Energetic, exergetic and economic analysis of an innovative Solar CombiSystem (SCS) producing thermal and electric energies: Application in residential and tertiary households

•The present work studies the potential of using innovative SCS in Tunisia.•In cold months the SCS provide about 50–75% of the total exergy provides.•The SCS produces between 70–150% of electric energy needs.•The SCS payback period (Pb) based on electric water heater was 10.2years.•The SCS payback period (Pb) based on gas/gas town was about and 8.7years. The endeavor of this paper is to study of the potential offered by the expenditure of an innovative Solar CombiSystem, SCS, used for the space heating load, the domestic hot water supply and the electric energy production. The investigation achieved in this work was based on an experimental and a simulation studies. A TRNSYS simulation program was achieved in order to evaluate the SCS monthly/annual thermal and electric performances. It was found that the proposed SCS covered between 20 and 45% of the SH energy needs by considering only solar energy. The result shows also that the SCS provided from 40 to 70% of the total DHW needs. It was also found that the SCS electric production ranged between 32 and 225MJ/m2 with a gain factor varying between 49 and 125%. An economic appraisal was also achieved to appraise the SCS feasibility. The results of the economic analysis show that the annual energy saved (ARE) and the payback period (Pb) based on electric water heater were respectively equal to 7618.3kWh/year and 10.2years. It was found that ARE and Pb based on gas/gas town were about 5825m3 and 8.7years, respectively. The results of the economic analysis shows that the adoption of the SCS saves about 48% of electric energy and about 46% of gas/gas town kept back by the conventional system.