A circulation pump is used to continuously pump up the water form the water pan, and spray it onto the evaporating curtain evenly through a water dispense system. This water takes heat from the air that is coming form the exterior. Therefore the water gets heat and evaporates, while the air loses heat and cooles down. After that, the cooled clean air is compressed and distributed into the interior by the low noise motor, meanwhile the stuffy interior air is sent out by the system, through which to achieve a cooled interior environment .