More cooling can be done by adding a 2nd stage to an evaporative cooler. This works by evaporating water, which cools it, and using that chilled water to cool the air before it goes into the main evaporative pads. This is done indirectly, so no humidity is added to the ambient air before it hits the main pads.
The results of this setup, is the pre-cooler lowers the ambient air temperature about 5-10 degrees. This may not seem like much, but when looking at the data for calculated output, it can be a huge improvement over just a single stage evaporative cooler. Instead of it being 82F in a home with a single stage evaporative cooler, a 2nd stage could make that same home 75F, while it is 110F outside with 15% humidity.
Something very interesting about these results, as the humidity goes up, the efficiency for a two stage evaporative cooler improves.
A evaporative cooler thermostat has recently hit the market that will add digital temperature control, auto fan speed switching, and automatic purge pump functionality to you existing evaporative cooler. This would normally only be equipped on a brand new unit, but now you can improve your own units functionality. This unit adds the purge pump capability directly, so you can use a standard pump and it will control the interval. The box contains the high voltage, and it has a low voltage line to the controller thermostat that goes inside the house. This can be found at Home Depot or online by searching for "Champion Cooler 110423-2"
A better method of keeping your cooler clean is to use a "Clean Machine" pump, or "Purge Pump". This is designed to dump the contents of your water basin after 8 or 12 hours of use. Normally, a water basin in a evaporative cooler will be around 8-10 gallons of water, so dumping the entire basin in this manner uses less water than the bleed off line method, by about 30% or more. This also gets rid of more of the junk that can clog your pads, giving more live to your unit.
After market purge pumps are not like you standard pumps. They have a special power plug so they are powered with your other pump, but they have a built in timer circuit. They time the amount of use, and only activate for 5 minutes, after the have had power applied to them for 8-12 hours (depending on their design).
The discharge water from either method can be used to water plants/grass during the summer. Plants usually like the calcium rich water that comes from the evaporative coolers.
Typical evaporative cooler systems come with a "Bleed off line", which takes a small amount of water from the pump line, and drains it form the cooler. This helps get rid of the scale and calcium buildup. This will usually drain about 2 gallon of water an hour or more. As water is drained, the float lowers and brings new water into the system. Although this does reduce the buildup on the pads as compared to not using this method at all, it is not the preferred way of changing the water and keeping your cooler clean.
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Some are roof mounted, others are on the side of the buildings, and ducted to the attic.
Typical Master Cooler unit used in this area
Diagram from a Champion 5000 Manual, located at: http://www.swampcoolersonline.com/Products/Champion/AD1C5112.htm
Evaporative Coolers are commonly used in this area from Early April to Late October, depending on the temperatures. The process of preparing the cooler for the winter is called "Winterizing". Usually, you will want to winterize your cooler before the first freeze of the season. Normally, we are done with 90+ degree days once the first freeze occurs, and opening the windows at night is sufficient to keeping the house cool for the daytime.
Parts for these type of coolers are available at local hardware stores, but not Walmart.
De-Winterize Cooler (Starting Cooler for Summer Mode):
1. Inspect water reservoir for cracks and potential leaks. Seal with tar as necessary.
2. Inspect supply line for ruptures.
3. Inspect pads, replace if overly obstructed with calcium.
4. Check water distribution lines for calcium buildup.
5. Inspect and install belt, replace if cracks or excessive wear found. Check tension of belt.
6. Oil bearings on fan axil.
7. Check water pumps, ensure the motor can turn freely.
8. Install overflow tube, and connect Clean Machine if equipped.
9. Turn on water supply.
10. Check float, and water levels.
11. Remove Winter Insert, check furnace for summer insert(mode).
12. Open Upducts or open windows in building.
13. Plug in fan motor and water pump(s).
14. Start water pump, check water distribution across pad.
15. Start motor, ensure bearings are stable on fan axil.
16. Close all openings of cooler, and check for leaks.
Winterize Cooler (Preparing Cooler for non-functional Winter Mode):
1. Remove Belt, and coil
2. Turn off supply water
3. Drain water reservoir
4. Drain supply line (Could rupture during the winter if not drained)
Based on current conditions, if your evaporative cooler is functioning properly, you should expect results as calculated above. Some systems are more efficient than others, and your results may vary.
Generally, the ambient temperature in your house would be a few degrees above the Output of your Evaporative Cooler.
Evaporative Coolers are a common alternative to conventional air conditioning systems in the Indian Wells Valley. Evaporative coolers are very energy efficient and work perfectly in the dry climate of the Mojave Desert. They work so well here because the relative humidity is usually really low. Through the process of evaporating water, the outside air is cooled and brought into the buildings.
Occasionally, we will get a thunderstorm in the area and the humidity will go up, making these coolers useless, but those events occur only a few times per year in the Indian Wells Valley.
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