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Airflow windows (AFWs) help to stabilize the thermal environment in the perimeter zone and also allows for switching between solar‐shielding and solar heat acquisition operations. This is based on the method of channelizing the air discharged from its cavity layer, either by using a total heat enthalpy exchanger and choosing to exchange heat or otherwise. It has a certain thickness owing to the blinds that are installed in its cavity layer. The purpose of this research is to develop a window system that uses electrochromic (EC) glass, instead of blinds, as a solar‐shielding device. This study also provides the specifications of the window system of reduced thickness. The performance of the window system is assessed by CFD analysis. The solar heat gain coefficient (SHGC) of the proposed window system is found to range from 0.083 to 0.268 and its solar radiation properties can be controlled in a flexible manner. These characteristics contribute to an improvement in the building environmental performance in the form of climate‐adaptive building shells (CABS) in places with four distinct seasons such as Japan that require solar‐shielding to reduce the cooling load in summer and solar heat gain to reduce the heating load in winter. [ABSTRACT FROM AUTHOR]

Urbanization causes the so-called heat island phenomenon that raises urban atmospheric temperature higher than that in the suburbs. The phenomenon leads to a decrease in heating load and an increase in cooling load in the urban buildings. In this paper, the effect of the heat island phenomenon on the heat load of buildings was analysed by year-to-year changes in the heat load both in the urban and suburban areas. Tokyo was selected as the target urban area and Choshi, as a less urbanized city, among 30 stations located in a range of about 100 km both east-west and north-south centering on Tokyo. Investigation on the relationship between the changes in heat load during the past 100 years confirmed that • The heating load of Choshi has decreased about 20% since 1900, whereas the heating load of Tokyo has decreased about 40% in the same period of time. Also • The cooling load of Tokyo has increased about 20% since 1900, but the similar increase can be seen in that of Choshi. [ABSTRACT FROM AUTHOR]

Considering the heat capacity inside vertical spiral ground heat exchanger (VSGHEX) in the simulation is one of the most noteworthy challenge to design the ground source heat pump (GSHP) system with VSGHEXs. In this paper, a new simulation model for VSGHEXs is developed by combining the ICS model with the CaRM. The developed simulation model can consider the heat capacity inside VSGHEX and provide dynamic calculation with high speed and appropriate precision. In order to apply the CaRM, the equivalent length was introduced. Then, the equivalent length was approximated by comparing the results of the CaRM and the numerical calculation. In addition, the calculation model of the VSGHEX was integrated into the design and simulation tool for the GSHP system. The accuracy of the tool was verified by comparing with the measurements. The error between supply temperatures of the measurements and calculation is approximately 2 °C at the maximum. Finally, assuming GSHP systems with VSGHEXs, whose spiral diameter was 500 mm and depth was 4 m, were installed in residential houses in Japan, the required numbers of VSGHEXs were estimated. The results showed a strong correlation between the total heating or cooling load and the required number. Therefore, the required number can be estimated by using the simplified approximate equation. [ABSTRACT FROM AUTHOR]

Most houses in Japan have the floor‐length windows to take the natural light into the room. Reflected solar radiation and Re‐radiation from the ground (Reflection) enter through the window and increase the cooling load, therefore reducing reflection to the building is necessary. We focused that reflection is greatly affected by the ground surface, its heat flux may vary depending on the height from the ground. This study presented the thermal influence by the vertical distribution of reflection on the building in various climate areas and considered the solar shading method based on that distribution. The calculation results using Sol‐Air Temperature showed that the incident heat flux of reflection increased on the lower part of the building surface, and the vertical distribution of reflection existed in various areas. We propose to shield up to the lower half part of the building as a solar shading method considering the vertical distribution of reflection. This method could be able to shield most of reflection and incorporate natural light from the top half of the window to ensure room brightness and view, that is expected to be effective in improving indoor comfort and reducing the load of cooling and lighting. [ABSTRACT FROM AUTHOR]

Climate change is an important issue that affects energy consumption, causes health problems, such as heat stroke, and requires urgent countermeasures. Serious health problems, including cardiac arrest, often occur in winter in traditional residences in Japan. Cooling-heating energy is required to maintain a healthy thermal environment. Although energy efficiency standards for buildings have been introduced worldwide to reduce energy consumption and various passive energy-saving methods are being investigated, traditional residences still face difficulties in conducting renovations because of various restrictions, such as the conservation of historical or aesthetic values. In this study, these issues and their appropriate countermeasures were investigated for a traditional townhouse in Kyoto, Japan, "Kyo-machiya" (including its new form "Heisei-no-Kyo-machiya"). The potential of reducing heating and cooling loads was examined by conducting numerical analysis considering residents' lifestyles. Field surveys of the indoor environment were conducted in both summer and winter. It was revealed that by optimizing the times and positions of opening and closing the windows and indoor partitions, the indoor air flow could be adjusted from both thermal comfort (cooling in summer) and discomfort (cold drafts in winter) perspectives, leading to improving the indoor environment without using energy. [ABSTRACT FROM AUTHOR]

Evaluation of appropriate areas to introduce a closed-loop ground-source heat pump (GSHP) system in the case of a standard detached residence was conducted in Akita Plain, Japan. Depth of borehole heat exchanger (BHE) required to use a GSHP system was taken as the suitability index, which is simpler for the general public to understand and to promote the system. Heating and cooling loads of the standard size detached residence were calculated based on the 2013 Energy Conservation Standard. To estimate BHE depths and estimate a suitable area, identical 3D BHE models were constructed at 30 points in the plain. Required BHE depths were determined by performing heat exchange simulations at each location using the calculated loads and heat exchange rates. A suitability map showing distribution of the required BHE depths was prepared. BHE depths were shorter in the north-western area compared to the other parts, implying that the coastal lowlands in this area are more suitable for closed-loop system in the standard detached residences in terms of heat exchange performance as well as the cost reduction. Thickly distributed Quaternary System with higher thermal conductivity is contributing to shorter BHE depths. The suitability map is effective to adopt potential areas for the system installation in the standard detached Japanese residences. [ABSTRACT FROM AUTHOR]