摘要
以严寒条件CO_(2)跨临界循环热泵系统为研究对象,采用涡流管技术与二级压缩技术对其进行优化,采用工程方程求解器(EES)软件建立四个热力学模型(单级循环、单级涡流管循环、二级循环、二级涡流管循环),模拟分析了性能系数(COP)、排气温度等参数随气冷压力、蒸发温度、过热度、级间压力的变化规律。研究表明气冷压力变化对严寒条件下优化系统的性能影响最大,在设定的压力变化范围内(7MPa~12MPa),单级循环、单级涡流管循环、二级循环、二级涡流管循环的COP变化幅度分别为74.40%、60.46%、110.38%、90.94%;涡流管技术在低压缩比条件下优化效果更佳,一定条件下,单级涡流管循环较单级循环COP可提高11.2%;二级压缩技术在高压缩比条件下优化效果更好,在最优气冷压力条件下,二级循环相较单级循环COP可提高18.2%,同时二级压缩技术可降低压缩机排气温度,使压缩机保持较高的等熵效率,且存在最优级间压力使得COP达到最大值。结果表明,当总压缩比不大、级间压力处于较低水平或者需要获取更高的第一级压缩出口温度时,通过改变涡流管参数调节过热度效果更好,与二级压缩技术匹配将更有意义。
Taking the CO_(2) transcritical cycle heat pump system under severe cold conditions as the research object,the vortex tube technology and two-stage compression technology are used to optimize the system.Four thermodynamic models(single-stage cycle,single-stage vortex tube cycle,two-stage cycle,and two-stage vortex tube cycle)are established by using engineering equation solver(EES)software.The variation of coefficient of performance(COP),exhaust temperature,and other parameters with gas cooling pressure,evaporation temperature,superheat,and interstage pressure is simulated and analyzed.The change in gas cooling pressure has the most significant impact on the performance of the optimized system under severe cold conditions.Within the set range of stress(7 MPa-12 MPa),the COP change amplitude of the single-stage cycle,single-stage vortex tube cycle,two-stage cycle,and two-stage vortex tube cycle are 74.40%,60.46%,110.38%,and 90.94%,respectively.The optimization effect of vortex tube technology is better under the condition of a low compression ratio.Under certain conditions,the COP of single-stage vortex tube cycle is 11.2%higher than that of single-stage cycle.The two-stage compression technology has a better optimization effect under the condition of a high compression ratio.Under the optimal gas cooling pressure conditions,the COP of the two-stage cycle can be increased by 18.2%compared with that of the single-stage cycle.At the same time,the two-stage compression technology can reduce the compressor’s discharge temperature and keep the compressor at a high isentropic efficiency.There is the optimal interstage pressure to make COP reach the maximum value.It is concluded that when the total compression ratio is small,the interstage pressure is at a low level,or a higher outlet temperature of the first stage compression is needed,it is better to adjust the superheat by changing the vortex tube parameters,and it will be more meaningful to match the second stage compression technology.
作者
吴锋明
李帅旗
李江峰
田佳垚
何世辉
宋文吉
冯自平
WU Feng-ming;LI Shuai-qi;LI Jiang-feng;TIAN Jia-yao;HE Shi-hui;SONG Wen-ji;FENG Zi-ping(School of Energy Science and Engineering,University of Science and Technology of China,Hefei 230027,China;Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences,Guangzhou 510640,China)
出处
《新能源进展》
CSCD
2023年第3期255-263,共9页
Advances in New and Renewable Energy
基金
国家重点研发计划项目(2021YFE0112500)。
关键词
热泵
涡流管
二级压缩
跨临界循环
heat pump
vortex tube
two-stage compression
transcritical cycle
