マイクロチャンネル熱交換器におけるアンモニア強制対流沸騰熱伝達特性

抄録

The plate heat exchangers (PHEs) with titanium plate are used on the Ocean Thermal Energy Conversion (OTEC) system. Because the system is using an ammonia as a working fluid and a seawater as heat sources. The OTEC system is required to improve the thermal performance of the heat exchangers. The author proposed that the application of microchannel heat exchanger as an alternative to titanium PHEs to improve the performance of OTEC. The microchannel heat exchanger has high heat transfer performance due to the boiling bubbles confined on narrow channel and the bubble formed narrow liquid film on the heated surface. Then, the heat transfer dominates evaporative heat transfer. However, there is few researches of the ammonia boiling in the microchannel heat exchanger. In this study, the unique designed microchannel heat exchanger was manufactured and the heat transfer performance of ammonia convective boiling in the heat exchanger was measured. The result of that the comparison of overall and boiling heat transfer at different mass flow rate of working fluid, hot water temperature and mass flow temperature of hot water conditions were reported.