You may be aware of the various benefits of spot cooling-- these portable units are compact air conditioners, very versatile and can cool many applications. What you may not be sure of is whether you'd be better off with a refrigerated spot cooler or an evaporative spot cooler. Understanding how each one works will better prepare you to make the best decision when purchasing or renting a spot cooler.
Refrigerated Spot Coolers
The most popular spot coolers run on the same refrigerant cycle as -- you guessed it -- refrigerators. Basically, they work through a mechanism in which a refrigerant chemical is pumped through the device by a compressor in order to change it from liquid to gas. This gas then absorbs heat moisture (humidity) from the air and then turns back into a liquid. The resulting heat is discharged from the condenser through a duct that needs to be ducted out of the space you are cooling -- usually into the suspended ceiling or out a window.
Because refrigerated spot coolers work by removing excess moisture from the air, this "excess moisture" becomes condensate which drains into a tank to be emptied or into a condensate pump to be automatically pumped to a drain or condensate line.
Personal spot coolers, manufactured primarily for residential comfort cooling, evaporate the condensate over the heat of the condenser coil into the exhaust air from the condenser. Although these are great for residential cooling where the condenser air is ducted out a window, you probably wouldn't want to use this type of spot cooler in a commercial application since that moist condenser air would be ducted into the area above the suspended ceiling.
Refrigerated spot coolers are a great choice anywhere but especially for equipment cooling as in data centers, LAN rooms and for telecommunications equipment. Since they dehumidify the air, these spot coolers are particularly useful in moist climates with high humidity, such as the southeastern United States.
Evaporative Spot Coolers
Evaporative coolers, also referred to as "swamp coolers", operate under another method of spot cooling. Rather than using vapor-compression or absorption refrigeration systems like refrigerant spot coolers, evaporative coolers do just as their name suggests. They work by evaporating water as the hot air passes over a moist pad. These units can offer significant cooling in the temperature of dry air and require considerably less energy than refrigerated spot coolers.
Evaporative spot coolers offer a special perk in dry climates, where the process actually adds moisture to the surrounding air making it more comfortable for users. Unlike refrigerant spot coolers, they require a constant source of water and must steadily consume water to do their job.
Evaporative spot coolers are best suited for comfort cooling in hot and arid climates. In the United States, such as the western Rocky Mountain states like Colorado, Arizona, New Mexico, and some parts of California. They are also popular systems in some factories, warehouses, industrial plants, greenhouses, and laundries or dry cleaners.
Spot Cooler Takeaway
With either system, spot cooling has wonderful benefits, especially for cooling small spaces or satisfying temporary and emergency cooling needs. Once you've chosen the type of unit that is best for you, you won't be disappointed with the results.