PURPOSE: To contrive to be able to operate as a heat dissipation device during a cooling operation and the like, operate as a heat absorption device during a heating operation and absorb effectively natural heat from the sun and the like.

CONSTITUTION: During a heating operation and the like, south side the first change-over valves 21 and 23 are opened, north side the second change-over valves 22 and 24 are closed, among valves, and a blower 25 is driven. Then, the air heated by the solar heat is sucked into a blow-off air duct 26 through a blast duct 30 and blown toward a heat exchanger 27. At this time, because of the lower temperature medium is circulated through a low temperature tank inside of the heat exchanger 27, said air heat is absorbed by the heating medium. Meanwhile, during the cooling operation, north side the second change-over valves 22 and 24 are opened, south side the first change-over valves 21 and 23 are closed, and the blower 25 is driven. Then, unheated air is sucked into the blow-off air duct 26 through a blast duct 32 and blown toward the heat exchanger 27. At this time, because of the high temperature medium is circulated through a medium temperature tank inside of the heat exchanger 27, the air heat is dissipated in the heat exchanger 27.