PURPOSE: To control the temperature of a specimen chamber to different prescribed levels according to the purpose by combining a heating action of an electric heater, a cooling action of an evaporator of a refrigeration cycle and a heating action of a reheater and controlling the temperature by the combined actions.
CONSTITUTION: A specimen chamber 1 is placed in a tank make of heat- insulation layers 12 and the tank is provided with a temperature and humidity controlling apparatus comprising a cooling and dehumidifying apparatus 6 for control the temperature and humidity in the specimen chamber, a reheater 7, an electric heater 8, a humidifier 9 and a circulation blower 5 and with an illumination apparatus such as illumination lamp 11 to apply illuminance necessary for the growth of a plant. In the case of a constant-temperature operation, the waste heat generated from a refregeneration cycle is utilized without using the electric heater both in the normal-temperature operation and the high- temperature operation. The consumption of electric power can be suppressed by the procedure.
HOSOE YOSHIHISA
OGAWA TAKEO
ONO MASATOSHI
