Cool your AC?

[zippyc]

This is not directly on topic, but here goes.

It's been hitting near 100F here in Austin, and the power bills for cooling my house keep going up. I'll have to quit folding on one or two of my rigs, or need to find a way to save money on my cooling bills.

I've installed Primary and Secondary TVSS units at my main in and sub-panel, that should help lower my power bills some.

But I was thinking about phase change and evaporative cooling, and it hit me.

What if I use evaporative cooling to lower the temp of the air that is used to cool my AC outside? Cascade cooling for the house!

Could I sorround my fan unit outside with pools of water to lower the temp of the intake air? (Build a 1 foot 'Moat" around the AC?)

Could I use the dripping condensation from the AC to keep the fluid levels in the pools up?

Should I use walls of a permeable membrane like commercial level evaporative coolers, forcing all the air that blows by the condenser have to travel through a wet sponge membrane first?

I remember there is a greenhouse in Austin where they have a very nice evaporative system that took temps down like 15-20 Degrees for a 40 x120 foot enclosed (20 foot tall, uninsulated) area.

If I was able to lower the temps of the air going by my condenser by that much, would it have enough effect on efficiencies to save some serious $$$, or would it be more like $1.00 a month?

Any AC experts out there have any idea if this has been tried, and if it is worth it?

I've even considered putting a decorative, solar-powered yard fountain right next to the unit, that could help a tiny bit maybe?

My concern is that if I design a sealed system (wall the unit with wet sponge), I might DECREASE the airflow by so much that any effencies gained would be lost by lower air speed?

I've even considered using solar power to drive a pump/and or a fan to help.

I "think" I've invented an idea...add on panels that would work for the membranes outside, fed by the condensation tube.....

And then there are the atomizer type misters (for mosquitoes, or simple hose attachments for cooling yards) that simply would use city water...but then thats more $$$ at the end of the month....

Finally, are there any ac's out there where someone has used water to directly submerge and cool the condenser...then use the evaporation and a pump for heat release? Isn't that what I see with the waterfall units on top of some commercial buildings?

I'm in need of an HVAC or otherwise informed opinion. Thanks!

[wdrzal]

Hi SEER codensor(13 to 14 +) for outside,locate on shaded side of house or provide shade for it. zoning for inside, don't cool rooms you don't use, programable set back thermostats,set back when at work or bedrooms during the day. I have a VAVVT system(variable air volume,variable temperature) that uses a york 2 speed compressor
+ a variable speed air handler, with motorized zone dampers.

A often over looed place is to have a well ventalated and insulated attic space if your home has one.Temps under a roof can go above 150f + powered ventalators bring down the temps to maybe 5 to 10 degrees above ambiant.

Basicly high effiecent equiptment to save $ or you can save by not cooling spaces not in use.

[zippyc]

You said:

Hi SEER codensor(13 to 14 +) : (zc response) Gotta wait for the other one to crap out to justify that expense, just got the whole thing updated thru insurance, but insurance only replaced with older technology. So thats a forlatter.

for outside,locate on shaded side of house or provide shade for it. : Done. Sits under huge 50 foot Live oak on east side next to the house, and I just laid grass on that yard so it should be even cooler.

zoning for inside, don't cool rooms you don't use, programable set back thermostats,set back when at work or bedrooms during the day. : Roger that! (done)

I have a VAVVT system(variable air volume,variable temperature) that uses a york 2 speed compressor
+ a variable speed air handler, with motorized zone dampers.: mmmmm, sounds nice....and expensive. But I'm sure that would pay for itself over time.

A often over looed place is to have a well ventalated and insulated attic space if your home has one.Temps under a roof can go above 150f + powered ventalators bring down the temps to maybe 5 to 10 degrees above ambiant. :

Thanks for reminding me! My termostat control for the attic fan is out (or the fan was deliberately disconnected).

...I believe it may be deliberate as the roof on this place is new thanks to Texas hailstorms and has peak venting all along the topmost ridges. Will I be reversing the natural flow by using an exhaust fan? Maybe I should flip it to blow IN and sleightly pressurize the attic? But wont that drive dust into the house?)

I think I'll actually put a remote temp probe up there and see how hot she gets up there. I can tell you from personal experience it's hot as hell up there!


I did read at higher temperatures and if you have a lot of wire in the attic, you'll lose conductivity (some) and even pay more that way.

Great suggestions, all. :)

I am STILL curious if lowering the intake temp at the condensor through some evaporative process next to it would have a measurable/worthwhile effect?

Like when I run a sprinkler over there, I know it cools the air noticably because the side yard is fenced on two sides and the deck and built in 4 foot brick wall/smoker and the house enclose the other two sides...the yard is square like 25 x25 over there, so its almost an outdoor room without a roof.

[wdrzal]

it works if you can make it cost effective

much easier to pull air, use exhast

[Levish]

How about energy saving bulbs? 100w of heat is 100w of heat, replace them with ~35w Fluorescent bulbs and you'll have much less to cool. In a house I'd assume those high wattage bulbs can add up quick, should be especially true in the case of halogen bulbs.

Also having your windows tinted with the right film should help as well.

[zippyc]

Good suggestions too. I buy the long life florescent bulbs at costco in eight packs. Motion activated floods (costco, $19.95 ea) outside are florescent too . ;) Only downside is they delay during turn on by about a second, guess it takes a while for the ballasts to put out the right volts.

And I am having Solar Screens cut to fit my windows on the west.

Funny you should mention window film. After watching the series 'To Catch a Thief" I'm searching for the right safety glass/tint for all my windows! (Also installing CCTV in the house, got the alarm working well too....)

Wonder if there is any of that solar sensitive saftey film that darkens in the sun like those sunglasses?

Anyhoo, I sent a couple of PMs to the HVAC pros here, they may be able to post and tell us if I'm :smoke: the funny stuff or have an idea here about evapo cooling the condensor's air intake.

[Sheograth]

I remember a system in India where the condensor of a split unit (it was one of those roundish consensors) was surrounded by a shrub on all sides, and the shrub was drip irrigated from above (in line with the top of the condensor).

[saratoga]

Hi SEER codensor(13 to 14 +) for outside,locate on shaded side of house or provide shade for it. zoning for inside, don't cool rooms you don't use, programable set back thermostats,set back when at work or bedrooms during the day. I have a VAVVT system(variable air volume,variable temperature) that uses a york 2 speed compressor
+ a variable speed air handler, with motorized zone dampers.

A often over looed place is to have a well ventalated and insulated attic space if your home has one.Temps under a roof can go above 150f + powered ventalators bring down the temps to maybe 5 to 10 degrees above ambiant.

Basicly high effiecent equiptment to save $ or you can save by not cooling spaces not in use.

Does shade make a big difference? My unit is on my roof, in direct sun light. How much trouble would it be worth going through to shade it? It'd be a PITA, but if it helps, I'll do it.

[wdrzal]

Does shade make a big difference? My unit is on my roof, in direct sun light. How much trouble would it be worth going through to shade it? It'd be a PITA, but if it helps, I'll do it.

I have seen studies that shadeing from landscape (trees and shrubs) can have a average savings of 2 to 10 percent. they reduce the ambiant air intake to the condensor from 4f to 8f degrees. The most benift can be achieved by shadeing a large area around the condensor, say by useing a tree or the building itself.

[illmatik]

What could you recommend for people who are limited to Window A/Cs w/ restricted power? I need a new unit for my main room, and I don't think I can manage more than 12Amps sustained draw (15 amp breaker). Is it possible to rig smaller units for a higher capacity refrigerant.

I live in nyc on the top floor of a very old bldg that eats up all the sun after 12:00PM or so. I have a 10,000btu unit thats on its last legs and would like to get something stronger. The room doesnt have to be an ice box, but it's gotta remove the humidity and deal w/ a lot of heat. This is the central room w/ 2 windows and 9.5 ft ceilings that also deals w/ a 30 foot entry corridor and a corridor kitchen thats about 25 ft long w/ 1 window (had a 5k btu unit in there, but it just wastes 'lectric more than anything.)

I would definately appreciate any input or some a/c models you'd recommend. When I have extra $$, I'm going to have a 220V line run in and hopefully will get approval from the co-op board to run one of those new misubishi or hitachi split units next year. In the meantime, I've been looking at this unit. (http://www.jr.com/JRProductPage.process?Product=3992129)

[runmc]

This thread is off topic. It needs to pertain to phasechange cooling of a processor not a house.
I'm putting it in the "Chat" forums where it belongs.

[wdrzal]

unfortunaly you can't do much without more power, the only thing I can think of is check the wire gauge on that 15 amp breaker, 14 gauge is min for that breaker size, if you are very lucky and the circuit was wired with 12 gauge you can put a 20 amp breaker on it.

I like those ductless splits, the blower is very quit and since the condensor/compressor unit is outside there no noise from it. Next to centrial air its the best thing going.much better than window units.

[wdrzal]

You could reason if your house is cool, so is your processor. LOL

its ok we can chat down here.

[illmatik]

I would venture to say that the gauge is heavier than the breaker rating, but it's old world braided wire covering (This is a pre-war building) and I'd rather not run anymore juice through them than I have to. If the summer is absolultely unbearable, I'll get an electrician in to run a fresh piece (or two) of romex so that I can be assured I wont set the place on fire. My box is rated for and can handle 2 more breakers, so 220 might be the way to go. It will just suck that I'll have bought a unit that will only get 1 seasons use.

[wdrzal]

I would run 220v that way if you get that split system the power will be there. they do have 12,000 btu splits that are 120v

the only problem is if you get a 220v window unit they are harder to resell , most people want 120v.

I seen some real good prices on ductless splits on ebay.

[zippyc]

From your studies that had data points showing that shaded areas that dropped 4 to 8 degree F temp and could result in 2-10% annual savings, at least I have something to work with now. I'm guessing a 5F average drop "could " equate to a 5% annual savings, and for me that makes it worth fooling with.

I do think it would take a lot of surface area of water to drop the intake temps by 8 degrees, or a lot of air pulled through a wet a porus membrane.

I might use loose bricks and some plastic sheets later and build a temporary moat / lake around the outside unit to see if I can measure a noticable drop in the exhaust temps afterwards (all other things being equal, of course). Like the appx size of a goldfish pond.

But I still wonder if I could wet some air filters with ambient temp water and cover the intakes with them, to see if there is a more dramatic exhaust temp drop that way.

Should I be worried that method used over time that might overwork the fan motor due to greater air restriction? The motor may actually be getting cooler air from the benefit of the evapo, but that could be offset and then some by the extra heat the extra work from the added constriction could cause....

Think there is anything at all to this, honestly?

[wdrzal]

put a amp meter on fan and don't let it go over the RLA. also monitor your liquid line temps that way you will know if you are helping or hurting. I don't think building a moat will help.

[illmatik]

is it possible to mount the ductless split condenser portion like a window a/c just in case I wanted to get one while I wait for the co-op to figure out how/where they'll let me mount it.

[wdrzal]

it would have to be outside the window, I guess you could getto rig a flat ledge like the way they hang flower boxes outside the window and leave the window open 1" for the pipes to come in.Your better off to do it right . you said you live on the top floor can you put it on the roof?

[illmatik]

it would have to be outside the window, I guess you could getto rig a flat ledge like the way they hang flower boxes outside the window and leave the window open 1" for the pipes to come in.Your better off to do it right . you said you live on the top floor can you put it on the roof?

Yeah, thats what I wanted to do.. Make a ledge. Regardless I'll have to make a foam baffle like I do for my portable bedroom A/C for the pipes as I dont think they'd be keen on me drilling holes thru the bldg, especially the window frames. The only problem theyre going to have w/ the roof is the running of the electrical cord outside the bldg. Dont think they'll allow me any holes thru it. I would prefer it that way, so that I can restore the place to 'stock' if needed. I dont see why window rigging would be a problem since its lighter and smaller than the A/cs most people hang out their windows w/ the factory accordions (I have a nice plexiglass mounting my dad and I made for my unit which is permanently mounted in the window).

The other reason the split is appealing is for heat.. The heat on my floor sucks in the winter and I could use a dual purpose unit to supplement the ancient steam radiators on frigid days.

[wdrzal]

heat pumps are only good down to 34f .then they lose their efficency .After that just use electric heat.

on ebay there is 2 ton ductless for 849.00 plus shipping thats a great deal.

when this style first came out about 15 years ago I paid over 2000.00 for one that size.Prices have really dropped.

1 ton is 535.00 +shipping hard to beat. I can't get them that cheap anywhere.

[chilly1]

THere is a commercially available evaporative cooler add on to your AC and yes it works quite well. usually dropping run currents by 3 to 5 amps on a 5 ton unit.

As for the TVSS I installed one and have been monitoring it for 2 years and they do not do anything alt all for my power bill here.

[zippyc]

Thanks for the reply Chilly1.

I am relieved I'm not entirely off my rocker about water helping the AC. You don't happen to have the linkage to that cooler, do you?


When I put my TVSS in, my food began to freeze in the fridge...I had to turn it up. So something good seems to be happening here. AC felt cooler too, although I did not think to get a baseline temp to prove it.

But the fridge dropping temp is the real deal....must be more efficient somehow...

It is my understanding that you will see better benefits (aka cost savings) with TVSS on old motors than new ones, because new motors are running at better efficiencies. I have a 30YO house and 11 YO fridge, so I may be in more of the sweet spot for savings.

I got TVSS mainly becasue a lightning strike took out my AC. Cost my insurance almost $2K.

Did you have a sub panel TVSS too? If you don't stadge them, you won't see the same savings benefits as as service entrance only install....

Did you know that in Europe a building does not pass code unless a tvss is installed? Got a buddy that works for Fox Service and he says they are installing more and more units on residences and businesses every year, so I guess it's catchin on.

I got a Brio Power Mach II and Mach I, single MOV (non-degrading) on the Mach II at the service entrance, good for 150+ KVA. It'll do....came with half a mil insurance for my electronics from the Hartford Group, so thats cool too.

http://www.briopower.com/FindOutMore.htm

But if ya got that linky, I'd appreciate it!

[illmatik]

I was wondering about a small chilled water system. I currently use a portable a/c in my bedroom since the window is very wide and I like to be able to open the window for air when the nights are cool and not too humid. I was looking at some watercooling gear i had in a box and an idea hit me (that I'm sure others have as well) so I was thinking I could build something smaller and lighter that I can put in and take out fairly easy. How well would a massive heater core work w/ 35-40F water flowing through it cool a room if its nicely rigged to a 500-600cfm blower? Is that extra heat exchanger stage just a loss of efficiency? Also, how would one deal w/ the condensate from the core?

[chilly1]

Put a condenser and HX with a water rez and pump outside and pipe in a couple lines for the chilled water. insude you have a coil and a fan and a condensate pumpe with a float.

[illmatik]

do you think a compressor from a 10000 btu ac setup to chill the water really cold will outperform a normal 10kbtu a/c?

[wdrzal]

20 years ago when I built a 30' x 40' garage at my house I removed the evaporator from a 24,000 btu a/c unit mounted it in the return for the hot air furnace and set the rest outside.Its been cooling and working great ever since. I did remove the blower wheel for the evap also.I just turned a window unit into a split system.

[gkiing]

The other day I was working on some ground source (geothermal) heatpump/ac units. They take/remove heat from the ground through 4500 foot lengths of tubing buried 4 feet underground. Now i know you couldn't do something on that scale but maybe you could bury some hard copper pipe in a shady area and use it as a radiator with a heatexchanger in the house to cool your house to the ground temperature, which remains fairly stable even on hot days. You wouldn't need to worry about condensate and the only stuff needed would be the copper tube, a strong pump (maybe 1/2hp), some heatercores, and a good blower.

[zippyc]

Well,

We've had the first rain here in Austin in 40 days yesterday, but it will be 102f again today.

I have decided the very best way to add additional cooling to that yard is to simply run a sprinkler in that yard for 30 Min a day at 1:00 PM.

This is making my grass grow like crazy, but also soaks the sod so that it is wet and evaporting for the rest of the day. The area is about 625 Sq feet. I believe this gives enough evaporative surface area to make a major difference, as temps there when wet run 5-10 Degrees less than dry parts of the yard, shade vs shade.

So it helps my efficiencies some, keeps the grass green, and keeps the birds happy.

I thought this was a new concept until my 85 YO great aunt told me that she regularly sprays her unit with water (on it and around the yard around it), and she claims it keeps her bills down vs not watering around there regularly. This woman is/was a Texas Farmer, safe to say she's learned a trick or two during her lifetime. :)

Still might grow some tubulars a few feet away from the unit, hoping I can keep them wet all the time to help with the cooling. Maybe build a water feature there....