Effects of load following operational strategy on CCHP system with an auxiliary ground source heat pump considering carbon tax and electricity feed in tariff

Abstract

Combined cooling, heating and power (CCHP) system plays a significant role in efficient usage of energy in field of small scale power system for application ranging from residence to utilities. In the paper, a new CCHP system is proposed which consists of a power generation unit (PGU), an absorption chiller, a storage tank and a ground source heat pump (GSHP) to substitute conventional electric chiller and auxiliary boiler to supply the deficient cooling or heating load. In the study, three basic load following strategies: following electric load (FEL), following thermal load (FTL) and following hybrid load (FHL) are employed to analyze the annual total cost (ATC), operational cost (COST), carbon dioxide emissions (CDE) and primary energy consumption (PEC) based on a case study of a regional energy system in Sino-Singapore eco-city. For the evaluated case, carbon tax and electricity feed in tariff are both considered to compare with the performances of following maximum electric efficiency of the PGU (Max-eff) strategy. The results show that the proposed system performed well on COST, CDE and PEC reduction and the ATC are all increased except that of Max-eff strategy with carbon tax and electricity feed in tariff. When carbon tax and electricity feed in tariff are considered, performances of the Max-eff strategy is the best. Otherwise, the application of FEL is better. Finally, for the Max-eff and FEL strategy, sensitivity analysis is performed and results are presented with varying of electricity and gas price.