5. ConclusionOur experimental and n

5. Conclusion
Our experimental and numerical works on evaluating the performance of the two common types of evacuated tube solar water heaters for DHW applications have been described. Our experimental results indicate that, for applications in the subtropical climate of Hong Kong, the daily thermal performance of the two-phase closed thermosyphon solar collector is marginally higher thanthe single-phase open thermosyphon design. Numerical system models were successfully developed to analyse the dynamic performance of the two types of thermosphon systems. Then year-round energy performances as applied to single-family DHW system were compared making use of the TMY weather data of Hong Kong and the IEA recommended domestic hot water draw-off pattern. The simulation results showed that the two-phase closed system is slightly better than the single-phase open system. Nevertheless, their payback periods are relatively the same (around 7–9 years) because of the higher first cost of the two-phase closed thermosyphon collector system. With an economical payback period of 6–8 years, the flat-plate collector system can be more attractive for low temperature DHW applications. The evacuated-tube collectors are therefore more suitable for integration with heat pump or absorption chillers to form advanced systems where a higher water temperature is desirable. However, the above recommendations depend very much on the market prices of the solar collectors that could be adjusted from time to time.

結果 (中文) 1:

5。结论
我们的实验和数值模拟研究两种常见类型的真空管太阳能热水器的DHW应用绩效评价了。我们的实验结果表明，在香港的亚热带气候应用，的两相闭式热虹吸管的太阳能集热器的热的日常表现略高于单相开式热管设计。系统数值模型成功地分析了两种类型的热虹吸管系统的动态性能。然后，全年节能性能，适用于单一家庭生活热水系统进行比较，利用香港TMY气象数据和IEA推荐国内热水拉伸模式。仿真结果表明，两相闭式系统是稍微比单相开放系统。然而，他们的投资回收期相对相同（约7–9年）由于对两相闭式热虹吸管的高成本收集器系统。随着6–经济投资回收期8年，平板集热器系统能够更加有吸引力的低温热水的应用。真空管集热器更适合于集成热泵、吸收式制冷机形成先进的系统在一个较高的水的温度是可取的。然而，上述建议在很大程度上取决于可能不时调整的太阳能集热器的市场价格。

結果 (中文) 2:

5.结论
我们实验和数值模拟工作业绩评价的真空管太阳能热水器的两个常见类型为描述了 DHW 的应用程序。我们的实验结果表明，为香港，亚热带气候中的应用两相封闭热虹吸管太阳能集热器的每日热性能是稍高的比单相开放热虹吸管设计。成功地制定了数值系统模型来分析两种类型的 thermosphon 系统的动态性能。然后全年能源性能适用于单户 DHW 系统比较香港和国际能源署的天气数据利用 TMY 建议国内热水牵引模式。模拟结果显示两相封闭的系统是略好于单相打开系统。然而，他们的回收期相对是相同的 （约 7-9 岁) 由于两相封闭热虹吸管集热器系统的第一次费用较高。与 6 至 8 年的年限-平板集热器系统可以对低温 DHW 应用程序更具吸引力。真空管集热器，因此更适合与热泵或吸收式冷水机组，形成先进的系统位置较高的水温度是可取的集成。然而，上述建议很大程度取决于市场价格的太阳能集热器，可以不时调整。