Commercial kitchen makeup air is often passed through a swamp cooler, even in humid environments. Better than nothing, since conventional AC is impractical for that much air volume.
If Evaporative Cooling (EC) replaced AC in all the cities and towns where it works well, this country would literally never need to build a new power plant. That's because all of our plants are severely underutilized except for a couple weeks in the height of summer when AC units are running full tilt. EC where effective would shave that peak demand, and brownouts would cease until we get enough photovoltaic and wind generation capacity installed. Then we can start decomissioning the coal plants, and voila, EC has solved global warming!
Got news for ya, Tucson Electric did a study a number of years ago and found in Arizona ( you could say its kinda dry here ) a 12 SEER will match the efficiency of an EC.
I have 2 on the place and mostly like the air throughput (remember they are 100% OSA). Plus the Utility bill is a bunch smaller than the neighbor with central A/C by about $40.00/mo.
I don't know if I would put in A/C even buying it at wholesale.
It's really nice in the evenings when we can simply use the fan and "Ventilate" the house.
I disagree about the 80* comment. If you do your homework the measured (DB) discaharge air temp drop should run 25 degree Delta T from OSA DB. I think the RSES SAM manual has a section that makes reference to a 34 Theoretical DeltaT but I can't find it right now. Lat time I checked it costs about 6 cents/hr to operate a EC (Swamp cooler) compared to around 26-30 cents/hr for A/C. If that has changed sigificantly I sure someone will correct me.
Last edited by Cagey57; 09-03-2009 at 09:23 PM.
Reason: Thought of more stuff.
If sense were so common everyone would have it !
All opinions expressed are my own. Any advice provided is based on personal experience, generally accepted fact or publicly available information. As such, it is worth exactly what you paid for it, not a penny more not a penny less !!
I had to shut down my swamp last weekend because of the LA fires. It was just passing through way to much smoke. I have the cheap straw pads and although they wash most of the desert dust and cool pretty good for me, they do not filter smoke. My neighbor has the top of the line MasterCool and she said she does not have a problem.
I changed my AC filters today with some filters that are supposed to remove smoke smell, but I haven’t noticed much difference. Maybe it takes a while.
I was reading about an all green building in a magazine at work today. They were using a cooling tower to cool water at night then store it for cooling during the day. I didn’t have time to read the whole article, but they said they were able to save 40% on the electric bill.
I was going to bring home the article to finish reading, but I forgot it.
H.E., I admit it's starry-eyed optimism, but it's an easy back-of-the-envelope calculation. On a hot day, figure maybe 20 million compressors, times what, an average 4kw each..... replaced by a 0.4kw EC unit that only runs at night anyway...etc., etc.. equals X number of 10MW power plants not needed.
CW, water is a non-destructible resource. If we vaporize some in Nevada, it will fall back to earth over Colorado, and flow downhill back to Nevada.
It's an awesome cycle, and talk about sustainable!
Suddenly this thread has become a lot more satisfying. Swamp cooler lovers and haters all coming out and stuff.
Last edited by kevin_in_denver; 09-04-2009 at 12:07 AM.
Reason: It was too snarky
Thanks for more info. Interesting to hear that EC's are sometimes piggybacked on a conventional ducted AC system. That means, of course, that the ducts are probably 5X too small. I've never heard of it, and it sounds pretty crazy unless the whole thing was engineered and controlled properly.
Now, the ducts may look kind of dirty, but the air in that house is going to be much cleaner and healthier than a non EC house because of all the fresh air that passes through the ad hoc scrubber:
ASHRAE Standard 62.1 requires a minimum of 100 cfm of fresh air to ensure acceptable IAQ for an average house. If the average EC is 3500cfm, that's 35 times better air than the ASHRAE minimum inside your house.
As you probably know from experience, undersized ducts always look dirtier because small dust particles get thrown so hard against the duct wall that they impinge and stick, instead of floating all the way through the duct system back into the house.
As far as electricity savings, the most important thing is demand reduction. In other words, keeping the compressors off in the hot afternoon is more important for eliminating coal plants than the total energy savings. Consumers are more worried about $ savings, which is usually at least 75%. My savings are higher, because, as I said, I run it only at night and when ambient is under 80*. My unit is really cheap with inefficient pads, and I never see a temperature drop of more than 10*, so I don't want to pump air warmer than 70* into the house when I want to cool it. Yes, theoretically they should work better than that.
It's true that EC's can't really do the job any more in Tucson and Phoenix. Thirty years ago they worked 95% of the time. It may be due to higher ambient humidity, but also higher average temperatures which are mainly due to the urban heat island effect and possibly global warming. I haven't seen the Tucson energy study, but I believe it. In more suitable climates, the EER rating for EC is usually quoted at around 40. (I'm trying to find the source of that number)
The 1000 gallons per month I use only cost about $2, or $8 per year for water. I don't have to bleed off, but I completely drain it 1-2 times per month. Not gross or overly saline at all.
Last edited by kevin_in_denver; 09-04-2009 at 12:05 AM.
Reason: addressing the Tucson Electric study also
I sincerely apologize, first I hijacked your thread and then I killed it.
Here's a positive review of a Coolerado that was just posted at Jetson Green:
"I recently installed a Coolerado C60 on my house to replace my swamp cooler in Louisville, CO. Instead of having 45 to 65% humidity in the house with the swamp cooler, the relative humidity indoors varies between 25 and 40 percent with the Coolerado. The Coolerado doesn't change the absolute humidity of the air coming into the house, but the relative humidity does increase due to the temperature drop. I prefer the Coolerado over a swamp cooler for several reasons:
1. The air smells great
2. Summer "warping" of my kitchen cabinet doors producing closure issues no longer occurs.
3. The variable speed motor largely runs in the lowest speed which is inaudible.
4. It is like an air conditioner in that it can actually reach the target temperature you have your thermostat set to; The air coming out of the ducts is quite icy.
5. Winterization procedure is just closing one valve (the water supply), and opening another (solenoid drain)."
Careful, Coolerados are pricey. But it appears they have solved all of the typical EC problems.