Development of world’s first passenger vehicle Air conditioning system using ejector technology
Denso Corporation a leading global supplier of advanced technology, system and components made an announcement on development of world’s first passenger vehicle air conditioning system that uses ejector technology. The ejector is a small refrigerant injector contributing to an overall reduction in power consumption. This newly developed system will be installed on the new Prius which was introduced by Toyota this month. The new air conditioning system is capable of reducing the compressor’s power consumption by up to about 25 percent in comparison to the conventional car air conditioning systems resulting in a fuel savings according to the company. Most of the consumed energy by air conditioning system is by the compressor to compress the refrigerant. Unlike the conventional air conditioning system where an expansion valve is used to reduce the pressure of the refrigerant before passing it through the evaporator to cool the air, Denso’s new air conditioning system uses an ejector. Through the use of ejector, the system is able to recover the expansion energy which was previously lost in the expansion valve and then convert this expansion energy to pressure energy resulting in reduction in compressor’s workload and air conditioner’s overall power consumption. Denso has already used the ejector technology in truck refrigeration units and household CO2 heat-pump water heaters but the size of the conventional ejector was a prohibiting factor in its installment in vehicles air conditioning systems. Denso has managed to reduce the size of the ejector by integrating the ejector into the evaporator tank where refrigerant flows eliminating any needs for a thicker structure ejector to withstand external pressure at the same time the new design eliminates pipe connection parts which is required to connect the ejector to the evaporator. The ejector cycle system evaporator (ECS evaporator) which is equivalent to the size of a conventional evaporator can be applied to conventional air conditioning systems.