Every year there seems to be more and more outdoor events. Whether attending festivals, concerts or planning a private wedding, more people are enjoying their time outside. As Spring and Summer approach you may be asked by one of your customers, “Which is the best way to cool off my outdoor event, portable misting fans or evaporative coolers?”

Passive Cooling System (Evaporative Cooler)

The most common kind of passive cooler works by moving air flow through a water soaked evaporation pad. This operates with a reservoir at the base of the unit from which water is pumped to the top of the unit. The water cascades down this evaporator pad via gravity. A fan in front of the unit pulls air though the soaked pad, thus cooling the air—somewhat similar to a car radiator. These systems are often referred to as evaporative coolers, swamp coolers, desert coolers or wet air coolers.

Besides the bulkiness of these units, the major drawback to this method is that the dampened pad will easily collect dirt, mold, minerals, debris, and allergens. The fan system pulls the cool air through these pads and then blows contaminate everywhere. Evaporative Coolers will also give off a swampy odor and the problems associated with the bad air quality, hence the name, “swamp coolers.” Because of this, evaporative coolers must be drained and cleaned often. Pads need to be cleaned once a month or more and replaced at least once a season. Individuals suffering asthma may need to avoid evaporative cooled environments with poor maintenance.

This “recycled” water also gets warm as it is collecting heat from the air. After a while the reservoir of warmed water diminishes the effective cooling ability of the system.

A couple other things to consider with evaporative coolers:

• Even though evaporative coolers recycle dirty water they require a direct water hook-up to operate.
• Evaporative coolers take up a large footprint of floor space. This is important to realize when your customer is typically leasing space that could be designated for an extra dining table or larger dance floor.
• Noisy when operating.
• Fans blow at floor level, which unsettles dust disturbing and blowing up into the air

Active Cooling System (HydroMist™ Misting Fans)

Hydromist Flash Evaporation Cooling Systems use an active method of cooling air, which does not reuse potentially dirty water.
Fresh water is drawn from a source and then double-filtered (10 microns and 5 microns) before use. A 1000psi pump forces the water through impeller-driven vaporizing nozzles. This high pressure and nozzle combination produce a very fine vapor which quickly evaporates—in fact it flash evaporates when introduced to moving air. This action requires energy, which is obtained by drawing heat out of the air, thus cooling the air dramatically (up to 30° F.) Since the water evaporates so quickly, the result is cooled air without creating a damp environment.

This active cooling method is effective up to 90% humidity in open/ventilated environments, without increasing local humidity. With enclosed/unventilated environments, such as greenhouses, humidity levels can be increased.

Active cooling also diminishes the level of outdoor pollens, dust, and smoke. Unlike passive cooling, the mist will actually limit the pollutants and odors in the air.

Other benefits of outdoor “active cooling” misting fans:

• Uses Fresh Water only
• Portable misting fans are extremely mobile and easy to transport, making a small footprint
• Self Contained units do not need a permanent water source
• Very quiet when operating.
• Fans blow elevated dry mist away from floor and oscillate for better air distribution
• Very energy efficient
• Attractive and non-obtrusive design.