For sake of getting more passengers, the subway station is always located at down town. In order to meet setting demand of cooling tower and not to destroy urban landscape, it is very difficult to find an appropriate location to install cooling tower. Hence, there is an impatient need to find an efficient heat exchanger to substitute the cooling tower, move the cooling tower into the subway station and solve the problem that there is no place for installing the cooling tower of the underground buildings. Th...