Hybrid solar–fuel cell combined heat and power systems for residential applications: Energy and exergy analyses

Abstract Small-scale solar PV–water electrolyzer systems are suggested for remote combined heat and power (CHP) applications. A residential solar PV–electrolyzer system is developed and coupled with a high temperature solid oxide fuel cell (SOFC) system (PV–FC) for supplying the electricity demand. It is possible for the PV system to generate electricity in excess of the demand during off-peak hours. The surplus electricity is used by the water electrolyzer for hydrogen production. The hydrogen produced is stored in a storage tank. The fuel cell is fed with the hydrogen generated by the electrolyzer. The PV–FC system is coupled with a heat recovery unit, which provides the residential area with thermal energy, to improve energy utilization. The heat recovery unit consists of a heat recovery steam generator and an absorption chiller utilizing the thermal energy of the SOFC flue gas for heating and cooling purposes. Determining system operational parameters is important for the design and implementation of the CHP system in a residential area. Therefore, the residential CHP system is assessed here based on energy and exergy. The hourly demand of the residential area is taken into consideration for component selection and sizing, and energy and exergy efficiencies of the developed system are presented.