Internal/ External mounted Air-to-Air Heat Exchanger is ideal for situations where the electronic controls operate at a temperature differential slightly above the ambient. Advance Cooling Systems P Ltd offers Internal/ External mounted Air-to-Air Heat Exchanger. Advance Cooling Systems P Ltd is an ISO 9001:2000 awarded company. Advance Cooling Systems P Ltd also offers wide ranges of heat exchangers, water chiller, oil chiller etc. Internal/ External mounted Air-to-Air Heat Exchanger incorporate a closed loop design that circulates air through the enclosure and cooling unit to maintain the desired enclosure air temperature, without outside air contamination.