TOKYO -DENSO Corporation has developed a unique double-pipe internal heat exchanger for a car air conditioning system, increasing cooling performance by up to 12 percent. DENSO is the first to develop the double-pipe internal heat exchanger for a front air conditioning system that needs to be installed in a limited space. The air conditioning system was introduced this year in the Middle and Near East on the Toyota Prado and in North America on the Lexus GX470.