DEVICE TO CONTROL DISCHARGED HEAT QUANTITY

PURPOSE:To make smaller the heat quantity required for preventing freezing by making the heat exchange section between a fluid loop on the heat source side and a heat pipe on the heat radiation side of a variable conductance heat pipe. CONSTITUTION:When the temperature of a heat source 6 falls below a set value, the pressure of nitrogen gas rises because the nitrogen gas in a gas reservoir 7 is cooled by a control circuit 9. On the other hand, because the temperature of the fluid loop 4 falls as the temperature of the heat source 6 falls, the temperature of ammonia in a variable conductance heat pipe (VCHP) 3 falls, and the vapor pressure of the ammonia in VCHP 3 falls. Because of this the nitrogen gas in the gas reservoir 7 goes into the VCHP 3, lowering the heat transportation capability of the VCHP 3. As a result, quantity of heat transfer from the flow loop 4 to a heat pipe 2 is lowered, making it possible to make the discharge heat quantity small. Conversely, when the temperature of the heat source 6 becomes high, inside of the VCHP 3 is filled by ammonia liquid and ammonia vapor, and the heat transportation capability of VCHP 3 becomes larger and the discharged heat quantity becomes large. Therefore, it is possible to control discharge heat quantity according to the temp. of the heat source 6 without changing the flow quantity in the flow loop 4.