James Allen Baker

R-152a Refrigeration System for Mobile Air Conditioning

In recent years, climate protection has become as important as ozone layer protection was in the late 1980s and early 1990s. Concerns about global warming and climate change have culminated in the Kyoto Protocol, a treaty requiring its signatories to limit their total emission of greenhouse gases to pre-1990 levels by 2008. The inclusion of hydrofluorocarbons (HFCs) as one of the controlled substances in the Kyoto Protocol has increased global scrutiny of the global warming impact of HFC-134a (called R-134a when used as a refrigerant), the current mobile air conditioning refrigerant. Industrys first response was to begin improving current R-134a systems to reduce leakage, reduce charge, and increase system energy efficiency, which in turn reduces tailpipe CO 2 emissions. An additional option would be to replace the current R-134a with a refrigerant of lower global warming impact. This paper documents the use of another HFC, R-152a, in a mobile A/C system. It compares its cooling and energy performance with that of a comparable R-134a system. This paper also highlights the environmental benefit of R-152a and pinpoints safety issues that need to be addressed in the future.

Experimental Evaluation of R134a Emission with Various Hose Constructions

The focus of this paper is to understand, from experimental data, the R134a refrigerant emission rates of various hose materials due to permeation. This paper focuses on four main points for hose assembly emission of R134a: (1) characteristics of hose permeation in response to the effect of oil in R134a and the characteristics of hose permeation of vapor vs. liquid refrigerant; (2) conditioning of the hose material over time to reach steady state R134a emission; (3) the relative contribution of hose permeation and coupling emission to the overall hose assembly refrigerant emission; (4) transient emission rates due to transient temperature and pressure conditions. Studies include hoses with different materials and constructions resulting in various levels of R134a permeation.