双级一次加热式热泵热水机的研究

通过对市场上存在的循环加热式和一次加热式2种传统形式的热泵热水机进行对比分析，发现前者工程系统复杂，且由于系统水泵功耗会造成系统能效下降，而后者虽然工程得到简化，但由于长期高压比工作，能效低下。为此，作者设计出一种高效节能的新型热泵热水器形式——双级一次加热式热泵热水机，既取消了循环泵，保持了一次加热式的工程优势，同时也降低了系统的压缩比，实现了高能效。本文重点阐述双级一次加热式热泵热水机的设计方案、主要性能优势和相关关键技术，通过理论分析和实验验证，得出如下结论：双级一次加热式热泵热水系统与传统单级一次加热式相比，输入功率大幅下降，COP明显提高；双级一次加热式热泵热水系统与循环加热式相比，省却循环水泵的功耗，COP也具有优势。

Research on two-stage direct-heating heat pump water heater

By comparing and analyzing the recycled-heating and the direct-heating heat pump water heaters, which are two main kinds of heat pump water heaters in the market, finds out that the former has a more complicated engineering system and the system＇s energy efficiency is low because of the power consumption of water pump, the latter has a simpler engineering system, however, the energy efficiency is also low because it works under long-time high pressure ratio. Therefore, designs a new heat pump water heater with high energy efficiency--two-stage direct-heating heat pump water heater system. This system dose not use the recycled water pump so that it can keep the advantages of direct-heating engineering system. At the same time,the pressure ratio is decreased in order to realize the high energy efficiency. Emphasizes on the explanation of design scheme, main performance and related key technology of this two-stage direct-heating heat pump water heater. Through theoretical analysis and experiment test, compared with the tradi- tional one-stage direct-heating heat pump water heater,finds that the power input of two- stage direct-heating heat pump water heater reduces largely,while the COP increases evidently;compared with the recycled-heating system, finds that two-stage direct-heating heat pump water heater system also has advantage on COP because it removes power consump- tion of water pumps.