newly emerged such as 'electric vehicles', 'zero-emission neighborhood' and 'smart buildings'. The findings offer a status-quo overview and critiques of research developments in NZEBs as well as emerging themes in the field that should be investigated by future studies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Classifications and strategies of NZEBs were reviewed. • Multi-criteria analysis supports NZEB designing. • Renewable energy supply options for NZEBs are summarized. • Cost-benefit analysis and life cycle assessment needed for criterion evaluation. Decarbonizing the building sector is extremely important to mitigating climate change as the sector contributes 40% of the overall energy consumption and 36% of the total greenhouse gas emissions in the world. Net-zero energy buildings are one of the promising decarbonization attempts due to their potential of decreasing the use of energy and increasing the total share of renewable energy. To achieve a net-zero energy building, it is necessary to decrease the energy demand by applying efficiency enhancement measures and using renewable energy sources. Net-zero energy buildings can be classified into four models (Net-Zero Site Energy buildings, Net-Zero Emissions buildings, Net-Zero Source Energy buildings, and Net-Zero Cost Energy buildings). A variety of technical, financial, and environmental factors should be considered during the decision-making process of net-zero energy building development, justifying the use of multi-criteria decision analysis methods for the design of net-zero energy buildings. This paper also discussed the contributions of renewable energy generation (hydropower, wind energy, solar, heat pumps, and bioenergy) to the development of net-zero energy buildings and reviewed its role in tackling the decarbonization challenge. Cost-benefit analysis and life cycle assessment of net-zero energy building designs and their challenges were reviewed to shape the priorities of future development. It is important to develop a universal decision instrument for optimum design and operation of net-zero energy buildings. [ABSTRACT FROM AUTHOR]

• Design optimization for grid-interactive net-zero energy buildings. • A heuristic glowworm swarm algorithm based optimization model. • A multi-objective optimization with multiple local optimal solutions. • An integrated NZEB model with energy generating, storage, and consuming systems. • Grid-interactive cost optimization with tariff and feed-in-tariff. As buildings account for a substantial amount of energy worldwide, many developers encourage self-sustained net-zero energy buildings (NZEBs) to minimize buildings' energy consumption and negative impacts on the environment. In contrast to regular buildings, NZEBs have interactive and complex energy systems that require synthetical evaluation of their complicated interplay with the grid. Many studies implemented various optimization approaches to improve the NZEBs energy system designed with a global optimal sizing solution. However, the optimal design is often infeasible due to the availability of proper equipment sizing on the markets. In addition, due to the uncertainty caused by different climate conditions, government feed-in-tariff subsidies, and availability of renewable systems, there could exist multiple distinctive design solutions for the same building. Therefore, this study intends to develop a heuristic multiple objectives algorithm based on the glowworm swarm mechanism to refine the optimization of the grid-interactive NZEB design. To validate the proposed method, a case study of the Hong Kong Zero Carbon Building was examined and three design variables (area of the photo-voltage system, installation power of the wind turbine system, and capacity of the thermal energy storage system) were optimized. The results suggest that the optimized design can outperform the baseline design in terms of operating costs and grid energy consumption. In addition, multiple local optima design solutions that represent different design strategies can be identified using the proposed non-linear model. [ABSTRACT FROM AUTHOR]