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This paper will examine the various design and performance criteria for optimized internal heat exchanger performance as applied to R134a and HFO-1234yf systems. Factors that will be considered include pressure drop, heat transfer, length, internal surface area, the effect of oil in circulation, and how these factors impact the effectiveness of the heat exchanger. The paper describes the test facility used and test procedures applied. Furthermore, some design parameters for the internal heat exchanger will be recommended for application to each refrigerant.

The purpose of this article is to study current refrigerant emission levels in China with reasonable accuracy of the first year vehicles. This is an initial survey on refrigerant irregular emissions based on JD Power investigation and warranty data from OEMs in 2008. Totally 49 brands and 8881 vehicles were included for the study, covering almost all the kinds of passenger vehicles in China market. Irregular emissions represent the refrigerant losses due to accidents and other environmental-related failures of the mobile AC system. This paper also wants to draw people's attention on irregular refrigerant emissions related to system design and reliability which is not focused yet. According to the calculation of irregular emissions from China vehicles by J.D Power result, the irregular emission is 5.8 g/yr, which can be a reliable number used in the GREEN-MAC-LCCP© model for China vehicles' refrigerant emissions.

The European f-Gas Directive phases out HFC-134a from Mobile Air Conditioning systems (MACs) in new vehicles by 2017. In the US pending California and USEPA regulations have incentives to phase out HFC-134a earlier than 2017. As a result industry is striving to transform all global markets to a single new refrigerant in order to simplify global marketing. One of the global tools to help evaluate alternatives during this transition is the global LCCP (Life Cycle Climate Performance) and the development of the GREENMAC- LCCP© model. This model has become the global standard to measure the Life Cycle Analysis (LCA) greenhouse emissions of any proposed alternative refrigerant for MACs starting from bench test results and supporting the car manufacturer choice of the best suitable alternative refrigerant from an environmental perspective.