Abstract
A solar-heat pump system was researched and developed by the authors at the Kitami Institute of Technology. Being simplified and reduced, it was introduced into a residence to test it under every day conditions for a long period.
The solar system works only for a hot water supply, and the heat pump works for space-heating using ground water as a heat source. In the usual case, two bore holes are necessary: one for production and one for returning water. However, this particular method, namde a“direct siphon well”systm, could be done by only one bore hole. Namely, a pump is set directly under the water surface, by which ground water is pumped up and forced into the heat pump, and after absorbing heat through an evaporator, the cold water is returned to a lower point in the same well. Water discharged from the heat pump flows partially into a road-heating system, and then flows out through a drainpipe. The ratio of the drainage to the returning water is 7: 3 in average for the cold seasons, and the temperature of the water pumped up is 8.5 to 9.0°C throughout the year.10 MJ / h of the extracted heat per bore hole is expected by this technique. The system is now working very well to make environment inside the house comfortable.
Advantages of the solar-heat pump system using the direct siphon well method are as follows:
