24 June 2014
With the advent of high efficiency residential heat pump systems, achieving even higher seasonal efficiency is becoming more complex and incremental in nature. For this
reason, component modifications that provide improvements of even a few percent can become very attractive. If these component level improvements can also provide secondary
benefits, such as a reduced bill of materials or more compact packaging, the likelihood of acceptance and market penetration becomes high. One example of such a component level
improvement is the novel integration of a stepper motor controlled electronic expansion valve with the distributor for a multi-circuited round tube plate fin heat exchanger. This paper
describes the experimental validation of the potential improvements in seasonal performance achieved by implementing this novel electronic expansion valve design into a high efficiency reversible 3-ton air-residential heat pump system. The implementation of this technology led
to increases of 3% in HSPF.