Thermal analysis of a compressor for application to Compressed Air Energy Storage

•We analyze heat transfer enhancement in a liquid-piston compressor for CAES.•Hydrothermal characterizations of the inserted heat exchanger media are obtained.•CFD simulations are done combining the VOF and porous media modeling methods.•The heat exchangers can effectively suppress temperature rise and secondary flows.•Results indicate optimization on the shape of the heat exchanger could be done.

In this paper, the topic of Compressed Air Energy Storage (CAES) is discussed and a program in which it is being applied to a wind turbine system for leveling power supplied to the grid is described. Noted is the importance of heat transfer in the design of the compressor and its effect on performance. Presented is a design for minimizing the temperature rise in the compressor during compression. The design requires modeling regenerative heat transfer from the compressed air to solid material inserted in the compression space. Modeling requires characterizing pressure drop through the porous insert, interfacial heat transfer between solid and fluid in the matrix, and thermal dispersion within the porous regions. Computation and experimentation are applied for developing correlations for such terms. Two types of porous media are applied: interrupted plates and open-cell metal foams. Cases with foam inserts are computed and the results are discussed. Discovered in the results are some complex secondary flow features in spaces above the porous inserts.