Guest contributor: Eric Corzine, Product Manager Climate Control, Rittal
Heat exchangers provide highly efficient cooling for electrical components. As energy costs increase, they are getting more consideration by system designers. Before making a design decision between air-to-air and air-to-water heat exchangers, it is important to weigh installation considerations and use-cases. Here, we have provided an overview of each technology to help you determine which can best impact your equipment and your bottom line.
Air-to-air heat exchangers are the most common type of exchangers. They work by utilizing the difference between the hotter internal temperature of an enclosure and the cooler, ambient air temperature. Engineers can implement air-to-air exchangers in a variety of industrial environments, including food and beverage, waste and wastewater, and automotive.
Air-to-air exchangers can utilize existing airflow patterns, through convection or forced air, and do not require additional accessories or equipment. The technology can utilize the airflow within an enclosure or can connect to existing ductwork and HVAC systems.
There are some limitations to air-to-air heat exchangers, particularly in the climates they could be installed. For instance, if the difference between indoor and outdoor temperatures is to great then the effectiveness of the exchangers can be significantly reduced. Recent technology upgrades, however, have made air-to-air exchangers functional even in climates that reach temperatures of -13°F.
These factors make air-to-air heat exchangers useful in applications where plumbing for liquid cooling would be difficult to install, and where existing air flow patterns and equipment layout allow for effective cooling. Often, this means situations with moderate thermal loads. HVAC engineers can install them quickly as well, which reduces setup time and costs. However, they are still less efficient compared to air-to-water exchangers because air is not as effective at transferring heat as water.
Air-to-water heat exchangers use the same principle of temperature differential to provide heating or cooling, however, they alter the temperature of air by forcing it across water coils.
Because of the efficient heat transfer capabilities of water, they can help reduce energy use and utility costs significantly. This is especially useful in situations with large thermal loads, such as IT mainframe applications or an automotive manufacturing environment where water is already available.
One of the drawbacks of air-to-water heat exchangers is the need to pipe water to the unit. The technology requires plumbing and a reliable water supply or recirculation system, which often means pumps, valves, and other accessories.
These plumbing concerns often mean higher installation costs, so engineers need to balance the initial cost with the expected savings over the lifetime of the exchanger. Overall, air-to-water exchangers are useful for high-demand, energy intensive applications.
Making the Right Choice
It is important to consider the right exchanger for your specific climate control situation. The ultimate decision will balance installation and operational costs, target cooling capacity and thermal loads.
Air-to-air exchangers can get up and running quickly and engineers can integrate them into many different kinds of applications easily. Air-to-water exchangers deliver better efficiency and can suit more energy-demanding applications, but they require plumbing and water supplies, which may not always be available. The ultimate choice, then, should consider these factors and engineers should thoroughly research both types of exchangers to understand which one will best suit their application.
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