Experimental investigation on electrochemical ammonia compressor

Improving the efficiency of vapor compression cycles has become a leading topic among the energy society. Current mechanical compressors have inherent thermodynamic limits, especially in small capacity systems. To overcome these limitations, an electrochemical compressor was suggested, and its performance was investigated in this study. The electrochemical compressor was designed based on the proton exchange membrane fuel cell, and utilizes hydrogen as a carrier gas to transfer ammonia across the membrane. In this study, ammonia was selected as the working fluid because of its high latent heat and electrochemical interaction with hydrogen and the proton exchange membrane. Fundamental studies were performed to study the transfer ratio between hydrogen and ammonia, as well as the effects of temperature and relative humidity on flow rates. In addition to the potential efficiency improvement, an electrochemical compressor working with ammonia can be an environmentally friendly option, and could have a much simpler design without using any moving parts or lubrication oil.