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The Unitary HPAC (Heat Pump Air Conditioner) System has been developed to enable a heat pump system in passenger vehicles. Unitary HPAC uses technology of reversing the coolant instead of refrigerant to distribute heat from where it is generated to where it is needed. Integrating this system in a plug-in hybrid vehicle reduces the energy required by the heating and air conditioning system, reducing the grams of CO₂ per mile by up to 25%. Although this system can be applied to any passenger vehicle, it is most beneficial to hybrid and electric vehicles, because it provides an additional source of hot coolant. These vehicles provide less waste heat than conventional internal combustion engine vehicles so they must rely on electric heaters to provide the heat needed for comfort. The electric heaters are an energy draw that reduces the electric drive range. The Unitary HPAC system will extend the electric range significantly.

The thermal systems of commercial vehicles are changing to reduce operational costs and tailpipe CO₂ emissions and to address anti-idling legislation. As these systems transition they must recognize that waste heat from the internal combustion engine can longer be the only means of providing hot coolant for heating. The Unitary HPAC (Heat Pump Air Conditioner) provides the hot coolant needed for heating in addition to cold coolant that can be used for cooling. The Unitary HPAC is a refrigerant system that is coupled with a coolant system. It produces hot and cold coolant that is used to manage the vehicles thermal needs. It has the ability to scavenge heat from unused sources, which allows it to provide heating with COP's (Coefficient of Performance) greater than 1. The Unitary HPAC can be applied to any vehicle that does not have enough hot coolant available for heating purposes.

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.