基于电子膨胀阀开度的直膨式太阳能热泵过热度智能控制  

Intelligent control of degree of superheat for direct-expansion solar-assisted heat pump based on electronic expansion valve opening

作　　者：孔祥强[1] 董山东 姜开林 唐雪山 李瑛[1] Kong Xiangqiang;Dong Shandong;Jiang Kailin;Tang Xueshan;Li Ying(College of Mechanical and Electronic Engineering,Shandong University of Science and Technology,Qingdao 266590,China)

机构地区：[1]山东科技大学机械电子工程学院,青岛266590

出　　处：《农业工程学报》2018年第12期230-235,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(51776115);山东省研究生导师指导能力提升资助项目(SDYY17037);山东科技大学研究生导师指导能力提升计划资助项目(KDYC17009);山东科技大学研究生科技创新基金资助项目(SDKDYC170331)

摘　　要：针对直膨式太阳能热泵系统的运行控制问题,提出了一种基于电子膨胀阀开度的过热度控制策略,主要包括电子膨胀阀初始开度算法和过热度控制算法,通过对试验数据进行拟合,得到了电子膨胀阀初始开度与太阳辐射强度和环境温度的函数关系。设计并搭建了以制冷剂R134a为工质的直膨式太阳能热泵热水器试验平台,主要由裸板式太阳能集热/蒸发器、滚动转子式压缩机、微通道冷凝器、蓄热水箱和电子膨胀阀等组成。控制系统采用单片机作为主控制器,单片机与数据采集控制器之间采用RS485总线方式通讯。在此平台上,对提出的过热度控制策略进行了全工况测试。试验结果表明:在系统开机后的25 min内,过热度有效控制在目标范围5~10℃内;在系统正常运行阶段,过热度控制平稳,最大超调量小于4℃。所提出的全工况过热度控制策略有助于系统稳定高效运行。The idea of the combination of heat pump and solar energy has been proposed and developed by many researchers around the world. Solar energy can be used to heat the refrigerant in the evaporator of a heat pump, by employing a solar collector as the evaporator, which is called a direct-expansion solar-assisted heat pump（DX-SAHP） system. Solar energy is intermittent and unstable, and it has significant effect on the thermal performance of a DX-SAHP system. How to develop a control strategy to match environmental parameters with operating parameters under various operating conditions is critical for the system performance. Aiming at the operation control of the system, a DX-SAHP system was designed and built in Qingdao China, which could supply domestic hot water in a whole year. The system mainly consisted of a bare solar collector/evaporator with area of 1.56 m2, a rotary-type hermetic compressor with rated power of 400 W, an electronic expansion valve（EEV）, and a micro-channel aluminum flat tube condenser with single surface area of 0.435 m2 surrounding a 195 L water tank. The system was charged with 800 g of R134 a. The temperature was measured with the platinum resistance thermometers（PT100, with grade A accuracy）. The pressure was measured by using pressure transducers with uncertainty of 0.1%. A pyranometer with sensitivity of 8.145 μV/（W/m2） was placed to measure the solar radiation intensity. The degree of superheat at the outlet of solar collector/evaporator was regulated by the EEV with full stroke of 500 steps. The control system was based on microcontroller. The opening of the EEV was regulated actively with the controller which communicated with a microcontroller. The output from the platinum resistance thermometers, the pressure transducers and the pyranometer was collected by a data acquisition logger at 5-second interval. The data acquisition logger transmitted the experimental data to the microcontroller via RS485. Based on the degree of superheat at the outlet of the solar collect

关 键 词：热泵 太阳能 温度 直膨式 控制策略 过热度 电子膨胀阀 单片机 

分 类 号：TK11[动力工程及工程热物理—热能工程]