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浙江大学学报(工学版)
J4  2011, Vol. 45 Issue (2): 217-221    DOI: 10.3785/j.issn.1008-973X.2011.02.004
    
Simulation of thermal performance on unglazed solar
collector for refrigerant
KONG Xiang-qiang, ZHANG Dong, LI Ying, YANG Qian-ming
College of Mechanical and Electronic Engineering, Shandong University of Science and
Technology,Qingdao 266510,China
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Abstract  

In order to analyze an unglazed solar collector’s thermal performance, a distributed parameter and homogeneous flow mathematical model was established based on the direct expansion solar assisted heat pump water system. The overheated and two-phase regions were compartmentalized by enthalpy difference from refrigerant outlet to inlet. And the heat transfer and heat balance equations for the inner and outside of tube were set up. With dichotomy iterative calculation of tube length, the model was solved. Theoretical calculation was carried out to analyze refrigerant phase change and the influences of structural, operational and environmental parameters on solar collector efficiency. Simulation results indicate that refrigerant dryness of two-phase region changes linearly approximately; solar collector efficiency increases evidently with increases of environmental temperature and solar collector thickness. However, solar collector efficiency decreases with increases of solar radiation intensity, water temperature and the distance between collector tubes. The increase of collector tube diameter has little effect on solar collector efficiency.

Published: 17 March 2011
CLC:  TK 519  
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Cite this article:

KONG Xiang-qiang, ZHANG Dong, LI Ying, YANG Qian-ming. Simulation of thermal performance on unglazed solar
collector for refrigerant. J4, 2011, 45(2): 217-221.

URL:

http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2011.02.004     OR     http://www.zjujournals.com/eng/Y2011/V45/I2/217


制冷剂工质裸板太阳能集热器热性能模拟

为了对裸板太阳能集热器进行热性能分析及优化设计,建立其分布参数均相流动数学模型.该模型基于直膨式太阳能热泵热水系统,利用换热管内、外换热方程和热平衡方程,对过热区和两相区按焓差均分进行划分,采用二分法以换热管长为迭代判据进行求解.通过理论计算分析集热管内制冷剂状态变化和结构参数、运行参数、环境参数对集热器集热效率的影响.模拟结果表明:两相区制冷剂干度变化近似为线性；室外环境温度升高和集热板厚度增大可显著提高集热器集热效率；太阳辐射强度、水箱水温和集热管间距增大使集热效率降低；增加集热管内径对提高集热效率作用不大.

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