Energy and cost analyses of a hybrid renewable microgeneration system serving multiple residential and small office buildings

Abstract

This study investigates the energy and cost performance of hybrid renewable ground source heat pump (GSHP) and natural gas fueled fuel cell (FC) microgeneration systems serving multiple residential and small office buildings in Ottawa (Canada) and Incheon (South Korea). The study is performed by simulations in TRNSYS environment. The performance of the microgeneration system is compared to a GSHP only system. In addition, the impact of the FC capacities, natural gas price and electricity price on the system's energy and cost performance is examined.The energy analysis results show that the GSHP–FC systems have less primary energy consumption compared to the GSHP only system in both geographic locations. However, whether a GSHP–FC system could achieve operational cost saving is strongly dependent on the local natural gas and electricity prices and also on the building heating, cooling and electrical loads and their patterns. The GSHP–FC microgeneration systems could yield operational cost savings at locations where the natural gas (or other input fuel to the FC) price is much lower than the electricity price, such as in Ottawa. At locations where with exceptionally high natural gas to electricity price ratio, such as in Korea, no operational cost saving could be attained by the GSHP–FC system.The cost analysis results indicate that, in Ottawa, the extra capital investment incurred to the GSHP–FC system is possible to be returned within its lifespan, especially with the current trend of continuous price reductions of FC equipment and installation resulting from economy of scale and market expansion. Nevertheless, the GSHP–FC microgeneration systems' capability to generate both electricity and thermal energy at the point of use is generally considered more attractive for inclusion in the “smart” energy networks, new and remote community applications.