Our Air to Air Heat Exchanger is a closed loop cooling system which employs the heat pipe principle to exchange heat from an electrical enclosure to the outside. Where ambient temperatures are suitable for heat pipes, they are the most efficient method of cooling as the waste heat is the engine which drives the system. The only power requirement is to operate two circulating fans or blowers. UL/cUL Listed; File No. SA33327.
ISC Features
- All units are available in NEMA Type 12, 4 and 4X
- Hazardous Location (Class 1, Div 2, Groups B, C, D) configuration available for all units
- Closed Loop & Filterless Operation
- Full use of insulation to preserve the cold fraction
- Deliberate use of physical isolation of coil from casing where we want to transfer heat
- Deliberate use of contact between coil and casing for another increment of heat transfer to the enclosure environment
- Available in 120V, 230V, 24VDC
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Heat Exchangers VS Filtered Fans
View A2A Installation&Operations Manual
Heat pipes have a liquid refrigerant under a partial vacuum inside sealed tubes. They operate with a phase change process which is much like that of mechanical air conditioning, but without the compressor. Each heat pipe has an evaporator section and a condenser section which are separated by a permanent baffle so as to provide a closed loop.
The bottom of each heat pipe is in contact with heated air from the electrical enclosure. When the enclosure air reaches approximately 75 degrees F., the refrigerant changes to vapor phase (boils) and the vapor (steam) rises to the top of the tube which is in contact with cooler outside (ambient) air. When the outside air temperature is lower than the enclosure temperature, the refrigerant vapor gives up heat to the outside air and returns to the liquid phase. It then falls to the bottom and repeats the cycle endlessly so long as there is a negative temperature differential between the enclosure and outside. Heat pipes will not operate in reverse cycle so heat cannot be transferred from the ambient to the interior of the enclosure.
Our design has a top-to-bottom enclosure air flow pattern with maximum separation of the inlet and outlet. This design pulls the hottest air from the top of the enclosure and returns the cooled air from the bottom of the heat pipe to the enclosure. The air flow on the ambient side is bottom in, top out, so that the hotter discharge air moves up and away rather than being recirculated.
As with all of our coil systems, we use aluminum end plates and baffles which improve conduction and reduce corrosion for longer life. The center aluminum baffle, which is swaged into the heat pipe coil, provides an air tight seal between the two air systems.


Notes:
- Heat Tubes utilize a methanol filled tube to prevent freezing and increase efficiency
- Design efficiency: 200 BTUH is gained from a single 16″ tube
- 11°C = 20°F
Watts/°C Delta is difference between ambient and enclosure temperature; with ambient always being lower. All units are rated in degrees C and degrees F


