Need a thermal switch

[DanaK]

Hi,

I've got a project in mind but I'm having problems finding the right equipment for it. I need a thermal switch or thermostat, whichever. I'd like to set up a set of water misters to run when the outside temperature gets to between 90 and

95 degrees. The spray system would need some kind of thermal switch or thermostat that was either weather proof or having a long coil of tubing to the sensing bulb that would allow the main switch unit to be out of the weather. The switch would then run a solenoid valve, probably something like the 24vac automatic sprinkler valves after applying electricity to a 120vac to 24vac step-down transformer.

The application for this is to provide a precooled air source to my air conditioner's compressor-condenser coil. Since we're in a hard water area I was figuring I'd need to provide some kind of conditioned water for this system to prevent the scaling up of the coil. I've seen some in-line chemical anti-liming filters for water misters and evaporative coolers in Lowe's but I was wondering if the added chemical(s) that these would provide wouldn't just add to the problem. The chemical is supposed to keep the calcium in suspension for evaporative a/c coolers as well as these water misters but, in my mind, the chemicals have to be deposited somewhere even if the mist is fully evaporated by the time it passes through the coils. Would I probably have to install a small r.o. unit for this? They don't make much water (10gpd usually) but the misters don't run all the time and don't use much water when they do.

All of this does cost a little but the electrical load reduction on temperatures from 95 to 105 degrees could be reduced by 23% and sometimes more from what I read.

This is just a crazy idea I had one sleepless night while listening to the outside compressor run ad nauseum trying in vain to catch up and not making much headway. The idea has been patented recently, darn it, by a person in Plano, TX but I don't have his/her address to see if they marketed any kind of kit for this. Also the concept has been around for as long as there have been refrigeration units judging from the patents referenced in this latest one.

Thanks for anyone's help. Dana

[DanaK]

Hi,

I've got a project in mind but I'm having problems finding the right equipment for it. I need a thermal switch or thermostat, whichever. I'd like to set up a set of water misters to run when the outside temperature gets to between 90 and

95 degrees. The spray system would need some kind of thermal switch or thermostat that was either weather proof or having a long coil of tubing to the sensing bulb that would allow the main switch unit to be out of the weather. The switch would then run a solenoid valve, probably something like the 24vac automatic sprinkler valves after applying electricity to a 120vac to 24vac step-down transformer.

The application for this is to provide a precooled air source to my air conditioner's compressor-condenser coil. Since we're in a hard water area I was figuring I'd need to provide some kind of conditioned water for this system to prevent the scaling up of the coil. I've seen some in-line chemical anti-liming filters for water misters and evaporative coolers in Lowe's but I was wondering if the added chemical(s) that these would provide wouldn't just add to the problem. The chemical is supposed to keep the calcium in suspension for evaporative a/c coolers as well as these water misters but, in my mind, the chemicals have to be deposited somewhere even if the mist is fully evaporated by the time it passes through the coils. Would I probably have to install a small r.o. unit for this? They don't make much water (10gpd usually) but the misters don't run all the time and don't use much water when they do.

All of this does cost a little but the electrical load reduction on temperatures from 95 to 105 degrees could be reduced by 23% and sometimes more from what I read.

This is just a crazy idea I had one sleepless night while listening to the outside compressor run ad nauseum trying in vain to catch up and not making much headway. The idea has been patented, darn it, by a person in Plano, TX but I don't have his/her address to see if they marketed any kind of kit for this.

Thanks for anyone's help. Dana

[RBM]

Look for a greenhouse supply catalog. They have both mister systems and enclosed and remote bulb line voltage thermostats, used for controlling fans

[nicksanspam]

How about running them when the AC fan runs?

How about 2 120V solenoid valves from a dead washing machine in series?

That won't help, if the water touches the coil. I save 20% by trickling rainwater from some tubing with holes over the coil of a window AC. The water runs down into a plastic drum containing a $10 10 watt Harbor Freight submersible fountain pump.

This works best with low outdoor humidity, although Yogi Gaswami saved about 20% in central Florida by building an evaporative cooler around an outdoor coil with standard commercial greenhouse parts.

Nick

[HeatMan]

You're asking for trouble.

Even without the hard water, there is a good chance that you will lime up that condenser with in a season or two. Then, you'll have to buy a new condenser coil and that can be nearly as much as a condensing unit.

There is a place on-line that sells these kits fairly cheaply and they even mention the need to de-lime the condenser coils regularly.

The best way, IMHO, is to insulate your house and put your straight cool condensing unit on the north or east side of the house. Keep shrubs, bushes, and any kind of overhang 36 inches from the sides and 6 to 8 feet from the top. Pull the curtains on the south and west side of the house to try to defeat the sunlight from heating up the house any more than it has to. Get the unit serviced professionally to make sure it's in tip-top operating efficiency.

[BrentH38]

Great minds, etc. I am working on exactly the same thing -- again. I looked at it a bit last summer, but couldn't find anthing of significance. Most equipment seems to be designed for commercial (high-tonnage) applications, so it appears that the use of misters may be the only alternative.

Last summer I found a system on-line that utilized RO water, but the description was so poor I doubted the claims they made. The water was applied directly to the condenser coils. RO water, like distilled water, is slightly acidic, so I didn't like the idea of applying directly to the aluminum coils. Also, they didn't describe nor indicate even there was any special effort made to distribute the water on the coils. It just seemed to be discharged from the end of a tube onto the coils. I e-mailed questions to them but didn't hear back.

As to your question, I don't have an answer, but scaling of the coil is important to address. I'm considering a system where the hard-water mist is discharged a few feet away from the AC and hoping the mist all evaporates before the air enters the condenser. If that occurs, then the dissolved solids might pass through as a dust. I'm not terribly comfortable with this approach since prevailing winds, etc., might drive it into the unit before evaporation can occur, so I wondered about adding swamp cooler dismisters between the two.

Perhaps we could collaborate.

Where are you located geographically? I am in north-central Utah.

[DanaK]

I'm located around San Angelo, TX so we're hot and dry like I assume you are. Currently we're on vacation in Baton Rouge, La. with my uncle but will be back later next week.

The patent description I mentioned showed the exact thing you're describing - showering the coils directly which I don't like as we're in limestone country and the water is hard, hard. I was thinking of putting the misters a few feet away and possibly adding a covering of sheet metal to help direct the fog and allow it to evaporate before it got the coils as you say. My uncle suggested the swamp cooler pads as well. R.O. is expensive and I haven't made the calculations of how much the coils can evaporate vs. how much the r.o. units can make and how long the filters and membranes will last but I feel that the savings on electricity would make it worth it.

There's a workable solution for my unit out there somewhere - it's a Ruud - but there's a lot of codenser designs and yours may require a totally different solution.

I'll check back when we get back home. Thanks for answering.

Dana

[bnlfan]

Contact a appliance parts house and see if they have a thermostat that operates within that range. I have several temporary controls used as temp. replacements for appliances. This may solve your problem.

Online you may find something useable at

or do a search for Fox appliance Parts.

If you like you can email me directly and I will see if I have anything within that temperature range.

You may want to just get a thermostat control for a central heating and air unit. This way you can adjust the temperature setting. Most will come with directions for hook up and can be picked up for less than $20.00.

Good luck, Bnlfan

[DanaK]

Thanks, that's what I was hoping to find out. I did drop in to my local a/c&r sales location and all they had was a Honeywell unit that was going for about $70 or so. I thought I'd better shop around before I laid out that kind of money on something.

I'm still on vacation but I'll try to find out some more later on this week.

Thanks, Dana