Simulation And Economic Analysis Of Heat Recovery Hot Water Supply System

Energy saving is imperative because serious energy problems are associated with central air-conditioning while it supplies occupants comfort environment. As everyone knows, cooling water carries away a lot of condensing heat while chiller produces cold. And the heat generally releases to outdoor air through the cooling tower. Not only wasting a lot of heat, but also having a tremendous effect on the environment, causing serious heat island effect. In such a central air-conditioning system, installing energy efficient heating unit-heat pump and preparing hot water by recovering condensing heat has got more concern.Combined system simulation with control, taken TRNSYS as the simulation platform, an air-conditioning system with heat recovery digital emulator was built. And then the models of the system has been separately introduced, such as chiller, cooling tower, variable speed pump, water-to-water heat pump, flow diverter and mixer and so on. The unknown parameters have been identified by using the parameters of samples provided by manufacturers and empirical value came from related studies. And after adjusting the control parameters, a complete system model was established at last.Then taken TRNSYS as the simulation platform, simulated each component's power consumption, performance parameters and the amount of heat recovery at the typical day in summer (21 July). Based on principles of technical economics and thermal economics, the simulation results have been analyzed by using heating cost, investment payback period and internal rate of return. After the three kinds of domestic hot water preparation programs have been compared in economics, a conclusion that using condensing heat recovery prepare hot water is feasible in economically was got.Finally, this paper simulated water-to-water heat pump in condensing heat recovery system with TRNSYS, and used orthogonal method to analyze the influence factors of heat pump. Then the paper summarized that the important factors of heat pump performance is evaporation and condensation side inlet water temperature. After the different temperatures and flow rates had been handed with orthogonal method and the performance parameters of heat pump had been analyzed in different operating mode, the paper summarized the parameter values of heat pump under the best operating conditions. Then establish multiple linear regression model of heat pump using regression. All of these provide a certain basis for system control and temperature setting.