Design and Operation of a Hybrid CCHP System Including PV-Wind Devices

CCHP systems based on internal combustion engines have been widely accepted as efficient distributed energy resources systems. CCHP systems can be efficient mainly because that the waste heat of engines can be recovered and used. If the waste heat is not used, CCHP systems may not be beneficial choices. PV-wind systems can generate electricity without fuel consumption, but the electric output depends on the weather, which is not reliable. A PV-wind system can be integrated into a CCHP system to form a higher efficient energy system. Actually, a hybrid energy system based on PV-wind devices and internal combustion engines has been studied by many researchers. But the waste heat of the engine is seldom considered in the previous work. Researches show that, 20∼30% energy can be converted into electricity by a small size engine while more than 70% is released. If the waste heat is not recovered, the system cannot reach a high efficiency. This work aims to analyze a hybrid CCHP system with PV-wind devices. Internal combustion engines are the prime movers whose waste heat is recovered for house heating or driving absorption chillers. PV-wind devices are added to reduce the fuel consumption and total cost. The optimal design method and optimal operation strategy are proposed basing on hourly analyses. Influences of the device cost and fuel price on the optimal dispatch strategies are discussed. Results show that all of the excess energy from the PV-wind system is not worth being stored by the battery. The hybrid CCHP system can be more economical and higher efficient in the studied case.