Integration of a Solid Oxide Fuel Cell with an Absorption Chiller for Dynamic Generation of Combined Cooling and Power for a Residential Application

Tuesday, 25 July 2017: 10:20
Atlantic Ballroom 1/2 (The Diplomat Beach Resort)
M. Asghari (University of California Irvine, National Fuel Cell Research Center), D. McVay (National Fuel Cell Research Center, UCI), and J. Brouwer (University of California Irvine, National Fuel Cell Research Center)
Our novel idea is a highly efficient, zero emission solid oxide fuel cell (SOFC) system that can be dynamically dispatched to produce electricity, hydrogen fuel, and cooling in various amounts to meet energy and power demands of a single residence. Although SOFC systems exhibit high electrical efficiency, in practical applications almost half of the fuel energy is converted to heat. The SOFC high temperature (high quality) heat can be used as the primary thermal energy source to supply cooling or heating or to produce extra electricity through a bottoming cycle. In this study the waste heat from the fuel cell is captured and processed through an absorption chiller (AC) to provide cooling for meeting the cooling demand of a single residence. High purity hydrogen gas can also be produced by the SOFC system as an energy co-product using the tri-generation concept of lower fuel utilization followed by hydrogen separation from the anode off-gas. Hydrogen as an energy carrier can be stored for later use, as fuel for transportation use in a fuel cell electric vehicle. The integration of an absorption chiller and hydrogen separation unit with an SOFC could create a highly dispatchable system that can meet the dynamics of measured residential power and cooling while producing hydrogen fuel for fuel cell electric vehicle demand. Dynamic dispatch and control strategies are needed to safely operate such an SOFC system, keep it within the required operating envelope, and avoid premature degradation.

A spatially resolved dynamic model was developed in Matlab/Simulink to simulate the dynamic operating characteristics of an SOFC system. A commercially available 1.5 kW SOFC system was selected and acquired for model verification and performance evaluation. Preliminary results from the dynamic model of the SOFC show that the SOFC exhaust retains sufficient quality heat for use in an absorption chiller. A dynamic absorption chiller model is developed to study the dynamic characteristics and the performance of the combined co-generation system. Actual dynamic data from a single residential house located in Irvine California is used as an input to evaluate the dynamic operation of the SOFC-AC model. The integrated Tri-generation system was then evaluated in terms of efficiency, capacity, dynamic operation and control to meet the measured power, cooling, and fuel demands of the residence. The proposed system may offer a high efficiency and low emissions conversion solution that meets the dynamic demands for residential power, cooling, and transportation end-uses.