Optimal sizing and performance assessment of a hybrid combined heat and power system with energy storage for residential buildings

Combined heat and power systems are emerging in the market nowadays. Using renewable energy resources is an inspiring idea to make these systems more efficient and environmentally friendly. This study aims to present a combination of photovoltaic array, wind turbine, and diesel generator to produce electricity and heat with 100% reliability, simultaneously. Also, a battery storage system is considered to save the excess generated electricity and supply the unmet load when enough production is not available. A step-by-step procedure is introduced for modeling different configurations of the system. The Grey Wolf Optimization, as a heuristic search method, is applied to find the optimal size of the system components. The results show that in the optimum state, a 4.1 kW diesel generator supplies the electrical load along with about half of the thermal load. The remaining thermal demand is provided by natural gas. Also, it has the highest share of electricity production in autumn and winter. Moreover, a 4.7 kW battery storage system has been used to meet the load when the production capacity of the generator is not enough. This layout has zero loss of power supply and the minimum net present cost. The net present cost for this combination is about 187,000 Swiss Franc, considering the initial costs, maintenance costs, replacement costs, and fuel costs.