真空管型太阳能热水器与中温集热器热性能研究

发布时间：2019-01-02 14:51

【摘要】：随着我国城镇化的不断发展,建筑能耗在全社会能耗中所占比例不断增加,推广太阳能热利用技术在民用建筑中的应用,是实现建筑节能减排,促进可持续发展的有效途径。本课题对全玻璃真空管型太阳能热水器和中温真空管型太阳能集热器两种典型太阳能热利用装置的热性能进行了模拟和实验研究,并对太阳能热利用系统在民用建筑中的应用效果评价方法进行了研究。首先,通过理论分析确定了影响全玻璃真空管型太阳能热水器热性能的主要因素。设计全玻璃真空管型太阳能热水器的热性能实验方法并研制开发了太阳能热水器热性能实验检测装置。通过实验分析了单位面积容水量、真空管管间距、真空管长度、保温厚度等参数对全玻璃真空管型太阳能热水器热性能的影响,发现以上参数中单位面积容水量对日有用得热量和日平均效率影响最大,单位面积容水量每增加10kg/m2,日有用得热量增加0.53~1.56MJ/m2,日平均效率增加3.1%~9.2%。将实验结论应用到太阳能热水器改进中取得了良好的效果,证明实验结论可用于指导全玻璃真空管型太阳能热水器的设计和开发。其次,以直流式真空管型中温太阳能集热器作为典型中温太阳能集热器,采用控制容积平衡法建立了集热器的热性能模型并开发了迭代求解方法。随后研制开发了中温太阳能集热器热性能测试装置,利用该测试装置对某厂家生产的直流式真空管型中温太阳能集热器进行实验,并与模拟结果进行对比发现,模拟得到的截距比实验值高0.0426,相对偏差约5.9%,热损系数增加了0.2140℃/(W·m-2),相对偏差约5.6%。所建立的模型得到了实验验证,可用于直流式真空管型中温太阳能集热器热性能的分析研究。再次,利用验证后的模型及其求解方法,模拟分析了影响中温真空管型太阳能集热器热性能的主要因素,发现真空集热管的吸热板和玻璃外管间的辐射换热是造成热损失的主要原因。因此提出了在吸热板背部增加遮热板的方式提高中温真空管型太阳能集热器的热性能。对改进后的集热器进行实验,得到其瞬时效率曲线为*??0.7763?1.8617T,比改进前截距升高了约7.2%,热损系数大幅下降了50.9%。说明增加遮热板对于降低直流式真空管型中温太阳能集热器的热损失,提高集热器的热性能具有明显作用。最后,本研究提出了更为适用的太阳能热利用系统评价方法,并应用该方法对工程实例进行测试和评价。该评价方法均衡考虑了技术、经济、环保指标,为太阳能热利用系统的设计和运行提供了参考,有助于推广太阳能热利用系统在民用建筑中广泛、合理地应用。
[Abstract]:With the development of urbanization in China, the proportion of building energy consumption in the whole society is increasing. It is an effective way to realize energy saving and emission reduction of building and promote sustainable development by popularizing the application of solar energy thermal utilization technology in civil buildings. In this paper, the thermal performance of two kinds of typical solar energy utilization devices, all-glass vacuum tube solar water heater and medium-temperature vacuum tube solar collector, are simulated and experimentally studied. The evaluation method of application effect of solar thermal utilization system in civil buildings is also studied. Firstly, the main factors affecting the thermal performance of all-glass vacuum tube solar water heater are determined by theoretical analysis. The experimental method of thermal performance of all-glass vacuum tube solar water heater was designed and the thermal performance test device of solar water heater was developed. The effects of water capacity per unit area, vacuum tube spacing, length of vacuum tube and thickness of heat preservation on the thermal performance of all-glass vacuum tube solar water heater are analyzed experimentally. It is found that the capacity per unit area has the greatest influence on the daily available heat and the daily average efficiency, with the increase of 10 kg / m2 per unit area and 0.53% 1.56 MJ / m2 per day. The daily average efficiency increased by 3.1 and 9.2. The experimental results have been applied to the improvement of solar water heaters. It is proved that the experimental conclusions can be used to guide the design and development of all-glass vacuum tube solar water heaters. Secondly, taking the direct current vacuum tube type medium-temperature solar collector as the typical medium-temperature solar collector, the thermal performance model of the collector is established by using the control volume balance method and the iterative solution method is developed. Then, a test device for the thermal performance of medium-temperature solar collector is developed. The test device is used to test the direct-current vacuum tube type medium-temperature solar collector produced by a factory, and the results are compared with the simulation results. The calculated intercept is 0.0426 higher than the experimental value, the relative deviation is about 5.9, the heat loss coefficient is increased by 0.2140 鈩，

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