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Evaluation of actual zero energy buildings (ZEBs) performance and identification of its regional characteristics are of great significance for similar future projects. Based on more than 400 cases in cold regions, this study compared the post-evaluation and drivers of ZEBs from China, the US and the European Union (EU). Results found that ZEB definition, energy drivers, standard, regional policies, technology adoption and their adoption ratio determine the energy performance of cases. Not all EU and China cases reach the net-zero energy target; however, most ZEBs in the US do. ZEBs in cold regions adopted multiple technologies to achieve high energy-efficiency. The adoption ratio of passive technologies is higher than that of active technologies, especially in China. The active technologies in cold regions are mainly seen in the application of advanced HVAC systems. Such application of renewable technologies exhibits strong regional characteristics; for example, the EU's carbon emission reduction policies promoted the use of biomass-based technologies. The analysis also found that energy policies greatly enhance the development of ZEBs. Overall, achieving zero energy is a process, not an endpoint and many projects need further refinement after occupancy.

• 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]

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.

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]

Ground heat exchanger takes the soil underground as heat source or sink to supply cooling or heating. It has been widely used in building heating and cooling systems due to high efficiency and environmental friendliness. This paper reviews the latest research on ground heat exchangers from several new perspectives and demonstrates their potentials in achieving zero energy buildings. Firstly, ground heat exchangers are classified into water-based and air-based ones based on the heat transfer medium. They can be used in a passive or active approach. Associated research and projects for each approach are introduced and analysed. Then the integration of ground heat exchangers with various cooling and heating technologies and related studies are reviewed. These technologies include solar thermal collectors, cooling towers, nocturnal radiative cooling technology, solar chimney, etc. Finally, a technical route for ground heat exchangers to help realize zero energy buildings is presented, which provides a promising solution to improve energy efficiency of buildings. [ABSTRACT FROM AUTHOR]

The electrification of cooking methods in Korea was investigated to understand the impact of different cooking methods on energy use and greenhouse gas (GHG) emissions in the building sector. Annual household cooking energy consumption was compared for the Nowon Energy Zero House Project, a zero-energy housing complex using induction cooktops, and a sample of households that used natural gas for cooking. The results showed that the former consumed less calories (a difference of 2.2 times) and emitted less GHGs (a difference of 2.6 times) compared to gas cooking households. A countrywide scenario analysis was conducted by combining the share of electric cooking households with the projected power generation mix in 2030. Under the 2030 Policy scenario for power generation, and with an electricity cooking share of 20%, cooking-related GHG emissions were projected to be 3.79 million t CO2/year; 3.8% (150,000 t CO2/year) lower than those in the present day, despite a total population increase. The electrification of cooking methods in Korea has the potential to reduce both the energy demand of the building sector and GHG emissions, in synergy with the decarbonization of the power generation sector.

A smart city (SC) is a modernized urban community, which incorporates information and communication technology (ICT) into the existing physical infrastructure. It offers reliable and uninterrupted services such as-intelligent transport and energy conservation to its residents. Among the various services offered, a continuous and widespread supply of electricity draws the maximum attention. Moreover, a substantial amount of this electricity is utilized by heating and cooling loads, making them significant contributors of global warming. Keeping focus on these points, a SC is modeled in this paper, wherein electricity consumption is minimized by modifying the traditional heating and cooling system. The proposed system collects solar heat and recovers industrial waste heat to deliver heating and cooling services to the SC residents. For the purpose of storing the heat energy, a seasonal thermal energy storage (STES) system has been proposed. The proposed STES system supplies stored thermal energy to heat-driven cooling and heating equipments. Moreover, central energy management system (CEMS) is also modeled for monitoring, regulating and controlling the flow of thermal energy. The designed CEMS consists of a Fuzzy rough set controller for scheduling heat to cater the instantaneous thermal energy requirements. Fuzzy rough set has been used because it eliminates the issues of vagueness, uncertainty, and ensures efficient real-time computations. Results depict that the heat energy obtained from solar thermal collectors and industrial wastes is able to meet the requirements of the SC after scheduling it using Fuzzy rough set algorithm. [ABSTRACT FROM AUTHOR]

The energy saving and electricity production schemes for a school building in hot and humid climate were studied by a building energy package eQUEST. High-performance building envelops, energy-efficient air-conditioning systems and lighting fixtures were employed to save energy consumption and building integrated photovoltaic (BIPV) panels were adopted to meet the energy needs. The annual electricity demand was 300 MWh, and 97.5% of it can be supplied by the vertical BIPV facades. Further PV installations on the roof can generate more electricity to balance the energy use. The results show that school block is possible to achieve the zero building energy consumption. [ABSTRACT FROM AUTHOR]

• An energy system optimization framework considering ZEB conditions and EV charging demand is proposed. • Machine learning models and Energyplus simulation are incorporated to predict building energy demand. • SGA2 and PROBID are applied to solve the multi-objective optimization problem. • EV charging demand can impact energy system design. • ZEB criteria can be the economic buffer to achieve zero carbon emissions. With increasing concerns over carbon dioxide emissions, the concept of Zero Energy Building (ZEB) has emerged. Electric Vehicles (EVs) are also considered environmentally friendly since they reduce greenhouse gas emissions, with a rapidly growing market. With these global trends of increasing EV amount and infrastructure, building energy systems should incorporate the ZEB concept and the increasing electricity requirements for EV charging. However, it is unclear how EV charging demand can affect building energy system design while aligning with ZEB requirements. Therefore, this paper develops a new framework to find the optimal energy system design that meets EV charging demand and ZEB requirements. The charging demand for EVs is predicted by the machine learning model, which combines the building energy demand from EnergyPlus. Ultimately, the Genetic Algorithm and PROBID method are applied to optimize the Total Annual Cost (TAC) and Self-Energy Sufficiency Ratio. EV charging demand has been found to affect energy system design, especially in small-size buildings. Using the proposed method, the building owner can determine the optimal capacity of an energy system based on economic and ZEB conditions, contributing to the future net ZEB and transportation systems. [ABSTRACT FROM AUTHOR]

There are high hopes and expectations in the potential of Net-Zero Energy Buildings (NZEB) to contribute to combat the adverse environmental effects from intensive human activity, including energy use. An important related question that has received insufficient attention and is therefore addressed in this study, is how NZEB equipped with renewable energy (RE) systems would perform in future climates that will be caused by the ongoing environmental impacts. In this research, downscaled future hourly weather data from the Global Climate Models (GCM) are used to predict future performance of RE systems for low energy using residential buildings in 10 different climate zones in the U.S. Renewable energy systems with different configurations of Photovoltaic (PV) solar energy and wind system power generation are modeled and coupled with hourly building energy loads. The research results show that buildings with the present configurations of RE will be losing their capability to meet the zero-energy goal in half of the considered climate zones. It was found that the RE systems for a future NZEB should be resized and reconfigured to accommodate climate change impacts. RE systems prioritizing PV systems shows good stability and performance in power generation under expected future climate conditions. A criterion was developed to assist a proposed grid search method for finding the RE system configurations for future NZEB that would identify vulnerabilities of present NZEB's performance under climate change. [ABSTRACT FROM AUTHOR]

The background of this research is based on the commercialization trends of the H 2 vehicles and the upcoming legislation on the zero-energy building (ZEB). Regarding these two backgrounds, there is special research interest to investigate the technical feasibility of integrating a H 2 vehicle with an on-site renewable electrical (REe) system in the ZEB. Hereby, a hybrid system consisting of an on-site REe and a H 2 vehicle integrated H 2 system is proposed and set up in the TRNSYS simulation with novel control logics defined by the authors. The essential principle is to drive the electrolyzer with the surplus on-site REe, and to drive the fuel cell to cover the on-site electrical shortage, while the cogenerated heat from the H 2 system will be utilized for domestic heating purposes. The simulation results show that with the support of a 14 kW wind turbine, the building will be a nearly ZEB with full annual availability of the H 2 vehicle, whereas with the support of a 178 m 2 PV, the building will be a net ZEB with 48 days’ annual unavailability of the H 2 vehicle. Via a seasonal matching analysis, it can be found that the H 2 vehicle integrated H 2 system has a significant effect on alleviating the monthly surplus on-site REe generation. By relieving the condition of discharging the H 2 storage by the fuel cell, both the on-site surplus REe and energy shortage will be further reduced and the cogenerated heat from the H 2 system can be increased. Therefore, the research approves that it is technically feasible to simultaneously meet the zero-emission fuel requirement of the H 2 vehicle, the convenient accessibility of the H 2 refuelling station, the fulfillment of the zero energy balance of the building, and the highest matching capability between generation and demand. [ABSTRACT FROM AUTHOR]

CasaZeroEnergy is the prototype for a building that does not use energy produced from non-renewable sources, but produces its require energy by using alternative energetic systems. Designed according to the principles of bioclimatic architecture, the building was integrated with passive systems for optimizing the site's climatic conditions for heating in winter and for cooling and ventilation in summer. The house was constructed with natural, renewable, recycled and recyclable materials. For this reason it can be classified as a "natural building". Its main feature is the integration between the building and the alternative systems in order to produce energy from renewable sources: sunspace, solar collectors, photovoltaic panels, a geothermal system and a pellet boiler system. Home automation manages all the mechanical systems to ensure comfort and reduced energy consumption at the same time. The sunspace is a passive solar system used mainly for heating indoor spaces during the winter season. The building's cooling system is based on natural ventilation strategies and on geothermal heat pumps. The building is provided with shading systems. A smart system was devised to guarantee user safety and security. This kind of system can be controlled remotely and provides constant security for the building. [ABSTRACT FROM AUTHOR]

In a historical period in which more than half the population lives in urban centres, tall buildings – which are a key instrument of densification – require a special focus. In the common imagination tall buildings are seen as ‘energy intensive boxes’, but the scientific community, even though divided between supporters and opposers, is investigating their potential in terms of energy efficiency. This chapter aims to highlight, by going through case studies, the limits and potential of energy-efficient (low energy) tall buildings and provides an outline of their key characteristics. It especially focuses on the possibility of implementing systems for generating power from renewable energy sources, in relation to the vertical development of these buildings, which enables the production of amounts of energy that are unheard of for other types of building. Based on the analysis of the state of the art in this field, and on a number of related considerations, we are able to assume that the objective of Net Zero Energy tall Building could potentially be achieved. [ABSTRACT FROM AUTHOR]

The electrification of cooking methods in Korea was investigated to understand the impact of different cooking methods on energy use and greenhouse gas (GHG) emissions in the building sector. Annual household cooking energy consumption was compared for the Nowon Energy Zero House Project, a zero-energy housing complex using induction cooktops, and a sample of households that used natural gas for cooking. The results showed that the former consumed less calories (a difference of 2.2 times) and emitted less GHGs (a difference of 2.6 times) compared to gas cooking households. A countrywide scenario analysis was conducted by combining the share of electric cooking households with the projected power generation mix in 2030. Under the 2030 Policy scenario for power generation, and with an electricity cooking share of 20%, cooking-related GHG emissions were projected to be 3.79 million t CO2/year; 3.8% (150,000 t CO2/year) lower than those in the present day, despite a total population increase. The electrification of cooking methods in Korea has the potential to reduce both the energy demand of the building sector and GHG emissions, in synergy with the decarbonization of the power generation sector. [ABSTRACT FROM AUTHOR]

• A multivariable nonlinear model with diversified energy conversions. • Energy flexibility quantification of the hybrid BEMS interacted with electric grid. • Advanced grid-responsive control strategy for the energy flexibility exploitation. • Solutions for energy congestion contradiction regarding different battery capacities. • Guidelines for policymakers and householders to promote energy flexible buildings. The energy flexibility of the sophisticated building energy systems with the integration of renewable systems, diversified energy storages, advanced energy conversions and electric vehicles, has attracted increasing attention. However, there are limited studies on the energy flexibility quantification and enhancement of the sophisticated building energy systems. In this study, a nonlinear component-based model, integrating building integrated photovoltaics and vehicle integrated photovoltaics, was developed for the energy flexibility assessment. A generic methodology with a series of quantifiable energy flexibility indicators (the off-peak renewable-discharging ratio and the off-peak grid-discharging ratio) has been presented to quantify the energy flexibility of the hybrid grid-connected building–vehicle system. Two dynamic advanced grid-responsive energy control strategies have been proposed for the energy flexibility enhancement. Techno-economic feasibility has been discussed regarding different off-peak electricity tariffs and different rated renewable capacities. Moreover, a technical solution is presented to solve the energy congestion contradiction regarding the exploitation of the off-peak grid electricity and the on-site renewable energy through electrical storage systems. The research results showed that the proposed renewable-to-demand and the off-peak grid-supported storage control (Control Strategy 3) shows the robustness and competitiveness, in terms of activating both the on-site renewable system and the grid to participate in the building energy system. By implementing the Control Strategy 3, 96.8% of the grid electricity can be shifted from the off-peak period to the peak period for the usage of the office building. Depending on the critical static battery capacity at 10 kWh for each floor, the energy congestion contradiction can be solved by managing the off-peak grid-battery charging power to minimise the energy-based operational cost. This study formulates a flexible energy management system and a flexible energy control strategy, which are important for the promotion of energy flexible buildings, with participation of both the policymakers and the householders. [ABSTRACT FROM AUTHOR]