Fuel Cell Distributed Generation System for Cooling

Air conditioning (A/C) systems are the major consumers of power in hot climates. In a country like Kuwait, A/C accounts for 85% of power supplied to homes during peak hours and 55% of annual energy consumption by the residential sector. A fuel-cell-based cogeneration system is proposed to improve the efficiency of generating and utilizing power for cooling in residential buildings. Distributed electric power is generated by a solid oxide fuel cell (SOFC). The electricity is used to operate high-efficiency water-cooled chillers in a district-cooling setup, which replaces packaged A/C units typically used for homes. The exhaust fuel and heat from the SOFC operate a gas turbine and an absorption chiller. A thermal energy storage tank is used for storing chilled water to reduce the total capacity of the system and, hence, capital investment. The integrated fuel-cell air-conditioning (FCAC) system improves the cooling-to-fuel efficiency, expressed as coefficient of performance, by 375%. The peak power requirement is reduced by 65% and the total fuel energy is reduced by 58%. An example system of 2 MW delivers 3750 RT (13.2 MW) of cooling to a district. Over a 9-month period, it saves 94 TJ of fuel energy and feeds 5.21 GWh of electricity to the grid as a surplus.