PURPOSE:To prevent dewing on vegitation and miniaturize the device by a method wherein indoor air is passed through a heat dissipating device and a heat accumulating tank during accumulating heat while the air passing through either the heat dissipating device only or the heat dissipating device and heat accumulating tank, in the heat pump type space heating device for a greenhouse for agriculture. CONSTITUTION:Heat accumulating operation is effected when indoor temperature is increased in daytime and the indoor air is introduced into the heat accumulating tank 2 by positioning dampers 4, 5 at the positions shown by full lines in the diagram to pass through silica gel 3 after heating it by the heat dissipating device 7 of a heat pump whereby the silica gel 13 is dried and the heat of the air is accumulated in the tank 2. At night, the dampers 4, 5 are positioned at positions shown by broken lines in the diagram and the indoor air is released into the room directly without passing through the heat accumulating tank 2 from the heat dissipating device 7. When the temperature is decreased further, a fan 3 is operated and the air is released into the room through the heat accumulating tank 2 after removing moisture in the air and heating the air. According to this constitution, dewing on vegitation may be prevented and the device may be miniaturized.
