Effects of cooling water flow rate of auxiliary condenser on performance of closed heat pump drying system

doi:10.16085/j.issn.1000-6613.2020-0814

Abstract

Abstract:

In view of the current situation of high energy consumption and environmental pollution for the metal cleaning and drying processes in industrial filed, a closed heat pump drying system with a direct series auxiliary condenser was established. The effect of cooling water flow rate through auxiliary condenser on the operating parameters of the system was experimentally studied. These operating parameters included operating conditions of the system, heating/cooling capacity, power consumption, COP (coefficient of performance), MER (moisture extraction rates) and SMER (specific moisture extraction rates). The results showed that when the cooling water flow rate was 30.6kg/h, the condenser outlet air temperature reached 72.8℃. And with the increase of cooling water flow rate of auxiliary condenser, the heating/cooling capacity, power consumption, condenser outlet temperature and MER all decreased, while COP was remained at 5.6. The highest MER and SMER were 3.80kg/h and 1.44kg/(kW·h), respectively. The change trends of MER and SMER were opposite as the increase of cooling water flow rate of auxiliary condenser, so the influence of cooling water flow rate needs to be comprehensively considered in practical production. Besides, under the experimental conditions, the maximum cooling water outlet temperature was 65.2℃, and hot water for industrial production could be provided and energy could be recovered. The research results can provide new ideas and references for the application of closed heat pump drying system in the metal cleaning and drying processes and its energy conservation.

Key words: drying, heat pump, auxiliary condenser, heat transfer, specific moisture extraction rates, system performance

摘要：

针对目前工业生产中金属件清洗干燥工艺中常用干燥方式存在能耗高且环境不友好的现状，提出并建立了一种采用直接串联式辅助冷凝器的闭式热泵干燥系统。基于所搭建的性能测试台，实验研究了流经辅助冷凝器的冷却水量这一关键参数对系统运行工况参数、制热/制冷量、系统功耗、性能系数（COP）以及单位时间除湿量（MER）和单位能耗除湿量（SMER）等性能参数的影响。结果表明：冷却水量为30.6kg/h时，冷凝器出风温度达72.8℃；随着冷却水量的增大，系统制热/制冷量、功耗、冷凝器出风温度及MER均呈现下降趋势，COP维持在5.6左右；MER最高可达3.80kg/h，SMER最高可达1.44kg/(kW·h)，MER和SMER的变化趋势相反，故生产实际中需要综合考虑冷却水量对两者的影响；另外，在实验研究工况下最大冷却水出水温度达65.2℃，可为工业生产提供可应用的热水，使能源得到充分地回收利用。研究结果可为闭式热泵干燥系统在金属件清洗干燥工艺中的应用及其节能降耗提供新的思路和参考。

关键词: 干燥, 热泵, 辅助冷凝器, 传热, 单位能耗除湿量, 系统性能

CLC Number:

TK173

WANG Jing, WU Weidong, WANG Hao, LI Zhenbo, LIU Hui. Effects of cooling water flow rate of auxiliary condenser on performance of closed heat pump drying system[J]. Chemical Industry and Engineering Progress, 2021, 40(3): 1307-1314.

汪静, 武卫东, 王浩, 李振博, 刘荟. 辅助冷凝器冷却水量对闭式热泵干燥系统性能的影响[J]. 化工进展, 2021, 40(3): 1307-1314.

Figures/Tables 9

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仪器	型号	量程	精度
热电偶	T形	-40~125℃	±0.5℃
湿度传感器	HMT120	0~100% RH	±2.5%相对湿度（RH）
压力传感器	PTX5072	0~6MPa	±0.1%量程
风速仪	FLUKE923	0.2~20.00m·s^-1	±0.01m·s^-1
功率计	8967B	0~30kW	±0.4%读数+0.1%量程
精密电子天平	JM-B30002	0~4000g	±0.2g

仪器	型号	量程	精度
热电偶	T形	-40~125℃	±0.5℃
湿度传感器	HMT120	0~100% RH	±2.5%相对湿度（RH）
压力传感器	PTX5072	0~6MPa	±0.1%量程
风速仪	FLUKE923	0.2~20.00m·s^-1	±0.01m·s^-1
功率计	8967B	0~30kW	±0.4%读数+0.1%量程
精密电子天平	JM-B30002	0~4000g	±0.2g

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