Transient analysis of thermostatic expansion valves for refrigeration system evaporators using mathematical models

An investigation into the behaviour of a thermostatic expansion valve used to control the refrigerant flow into an evaporator was undertaken using a thermodynamically based mathematical model. The emphasis of the paper is on the behaviour of its sensor, which is a remote bulb charged with a refrigerant liquid/vapour mixture. The model was used to test the influence of simplifying assumptions and to determine the simplest model that could be an adequate representation of the TEV. Possible applications for the simplified models are discussed.