Water cooled Air

[Sibling Zono (anon1mat0)]

As a happy resident of sunny Florida I have to deal with the side effects of a hot an humid weather most of the year; as a result I spend a fair amount of money (and electricity) on AC (turning my AC on, costs me $100 a month). This year so far I've been able to go by with fans (which are substantially cheaper to operate) but soon those will only circulate hot air.

I've been looking for alternatives and one I found is water cooled air systems, but those tend to be extremely expensive ($500 - $2500), therefore I'm thinking on doing one myself.

My idea is to use a car radiator (I found this for ~$60) a cheap electric water pump and with a simple reservoir and a regular fan make the system.

Does anyone know something on the subject? Any recommendations? Warnings?

[beagle]

What's the plan? The radiator goes in the house with the fan blowing air over it , while on the roof the reservoir side is open to evaporation? Or the fan blows outside air over the reservoir?

Don't know much about A/C but would suspect  that the high ambient humidity you talk about might sink the idea, and that you might even get a temperature gain from the water pump heat generation (unless it's outside).  A typical central heating pump (at least in the U.K.) dumps about 0.1KW when running.

I'd suggest a Google search for "evaporative cooler" and/or check if anyone else uses them in Florida, or only in more arid places.

[Griffin NoName]

There are loads of evaporative coolers on the intreweb - the downside seems to be water is heavy, but that is from a fatigued person's viewpoint.

I dont have any idea how much my unit (non-evaporative, no outside unit either, a gem) costs to run. It was supposed to increase the value of my home but that's gone pear shaped - lack of hot weather and economic downturn in the housing market.

You may do better to wait til global warming kicks off the imminent ice age Zono.

[Sibling Zono (anon1mat0)]

Actually I was thinking in something far simpler: a fan blows air into the radiator which cycles cool water from the reservoir which can be open and even (manually) receive ice from the fridge, all indoors as a single unit. I'll have to make a duct and use a high flow fan.

I imagine that the downside is the noise of the fan, but if I can make the air cooler by 8-10C and the power usage is lower it could be functional. I would be counting on the ice maker from the fridge but that energy (to power the fridge) is already been used. I guess I'm also counting with a level of de-humidification from the system provided that the water pump will not end up heating the water.

[Griffin NoName]

Zono, it sounds like one of my typical home improvements. Like the sound of it.

I have alternative suggestion.

Get one of these:



Punch holes in side and finish off with rubber to fit cricumference of your arms. Punch hole in lid likewise with rubber to seal to size of neck.

Optional: hole for feet or fit hand operated wind up to turn wheels.

Fill withh water and ice chunks.

Climb in. Adjust arms and head to comfortable and tight fit round neck.

Fully mobile and definetely green.

[Sibling Chatty]

How high is the humidity level where you are? Most water cooled air systems are evaporative in nature. Much different from an air-over-cool metal system.

Depends on average humidity level as to whether it'll help. In Florida, you might not have such great luck.

http://www.coolmax.com.au/evaporative-cooling/evaporative-cooling-areas.htm

According to the map, it's too humid to have much success. Water-cooling is done with pads that hold the water, not a radiator. Whether the material of the radiator will provide enough surface area to cool the temps to a point that the 'ambient costs' aren't counterproductive is a good question. Radiators are designed to radiate heat, not cold, so that's an issue as well. What type of baffle system is there in order to maximize heat loss? Much like a heat pump, your ambient temp and humidity will affect the outcome.

You might do better by limiting the amount of heat gain with a reflective glass or glass application and running fans to circulate the air more efficiently. When we moved to Houston in the '60s, I started putting aluminum foil on my windows in summer. Even before we had AC, it was easier to MAINTAIN cool that create it. Open windows for high winds and cool nights, close it down before daylight or at least the hottest part of the day.

http://eartheasy.com/live_naturalcooling.htm   has some info as well.

To actually help, you're going to have to devote a LOT of extra energy to the ice making, as your ice is going to melt fast. You're in a condo, right? And no deep lakes nearby...

Good luck.

[Griffin NoName]

Ice pits. Dig Ice Pits. Digging may be the hard work part

market opening: sell ice pit diggers

in fact: with the immigration rows going on over here, we can probably sell you some cheap labourer

[Bob in a quantum-state-of-faith]

*ahem* I'm in the A/C biz myself.

You can reduce the cost of your electrical A/C by simply shading the outside part. 

Electrical A/C units work by compressing a working gas (usually Freon in home A/C), which raises it's temperature to around 120 degrees F.

Move this hot gas through a radiator.  Even if it's 100 degrees F outside, that's still cooler than 120-ish.  Hot freon looses it's heat, so that it's now only at ambient temp (100 in this example).

Then, the freon is allowed to expand, which thanks to physics, it's temperature drops roughly 40 degrees (around 60-ish in this example).  The now cool gas passes through another radiator, and the inside air is forced over this.  The freon gets hot, from the inside air, to whatever the inside temp is (roughly 78 degrees F).  Rinse and repeat.

Thus, if you cool your outside unit with shade, it is more efficient-- the hot gas gets cooler, and when it expands, cooler still.

The greater the difference between one and the other, the quicker the heat goes to the colder item.

A water-source A/C uses some form of water, instead of air, to dump it's heat.

.....

Evaporative coolers.  There's two basic types, the kind that Chatty mentioned and another type (will describe in a minute).  The former uses the fact that when water evaporates, it requires heat.  It will remove heat from the air, if needed.

In Arizona, where it's very dry (Except Phenox) these things work extremely well.   But, in Florida (or Oklahoma for that matter) too much nearby water, and the relative humidity is always greater than 50%.   

An evaporative cooler just increases this number, and you may get cool air, but it'll feel like a damp cave-- who cares if it's 70 degrees, if the humidity is 90%?

Not recommended.

----

The second type puts the evaporation completely outside.  It's quite simple, really, and works very well.

You  _can_ "roll your own" easily enough.  The heat added by the pump is minimal, if you use a small pump.   A car radiator would work for the inside unit, provided you had a catch-basin under it.  The cooled water should hopefully get cool enough to help reduce your inside humidity, which will collect on the cool radiator.  You'll either need to periodically dump the catch basin, or plumb it to the outside.   The amount won't be all that much.

But for the rest.  You'll need tubing, a pump, and some sort of cooling tower.  Home-made ones work well enough.   This must be outside.  Basically, you need to get the water moving over many surfaces, so that the air will evaporate some of it.  This will cool the water, which you pump back inside through the radiator.   You'll need a system to check the water level, to top it up every day or so.

I've seen very small cooling towers made out of plastic trashcans, and a very small electric fan to blow the outside air over the assembly.  One can is the catch basin.  A smaller one, upside down, with many holes in it, over which the water flows.  Fan inside the inside can, blowing through the holes.  Need a chimney in the top of the inner can, to permit air to be drawn into the whole assembly.  Pump mounted in the bottom of the larger can, forces cooled water though the house-loop, back outside, drains over the top of the upside down can.  An outdoor pond pump works very well for this. 

You can even use an ordinary toilet-tank valve assembly to automatically top-up the reservoir (the large can).  Nice thing about using city water, is that it's usually chlorinated, and this keeps the alge growth low.

Here's a sketch of what I meant:

[Griffin NoName]

My AC unit doesn't have an outside bit.

Unico range here.

It's ace.

But I don't know how to answer your questions in relation to it.

[Bob in a quantum-state-of-faith]

My AC unit doesn't have an outside bit.

Unico range here.

It's ace.

But I don't know how to answer your questions in relation to it.

It draws air from the outside, into the unit, and then back outside.   It has to, else it couldn't possibly work.

We have these over here, too-- my partner call'em PTAX units, after a major brand-name.  Common in motels.

It's basically a glorified window unit.

Look for air-ducts somewhere or other.  I've seen the air ducted to and from, under the house. 

If it's mounted in a wall, it will have some outside grilles.

As for assisting it's efficiency?  Basically your only option is to plant shade on that side of your house-- be careful to avoid blocking the airflow from the vents.

Big shade trees all around the house works No Matter What.  If you can reduce or eliminate direct sunlight onto your house with trees, etc, you can cut your cooling bill literally in 1/2 or more.   

Windows are the worst, for heat-gain.  Glass acts like a "one way valve" letting heat in, but blocking infra-red (re-radiated heat waves from your furniture, walls, floors, etc) from getting back out.   Think "green house". 

If you can arrange to have your windows shaded by trees or awnings, you can cut quite a bit off your cooling bill.   Shade the roof-- cut some more.

The walls are usually the least affected, but there is some heat gain from them, too (especially if your house was built prior to 1970, when energy was CHEAP..... insulation?  Who needs stinkin' insulation?  We gots ATOMIC 'lectricity! Pract'ly free.....)

[anthrobabe]

Griffin-- you kill me!

anyway,  Zono it's called a 'swamp cooler' and we never had anything but in Arizona-- of course they do add moisture to the air -- like Bob says. I like them, the ones we had were like 5 moving parts and they you just buy the pads for them and keep the water supply going (do not like my first husband decide to shut off the water supply by simply putting a crimp in the copper line running up to the roof--- water spout-- dumb boy) anyway not bad at all.

The only real drawback we ever had was that from time to time someone (ME) had to take the metal louvered doors and scrape and clean the hard water deposits off of them-- that sucked-- I am sure that there are water softeners for them now (and probably then).

But they add moisture to the air-- and you are already humid enough in Florida! so unless you can make the low humidity one, not recommended for your area.

[Sibling Chatty]

As I remember, Zono's in a condo, so outside is probably not available, unless it's a patio home situation.

I'm all about keeping the heat out. Drapes with foam-backing in white that are drawn against the sun are an inexpensive 'help'. Duette shades, with the better ratings especially, http://www.hunterdouglas.com/hdg_product_detail.jsp?id=6
are wonderful, but expensive. Both are much more attractive than the aluminum foil...

[Sibling Zono (anon1mat0)]

The second type puts the evaporation completely outside.  It's quite simple, really, and works very well.

You  _can_ "roll your own" easily enough.  The heat added by the pump is minimal, if you use a small pump.   A car radiator would work for the inside unit, provided you had a catch-basin under it.  The cooled water should hopefully get cool enough to help reduce your inside humidity, which will collect on the cool radiator.  You'll either need to periodically dump the catch basin, or plumb it to the outside.   The amount won't be all that much.

But for the rest.  You'll need tubing, a pump, and some sort of cooling tower.  Home-made ones work well enough.   This must be outside. 

This sound close to what I have in mind, except for the 'outside' part:

As a proof of concept, while explaining it to a relative we did a base experiment using a small fan, an empty sodacan box and a few soda cans out from the fridge, using the box as a duct and placing the cool cans inside and checking the temperature of the air before and after and there is a drop in temperature, plus a slight level of dehumidification.

Have in mind that I'm not looking to a fully automated system, so I don't care if I have to put ice in the box every 2 hours. Also my relative suggested using a portable cooler as a reservoir (which makes a lot of sense).

As I remember, Zono's in a condo, so outside is probably not available, unless it's a patio home situation.

Indeed. BTW the honeycomb shades are nice!

[beagle]

I have a bad feeling about the energy balances here, unless the refrigerator making the ice is outside the region being cooled. But my a/c knowledge is minimal.

[Bob in a quantum-state-of-faith]

Have in mind that I'm not looking to a fully automated system, so I don't care if I have to put ice in the box every 2 hours. Also my relative suggested using a portable cooler as a reservoir (which makes a lot of sense).

As I remember, Zono's in a condo, so outside is probably not available, unless it's a patio home situation.

Indeed. BTW the honeycomb shades are nice!

I have a bad feeling about the energy balances here, unless the refrigerator making the ice is outside the region being cooled. But my a/c knowledge is minimal.

What beagle said.

Heat has to go somewhere.

Your system can be effective at cooling a small space, like the immediate area around a chair, or a very small room.

Using the ice from your frige, you won't be able to keep up with demand.  I know, a typical frig can make about a 1/2 pound of ice every 4 hours or so (or less).  Your setup would go through that much every hour, so you'd be behind pretty quickly.

Your cooler need not be huge.  Do you have a patio that you could put an outside radiator of some sort in or on?

I remember another easy home-rolled system, uses compressed air.  You need a small QUIET air compressor, and a radiator capable of relatively high pressures.

Pump room-air into the radiator (which is preferably either outside, or in a window, with air blowing outside with a small fan).  This air needs to be at least 100 psi or more while in the radiator.  You'll need a water trap of some sort, because pressurizing the air will condense out some of the water in it.   Anyway, the air flows under high pressure through the radiator, where the inside room air blows over it, cooling the air to near room temperature before flowing back to your point-of-cooling.

Then, you release the high-pressure air into the space you're trying to cool.  If you wish to cut the noise, a long pipe with many holes in it, and the far end capped will let the air expand over a large area.  This pipe will need a water drain, too, as the expanding air will cool quite a bit, and much of the remaining humidity will condense out.   Let the air blow into your small-space, or over your favorite chair/bed/etc.

A small fan can help distribute the cooled air around the space, if desired.  Let the air out just behind this fan.

You'll want a filter on your compressor.  You'll want a control valve in the line, that lets you regulate the air-flow (a simple ball valve works, but is finicky to adjust precisely).  You'll want the out-flow to just balance the in-flow from the compressor, so as to maintain approximately 100 psi in the cooling radiator (or higher).  Higher pressures means you remove that much more heat.  You have to get the air's internal temperature [in the radiator] above ambient, or it won't work.    A pressure switch mounted somewhere or other, set to cycle the compressor on and off at preset pressures would make this automatic.   Pump comes on at say 90psi, turns off at say 150 psi.   You can add a large air-tank between compressor and the radiator to make the pump cycle less often.  Put the pump, tank and radiator on your patio if you can, or mount in a window-box hanging from a window.  Or you can box-in the pump with noise padding-- just allow adequate ventilation to the pump's cylinder (they are almost always air-cooled).   

This system is simple, cheap to make, and can potentially run forever. 

The problem areas are:
- pump/compressor noise
- water condensation in the system can rust steel materials
- dust coming into the system can clog the final pressure-drop openings (input filter is a must)
- A home-brew system will only be effective for small areas.  A system to do a whole-house would need a huge compressor.

Advantages:
- can be cheap or even free, if you convert junk-pumps yourself.*
- easy to maintain.  Rust and water condensate are the biggest headaches, and preventative maintenance solves this easily.
- it Just Works.

---------------

*   Old automobile A/C pumps/compressors can often be had for free at auto salvage yards, or nearly so.   But you have to add an electric motor, and a belt-drive.

Old refrigerator/freezer compressors work just as well, and these are almost always free at the dump.  They work on mains-power already.  Most old refrigerator/freezers were tossed out NOT because the compressor quit, but because they were dirty or out-of-style.  Just remember to keep some oil in the compressor's casing from time-to time.  If you keep the compressor low, and run the lines into and out of it from a higher elevation, the oil will stay inside the compressor's can.  And when it quits, finally, just toss it back in the dump and salvage another one.