Air to Air Heat Exchangers
Air to air heat exchangers are closed loop systems that use heat pipes filled with a special refrigerant liquid to transfer excess heat from an enclosure to the ambient air outside. Controlling the temperatures inside of electrical cabinets prevents malfunctions and extends the life of sensitive components.
All A2A heat exchanger units carried by ISC Sales are available in NEMA type 12, 4 and 4X and can be configured for hazardous locations Class 1, Div 2, Groups B, C, D.
or browse models below.
- 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 120VAC, 230VAC, 24VDC, 48 VDC
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 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 Fahrenheit, 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 airflowon 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 airtight seal between the two air systems.