What Kind of Research are You Doing?

Test facility Simulation results during planning: When using a general method. improved heat insulation was not very effective, but smaller simulations proved more effective.

Actual primary energy consumption (stacked bar chart):
Both first year and second year reach the target value of 1200 MJ/m²-year.

We are mainly conducting research on indoor environments and energy conservation of buildings in cold climate areas with high thermal insulation and high efficiency building equipment. After the Great East Japan Earthquake, energy consumption related to our life has attracted attention. This attention has gained focus particularly on electricity because in colder areas a lot of energy is used for space heating and hot water supply. Recently, attempts to efficiently utilize renewable energy with use of various ICT equipment are being made. On the other hand, improving the thermal insulation (preventing heat transfer between inside and outside) enables significant energy savings when most of energy is used for heating. In a building with improved thermal insulation, a more comfortable indoor environment can be achieved without sophisticated equipment. In this way, the energy issue can be solved by not only using high-performance facilities but also by improving the building itself, and that type of building design is called passive design. Concerning passive design, we conduct numerical simulations of temperature and energy for planning and operation of an actual building.

For example, one of the buildings that we conduct the numerical simulation is shown in the figure above. This building is a facility that integrates a medical clinic, a medical ward and a dormitory. We were able to successfully reduce the energy consumption of the primary energy to a half, in comparison with the conventional facility, by enhancing the thermal insulation of the building and analyzing its operation method while collecting data. Moreover, the cost of operation required for the hybrid hot water supply system, combining the pellet boiler and the heat pump, can be reduced by more than one million yen per year.

 

Insulation of Housing in Hokkaido

Hokkaido is a region that leads the world in the field of passive housing design. After the World War II, people who returned to Japan and who lost their houses were living in poor housing conditions in Hokkaido. In order to improve the situation, the Cold Region Housing Construction Promotion Act was created, and the public, private and academic sectors co-developed housing suitable to the climate and natural features of the cold area. Throughout this process, various housing techniques have been developed, and housing featuring world class thermal insulation and airtightness (technique for prevention of infiltration) has become a reality only through trial and error. In the meanwhile, these techniques have been supported by engineers. In Hokkaido, where the population has decreased significantly, we are afraid that these precious techniques we have cultivated over seventy years will be lost.

 

What Will be Your Next Goal?

Integral amount of solar radiation in the central part of Sapporo

Right now, the main topics I am studying are (1) the support of passive design through simulation and (2) the relationship between the community and energy in a region of depopulation. With regard to the former, in recent years, we have been able to access more easily various data related to architecture, cities and the global environment. I would like to simulate the effects of passive design using this data to support the increase of effective passive design as much as possible. For example, the integral amount of solar radiation in the central part of Sapporo city was created based on GIS (Geometrical Information System) shown in the right figure. The thickness of the white color indicates the amount of solar radiation (thicker is more). This figure shows the conditions of the roof on buildings. According to this figure, there are buildings that can receive a large amount of solar radiation and those that can receive only a little. Sapporo city encourages the installation of solar cell systems on buildings, but it is shown that its effect varies significantly depending on the peripheral conditions. We would like to conduct simulations of the indoor environments and the energy of buildings that use passive design and apply data that has not been used before.

The latter is still vague, but depopulation has been accelerating sharply in various regions, and not only in Hokkaido. The conditions of energy conservation may be improved because energy savings decrease automatically as the population who use energy decreases. However, if the energy price remains at high levels while the demand for energy worldwide increases, problems could potentially arise with the procurement of energy on an individual level and with maintaining infrastructure on the community level. In particular, these problems tend to be realized in cold areas because more energy is required for living there. We would like to pursue realistic solutions, not lofty dreams, concerning the issue of how to sustain lifestyles in these regions in the future.