The Science of Misting Fans
The towering Pyramid of Giza and the reputed fame of the Hanging Gardens of Babylon remind us that the ancient civilizations of Egypt and Persia left us with rich architectural and engineering feats that baffle the modern imagination in their complexity and sophistication. Indeed, in addition to constructing vast monuments to the God's, these pre-industrial societies turned their considerable talents to the development of technologies designed to provide comfort in inhospitable climes. Specifically speaking, when one contemplates the climate of northern Africa and the Middle East, the number one impression that people walk away with is one of a region that is both hot and dry. That impression is not wrong.
These ancient dwellers transformed their abodes into cool, relaxing oases of comfort. Using what were known as wind catchers, these intrepid people installed wind shafts on their roofs, which caught the wind before passing it over subterranean water of a qanat, a series of well-like vertical shafts connected by sloping tunnels, before discharging the cooled air throughout the rest of the building. The idea of an evaporative cooler saw its first modern usage and application only in the 1960s.
The beginning of the 20th-century witnessed the beginning of patent applications for evaporating coolers, but widespread usage of the misting fan and electric fan only began receiving widespread consideration over the past three decades. In that time, the concept of the misting fan has received wide currency at outdoor venues from rock concerts to the sidelines of sporting events.
Science of the Misting Fan
Anyone who has ever attempted to "beat the heat" by sitting in front of an electric fan with a wet cloth over their head has taken advantage of the properties of evaporative cooling. The standard misting fan operates on the principle of thermal dynamics and evaporative cooling. The science of how a misting fan works is pretty basic, however.
When liquid evaporates, it has the physical affect of cooling the air immediately around the area. When latent heat, the amount of atmospheric heat that is required for liquid to evaporate, is drawn from the air, the cooling effects can be quite dramatic in the affected area.
The key index in determining the effectiveness of an evaporative cooling system is found in the difference between dry-bulb and wet-bulb temperatures. The former measures the temperature of the air, and is considered the "true" temperature of the surrounding air, while the latter, the wet-bulb temperature, is indicative of the temperature of a parcel of air were it to be cooled to saturation via relative humidity. Indeed, the wet-bulb temperature is the lowest temperature that the air can reach through evaporation alone, and is determined by the actual air temperature (dry-bud) and the amount of moisture in the air.
Gaining the cooling advantages of a misting system begins with water. High-pressure pumps, creating pressure upwards of a thousand pounds per square inch (PSI), is pushed through small sized nozzles that restrict the outward flow of water thus creating a fine thin mist. As soon as the water hits the hot air, the droplets evaporate and pull the heat energy from the surrounding areas, creating a comfortable zone that overheated people immediately flock to for comfort. Often times, an electric fan will be used to blow the cold air and mist over a wider range.
A professional-grade misting fan, typically propelled by an electric fan, creates a mist of minimal moisture that evaporates upon touching an available surface. In the same way that a foggy morning will result in a cool feeling on the skin, so too will the moisture of the misting fan provide comfort to people within a designated area. Normally filtered for impurities, the water used in such a system will only draw approximately one to two gallons of water per hour.
Materials, Maintenance, and Cost to Operate
Portable misting fans deliver an excellent solution for area cooling coverage whether it is at a local concert venue, or set up on the back patio on summer afternoons. As an example, the Luma comfort misting fan offers an array of features for the backyard warrior who is looking to cool down his or her pool area.
Typically speaking, a unit like the Luma comfort misting fan, for instance, offers portability and dependability of operation. Easy to assemble, such units combine the typical attributes of an electric fan coupled to a water disbursement system that provides an added measure of comfort, which a misting fan brings to an overheated environment.
Manufactured with rust-resistant material, in order to glean the maximum effectiveness from a personal misting fan, regular maintenance is not only recommended but also required. Towards that end, regular cleaning is imperative to maintaining the lifespan of the misting fan.
As such, maintain that fan in the following ways:
- Always unplug the misting fan from the power supply prior to conducting any maintenance
- Clean the exterior of the fan using a soft cloth and mild soap. Harsh chemicals such as gasoline, paint thinner, and the like can cause damage to the unit
- Completely dry all components before reconnecting the power supply
- When not in use for extended periods, it is recommended that the unit be covered and stored in a clean, dry place
Cleaning the Misting Nozzles
There is nothing quite as frustrating as a misting nozzle, which is not delivering enough mist. The chances are good that sediment has clogged the nozzles. Should that be the case, follow these steps to get the flow going again:
- Turn off the fan and disconnect the water supply. Gently tapping a screwdriver against the nozzles should dislodge any accumulated sediment
- Failing that, remove the nozzles and leave them to soak on a bowl of vinegar or household lime and scale remover for a half an hour. Heavier deposits might necessitate a longer soaking time and scrubbing with a stiff brush.
- DO NOT clear misting fan nozzles with sharp objects as this can damage the unit
Fan does not turn on
Power cord is not plugged in
Ensure that the plug is plugged into an outlet, and hit the reset button on the GFCI plug
No mist is coming from the nozzles
The water hose is not connected to a water supply, or nozzles are clogged
Make sure the electric fan is connected to spigot of garden hose, and clean nozzles as directed above
Water is leaking from water hose
Connections are not tightly secured
Make sure the fan's components are securely connected
Produces uneven mist
Insufficient water flow or leak in the water hose
Adjust the water flow from the source. If that fails to produce results, turn off the misting function and check for any air leaks in the hose
A Low Cost Way to Cool your Home
A properly managed and maintained misting fan is a highly effective and affordable way to provide instantaneous comfort in the effective area. As mentioned, using less than two gallons of water per hour, and drawing only the electricity needed to power an electric fan, a misting fan is an excellent solution for the scorching heat of summer. For those looking to cool down their home without overheating their budget, a well-maintained misting fan is a great way to go.
Venues and Geography
As mentioned, misting fans have been widely used at sporting events and entertainment venues for the past 30-years when temperature spikes threaten the health of event participants through heat exhaustion. The cooling mist provided by these systems is excellent for providing a cooling refuge that lowers the temperature and provides immediate relief against stifling heat. Additional venues include:
- Pool parties
- Family gatherings
- BBQ parties
- Local fairs
- Swap meets
Additional industrial applications include:
- Green house agriculture
- Livestock care
The natural evaporative cooling that a misting fan provides replicates the body's natural deterrent to heat exhaustion: perspiration or sweat. As mentioned above, the key indicator of evaporative cooling system effectiveness is rooted in the relationship between dry and wet bulb temperatures, and as such misting fans operate best in conditions of high heat in the air and low humidity.
These conditions are found throughout the southwest United States. Indeed, from Denver to Salt Lake City to Phoenix and Tucson, and all points in between the use of misting fans is widespread in the battle to keep their overheated populous cool and comfortable when summer temperatures skyrocket.