热力站多级涡旋热泵参数优化及变工况运行调节

Parameter optimization and off-design operation strategy of multistage scroll heat pumps in heating station

多级涡旋电动压缩式热泵可以将一次网回水温度降低到15℃,增加供热能力。在三级热泵结构中,采用一次水等温降的分级方式,热泵总COP达到最大值5.62;而采用等排量方式时,总COP为5.41,相比最大值降低了3.7%,但更便于进行压缩机的改进设计。实验结果表明,初步改进后的压缩机等熵效率比原型机有了明显提高,但仍有进一步改进空间。采用压缩机启停控制的质调节方式,能够使供热温度保持在理论值±2.5℃范围内,可以满足热用户的需求。

Multistage scroll heat pumps can reduce the primary return water temperature to 15 ℃, and increase the heating capacity as well. In the three-stage structure of heat pumps with primary water temperature dropping equally, the total COP reaches maximum value of 5. 62. While in the equal displacement mode which is easier for improving the design of the compressor, the total COP is 5.41, only declines by 3.7% compared to the maximum value. The experimental results show that the isentropic efficiency of the preliminary improved compressor is significantly higher than that of the prototype, but there is still room for further improvement. By means of quality regulation with the compressor starting and stopping control, the heating temperature can be kept within± 2.5 ℃ difference from the theoretical value, which can satisfy the heating demand of heat consumer.