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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.

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.

The paper aims to examine the possibility of adapting an existing school building to the standard of a zero energy building. The school building is a specific case of a building in which the energy consumption is periodic, except for the months with the most sunshine. Therefore, it is necessary to look for a solution that will allow storing the energy obtained, for example, from solar collectors. Based on the analysis of the literature, it was concluded that the use of borehole thermal energy storage might be the right solution to the problem. The article presents the energy balance of the building with and without the use of renewable energy sources and the benefits of using an energy storage system.

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.

There is much research on zero energy buildings. In this paper, technologies and policies to improve the building energy efficiency of zero energy buildings are presented. The zero energy building certification system in Korea is introduced, and the evaluation is carried out based on the energy self-reliance rate that enables zero energy buildings. Zero energy buildings are able to minimize energy consumption due to the application of highly efficient building materials and equipment technology. In this research, to increase the prevalence of zero energy buildings in Korea, the authors propose a zero energy building technology package. Using a passive and active technology package, we confirmed the necessity and detailed requirements of each technology parameter. We analyze and classify Korean building material testing methods and performance standards, and propose passive and active technology packages, modules, material performance testing methods and minimum requirement performance standards. Finally, this study proposed a table presenting the test methods, standard and minimum value of performance. By these results, the authors confirmed the effectiveness and availability of passive and active technical packages.