基于余热回收的燃气热泵性能及控制系统

Performance and control system of gas engine heat pump based on waste heat recovery

燃气热泵(gas engine-driven heat pump,GHP)具有环境适应性强、能效高、耗电量少等优点,能够解决一次能源利用率低、资源浪费和环境污染等问题。当前研究重点是通过模拟和实验方法开展燃气热泵的运行特性研究,而忽略了控制系统。控制系统是燃气热泵的重要组成部分,对于保障机组高效、稳定运行至关重要。本文提出一种嵌入式控制系统,监控GHP冷热水机组(gas engine driven heat pump cold-hot water equipment,GHPW)。详细阐述了多输入输出控制模块、发动机控制模块、蒸发温度控制模块、人机交互模块等燃气热泵核心控制模块的设计原则和方法。通过实验验证了GHPW的运行性能,实验结果表明,控制系统能够准确、稳定地控制机组,实现快速制冷/制热。通过主控制器对发动机转速和蒸发温度的双闭环控制,实现对系统出水温度的稳定性和准确性控制。当环境温度较低时,由于回收发动机余热,GHPW系统的制热能力优于EHP(电热泵)系统。随着环境温度从-20℃上升到7℃,实验系统的制热量从52.94kW逐渐上升到105.87kW,系统一次能源利用率(primary energy ratio,PER)从0.819上升到1.489。发动机余热回收显著提高了系统制热能力和PER。

Gas engine-driven heat pump(GHP)has the advantages of strong environmental adaptability,high efficiency and low electricity consumption.It can solve the problems of low primary energy utilization,waste of resources and environmental pollution.Current research focuses on the operational characteristics of GHP systems,while neglecting design of the control system.A control system is very important to ensure efficient and stable operation of GHP systems.In this study,an embedded control system was proposed to monitor gas engine driven heat pump cold-hot water equipment(GHPW).The design principles and methods of the core control modules were described in detail.The operational performance of experimental system was tested by experiments.Experimental results indicated that the control system could monitor the experimental system accurately and stably,and rapid cooling/heating and precise temperature control could be realized.Through double closed-loop control of the main controller on engine speed and evaporator superheat,the stability and accuracy of the outlet water temperature could be achieved.When the ambient temperature was low,heating capacity of GHP systems was better than that of EHP systems due to recovery of engine waste heat.As the ambient temperature rises from-20℃to 7℃,heating capacity of the experimental system gradually improved from 52.94kW to 105.87kW,and primary energy ratio(PER)of the system steadily increased from 0.819 to 1.489.The recovery of engine waste heat improved heating capacity and PER of the experimental system.