Briefs: First MAC system using an ejector

Denso Corporation has developed the world's first passenger mobile air-conditioning system that uses ejector technology. The ejector, which is a small refrigerant injector, was installed on the new Prius introduced by Toyota in May 2009. According to Denso, the new air-conditioning system reduces the compressor's power consumption by up to about 25%, compared with conventional car air-conditioning systems. In conventional air-conditioning systems, an expansion valve is used to reduce the pressure of the refrigerant before passing it through the evaporator to cool the air. This new system uses an ejector instead of an expansion valve. The ejector recovers expansion energy, which was previously lost in the expansion valve, and converts it into pressure energy. This reduces the compressor's workload and helps reduce the air conditioner's overall power consumption. Denso has applied ejector technology to truck refrigeration units and household CO2 heat-pump water heaters. Previously, the conventional ejector was not small enough to be installed in vehicle air conditioning systems. This problem was solved by integrating the ejector into the evaporator tank, where refrigerant flows.