Kowsky, C., Leitzel, L., Oddi, F., and Wolfe, E., "Unitary HPAC System - Commercial Vehicle Applications," SAE Technical Paper 2012-01-2025, 2012, doi:10.4271/2012-01-2025.
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. When applied to a heavy-duty truck it would provide heating and cooling for the sleeper cab without needing to run the engine. When applied to a hybrid vehicle it improves the electric drive range and reduces fuel consumption costs.This paper will explain what a Unitary HPAC system is and show how it can be applied to commercial vehicles.