Indirect evaporative coolers use the same principle as direct coolers. Water evaporates, the air cools, and a fresh breeze is expelled. There are zero chemical compounds involved in either equipment makeup. There is, however, one patently obvious difference between them. In that indirect cooling equipment, a heat exchanger separates the input and output stages. Simpler by design, direct evaporative coolers don’t incorporate complex thermal transferring mechanisms.
Indirect Evaporative Coolers Use Heat Exchangers
Traditionally, heat exchangers are used in boiler systems to convert thermal loads. A solid vessel wall separates the two differently heated water streams, so the dual thermal loads never mix; they transfer their thermal energies. Cooling systems also use heat exchanger technology. Only, this time around, the cooling circuit uses a waterside coil, which is piped to a specially contained open-ceiling area. Cooling towers use this design to keep large spaces chilly. There are benefits to using this overcomplicated system architecture, of course, but there are also drawbacks. For starters, there’s all of the water sprays and wet tubes to maintain. They need to be conditioned all the time so that microbial growths cannot gain purchase within a system that emits breathable air. Left unconditioned, respiratory illnesses, including Legionnaires Disease, can spread. Direct evaporative coolers are less complex, more mobile, and typically more efficient than indirect cooling equipment, which requires much more maintenance.
Indirect Evaporative Coolers: Full of Self-Contained Advantages
Since outside air doesn’t enter a building directly, there’s no need to worry about outside humidity. The heat exchanger stage effectively eliminates that possibility. The air cools when it passes through the waterside coil. Sprays and water currents evaporate and absorb the thermal energy. The cooled water from this coil passes into a structure, where it’s further cooled. Passed through ducts and blown by circulating fans, the cool air is fresh and humidity-free. It’s sort of like a central air conditioning system, this indirect cooling technology, with its chemical-less build ensuring an environmentally friendly heat management system. Better yet, the equipment, which incorporates a humidity-isolating design, is efficient and viewed as a financially attractive air conditioning substitute.
All the same, even though there are no CFCs to worry about when using indirect evaporative coolers, there are still the water conditioning chemicals to purchase and mix. With direct evaporative cooling, the heat management effect can be localized far more effectively. Better yet, without heat exchangers, the directly cooled equipment is easier to maintain and simpler to design. Using those features, a streamlined portable model, one that uses a directly cooled layout, can go anywhere to immediately deliver its more efficiently generated air chill.