A system for cooling heat-generating objects, such as computer boards situated in a rack, includes an enclosure in which the heat generating objects are situated. The enclosure has an air inlet and an air outlet, and a fan induces airflow into the air inlet, through the enclosure and out the air outlet. A heat exchanger is situated in the enclosure such that the heat exchanger is in a spaced apart relationship with the heat-generating object. Air moving through or past the heat-generating object is warmed, and the heat exchanger removes the heat before the air exits the enclosure.