R417A热泵热水器性能及螺旋套管冷凝器换热研究

发布时间：2018-06-14 18:16

本文选题：R417A + 热泵热水器　；参考：《西安科技大学》2017年硕士论文

【摘要】：随着经济的快速发展和人们生活水平的提高,城乡居民生活热水的需求量越来越大,形成了一个量大而面广的热水消费市场。空气源热泵热水器作为一种高效节能装置,在国际市场中占据着重要的位置。利用空气源热泵热水器生产生活热水不仅可以有效的节约能源,而且能够“移峰填谷”,缓解电网紧张状况,因此在国内市场上有着广阔的发展空间和应用前景。热泵热水器运行性能的好坏在一定程度上取决于制冷工质的特性,R417A臭氧消耗潜值ODP为零,且具有节能、环保、高效和替换简单等特点使其已成为良好的R22的替代物,为目前全世界广泛接受的环保制冷剂。冷凝器更是其中的关键部件,它的换热效果直接影响着整个热泵系统的性能。本文搭建了以R417A为工质的空气源热泵热水实验台,冷凝器采用螺旋套管换热器,实验的工况范围为:水的体积流量为0.6～1.0m3/h,螺旋套管的进水温度为20～55℃。在不同的工况下,研究了环境温度为15℃和29℃时,空气源热泵热水器吸热量、系统性能(COP)、压缩机耗功等的变化,螺旋套管内制冷剂R417A的凝结换热特性,制冷工质R417A与R134A、R22在热泵热水器运行性能的对比分析。(1)冷凝器入口水温一定时,冷凝器总换热量、总换热系数随进水流量的增大而增大且环境温度越大换热能力越大。冷凝器进水温度为20℃,环境温度为29℃,进水流量由0.6m3/h增加到1.0m3/h时,总换热量、总换热系数分别增加了约18.8%、20.6%且环境温度为29℃时总换热量和总换热系数平均比环境温度15℃时高5.2%～9.7%、6.4%～11.7%;直流稳态情况下,冷凝器进水温度为17℃,环境温度为29℃,进水流量由0.6m3/h增加到1.01.0m3/h,总换热量、总换热系数分别增加了约23.6%、27.8%且环境温度为29℃比15℃时总换热量、总换热系数分别增加了约7.2%、10.5%。(2)冷凝器入口水温一定时,随着进水流量的增大,压缩机吸排气压力、输入功率、热泵系统的制热量、制热系数COP均增大。进水温度为25℃,环境温度为29℃,当进水流量由0.6m3/h增加到1.0m3/h,压缩机吸、排气压力和输入功率分别减少了 5.1%、16.7%、5.3%,热泵系统的制热量、制热系数COP分别增加了约13.2%、15.2%。环境温度29℃相比较于15 ℃压缩机吸、排气压力分别增加的范围约51.4%～60.8%、11.3%～13.7%,热泵系统的制热量、制热系数COP分别增加的范围约23%～39%、14.6%～23.5%。直流稳态情况下,冷凝器进水温度为17℃,进水流量由0.6m3/h增加到1.Om3/h,环境温度29℃相比较于15℃时吸、排气压力分别提高约21.3%、28.4%,输入功率约提高14.8%。(3)冷凝器进水流量一定时,随着进水温度的升高,压缩机排气压力、输入功率均增大,热泵系统的制热量、制热系数COP减小。进水流量为0.6m3/h,环境温度为29℃,当进水温度由25℃上升到55℃时,压缩机排气压力和输入功率分别增加了 55%、46.4%,热泵系统制热量、制热系数COP分别减小了约54%、58.3%。同时环境温度29℃相比较于15℃时压缩机排气压力平均提高约14.4%～18.7%,热泵系统的制热量、制热系数COP 分别平均提高约 18.4%～31.7%、23.6%～39.5%。(4)环境温度为15℃,螺旋套管内R417A的凝结换热系数随冷凝饱和温度的升高而减小,局部凝结换热系数随干度的增大而增大。当冷凝器进水流量为0.6 m3/h,饱和冷凝温度由40℃增加至60℃时,冷凝器制冷剂侧凝结换热系数从3839W/(m2·K)减小至2372W/(m2·K),约减少了 38.1%。当冷凝器进水流量为0.6m3/h,制冷剂干度由0.7减小至0.1,冷凝饱和温度分别为40℃、50℃和60℃时,R417A的局部凝结换热系数分别减少了 17.5%、24.1%、29.4%。(5)环境温度为15℃,冷凝器进水流量为1.0m3/h,R417A、R134a和R22分别在热泵热水器螺旋套管冷凝器中运行,随着冷凝器进水温度的升高,压缩机吸排气压力及输入功率变化基本一致且R2 2R417 AR13 4 a。螺旋套管换热器入口水温为20～55℃,R417A系统的排气压力比使用R22低3.68%～4.89%,比使用R134a高27.6%～30.9%;R417A的吸气压力比使用R22低14.76%～19.85%,比使用R134a高12.76%～17.85%;R417A系统的输入功率比使用R22低11.76%～15.85%,比使用R134a高 20.76%～26.85%。(6)环境温度为15℃,冷凝器进水流量为1.0 m3/h,三种制冷剂的系统制热量和COP均随热水器螺旋套管换热器进水温度的升高而逐渐减小且制热量R22R417AR134a和COP R134aR22R417A。螺旋套管换热器入口水温为20～55℃,R4117系统的平均制热量相当于R22的88%,R134a系统的平均制热量相当 R417A的74%;R417A系统的COP比使用R22低2.45%～3.76%,比使用R134a低4.6%～7.9%。本文的研究成果对于制冷剂替代中冷凝器的优化设计与热泵系统的节能运行都具有十分重要的理论意义和工程应用价值。
[Abstract]:With the rapid development of the economy and the improvement of people's living standards, the demand for hot water in urban and rural residents is becoming more and more large, forming a large and wide hot water consumption market. As an efficient and energy-saving device, air source heat pump water heater occupies an important position in the international market. The use of air source heat pump water heater to produce life Hot water can not only save energy effectively, but also "shift peak to Valley", alleviate the tension of power grid, so it has a broad development space and application prospects in the domestic market. The performance of the heat pump water heater depends to some extent on the characteristics of the refrigerant, the R417A ozone depletion value ODP is zero, and it has energy saving, Environmental protection, high efficiency and simple substitution have made it a good substitute for R22, which is widely accepted worldwide as an environmental refrigerant. Condenser is a key part of it. Its heat transfer effect directly affects the performance of the whole heat pump system. In this paper, an air source heat pump hot water test bench with R417A as the working quality is built, and the condenser is set up. With the use of spiral casing heat exchanger, the experimental conditions are as follows: the volume flow of water is 0.6 ~ 1.0m3/h, and the inlet temperature of the spiral casing is 20~55. Under the different working conditions, the heat absorption of the air source heat pump water heater, the system performance (COP), the power consumption of the compressor and the refrigerant R41 in the spiral casing are studied under different working conditions. The condensation heat transfer characteristics of 7A, the refrigerant R417A and R134A, R22 in the performance of the heat pump water heater. (1) when the inlet water temperature of the condenser is certain, the condenser total heat transfer, the total heat transfer coefficient increases with the increase of the influent flow and the greater the environmental temperature, the greater the heat transfer capacity of the environment. The inlet temperature of the condenser is 20, and the ambient temperature is 29 C. When the flow of water is increased from 0.6m3/h to 1.0m3/h, the total heat transfer and total heat transfer coefficient increase by about 18.8%, 20.6% and the total heat transfer coefficient and total heat transfer coefficient are 5.2% to 9.7%, 6.4% to 11.7% when the ambient temperature is 29 C. Under DC steady state, the water inlet temperature of the condenser is 17, the ambient temperature is 29, and the influent flow is 0.. 6m3/h increased to 1.01.0m3/h, the total heat transfer, the total heat transfer coefficient increased by about 23.6%, 27.8% and the ambient temperature was 29 C at 15 C. The total heat transfer coefficient increased by about 7.2%, 10.5%. (2) when the inlet water temperature of the condenser was certain, with the increase of the inlet flow rate, the pressure of the compressor, the input power, the heat of the heat pump system, The heating coefficient COP increases. The water inlet temperature is 25 C and the ambient temperature is 29. When the influent flow is increased from 0.6m3/h to 1.0m3/h, the compressor suction, the exhaust pressure and the input power are reduced by 5.1%, 16.7%, 5.3%, the heat of the heat pump system and the heat coefficient COP are increased by about 13.2% respectively, and the 15.2%. environment temperature is 29 centigrade compared to the 15 c compressor. The range of exhaust pressure increased by 51.4% to 60.8%, 11.3% to 13.7% respectively, heat of the heat pump system and the increase of heat coefficient COP were about 23% ~ 39% respectively. Under the steady state of 14.6% to 23.5%., the inlet temperature of the condenser was 17, the influent flow was increased from 0.6m3/h to 1.Om3/h, and the ambient temperature 29 was compared to 15 centigrade, and the exhaust pressure was divided. Do not increase about 21.3%, 28.4%. When the input power is raised about 14.8%. (3) the influent flow of the condenser is certain, with the increase of the inlet temperature, the exhaust pressure and the input power of the compressor are increased, the heat of the heat pump system and the thermal coefficient COP decrease. The flow rate is 0.6m3/h, the ambient temperature is 29 C, when the inlet temperature rises from 25 C to 55 C The exhaust pressure and the input power increased by 55%, 46.4%, heat pump system heat, the heat coefficient COP decreased by about 54%, 58.3%. at the same temperature 29, compared with the compressor exhaust pressure increased by about 14.4% to 18.7%, heat pump system heat, heat coefficient COP increased by about 18.4% ~ 31.7%, 23.6% ~ 39., respectively. When the temperature of 5%. (4) is 15, the condensation heat transfer coefficient of R417A in the spiral casing decreases with the increase of condensation saturation temperature. The local condensation heat transfer coefficient increases with the increase of the dry degree. When the flow rate of the condenser is 0.6 m3/h and the saturation condensation temperature increases from 40 to 60 C, the condensation heat transfer coefficient of the refrigerant refrigerant side condensing agent decreases from 3839W/ (m2. K). To 2372W/ (m2. K), the decrease of 38.1%. when the influent flow rate of the condenser is 0.6m3/h, the dry degree of refrigerant is reduced from 0.7 to 0.1, the condensation saturation temperature is 40, 50 and 60, respectively, and the local condensation heat transfer coefficient of R417A is reduced by 17.5%, 24.1%, 29.4%. (5) is 15, and the influent flow of the condenser is 1.0m3/h, R417A, R134a and R22. In the spiral casing condenser of the heat pump water heater respectively, with the increase of the inlet temperature of the condenser, the change of the suction and exhaust pressure and the input power of the compressor is basically the same, and the inlet water temperature of the R2 2R417 AR13 4 A. spiral casing heat exchanger is 20~55. The exhaust pressure ratio of the R417A system is 3.68% to 4.89% lower than that of the use of the R134a, and 27.6% to 30 higher than that of the use of R134a. The suction pressure of.9%, R417A is 14.76% to 19.85% lower than that of R22, 12.76% to 17.85% higher than that of R134a, and the input power of R417A system is 11.76% to 15.85% lower than that of R22, 20.76% to 26.85%. (6) is higher than that of R134a, and the flow rate of condenser is 1 m3/h, and the system heat and COP of the three refrigerants are all with the spiral sleeve of the water heater. The inlet water temperature of the tube heat exchanger is gradually reduced and the inlet water temperature of the heat exchanger R22R417AR134a and COP R134aR22R417A. spiral casing heat exchanger is 20~55 C. The average heat of the R4117 system is equivalent to 88% of R22, the average heat of the R134a system is 74% of the R417A, and the COP of R417A system is 2.45% to 3.76% lower than the R22, and is more than the use R134a. The research results of low 4.6% ~ 7.9%. in this paper are of great theoretical significance and engineering application value for the optimal design of refrigerant substitute for condenser and the energy saving operation of heat pump system.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU822.2

【参考文献】