DENSO Develops World's First Passenger Vehicle Refrigeration Cycle System Using an Ejector
—Achieves High Cooling and Refrigeration Performance—
KARIYA (Japan) – DENSO Corporation 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 (vehicle refrigerator) and is installed on Toyota Motor Corporation’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*1, 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*2. 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.
DENSO Corporation, headquartered in Kariya, Aichi prefecture, Japan, is a leading global supplier of advanced technology, systems and components. Worldwide, the company employs approximately 112,000 people in 32 countries and regions, including Japan. Consolidated global sales for the fiscal year ended March 31, 2007 totaled US$30.6 billion. DENSO common stock is traded on the Tokyo, Osaka and Nagoya stock exchanges in Japan. For more information, go to www.globaldenso.com or visit our media website at www.densomediacenter.com.
*1. In the conventional refrigeration cycle, the refrigerant is cooled by outside air while it passes through the condenser. An expansion valve further cools the refrigerant by expanding it in the decompression process.
*2. Cooling capacity per power consumption. A larger value indicates higher efficiency.