Swamp Cooler energy savings idea that people don't realize - please pass it on

SUBJECT: An energy savings idea that people don't realize about Swamp Coolers - please pass it on

This energy savings idea involves the saving of a small amount of energy that people don't realize for Swamp Coolers.

All swamp coolers run their water pumps at full capacity all the time. But running the water pump all the time wastes energy and causes the swamp cooler to run hotter. If a repeat cycle timer is used to control the water pump cycling, then the swamp cooler will use less energy and at the same time the swamp cooler will put a little colder air out than it would otherwise.

I found this experience to be truthful by using an electronic repeat cycle timer to repeatedly turn the water pump on for one minute and then follow this with the water pump turned off for the next four minutes. I believe that having the water pumping on all the time causes the swamp cooler pads to remain at a warmer temperature than the cooling pads would be otherwise if the pump was turned off for short periods of time. The evaporation of water is the cooling action. And the pads will not dry out in just a few minutes. But the pumping of water interferes with the evaporation cooling action, due to the water continually and all the time replacing the pads with warmer water.

Some repeat cycle timers use more energy than others. Electronic repeat cycle timers use the least amount of energy, and electric motorized repeat cycle timers use the most energy.

Please pass this easy to apply idea on to anyone using a Swamp Cooler.

a reply to: trader21

Most of these pumps are about the size that require about the same wattage as a 75 watt light bulb.

Your 75 watt bulb, if it burns for an hour, will use 75 watt-hours of electricity. Typical cost for electricity (check your bill) is 10¢ per kW-hr or per 1000 watt-hours. So in one hour your bulb uses 75/1000 x 10¢ or 0.75¢

10 cents was used as a round number, but a old number, insert your amount from your electrical bill.

a reply to: trader21

I think you might save energy. Not sure. The cycling of the motor in the pump will draw FLA (full load amps) on every cycle.
I think you might lose life on the motor and what does it cost to replace? I work with industrial equipment and the stop start wear on motors coasts more in power and burns them out quicker. I think you might want to try a VFD (variable frequency drive) to slow the pump down on a timer. It will save you energy and parts.

originally posted by: d8track
a reply to: trader21

I think you might save energy. Not sure. The cycling of the motor in the pump will draw FLA (full load amps) on every cycle.
I think you might lose life on the motor and what does it cost to replace? I work with industrial equipment and the stop start wear on motors coasts more in power and burns them out quicker. I think you might want to try a VFD (variable frequency drive) to slow the pump down on a timer. It will save you energy and parts.

I have worked and programmed a few VFD's, softstarts and various other electromechanical parts. You could pay for years of electricity for what a VFD cost. I haven't even seen a VFD last more than 2 years. These motors are typically 1/50th HP they are disposable, and sell for about 30 bucks at home cheapo. Even a cheap ass 1 hp VFD cost about 150 bucks thats a lot of juice for a 75 watt motor. You would appreciate conditioned water before the cost savings of a repeat cycle timer, even those are not cheap for good quality.

a reply to: MarlinGrace

What you say is true.

But, when you consider that many people use their swamp coolers for 10 to 30 years or longer ( if they take proper yearly care of it ), then over this long period of time the cost and energy savings is very significant.

Also if you consider the total number of swamp coolers that are in use, then the overall total energy and cost savings is also very significant.

Besides an energy and a cost savings ( over a long period of time ), there is also a little performance improvement.

You are right that the electronic Repeat Cycle Timers may be expensive, but possibly if more people used them then the price would come down. One may save money on a very good Repeat Cycle Timer by wiring up the plug-in electronic type themselves, if they know how to do it, and also wire in the on/off switching relays with it. These all may sometimes be purchased at wholesale, if you know how.

a reply to: d8track

Maybe, since the water pump motor would be working 20 per cent or even less time wise than it was used previously ( controlled by a repeat cycle timer ), then it's total life usage expectancy in service years would increase ( since it's actual running usage time will decrease ).

originally posted by: trader21
a reply to: MarlinGrace

What you say is true.

But, when you consider that many people use their swamp coolers for 10 to 30 years or longer ( if they take proper yearly care of it ), then over this long period of time the cost and energy savings is very significant.

Also if you consider the total number of swamp coolers that are in use, then the overall total energy and cost savings is also very significant.

Besides an energy and a cost savings ( over a long period of time ), there is also a little performance improvement.

You are right that Repeat Cycle Timers may be expensive, but possibly if more people used them then the price would come down.

The long term cost savings can only be calculated based on the number of cycles per hour. With inrush and short cycle times the cost savings could go in reverse.

Repeat cycle timers are used extensively in commercial applications, a lot of sign people like them. I my business we used timer relays which can be set for several functions from on delay to repeat cycle. In some cases we would turn on up to 10 15hp motors at once on delay is worth it weight in gold then, the inrush would kill your electric bill. In commercial buildings they now charge you on a separate meter for inrush.

What performance improvement would you expect to see?

There is a much less expensive way to control the water pump timing, than to use a Repeat Cycle Timer ( which is very expensive since it gives so much easy flexibility with changing the on/off times ).

If one knows exactly what the on/off times are that they want to use, then a simply wired switching relay with some kind of a simple inexpensive fixed delay timer would work equally as well as using a very expensive Repeat Cycle Timer.

I may eventually replace my present Repeat Cycle Timer, with this simpler device as my present Repeat Cycle Timer's complexity and flexibility is not needed or being used. I'll find another use for my Repeat Cycle Timer.

I would appreciate any ideas, directions, and suggestions of how to wire up and to make a much simpler on/off timer with about one minute on and four minutes off timing that uses 115 VAC at 60 cycles at 10 amps.

originally posted by: trader21
There is a much less expensive way to control the water pump timing, than to use a Repeat Cycle Timer ( which is very expensive since it gives so much easy flexibility with changing the on/off times ).

If one knows exactly what the on/off times are that they want to use, then a simply wired switching relay with some kind of a simple inexpensive fixed delay timer would work equally as well as using a very expensive Repeat Cycle Timer.

I may eventually replace my present Repeat Cycle Timer, with this simpler device as my present Repeat Cycle Timer's complexity and flexibility is not needed or being used. I'll find another use for my Repeat Cycle Timer.

I would appreciate any ideas, directions, and suggestions of how to wire up and to make a much simpler on/off timer with about one minute on and four minutes off timing that uses 115 VAC at 60 cycles at 10 amps.

One of the most used circuits, if not the most used circuits is one with a 555 timer. There are many schematics on the net if you have a little soldering experience. Examples Pretty simple to do and has a variety uses. Very cheap to work with, and something you should be able to get at Radio Shack.

a reply to: trader21

You know, this is a truly interesting thread. And I read all the responses. But really....,my best guess estimate is that less than 5% of the US adult population even knows what a swamp cooler is. And 100% of that percentage probably lives in west Texas, Oklahoma, Arkansas and possibly Missouri. And I'm not too sure of Missouri. There might be a few in Kansas and possibly New Mexico. But seriously, can a person even buy a "new" swamp cooler in this day and time? I think there might be one manufacturer left. Well, apparently Walmart still sells them, portable versions that is and there's a guide on them at Home Depot, but I didn't see any for sale.

Interesting idea though.

a reply to: TonyS

they are very common in Az,I have one and central air. The biggest problem is not the pump running continuosly,its the pump rusting out,or the hard water in the cooler.20-30 yrs off a cooler? no way! They rust out,or the plastic sun rots.They only work if the dew point is 55 or less,or low humidity.I've seen them as far north as nebraska,and the walls would drip water in the summer! And the temp is uncontrollable,depends on the weather more than anything.
As far as cycling the pump on and off to save energy,I think the hard start would use as much as it would running non stop.Without real data,energy use/temp change,I don't see any real gain.You'd probably see more savings in water use,if you have a bypass fitting. A person could also bypass the pump completely by tapping into a main water line and use a control valve,the float valve,at low pressure.Imagine a drip irrigation system,instead of a pump,use city pressure

originally posted by: blkcwbyhat
a reply to: TonyS

they are very common in Az,I have one and central air. The biggest problem is not the pump running continuosly,its the pump rusting out,or the hard water in the cooler.20-30 yrs off a cooler? no way! They rust out,or the plastic sun rots.They only work if the dew point is 55 or less,or low humidity.I've seen them as far north as nebraska,and the walls would drip water in the summer! And the temp is uncontrollable,depends on the weather more than anything.
As far as cycling the pump on and off to save energy,I think the hard start would use as much as it would running non stop.Without real data,energy use/temp change,I don't see any real gain.You'd probably see more savings in water use,if you have a bypass fitting. A person could also bypass the pump completely by tapping into a main water line and use a control valve,the float valve,at low pressure.Imagine a drip irrigation system,instead of a pump,use city pressure

Sears makes a version where there is a tank at the bottom of each roller where the pad rolls through before coming up again. The only electrical consumption was the fan motor. Had one for years, I will say it again conditioned water is where your performance and cost savings are at. The hard water builds up on the pads when the water evaporates and the minerals remain behind often times making the pad very heavy and restricting air.

a reply to: blkcwbyhat

I've actually considered trying one. I live in the extreme western edge of the Texas Hill but I think its too humid out here.

Thanks for the info!

originally posted by: TonyS
a reply to: trader21

You know, this is a truly interesting thread. And I read all the responses. But really....,my best guess estimate is that less than 5% of the US adult population even knows what a swamp cooler is. And 100% of that percentage probably lives in west Texas, Oklahoma, Arkansas and possibly Missouri. And I'm not too sure of Missouri. There might be a few in Kansas and possibly New Mexico. But seriously, can a person even buy a "new" swamp cooler in this day and time? I think there might be one manufacturer left. Well, apparently Walmart still sells them, portable versions that is and there's a guide on them at Home Depot, but I didn't see any for sale.

Interesting idea though.

We use swamp coolers in the calif desert all the time.
I have i small one pad model in the back window of my 34 foot motor home as the AC units on the roof cost a fortune to run.
its a model to cool 600 SF and my motor home is only 240 sf so even when its 115 out side its cold inside.
www.globalindustrial.com...

a reply to: ANNED

Well, that's great for you. Its too humid where we live.

I agree about the humidity problem. We only use our cooler (Tucson, AZ) for the first part of summer, then are forced to switch to AC (about 3x the kWh of the swamp in my house) because it's just too miserable once the Monsoon rolls in. We usually manage to run the swamp again at the end of the cooling season once the humidity leaves.

It is not just possible to use the swamp cooler for part of the summer here, but desirable. In addition to lower energy bills, when the humidity outside is 9 or 6% it's kinda (a lot!) nice to have the humidity from the cooler! True it uses some water, but a lot less than the landscape. We have a bleed drain so the water in the cooler gets refreshed constantly. (The bleed water goes to plants that aren't hugely salt sensitive.). Without bleed water the pads would get trashed in two seasons at my use rate due to mineral build-up. I'm on at least the 5th year of these pads (were here when I got the house) and there's no end in sight yet!

We have been doing this pump cycling for the last several years, albeit manually. (yes, very irritating!) The cost of a repeat timer is prohibitive and I never seem to have the time to finish that 555 circuit, but maybe this summer! Ours is a Mastercool with 8" pads.

I think this scheme works because there is more water surface area for air to flow over when the pads are partly wet and the pad fibers can protrude from the water instead of having a sheet of water flowing over them constantly. To achieve the optimum the duty cycle needs to vary with outside temperature and humidity so there are shorter pump ON cycles when it's cooler or more humid outside because evaporation isn't as rapid.

As far as motor start current (inrush): a cooler pump impeller is a small load physically, not too difficult to start. True, many motors do draw about five times running current when starting, but in this case maybe not that much and probably for only half a second or even less. Not much extra wasted kWh in that unless your cycles are measured in seconds rather than minutes, which they don't need to be.

As far as using a VFD to reduce pump speed: even if it could be afforded and were reliable, there's still the problem that if you reduce speed very much the pads likely won't get fully wet all the way across. Some spider or distribution tube holes will go unused. It seems that on/off is indeed the best control scheme unless your pump is significantly oversized, and even then a new, smaller pump would be much cheaper than a VFD.

One last point: these pumps (at least the ones I've looked inside of) use shaded pole induction motors, which are hugely inefficient.

The price of CELdek media has dropped quite a bit lately not sure why.
Has the southwest water shortage turned people away from swamp coolers?

I have worked on house top swamp coolers (36" cubes) and have had to repair Industrial sized water towers... in Phoenix AZ

the few water towers I had to crawl into had super cool water cascading down,
all the roof top evaporative coolers on homes had very warm tap water supplied to a reduced fitting & float mechanism

the pads got corroded fast, the water drip holes get clogged so the pads have dry sections,
I agree that conditioned water is a necessity but cost prohibitive,
what may help is a cooler water supply, perhaps...but a private cistern is too costly, and the water supply getting routed through ~50' of interior plumbing lines increases the temperature at the tap to 'un-cool' from the ambient underground temperature of city supplied water (say 55-58 degrees)

the industrial coolers use huge fans, the home coolers use squirrel cages to pull air through the water laden pads and into the interior space....and the fact is 'one size does not fit all' ... a motor with various pully combinations might get better efficiency (with out blowing your hat off in front of a duct vent) ,
being solar powered, a better profile, better insulated, all might result in a cooler water feed~ because evaporation is only part of 'cooling', the larger the ventelation volume helps the action of wicking moisture away better which you feel as cooling...

swamp coolers are primitive but very better than just a box fan and way le$$ than HVAC/water source heat pumps/coolers or other energy source (gas, propane, etc.)

originally posted by: St Udio
I have worked on house top swamp coolers (36" cubes) and have had to repair Industrial sized water towers... in Phoenix AZ

the few water towers I had to crawl into had super cool water cascading down,
all the roof top evaporative coolers on homes had very warm tap water supplied to a reduced fitting & float mechanism...

... the water supply getting routed through ~50' of interior plumbing lines increases the temperature at the tap to 'un-cool' from the ambient underground temperature of city supplied water (say 55-58 degrees)

Yes water towers are a different beast I agree, since they operate as a heat sink for a separate cooling mechanism. Towers constantly have a new supply of air at the ambient outdoor humidity level. A swamp cooler does too, but it's being routed into the space that's being cooled, which quickly builds up to a much higher than outside ambient humidity condition. That starts to feel uncomfortable as the outside humidity increases.

A water tower dumps waste heat (from a chiller(s)) but the chiller operates like an AC unit and the humidity from the cooling tower evaporation never reaches the building's interior. So in theory as long as the temperature of the cooling tower working fluid (treated water) doesn't go above the chiller's design limits the occupants don't even notice when the outside humidity increases, unlike a swamp cooler. (Assuming of course not too much humid air gets in from the doors being open).

At my house the city water supply gets quite warm in the summer. It's not just the house piping causing this, but to a large extent the underground steel line leading from the curb to the house picking up heat from the surrounding soil. Also I suspect the water in the city main has a significantly higher temperature in the summer than in the winter, even though it's typically buried much deeper. That is especially true i'm sure where there are aboveground reservoirs or water source.