LAUSR

Abstract Given size and performance advantages, microchannel heat exchangers are becoming increasingly important for various energy recovery and conversion processes. In this study, detailed experimental measurements were conducted to characterize flow and heat transfer performance of a microchannel heat recovery unit (HRU) manufactured using standard photochemical etching and diffusion bonding processes. According to the global flow and temperature measurement, the HRU has delivered the predicted thermal performance under various oil and air flow rates. As expected, the heat transfer effectiveness varies between 88% and 98% for a given air and oil flow rates while it increases with air inlet temperature due to the improved thermal conductivity. However, significant flow mal distribution is identified among the air channels according to the in-depth flow distribution measurement using hot wire. The flow measurement also indicates visible misalignment of the air channels caused by the manufacturing processes. In addition, the excessive pressure drops occurred for both air and oil channels indicating reduced flow areas due to the photochemical etching process. The results of this experimental study can hopefully provide insights in improving designs of microchannel heat exchangers using the same manufacturing processes.