Double-pipe Internal Heat Exchanger for Efficiency Improvement in Front Automotive Air Conditioning System 2007-01-1523

In automotive air conditioning, balancing comfort and fuel efficiency is very important. Vehicle cooling performance improvements during initial cool down has reached a limit in recent years, especially in very hot regions. We have addressed this issue by developing a unique double-pipe internal heat exchanger. In the main discourse, we first clarify the concept of the internal heat exchanger system (IHE) using the temperature difference between the high and low pressure pipes in the refrigeration cycle, and propose the application of an efficient internal heat exchanger. This unique double-pipe internal heat exchanger can easily be manufactured by inserting the inner pipe into the outer pipe and by fixing the pipes at both ends. The length of the IHE is 400mm. This double-pipe internal heat exchanger can increase cooling performance by 5-12% at the equivalent power consumption levels in the same space as a conventional front air conditioner system. The result is an increase in the coefficient of performance (COP) by 10-15% at equivalent cooling performance.