With the development of telecom technology in 1990's, air to air plate heat exchangers are widely used in cooling enclosed outdoor cabinets, telecom rooms and big computer centers. As one of the leading manufacturers of air to air heat exchangers, cabinet air conditioners and BTS compact air conditioners, we are concentrating on researching and developing air to air plate type heat exchanger technology. In the 21st century, power demand is increasing. Energy saving and environmental protection are recognized by people. Air to air heat exchangers are used for building ventilation such as commercial centers, houses and office buildings in order to exchange fresh air and heat recovery. In summer, air to air heat exchangers can collect cool energy from exhausted air and pre-cooling inlet hot air. In winter, our air to air heat exchangers can collect heat energy and preheat inlet air. Our