History of Evaporative Cooling

     Evaporative cooling operates by harnessing the evaporation of water. The technology is primarily used in regions with low humidity. The technique works by passing air over pads that are saturated with water, which results in the evaporation of water from the pads into the forced air. Temperature reductions of 15 to 40 degrees Fahrenheit can be obtained this way. The air is directed into a building, forcing warmer air out the windows.

Ancient Technology

Fresco paintings from ancient Egypt depict slaves waving fans over containers of water. This appears to be the earliest recorded use of evaporative cooling. Wealthy citizens of Rome during the Roman Empire had water circulated through their walls. The common people hung wet mats over their doors for cooling.

Other Early Applications

Cooling towers were constructed in medieval times. The towers were designed to trap wind and funnel it past water before it entered a building. This method is believed have to have been developed in Persia. Water evaporative cooling was used in New England textile mills during the 1800s.

Willis Havillard Carrier

Willis Carrier was born in 1875 on a small farm in Angola, New York. Carrier’s mother taught math and problem-solving skills to her son. Carrier graduated from Cornell University with a master’s degree in engineering. From there, Carrier went to work at Buffalo Forge Co., which manufactured heaters, air exhausts and blowers. Carrier was appointed head of the company’s experimental science department.

Apparatus for Treating Air

Carrier was assigned the task of controlling the humidity in a Brooklyn printing plant.

Carrier gained an understanding of the relationship between the dew point, humidity and temperature while waiting for a train one evening. The young engineer designed a system that controlled temperature and humidity.

Southwestern United States

Residents of the U.S. Southwest tried various methods to combat summer heat. In the 1920s and 1930s, people hung wet sheets to capitalize on the evaporation process. Others risked pneumonia by sleeping in wet sheets with electric fans blowing on them.

Swamp Coolers

Several designs of evaporative cooling devices were tested in the Southwest. Until the 1960s, the swamp cooler was predominant. The swamp cooler used aspen pads to contain the water for evaporation. A swamp cooler was demonstrated in Phoenix at the Adams Hotel in 1916. Two professors at the University of Arizona experimented with methods to improve performance in evaporative coolers, and in 1939, they published instructions for cooling homes in Arizona.

swamp cooler

Recent History

Around the time of the professors’ instructions, the Emerson Company began mass production of evaporative coolers. Other companies soon entered the market. By 1939, drip coolers were being used at businesses and homes throughout the Southwest. Many companies were manufacturing evaporative coolers by the 1950s, and the market had expanded to include other parts of the United States, Canada and Australia. Advances continued on the technology. Improved pads reduced some issues such as the amount of power needed to push the air. However, the newer pads created the need to use recirculating systems to wet the pads. This in turn led to problems that affected unit size and location. Use of units that do not recirculate is one possible solution, but this increases water consumption.

How to Run a Swamp Cooler on Humid Days

    Swamp coolers are portable machines that cool the air with water. You fill the tank to the maximum level and turn on the appropriate setting. A swamp cooler is environmental friendly as well as less expensive than air conditioners. Typically, swamp coolers are located in the western and mountain states where there is low humidity. However, you may also use the cooler under certain humid conditions to keep a room in the home comfortable during the hot summers.
Instructions

1

Watch the weather forecast the night before using the swamp cooler. It is important to know the humidity the next day to prepare to set up the swamp cooler.

2

Close all windows and shades in the room with the swamp cooler. Start at approximately 7 a.m., before the humidity arrives.

3

Fill the tank after closing the windows. Begin running the swamp cooler right away. This will allow the room to become cool before the warm and humid day begins.

Swamp cooler

4

Shut any doors to the room. This includes bathroom, bedroom or kitchen doors. Avoid using the stove or oven if the room is adjacent to the swamp cooler area, unless a door blocks the heat.

5

Add water to the tank often throughout the day. When the water level drops, the swamp cooler must work harder to keep the area cooler.

How to Soften Hard Water in Evaporative Air Coolers

Evaporative air coolers, or "swamp coolers," cool the air through water evaporation. One of the biggest maintenance issues facing people who use evaporative coolers is the hard water buildup that occurs on the pads. Removing these deposits is important, because clean pads improve the efficiency of the cooler. Mineral-clogged pads cut down on the amount of water inside the pads and reduce the air flow necessary for creating comfortable indoor temperatures. Softening the water used in your cooler will reduce mineral buildup.

Instructions

    1.

Install an in-line filter for the cooler. These filters remove the dissolved minerals in the water before the water enters the cooler, cutting down on the minerals that can ultimately deposit themselves on the pads. This may be one of the easiest ways to maintain evaporative coolers that sit on roofs, since the filter can be at ground level where it is easier to change.

2.

Add a cap of unscented fabric softener to the cooler once a week, or more frequently during extremely hot, dry weather.

3.

Sprinkle a handful of borax into the water pan in the cooler weekly. The borax softens the water and has no odor.

Evaporative air cooler

4.

Add vinegar to the cooler. During the early morning when it's cooler outdoors, put a gallon of vinegar in the cooler pan, then turn off the fan but keep the pump running to dissolve the mineral deposits in the evaporative air cooler and on the pads. Then, drain the water and refill the cooler with fresh water, turning the fan back on to resume cooling.

5.

Use commercial products designed to reduce the hardness of water in the cooler. This is an alternative to Step 4 if you object to the smell of vinegar. These products are odorless and slightly acidic, which helps counteract the alkaline minerals in the water and dissolve the existing mineral buildup on the pads.

Does a Window Have to Be Open When Running a Swamp Cooler?

Fundamentals

Air conditioning cools and recirculates air in a room or in an entire building. It is essential to keep the windows closed so the cooled air does not escape. However, swamp coolers work differently. They pull fresh air into a room, and as it passes over damp pads, it cools the room. As the cool air fills the room, the hotter air is forced out. With really efficient evaporative cooling, a total air change in the space can take place every two minutes.

Varieties

Evaporative air cooler systems can cool an entire dwelling or a single room. The room units are often placed in windows, not unlike window air conditioning units. In larger systems, duct work and fans together move air throughout the space to allow cool air to enter each room. A simple system uses one duct and fan setup to let in air and blow it into the house.

pace can take place every two minutes.

swamp cooler

Balance

The purpose of opening a window is to let the warm air escape as the cooler air is circulated by the swamp cooler's fan. Open the door and a window inside any room you wish to cool so the air can move through. To get a balance of cool air throughout the space, leave both a door and window open in the room to allow air to circulate.

Adjustment

How much you open a window can determine the swamp cooler's efficacy. Open the window just enough so the door closes very slowly. This means the pressure is balanced, and the hot air is moved through the window as exhaust. If the door slams, the window is not open wide enough. However, don't open the window too far. If the door does not move, the window is too widely open. When the door closes completely, open it and start the process over.