Evaporative Cooling: Cooling through the evaporation of water
Water absorbs heat when it evaporates. It’s basic physics. Water requires more energy to be in the state of a gas than it does to be in liquid form. So when it evaporates, it actually uses or absorbs energy (in the form of heat!) from the air.
Ever notice that you get a chill for a little while after you get out of the pool, even on a warm day? Why is it cooler being outside of the water than in it? It’s the evaporation going on. As the water evaporates it makes both the water and air around your skin cooler.
High Pressure Misting takes it to the next level
With misting you are using the same principle. Only without the wetness! Most of the time wetness is a problem on patios, floors, tables or people. Its fine when you’re swimming, but when you’re having lunch on the patio? Or working on the warehouse floor? No.
That’s where the pressure comes in. If you pressurize the water enough using a high pressure misting pump, you can create a fine enough mist that it will completely evaporate into the air almost instantly. When you introduce that air into your space you are physically taking heat from the air with every tiny droplet that evaporates. When you are talking about millions of droplets per second, you can really do a lot of cooling with this technique. With a misting pump producing 1000psi in pressure, this is the powerful cooling you will get.
How much cooling can you expect?
The cooling effectiveness of any evaporative cooling system depends on the starting temperature humidity of the air. You can still achieve solid cooling in more humid areas, but the systems go the next level in really dry air. Keep in mind when you are considering your humidity that you need to determine what the humidity will be in the afternoon…when temperatures rise and humidity levels drop. The TV or radio weather report normally quotes the highest humidity of the day. But when you will be using your misting system, it is typically after it has warmed up and relative humidity levels have dropped. So the highest number of the day is not helpful. This link provides great historical climate data including afternoon humidity levels. Just enter your zip code and check July or August numbers in your area…
Patio Misting System Strategies
2 Approaches for Patios: Misting Systems or Misting Fans
With patio misting systems, we have 2 approaches. If you have a patio shade structure or cover, we would typically recommend hanging misting lines around the outer perimeter of the structure, forming a “curtain of mist.” The misting lines would be hung over any open sides, not against any house or building. With that curtain of mist you accomplish 2 things: any air that enters your space is pre-cooled as it enters the space. Also, the evaporation of the mist into that air constantly cools the air on the interior as well.
If you don’t have a shade structure on your patio, then you simply need to direct nozzles into that space to evaporate enough water to cool that air. You can position misting lines along the bottom of the roof line of a house, along the top of a fence, or use landscape risers to come up out of a planter box. Or use a combination of the above. Keep in mind you will be able to cool out to a distance of about 15 feet with this method. If it is a large patio, you will likely need to spread the cool air by using misting fans.
With misting fans, misting nozzles are placed right on the face of a fan. The wind of the fan allows you to introduce more mist because that breeze accelerates the evaporation. It also helps to distribute that cool air over a larger distance.
Warehouse Cooling Strategies
Cool Large Spaces at a Small Fraction of the Cost of A/C with Evaporative Cooling
With warehouses or large manufacturing facilities we can use misting lines or misting fans. Many businesses choose to do spot cooling in busier work areas by using smart placement of misting fans. The fans provide focused cooling on specific areas.
Misting lines can be used over any open dock doors or vents to pre-cool air that would enter the space.
The other alternative is to do misting lines along the ceiling in the interior of the space. With nozzles placed about every 10 feet on average, you can achieve an even spread of mist across the space to cool the air starting from the top, where it is hottest. This method works best with the addition of circulation fans stirring the air throughout the space.
Industrial cooling is a more precise science. Please call for our free system design assistance and advice before purchasing a system.