Design and analysis of a FAMe-MLL vapor-compression refrigeration cycle compressor

This paper presents the analysis and design of a vapor compressor refrigeration cycle compressor using Fatty Acid Methyl Ester Methyl Linoleate (FAME-MLL) as the working fluid. The FAME-MLL working fluid is a biofuel derived from rapeseed oil. This working fluid is currently being considered by our research team as a natural refrigerant for use in the active electronics payload cooling of Venus Lander in-situ missions. The novelty of this present research lies in the development of a compressor that can handle the FAME-MLL fluid at the high temperatures and high pressures (738 K, 9.3 MPa) of the Venus environment. The particular selection of the FAME-MLL working fluid is based on it’s critical temperature of 799 K, which is larger than that of the local Venus environment of 738 K. Thus, using FAME-MLL takes advantage of latent heat transfer for a continuously operating heat rejection system. Use of the Cordier diagram places the compressor in the piston pump regime with specific diameter and speed of Ns = 1.019, and Ds = 4.22, respectively. The compressor is baselined with a piston diameter of 3 in, stroke of 3 in, FAME-MLL flow rate of 2.7 kg/hr, rotational speed of 3600 rpm and compressor power of 88 W. A polytropic thermodynamic analysis that incorporates the compressibility factor is used to model the compressor work. A series of compressor pressure head flow rate design curves for the compressor are also presented.