I live in Las Vegas. We use evaporative coolers here. I want to add a
5,000 cfm for one side of my house.My questions are:
Is there a special ducting that is used for this and is different than AC ducting? Do I need to run ducts to all the areas, or would just ducting into the largest room do it? (The kitchen, living room, and family room are all open to each other.)
I have to make a stand for this to go in through the attic. Making a hole in a wall is not an option.
TIA
Steve
yes. they are typically bigger since you're moving a lot more air. you need to talk to someone to design the ducting issues you're going to encounter.
Yes, the ducting is larger than used for AC. To one room will be adequate. Much depends on where the air will be exhausted.
There is lots of information on the web: Do a net search for evaporative cooler duct.
5000 cfm is rather small. One source specifies that the unit needs to be sized to supply 2 to 3 cfm for each square foot of floor space. That is 5000 cfm would be adequate for a 666 to 1000 square foot residence.
Another method says that to cool a 1500 sq. ft. residence (with 8 ft ceilings) needs 6000 cfm. That is the maximum. Usually I found I have run them at lower speeds.
In any case if ducts are used they need to be large.
"SteveB" wrote in message news:vvfDd.51954$Cl3.7522@fed1read03...
Ahhh the ole swamp cooler.
aluminum ducting is best, holds up to the moisture better. You'll crap when you see the cost. Sheet metal is ok and used a lot in Phoenix. Plastic ducting is a no-no, can not handle the pressure for long. No fiber ducts and no insulation on the inside. If you do the moisture and dirt in time WILL grow mold. (Did in my first Phoenix home).
Trying to cool part of the home is not a good idea unless you have a physical barrier like an outside door between the parts of the home. I had a home with 2 5500 coolers, had to run them both or the home would not cool well.
You need ducts to each room just like A/C, only bigger. Install upducts 1 per each 12 square inches of register, cause you need an exhaust from each room especially if you close doors. When I ran a cooler on my last home (6500) mounted on the roof. I had a damper that prevented the cooler air from going into my a/c- gas furnace. Since the air handler was in the hall closet I used it as the up duct for the whole house. Really needed one in the kitchen especially when cooking.
A 5000 cfm cooler will really only deliver about 4500 cfm, a mere whisper. Bigger is better with coolers. You will need an amp meter to set the unit up the first time. Set the motor to FLA, that is the only way to get close to the advertised air flow. You may have to change pulleys, I have several times. 2 speed motors help a bit in the early cooling season. As well as a t-stat. The stats do not have actual temp settings just numbers 1-5. They do prevent you from waking up and having the house 60 degrees. The stats also have a pre wet timer, helps stop that 120 degree air blast in the beginning. The single pad units are the best performers, 12 inch wet section, there is an 8 inch section as well. Forget about the "pre coolers". Unless they want to give you one. A friend had one and I did not. We would call each other and I was always within a degree of his output temp. A degree is nothing. The precooler was always clogging up and he finally ditched it. A timed dumping pump helps keep them clean. A little more in cost than a regular pump. You will replace the pad every couple of years, $100-200 bucks depending on who you know. Calcium is the killer here, no matter what chemicals you use. I ran my last cooler on soft water. Slowed the calcium down to changing the pads every 3 years. The soft water was an accident. Go with 220v for everything if at all possible. There are lots of places to get motors and pumps on weekends.
Coolers are NOT for setting and forgetting. They need to be clean to work. I know you get the same kind of dust storms that we do here in Phoenix. I cleaned mine 3 times a cooling season. I was experimenting with air filtration when I moved. Coolers put a lot of dirt in the home. Now that I am approaching 55 I do not want to get on the roof nor do I want to clean them anymore. Del Web the original Sun City in west Phoenix mounted the a/c and cooler units on the gable ends of the homes. That way they were not on the roof (ambient summer heat) and there was a straight shot into the duct work. Better air flow.
Several HVAC companies here sell cooler kits for installing into duct work. Do you have the chain called Evergreen Hardware there?
Coolers only work until the dew point reaches 45 degrees, for me it is 40 degrees. It is just to humid after 40. I used to get a couple of months of cooling early in the season and maybe a month on the end. What I saved in electricity was used up in water and maintenance. Water here in the summer time gets pricey. A cooler can go through several hundred gallons a day. I would have 60 dollar electric bills and 80 dollar water bills, a/c cost 150.
Good luck to ya.
I think you are way off on the water use. They may use a few hundred gallons a month:
This study goes along with my experience. (3.5 gallons per hour without a bleed. 10.5 gallons per hour with a bleed). Instead of a bleed I ran a hose down with a faucet on the end so I could dump the reservoir every now and then.
I found they became marginal when the humidity level was above 30 to 35%.
Well, I went to XYZ, Inc, yesterday, and was outfitted immediately. The counter man was helpful in calculating which CFM I needed, and duct sizing. I called other supply houses, and they treated me like I was intruding. Smartass primadonna HVAC people, I assume. I am calling them XYZ because I want to protect them from any HVAC people who might call them and bitch that they are selling to "citizens."
I got a bid from a "friend" who is a licensed HVAC person. 24' of 14" dia. spiral, 8 90 deg. elbows, two 14" cans, and two grates. Two custom made pieces of sheet metal. ................ $3200. I was to provide the swamp cooler and stand. All materials at jobsite, and cleanup by owner.
So far, the total is $256 for parts, $550 for cooler, about $30 for stand. All materials are on site at this time, having picked them up yesterday.
I estimate it will take two guys two days at tops for installation, and I would estimate we do it in less time. One of them will be me, and one is my hired ex-contractor friend who I pay $25 per hour, so I would estimate that cost at $800 if I were to pay myself. I know my other HVAC "friend" would have hired a $10 (or less) per hour grunt, therefore getting $40 per hour for his side.
That leaves $1,564 for what? Some Primadonna HVAC person?
I don't think so, Tim.
Since this group is alt.home.repair instead of alt.HVACkvetching, I have chosen to post this here as an example of how one can save money getting a job done right, and for about half the cost.
Hell, for the $1,600 saved, I could take a hell of a ski trip. Or a cruise. Or just go rent a couple of bimbos and spend a day diving in the hot tub. drool...............
OR, I could just buy more tools ................ double drool.......................
Figger it out, people. It ain't rocket science. BTW, the original contractor is yet to show up to give his estimate. I will report back if and when he does with his price.
Steve
Wow.
With a 5000cfm/1.07ft^2 = 4677 fpm (54 mph) air velocity?
Nick
Sounds a little high. That's a fairly large Evap for such a small duct opening. Usually the openings are a little larger. And these things do blow a LOT of air if you want them to.
-- Elbridge Gerry, of Massachusetts:
"What, sir, is the use of militia? It is to prevent the establishment of a standing army, the bane of liberty. . . Whenever Government means to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise a standing army upon its ruins." -- Debate, U.S. House of Representatives, August 17, 1789
My questions are:
Is there a special ducting that is used for this and is different than AC ducting? Do I need to run ducts to all the areas, or would just ducting into the largest room do it? (The kitchen, living room, and family room are all open to each other.)
I have to make a stand for this to go in through the attic. Making a hole in a wall is not an option.
TIA
Steve
Just make sure you treat your water system regularly. Open tanks and Legionaires Disease are very friendly with each other
ReRe
The main difference is that Evap Ducting is usually larger because on a hot day you need to blow a lot of air thru it. If you look at old homes that originally had Evap you generally see ductwork and registers that are larger then you would see on new homes that started out with Central air. If you are adding an Evap to a house that originally had AC you may have a hard time pushing 5000 cfm thru the ductwork and when it comes out the register it will possibly make a lot of "whooshing/whistling" noise. If you try to blow that thru the round plastic flexible tubes used for some central AC you may pop the tubes loose.
-- Elbridge Gerry, of Massachusetts:
"What, sir, is the use of militia? It is to prevent the establishment of a standing army, the bane of liberty. . . Whenever Government means to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise a standing army upon its ruins." -- Debate, U.S. House of Representatives, August 17, 1789
Perhaps the OP meant "500 cfm."
Nick
no. evap requires much more air movement than central a/c. 5000 was probably on the low side.
He said he paid $550 for the unit. Bare 5000 cfm blowers cost over $1000.
Evaporative cooling can be very efficient with small airflows in a well-insulated airtight house in a dry climate.
Nick
Installed perhaps but a 5000 cfm window mount can be purchased for slightly over $300 from SAMS.
Still wondering how to push 5000 cfm through a 14" duct (at 54 mph :-)
Perhaps you are thinking about a 5000 Btu/h window AC. Grainger sells a 7F889 blower that will do 5000 cfm for $1324 in a box, vs installed. It has a 20" wheel and a 1 HP motor and weighs 240 pounds and measures
38"x37"x33", with a 25"x25" air outlet...Nick
here in phoenix, one can get a cheap rooftop 5000 cfm, with motor, blower, out the door for about $400.
perhaps you wouldn't sound so pompous if you lived in a place where these were more common.
Others:
That is probably to feed two or more rooms. The outlet of the cooler is probably 18 x 18 inches (324 sq in). Run that into a plenum and then feed two or more of the 14" ducts.
Regardless there is still a significant amount of air being moved. That is the whole principal of a swamp cooler. You have to provide adequate exhaust too by keeping windows open. You open windows in rooms you want cooled.. For a single outlet unit such as a window mount it can get downright cold in the room it is installed. Note in the following chart if the humidity is 10% and the outside temperature is 85 degrees the outlet temperature will probably be about 63 degrees.
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