An air to air heat exchanger is a closed loop cooling solution with significant cooling capacity. Apart from air circulation fans, it contains no moving parts and energy consumption is extremely low, meaning annual running costs are low. Air to air heat exchangers are available for cooling NEMA 12, 4, and 4X sealed enclosures.
The heart of the air to air heat exchanger is a static heat pipe that transfers heat from the enclosure to the ambient air. The heat pipe, fitted with aluminum fins to improve heat transfer, is evacuated and filled with a special refrigerant. The refrigerant is heated by the air circulating inside the enclosure and vaporizes. The vaporization process absorbs heat from the air. The hot vapor rises to the top of the heat pipe where it’s cooled by ambient air. The vapor then condenses giving up its latent heat to the air. This simple process continually repeats itself.
With a few limitations, the air to air heat exchanger is suitable for most cooling applications. How do you know if an air to air heat exchanger will cool your enclosure?
1. If You’re Looking for Closed Loop Cooling
An air to air heat exchanger is designed for closed loop cooling of a sealed enclosure. It cannot be used in a ventilated enclosure as are filtered fan solutions. However, as the energy consumption is similar to filtered fans, an air to air heat exchanger is a very economical solution for cooling an enclosure that is sealed against dust, pollution, and water.
2. The Thermal Capacity is Appropriate
The thermal capacity of the air to air heat exchanger is related to its size and the temperature difference between the enclosure air and the ambient air. Air to air heat exchangers are rated in watts per degree Fahrenheit, and their capacity is simply calculated by multiplying the heat load in watts by the maximum allowed temperature difference between the enclosure air and the ambient air. Assuming a 20 °F temperature difference, a 40 W/°F air to air heat exchangers can remove 800 watts of heat.
3. The Ambient Air Temperature is Low Enough
It’s vital to appreciate that an air to air heat exchanger acts by removing heat from the enclosure and discharging this heat to cooler ambient air.
This means that the enclosure will always be hotter than the ambient air. The temperature differential between the enclosure and the air temperature is determined by the heat load and the capacity of the heat exchanger. This characteristic limits the use of a heat exchanger to those situations where the ambient air temperature is low enough to ensure that the enclosure temperature is maintained at a temperature within the thermal limits of the equipment inside the electrical enclosure.
Before selecting an air to air heat exchanger, establish the maximum allowable enclosure temperature by assessing the temperature limitations of the equipment in the enclosure and choose a slightly lower temperature that provides a reasonable safety factor. The ambient air temperature used in the thermal calculations should be the peak temperature expected in the applicable location.
4. Your Enclosure is in a Harsh Environments
Air to air heat exchangers are suitable for electrical enclosures located in harsh environments. Models are available with NEMA ratings that protect against dirt and dust, corrosive gases and vapors, rain, and high pressure water hoses. Units can be ordered with corrosion-resistant stainless steel exteriors, and there are units that are approved for use in hazardous areas. All air to air heat exchangers should have UL or similar approvals.
5. You’re Looking for Low Energy Consumption
The most attractive feature of the air to air heat exchanger is its low power consumption. Even larger units only draw about 50 watts, and DC powered models are available that may be energized from low voltage DC power supplies that are often available in electrical enclosures or through the use of solar power.
6. You need a Green Solution
Air to air heat exchangers draw little power yet provide significant cooling. They permit the use of sealed enclosures in situations where there is contamination in the air. Their running costs are negligible and they require virtually no maintenance.
Do you think an Air to Air heat exchanger is the right solution for your application? Contact our Sales Team and find out for yourself how these environmentally friendly devices present an effective and economical solution for enclosure cooling.