Performance of hybrid quad generation system consisting of solid oxide fuel cell system and absorption heat pump

摘要

In this paper a system consisting of an SOFC system for cogeneration of heat and power and vapour absorption heat pump for cooling and freezing is assessed and performance is evaluated.Food industry where demand includes four forms of energy simultaneously is a relevant application such a system.The heat pump is a heat driven system and is running with the heat recovered by a heat exchanger from the exhausted gases from SOFC.The working fluid pair is NH3-H2O and is driven in two evaporators which are working at two different pressures.Thus,the heat pump will operate at tree pressure level in order to meet both cooling and freezing demands.This is an innovative configuration for absorption heat pumps because the cascade is implemented only in vapour compression heat pumps.A smaller ratio of the exhausted gases supplies the energy demand for space heating.The SOFC is fuelled with natural gas.The natural gas is first converted to a mixture of H2 and CO which feed the anode after a preheating step.The cathode is supplied with preheated air and gives,as output,electrical energy.The anode output is the exhaust gas which represents the thermal energy reservoir for heating and absorption heat pump.The model is validated using data available in open literature.Overall this system shows better performance in terms of efficiency and CO2 emissions compared with cogeneration or tri-generation systems.Specifically,it is better for applications,such food industry,where refrigeration and cooling requirements are high,and a small amount of space heating is needed.