Heat Transfer Performance of Aluminum-Ammonia Heat Pipe at Low Temperature Under Various Heating/Cooling Conditions

For understanding the thermal performance of heat pipes at low working temperatures, this study conducted an experimental measurement of heat transfer performance of grooved aluminum-ammonia heat pipes at condensing temperature from -10 to -40°C. The test results showed that the effect of condensing temperature on thermal resistances was not significant while the heat pipe dried out earlier at the lowest condensing temperature (−40°C) condition. The heating surface did not affect the thermal resistance obviously. However, the thermal resistance under 2-side cooling was just about half of that under I-side cooling.