Experimental Testing of a Novel Kilowatt-Scale Multistack Solid-Oxide Fuel Cell Assembly for Combined Heat and Power

Abstract

This paper describes experimental testing of a “geothermic fuel cell (GFC),” a novel application of solid-oxide fuel cells for combined heat and power. The geothermic fuel cell (GFC) is designed for in situ oil-shale processing. When implemented, the GFC is placed underground within an oil-shale formation; the heat released by the fuel cells while generating electricity is transferred to the oil shale, converting it into high-quality crude oil and natural gas. The GFC module presented here is comprised of three 1.5-kWe solid-oxide fuel cell (SOFC) stack-and-combustor assemblies packaged within a stainless-steel housing for the ease of installation within a bore hole drilled within the earth. The results from above-ground, laboratory testing of the geothermic fuel cell module are presented, with a number of operating conditions explored. Operation is demonstrated under hydrogen and natural-gas reformate fuels. The combined heat-and-power efficiency ranges from 56.2% to 74.2% at operating conditions that generally favor heat generation over electricity production. Testing of the geothermic fuel cell module over a wide operating range in a controlled, laboratory setting provides a valuable data set for developing more-detailed electrochemical and heat transfer models of module operation.

Modeling and simulation of a novel 4.5 kW multi-stack solid-oxide fuel cell prototype assembly for combined heat and power

“…This modeling approach for estimating SOFC stack temperature is in close agreement with measured values [28] for the operating conditions simulated.…”

“…Following calibration and validation of the thermal-electrochemical model, the model is used to simulate the impact of variations in electric current, fuel utilization and stoics of air on GFC-module performance. As noted in Anyenya et al [28], the Geothermic Fuel Cell was placed within a furnace containing refractory insulation to simulate geology heating within the laboratory setting. The GFC was not subjected to any external heating, as the furnace elements were not activated.…”

“…The experimental testing and performance of this Geothermic Fuel Cell module is described in Anyenya et al [28], where electrochemical and thermal performance were quantified over a wide range of operating conditions. In this paper, we present a computational model that simulates GFC thermo-electrochemical behavior.…”

“…In this paper, we present a computational model that simulates GFC thermo-electrochemical behavior. The model is validated using experimental data from laboratory testing presented in Anyenya et al [28]. A thermal-resistive network simulates heat rejection from the stack and burner components to the surrounding outer wall.…”