Energy and Exergy Analysis of a Micro CCHP System Based on Fuel Cell for Absorption Refrigeration

In this article a CCHP system has been proposed for recovering waste heat of PEM fuel cell and this system can be used for residential applications. Main components of the system are PEM fuel cell, absorption chiller, fuel processor and heat storage tank. Electrochemical equations of PEM have been modeled by MATLAB and the chiller, fuel processor and boiler have been modeled by EES. In addition, the energy and exergy performances and emission reduction of the proposed system have been analyzed; also effect of operating temperature on performance and irreversibility of the system have been studied. Performance of the system has been compared when the system works as a power system or a CHP and a CCHP system. Results demonstrate that the refrigeration capacity of absorption chiller is 12.24 kW, output power of fuel cell 38.63 kW, heat generation of PEM fuel cell 39.12 kW and irreversibility losses of PEM-FC is 84.21 kW. Finally when the system works as power system its efficiency is 32.6%, and in CHP and CCHP modes the efficiencies are 66.1% and 75.8 % respectively. Also by increasing operation current density of fuel cell, exergy efficiency of CCHP system decreases but COP of absorption chiller increases.