<div class="section abstract"><div class="htmlview paragraph">This paper will examine a mobile air conditioning (MAC) system optimized for efficiency as well as evaporator cooling capacity. Different internal heat exchanger (IHX) capacities and various thermostatic expansion valve (TXV) parameters will be applied using R1234yf refrigerant. Factors that will be considered include IHX heat transfer and pressure drop, TXV superheat setting and slope, the effect of oil in circulation and how these factors impact the efficiency and capacity of the MAC system. The paper describes the test facility used and the test procedures applied.</div></div>