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A class of chemical substances called ‘fluorocarbons’ has been used as a refrigerant for transferring heat in car air conditioners (moving the heat outside causes the interior to cool down). A class of five “Specified Chlorofluorocarbons” were first used as refrigerants. They have not been used since 1995 because they destroy the ozone layer in the atmosphere which protects living things from harmful ultraviolet rays, and also have a great impact upon global warming when discharged into the air. Instead of these Specified Chlorofluorocarbons, hydro-chlorofluorocarbons have been used. In recent years, it was discovered that these alternative substances also have an adverse impact on global warming.
DENSO took the view that ‘natural substances can be eco-friendly refrigerants’ and finally decided on CO2. Compared to other currently used refrigerants, CO2 has an extremely low impact upon global warming, only 1/1300 of that for the same quantity of chlorofluorocarbons. In 2002, DENSO developed a car air conditioner with CO2 as a refrigerant for the first time in the world. This air conditioner is equipped on Toyota’s fuel-cell electric vehicle.* |
| *Fuel-cell electric vehicle: A vehicle powered by the electricity generated from hydrogen and oxygen reaction (a fuel-cell) to drive an electric motor. |
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