Membrane-enhanced M-cycle coupled with VCRS for improved cooling

Abstract

The Maisotsenko Cycle (M-cycle), comprising of primary (dry) and secondary (wet) air channels, can cool atmospheric air down to its dew point temperature without increasing its humidity. The driving force for cooling, i.e., the difference in temperature between the primary channel and the thin water film evaporatively cooled in the secondary channel, can be increased to improve the performance of a conventional M-cycle. This study aims to reduce the M-cycle's transfer area (or the cooler's size) by adding a porous vapor permeable membrane to the warmer section of the secondary channel. A coupling of membrane-enhanced M-cycle with a vapor compression refrigeration system (VCRS) is investigated. The membrane allows for the continuous removal of water vapor, ensuring a lower secondary stream humidity ratio and greater driving force for heat transfer. Analytical modeling is used to construct and simulate the Mcycle/Membrane-M-cycle + VCRS process for different geographical conditions based on heat and mass transport equations. The results show that the Membrane-M-cycle (with hydrophobic membrane) + VCRS coupled system can be up to ~28 % more efficient than the standalone VCRS and M-cycle+VCR systems.