Comparative Study on Heating and Cooling Systems Integrated with Energy Storage

Taking a commercial building in Shanghai as an example, a list of cooling and heating systems are established and operation strategies are formulated. Based on the precondition that the excess electricity can be sold to the grid, the primary energy utilization rate and economices of the energy supply schemes are analyzed. The results show that compared with the traditional heating and cooling supply method, the combined cooling, heating, and power systems have better energy-saving and economic benefits. Additionally, the inclusion of the thermal energy storage yields additional economic benefits (up to 36% reduction in the CO2eq emissions and up to the 21% reduction in the total annual cost). Under the following-electric-load operation mode, the role of the thermal energy storage is to alleviate the temporal mismatch between the electric demand and the heating or cooling demand. To be specific, in the combined cooling, heating, and power systems, the total annual cost is reduced by up to 5.8% and the annual carbon dioxide equivalent emissions are reduced by up to 2.4% when the thermal energy storage is used. While under the following-electric-price operation mode, the performance of the CCHP system is largely subject to the natural gas price. Last, although heat pump systems are often regarded as efficient systems owing to the relatively high coefficient of performance of the heat pump, the energy supply through the heat pump systems may be carbon-emission-intensive currently.