How does the EVI heat pump compressor work?

Question

Accepted Answer

Copeland EVI Scroll compressors are equipped with a vapor injection connection for Economizer Operation. Economizing can be accomplished by utilizing a subcooling circuit similar to the circuit shown in Figure 1. This increases the refrigeration capacity and the system efficiency. The benefits provided will increase as the compression ratio increases.

The schematic shows a system configuration for the economizer cycle. A heat exchanger is used to provide additional subcooling to the refrigerant before it enters the evaporator. This subcooling process provides the increased capacity gain measured in the system. During the subcooling process, a certain amount of refrigerant is evaporated. This evaporated refrigerant is injected into the compressor and provides additional cooling at higher compression ratios.

The P-h diagram (Figure 2) shows the theoretical gain in system performance acquired by using the economizer cycle. The extension outside of the vapour dome provides the enthalpy increase, enhancing system performance. Although power increases due to the vapour injection into the compressor, there is still a significant efficiency gain because the capacity gain exceeds the power increase.

(The above content is from EVI Theory of Operation by EMERSONSON Climate Technologies)

With the EVI heat pump compressor technology, the EVI heat pump is able to work down to -25℃ the minimum. It works efficiently in heating to provide stable and comfortable heating or hot water for our house.