2020 Volume 37 Issue 3 Pages 329-
The Fukushima Demonstration House (80.6 m2) for the shallow ground-source heat-pump system developed by Nihon Univ., which have 10 shallow (10 m) heat wells, was built in 2013. The results of heating experiments from Jan. 2014 to March 2020 are reported in this presentation. The ground source fluid temperature was 3°C or above throughout each winter season when the heat of 220 MJ/day (2.5 kW) or below was extracted. Time dependent decrease in the temperature was negligible. The energy efficiency of the system ranged from 2.5 to 3.7 depending on the operating conditions. The height distribution of the room temperature was ±1°C for floor heating and 6 to 10°C for air heating. The overall heat transfer coefficient of the house estimated from the results is 0.78 W/(m2･K), where the heating power to keep the room 20°C higher than the ambient is 3.5 kW with the system efficiency of 2.5.
