Experimental and theoretical analysis of a trigeneration system consisting of adsorption chiller and high temperature PEMFC

Abstract

Trigeneration system offers an effective way to utilize the waste heat from the primary power generation unit and to produce refrigeration. This can be accomplished using adsorption chillers capable of producing chilled water above its freezing point. Experiments were carried out to measure the performance of the adsorption chiller as a standalone system as well in trigeneration system coupled with HT-PEMFC. Waste heat recovery of 2.76 kW was achieved from a 5 kW HT-PEMFC operating at full load condition using an adsorption chiller of 1.99-2.84 USTR refrigeration capacity increasing the full system efficiency from 32.0% to 39.8%. Waste heat recovery can be further improved by employing a common intermediate buffer tank heated via heat exchangers connected with multiple fuel cell systems supplying heat to a single high capacity adsorption chiller increasing the expected total system efficiency to 44.9%. Simulation of the adsorption chilling system was accomplished providing further insights of parameters affecting its performance as well as design criterion for heating and cooling requirements for a target refrigeration capacity of the adsorption chiller. The heating requirements were underestimated by 24% for a standalone system and 32% for trigeneration system primarily due to non-accountability of the gaseous adsorbate withheld within the adsorbent bed.