Analysis of the impact of heat-to-power ratio for a SOFC-based mCHP system for residential application under different climate regions in Europe

In this paper, the ability of a micro combined heat and power (mCHP) system to cover the heat and electricity demand of a single-family residence is investigated. A solid oxide fuel cell based mCHP system coupled with a hot water storage tank is analyzed. The energy profiles of single-family households in different European countries are evaluated. The range of Heat-to-Power Ratio for the SOFC-based mCHP System of 0.5–1.5 shows good agreement with the hot water, space heating and electricity demand during the warm seasons across Europe. This suggests that the fuel cell system should be sized according to the summer energy demand. The winter energy demand shows a Heat-to-Power Ratio which cannot be covered by the mCHP unit alone. To ensure that the mCHP system meets both the thermal and electrical energy demand over the entire year, an auxiliary boiler and a hot water storage tank need to be coupled with the mCHP unit. It is further noted that the size of the auxiliary boiler should match the larger winter space heating demand. In contrast, the hot water tank volume should be sized according to the warm season space heating requirement, when space heating is not required but electricity and hot water are still in demand. This maximizes the running time of the fuel cell, and thus the economic and environmental benefit of the system, without wasting produced heat.