Abstract: A sealed cabinet is provided for housing heat generating electronic equipment. The sealed cabinet includes access doors which sealingly engage the cabinet in a closed position and a head space within the cabinet and above the doors for housing a heat exchanger. The heat exchanger includes longitudinal air channels, and transverse air channels, the channels formed by a stacked arrangement of longitudinal convoluted fins and transverse convoluted fins, each separated from the other by a heat conductive sheet. Outside air access to the heat exchanger is provided by louvered openings in opposite faces of the cabinet. The heat exchanger is sealed into the head space to keep outside air separated from air within the sealed cabinet. Fans force outside air through the longitudinal air channels and air within the sealed cabinet through the transverse air channels.