Abstract
Vapor-compression systems are still the most widely used type of automotive cooling systems despite their high energy consumption and negative environmental effects. This article gives a review of the carried out developments and the future trends for this type of automotive air-conditioning systems which have served vehicle occupants for more than 50 years. After going over a brief historical progression of the system, the circulating refrigerant developments were presented. Only few refrigerants meet the imposed attributes (e.g. zero ozone depletion potential, low global warming potential), and CO2 as well as R1234yf have a big potential to be the future refrigerants. Then, the developments related to the other major system components were outlined. In this context, the future trends show that the scroll compressor besides the evaporator and the condenser having parallel flow and micro-channels are the most promising for the next generation of (air-conditioning) systems. Concerning the control of the compressor and the expansion device, the advanced electronic control is the most attractive for the future systems. This is due to its provision to better improvement for the air-conditioning system performance. The present vapor-compression air-conditioning systems still have some weaknesses despite their eminent achieved improvements. Models developed for air-conditioning systems still have some shortcomings (e.g. low accuracy). Also, the test procedures for air-conditioning extra fuel consumption are still not worldwide in all aspects. Therefore, more efforts should be made to solve these problems.