Technical And Economic Analysis Of Gas Combined Cooling Heating And Power System For An Industry Park

Combined cooling heating and power(CCHP) system based on the principle of thermal energy cascade utilization is an efficient, environmentally friendly, high reliability system, with the persistent development of natural gas transport project and more attention in environmental problems, gas CCHP will become an important development direction of China’s future energy techno-logies. How to optimize and increase the technological and economy of the system has become an imperative problem.An industrial park was considered in this paper, firstly, the performance of three district CCHP system schemes based on steam turbine, gas turbine, gas-steam combined cycle unit were compared from the perspectives of cooling system energy consumption and system exergy efficiency. The results show that, compared with electric compression refrigeration system, absorption refrigeration systems based on gas turbine and gas-steam combined cycle unit are all energy saving, the high-pressure steam turbine need to be utilized for the system that take steam turbine as prime mover. Exergy efficiencies of systems based on gas turbine and gas-steam combined cycle units are higher than the system base on steam turbine.Then, a mathematical model of CCHP system based on the gas-steam combined cycle was established to evaluate the CCHP system performance, the effects of unit parameters were discussed. Specific consumption analysis theory was applied to find the weak link in system energy utilization and provide directional guidance for energy conservation improvement. The results show that, the increase of high-pressure steam pressure and decrease of its temperature are conducive to the improving of system fuel energy saving ratio. Low pressure steam parameters have little effect on system performance, but can influence the equivalent thermal efficiency of heat recovery steam gene-rator significantly. Combustion chamber and heat recovery steam generator are the weak links in energy utilization.Finally, applicability of cold and heat source schemes in Changsha was compared from the perspectives of annual primary energy consumption and economic. Compared with conventional central air conditioning systems, district heating and cooling can reduce annual primary energy consumption of cold and heat sources significantly. The cogeneration scheme applied steam absorption chillers and water source heat pumps has the lowest annual primary energy consumption, but its life cycle cost is high. The results are of significance for district CCHP application and generalization.