Mathematical Model And Experimental Investigation Of Heat Pump Water Heater System With Waste Heat And Air Energy

The major problem in China's energy issues is the low energy utilization ratio which leads to the low efficiency and severe environmental pollution.The effective solutions for China's energy situation will enhance people's awareness of environmental protecting and energy saving.Industrial waste heat can be divided into high temperature,medium temperature and low temperature according to temperature grade in our country.The technology of the waste heat recovery on high temperature and medium temperature has been mature.While over 50% of low temperature waste heat with temperature blow 150? causes a low energy utilization ratio and serious environmental pollution,which is due to the deficiency of the technology of waste heat recovery and the lacking of equipment.It is found that there is a huge amount of waste heat resources for us to fully utilize in our country.Though it's a complicated process,the recovery of low temperature waste heat would help to promotes energy saving,environmental pro tection and economic income.As air-source heat pump water heater uses the air which is a kind of renewable energy,thus the recovery of low temperature waste heat discharged by pharmaceutical equipment can be achieved.Combined with the system mathematica l model based on the research of air-source heat pump water heater,the optimum temperature and the rational range of air quantity can be calculated by simulation calculation,and then the stimulation results can be verified through the building of experimental platform on waste heat recovery system.The main contents are presented as follows:(1)The influence of condensation,evaporation temperature,sub cooling and superheating on the theoretical cycle of air-source heat pump system and the actual cycle process of the system are analyzed.A simplified analysis model of air-source heat pump water heater system is established,and the effective energy efficiency and loss of the system in using four kinds of working fluids(R22?R134a?R407C?R410A)are theoretically compared,which helps to give suggestions for the optimization of the following system.(2)Combined with the existing research on air-source heat pump,a method of coupling mass,energy and momentum can be given to solve the model by establishing a simple mathematical model of compressor,condenser,evaporator and electronic expansion valve without considering the influence of internal pressure drop in the system pipeline.(3)Through solving the mathematical model,the optimal temperature and air volume range for recovering waste heat of the air energy heat pump water heater are 45?and 4500m3/h respectively.and the dynamic performance parameters of the air-source heat pump water heater are obtained under different compressor rotating speeds,condensing temperatures,cold water inlet temperatures and flow conditions.(4)The operating performance parameters of the ai r-energy heat pump water heater under different waste heat temperature,air quantity and cold water inlet temperature are tested on an experimental platform,and then the actual changes such as pressure ratio,exhaust temperature,power consumption,heatin g capacity and COP are also obtained.Then the error between simulation and experiment value is compared to verify the correctness of the established mathematical model,which is helpful for the following further research on the issue of waste heat recovery.