To provide a heat pump making it possible to take out underground heat at a high efficiency of heat exchange by improving an underground heat exchanger of the U-pipe type.
The heat pump includes an underground heat exchanger which causes a heat carrier to circulate into a circulation line 12 comprising at least two or more first pipes 14 and second pipes 16 communicating with the first pipes and consisting of a number of pipes equal to or smaller than the first pipes. The heat pump is thermally coupled to the heat exchanger of a heat using facility above the ground. The heat carrier heated to medium temperature after heat transfer with underground heat has its flow speed increased within the second pipes and then undergoes heat transfer with the heat exchanger of the ground facility while held at medium temperatures without being affected by the high or low temperature heat carrier flowing down the first pipes, resulting in a greatly increased efficiency of heat exchange.
TAKASUGI SHINJI
KUWANO YASUSHI
