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| CO2管翅式蒸发器低温工况下运行的实验研究 |
| Experimental investigation on the performance of finned tube vaporator in transcritical CO2 heat pump water heater |
| 投稿时间：2023-08-08 |
| DOI：10.13259/j.cnki.eri.2025.01.003 |
| 中文关键词: CO2热泵热水机 管翅式蒸发器 低温工况 运行性能 |
| 英文关键词:CO2 heat pump water heater finned tube evaporator low temperature conditions operating performance |
| 基金项目: |
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| 中文摘要: |
| 受低温环境的影响，CO2空气源热泵蒸发器性能不佳，从而使得热泵性能下降。通过实验研究CO2热泵热水机管翅式蒸发器在夏热冬冷地区低温环境下的运行性能，分析了进水温度、进水流量、环境温度和相对湿度对其性能的影响。结果表明：进水参数间接影响蒸发器性能，当进水温度由9 ℃上升至15 ℃时，CO2干度、质量流量均增大，使得蒸发器吸热量减小，从而缓解了结霜导致的蒸发温度降低问题，但机组功耗增大。随着进水流量由80 L/h增加至120 L/h，蒸发温度和蒸发器入口CO2干度均减小，但蒸发器吸热量增大，使得结霜导致的性能恶化情况更为严重。当环境干球温度由–4 ℃上升至4 ℃时，蒸发温度由–9.1 ℃上升至1.6 ℃，且蒸发器与环境的换热温差增大；而相对湿度越大，蒸发温度和蒸发压力越早开始下降且降幅越大。进水流量越小，进水温度越高，则蒸发器吸热量越小；低温高湿工况下空气更容易在翅片管上形成霜层，从而使得蒸发器换热性能恶化。 |
| 英文摘要: |
| The efficacy of CO2 air-source heat pump evaporators is adversely influenced by low-temperature environments, thereby diminishing the overall efficiency of the heat pump system. The performance of a CO2 heat pump water heater equipped with a finned tube evaporator under low temperature conditions in hot summer and cold winter zones was examined in this paper. The influence of inlet water temperature, flow rate, ambient temperature, and relative humidity on the heat pump's performance was systematically analyzed. Results show that the performance of evaporator is indirectly affected by the parameters of the inlet water. Increasing the inlet water temperature from 9 to 15 ℃ enhances the CO2 dryness and mass flow rate, thereby reducing the heat absorbed by the evaporator and lowering the evaporating temperature because of frosting. Consequently, more power is consumed. Increasing the inlet water flow rate from 80 to 120 L/h reduces the evaporating temperature and the CO2 dryness at the evaporator inlet and increases the heat absorbed by the evaporator, which significantly impairs its performance due to frosting. As the ambient dry bulb temperature elevates from –4 to 4 ℃, the evaporating temperature increases from –9.1 to 1.6 ℃, accompanied by an increase in the heat transfer temperature difference between the evaporator and the environment. With higher relative humidity, there is an earlier and more pronounced decrease in evaporating temperature and pressure. A lower inlet water flow rate and a higher temperature result in reduced heat absorption by the evaporator. Under low-temperature and high-humidity conditions, frost formation on the finned tube is more likely, which degrades the heat transfer performance of the evaporator. |
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