Combined heat and power system based on Solid Oxide Fuel Cells for low energy commercial buildings in Qatar

Abstract

Commercial buildings in Qatar account for 19% of the total energy consumption in the country. To reduce this significant amount of energy, a Solid Oxide Fuel Cell Combined Heat and Power (SOFC CHP) system with natural gas as fuel is studied. An office building model is created in eQuest energy modeling package. Several baseline cases were considered to optimize the HVAC system and loading profile to utilize the SOFC to its full extent. These baselines are: electric chiller, absorption chiller, and combined electric-absorption chiller systems. Performance curves were analyzed for a range of SOFC CHP system capacities (25-250 kW) in terms of energy produced, utilized thermal energy, overall efficiency and annual energy costs to assess potential cost savings. Results showed that using SOFC CHP with combined electric-absorption chiller system can reduce the annual energy cost by 67% compared to the baseline case with electric chiller. Moreover, optimum overall efficiency of the system can reach 73%. Finally, an environmental impact assessment was evaluated in terms of CO2, NOx, and SO2 emissions. It was found that application of SOFC CHP system resulted in reductions in CO2 emissions of 30%, NOx of 90%, and SO2 of 90%.