The A/C compressor aids the movement of the refrigerant for the cab air conditioning system. Although it only operates as required, sleeper compartments require A/C when the truck is parked. The modern air conditioning system for vehicles includes a belt-driven, clutched compressor that takes power from the engine to drive a refrigerant through a closed-cycle system of heat exchangers and valves. The heat exchanger and refrigerant system are designed to remove heat from the passenger compartment of the vehicle and reject that heat through the air conditioning condenser coil that is located in front of the radiator.
The only electrically-driven air conditioning compressors on the market now are ones used for battery APUs and ones that are installed on hybrid-electric transit buses. Currently, none are available or projected for standard on-highway vehicles.
The study team developed a Confidence Matrix, an OEM Availability Matrix and an Engine-driven Accessories Power Use Chart to assist fleets. The Confidence Matrix is designed to inform fleets of the study team’s confidence in the technology being studied vs. the payback the fleet should expect to receive from the technology. Technologies in the top right of the matrix have a short payback, usually thanks to their low upfront cost, and moreover are found to have enough performance data that fleets can be highly confident in those short payback times, usually because the technology is more mature or otherwise has a more substantial track record of results. The OEM Availability Matrix shows the current availability (as of March 2017) of these engine-drive accessories at the various truck builders. The Engine-driven Accessories Power Use Chart shows the various places the energy from fuel is used in a Class 8 truck.