In the cold region of Hokkaido Island, most of today's heating systems are using fuel oil.
For this area, adequate heat pump solutions shall be developed for the low energy house applications.
Two ground-coupled systems have been field-monitored by Hokkaido University. The systems use inverter-controlled ground-coupled heat pumps
with borehole heat exchangers, mechanical ventilations systems, heat pump water heaters as well as solar technologies.
Moreover, other prototype technologies like a passive humidity control by packed beds of siliceous shale in the ventilation system
are evaluated in the field monitoring. Results are documented in Best Practice Sheets
and in the field monitoring report.
However, 80% of the Japanese population lives in the moderate climate zone (Tokyo, Osaka),
where space heating and space cooling requirements exist. Reverse operating heat pump air con-ditioners for space heating in winter and
air-conditioning in summer are very popular. However, the design of the system is not adequate for highly-insulated dwellings.
In the frame of the Japanese project, a design method has been derived, which matches the heat load of low energy buildings and
yields a better seasonal performance due to higher part load efficiency.
Moreover, the control of the systems has been evaluated. Last but not least, developed methods have been integrated in the new Energy Efficiency Act
enacted in 2009.
Results are documented in the field monitoring report.
