CH-18-C037 -- Economic Feasibility of Hybrid Solar-Combined Cooling, Heating and Power (CCHP) Systems for a Large Office in California PDF

Economic and environmental benefits of combined cooling, heating and power (CCHP) systems can be enhanced with integration of solar photovoltaic (PV) arrays by virtue of recent cost reductions of PV arrays. Such hybrid PV and CCHP systems could be potentially profitable in California (CA) that has one of the most expensive electric rates in the U.S and also provides incentive programs favorable for distributed and renewable energy systems. The objective of this study is to investigate economic feasibility of implementing the hybrid PV and CCHP system with a grid connection for a representative large office building in CA.

The payback period of such combined system is estimated based on a conventional separated production system where electricity is imported from the grid and heat is produced from a boiler. For the economic analysis, actual electric and gas rates in CA and the market price for each unit of the hybrid systems are used. In this study, the modified following electrical load (MFEL) strategy is applied to operate hybrid PV and CCHP system. The MFEL can determine the required power output of the power generation unit (PGU) accounting for the electricity requirement for the electric chiller that dynamically varies depending on the electrical, cooling and heating loads of the building while avoiding excess electricity production.

In the studied hybrid system with the MFEL, 28% and 66.5% of the annual electrical load of the building is met by PV and PGU, respectively. Only 5.5% of the electrical demand is purchased from the grid. Due to reduced electrical dependency on the grid mostly during the peak time in summer, significant amount of the annual cost saving as much as $965,000 is achieved and finally the payback period of the hybrid PV and CCHP system is 5.9 years. This payback period can be reduced when considering additional incentive programs provided from CA. Therefore, implementing hybrid PV and CCHP systems in CA is cost-competitive to the conventional systems and economically feasible.