KARIYA, Japan DENSO Corp., parent company of Long Beach-based DENSO Sales California has developed the world’s first refrigeration cycle system for passenger vehicles that uses an ejector. The system is used for both an air conditioner and cooler box and is installed on Toyota Motor Corp.’s Land Cruiser, launched in Japan in September. This system will also be installed in the Land Cruiser launched in October in North, Central and South America, Asia and other regions throughout the world.
The car air conditioner and cooler box use the same refrigeration cycle. In a conventional refrigeration cycle, a solenoid valve switches between refrigerant flow for cooling in the air conditioner and refrigeration in the cooler box, which effects air conditioning performance when the cooler box is used. In contrast, the new system eliminates the solenoid valve and uses a small refrigerant injector called an ejector instead of an expansion valve, which allows cooling via the car air conditioner and refrigeration through the cooler box simultaneously.
By using an ejector that rapidly injects and expands high-pressure refrigerant, the energy that previously was lost in the expansion valve is converted to pressure energy and reused, thus boosting energy efficiency. As a result, high cooling and refrigeration performances are both achieved even when the cooler box is used.
“An ejector system can drastically improve the energy efficiency in the refrigeration cycle, and we are now working to develop a system specifically for car air conditioning systems,” said Hikaru Sugi, managing officer in charge of DENSO’s Thermal System Business Group.
In 2003, DENSO was the first in the world to introduce an ejector system, which was installed in refrigeration units for refrigerated vans. This system is also used for a carbon dioxide refrigerant heat-pump water heater for households.