Coordinated heat and power system and its energy saving and economic evaluation

The rate of CHP plants has been rising continuously in Northern China, together with the growth of wind power. Due to traditional operating ways of Heat-Load-based CHP plants, the problem of wind power abandonment in Northern China in winter has become more and more serious. A new coordinated heat and power central heating system is carried out in this paper, which contains absorption heat pumps, compression heat pumps and thermal storage tanks. Heat pumps are used to recover waste heat which plants discharge. Power plant’s wasted heat can be fully recovered by heat pumps, so as to raise the thermal efficiency of the heating system. Thermal storage tanks are used both at power plants and heating stations. With thermal storage tanks, power plants can reduce its power output when the load is low, so as to leave space for wind power generator. And heat pumps at heating station can consume surplus wind power at valley hours and consume less power at peak hours. Thermal storage tanks are used to maintain the stability of heat supply and the stability of waste heat recovering. Mathematical models for evaluating energy saving and economic availability is built. According to the results, thermal efficiency is raised, surplus wind power is consumed during valley hours and economic efficiency is improved.