Vapor injection, R410A, Heat pump, Post expansion
The performance of the two types of vapor-injection (VI) cycles in a heat pump system is compared. The vapor-injection cycle using an internal heat exchanger (IHX) has a choice to select the branching point of the injection stream. The two VI cycles are different in terms of branching points of the injection stream. Different branching points of the injection stream influence the heating capacity and the COP of the heat pump system. Especially, at a given geometry of the IHX, the PEVI (post-expansion vapor-injection) cycle can increase the inject-able mass of the injection stream as well as heating performance.