Author Topic: Jury rigging your A/C  (Read 8125 times)

trigzy

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Jury rigging your A/C
« on: March 31, 2006, 11:59:35 PM »
Ok,
     So I've had this idea in the my head for a while, but I want to see someone build it.  Here's what you need

1) A/C unit, and preferably the equipment to dis/re charge it properly
2) An open lake, river, stream or large continous supply of water that isn't your drinking water that's cooler than the outside air
3) Some small pumps

Now, lets say you have a window A/C unit.  (This part of the experiment we can all try)  Wait for the hotest day on record - set it to max and allow it to try and cool a very large room.  (Use fans in the room to cirulate as much air as possible.  Let's say it's 30C out, and your A/C can get your room down to 25C.  Now go outside with your garden hose and set it to spray cold water one the condenser, and you'll notice the A/C can take it down a couple of degrees, lets say to 23C.

So that just gets you warmed up to my idea.  Here are some of the factors limiting how much your little A/C can cool:

1) Surface area of evaporator
2) Aluminum/Air heat exchange coefficent of evaporator
3) Amount of air the you can move over the evaporator
4) Amount of refrigerant compressor can actually move through the lines
5-7) Items 1-3 of the condesner

So, we cant adjust item #4 without getting a bigger compressor, ie new air conditioner and away from the point.
Items 1 & 5 are hard to adjust, so for the purposes of the discussion, we'll leave them alone too.

So, we pump water from our lake over the condensor (outside) portion of our air conditioner and return the slightly heated water to waste (or some other use??).  This accomplishes two things.  The heat capacity (by volume) of water is greater than that of air, and the efficency of moving heat from Aluminum to water is much better than Aluminum to air.  So on both accounts, we have removed more heat than the stock setup.  The more water and the colder it is, the better this will work.

Ok, but dont get your mig welder out yet.  The Evaporator coils on the inside of your house will be much cooler than they were before, and the water that normally condenses on them freezes up and then your whole evaporator becomes a block of ice.  Your A/C stops cooling because no air is flowing, this is not good.  So, you need a bigger fan or bigger evaporator, either will do; but here is the third way:

Run water over the evaporator and pump it to a big radiator or smaller radiators in other areas of your house.  You may wish to use anti-freeze in this system in case it falls below freezing.  The efficively increases the suraface area of your evaporator and allows for different fan setups......  Keep in mind that you dont want thiese other radiators to fall below freezing, or the water will freeze on them as well.

You've effectivley greatly improved the efficency of your A/C.  The EPA will hate you for warming up the fishes water and leaking all that freon when you take the AC apart, but will hug you for using less kW*hrs to run your A/C.  Not tested past experiment stage.  Your milage may vary....


Steve
Power Anand 24/2, Brushless 20kW, some other antique iron.
Vendor of AVR's, Small Clones of Yanmar Diesel and Honda Gasoline Engines

GuyFawkes

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Re: Jury rigging your A/C
« Reply #1 on: April 01, 2006, 12:12:28 AM »
I grew up in the far east and have lived in some of the hottest places on the planet.

A/C is nice, cold beer is nice too, in theory.

In practice I always preferred ceiling fans, they are one hell of a lot healthier than A/C, and for "our" applications here one hell of a lot more sense.

if you MUST run an A/C, why on earth waste all the power going from motive energy to electric and back to motive, you are only going to be running the sucker when the generators is running anyway, so drive the A/C compressor pump directly off the lister.

this will give you hell of a lot of spare AC mains power from any given lister / gen head arrangement than doing it any other way.

but ceiling fans, they are the way to go.
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Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
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Current status - project / standby, Fuel, good old pump diesel.

trigzy

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Re: Jury rigging your A/C
« Reply #2 on: April 01, 2006, 12:35:35 AM »
Of course Guy has the right idea here.  (Hey!  I didn't even shudder when I said that.........hehehe)  Just move to a region with a more mild cilmate, and/or lower your fussyness about high temerpatures.  But lets say your wife/gf is a little less flexible than you are....

If you can get one from a car/truck/bus/train that is mechancially operated even better, the serpentine belt system might even work on the Listers flywheel!!  :P.  You can still apply what I discussed to a non-electric A/C, to improve it's efficency.  That means you can use a smaller A/C unit, and use less HP and fuel to get the same amount of work done. 

From my observations celing fans make it "feel" cooler than it acutally is when you set them to blow downwards, and you dont need to run your A/C as cold as if you dont have them.....  For you off grid types I've even seen some 12V celing fans for sale......

12V celing fan, 12V compact florescent installed in it means that you dont have to run your AC/generator as long.....

New thought, run domestic water through the condensor portion, so that it (if only slightly) preheats your domestic hot water...

Steve
Power Anand 24/2, Brushless 20kW, some other antique iron.
Vendor of AVR's, Small Clones of Yanmar Diesel and Honda Gasoline Engines

rsnapper

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Re: Jury rigging your A/C
« Reply #3 on: April 01, 2006, 01:38:12 PM »
I have one of the heat recovery units on one of my condensers that preheats circulated water from the wter heater. It recovers a LOT of heat. I haven't attempted to measure how much the water heater doesn't run in the summer here on the Gulf Coast in the summer as opposed to the winter. I can tell the difference in the temperature of the water in the shower though. In the summer when the AC runs a lot the water is significantly warmer than in the cooler weather.

I'm pouring the slab for my shed/engine room today. One step closer...


SHIPCHIEF

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Re: Jury rigging your A/C
« Reply #4 on: April 01, 2006, 05:03:29 PM »
When I visited my friend who works in Edwards Airforce Base, I noticed that the old houses had some weird kind of steeple looking thing sticking up out of the roof. Brian said they were evaporative coolers. Appearantly water was put in then and it wicked out into a loose weave fabric. The house fan would blow air thru and the latent heat of vaporization (of the water) would cool the air. Much cheaper than air conditioning. I guess you need a dry climate. So Guy, are you familiar with these? maybe you could give more detail?
Scott E
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GuyFawkes

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Re: Jury rigging your A/C
« Reply #5 on: April 01, 2006, 06:22:46 PM »
yeah, there's modern versions of the same thing doing without the wick and relying on a very very fine mist of water from high pressure, less energy efficient.

if you want to know how it works next time you go out for a drive hang a wet flannel out the window at 50 mph for a few miles.

the mechanism is "phase change" and "latent heat" etc

doesn't actually matter what liquid you use, the principle works the same for everything, you could use benzine or ammonia and get the same result, but with other attendant problems.. water is non toxic, non flammable and in most places not in short supply.

the arabic style of a tower somewhere to absorb heat and "chimney" a thermal syphon creating a draft throughout the building is similar, esp if you surround the building with ornamental ponds and make the building with high ceilings and narrow windows...  those "artistic" glazed tiles reflected a lot of heat too.

you can easlily get internal ambient temperatures 20 to 30 degrees farenheit lower with these systems for a sum total of zero energy input.

A/C just uses a pump and a nozzle to get the pressure drop required to make that phase change work in your chosen liquid.

in the old days gas powered refrigerators drove the system from the heat of a gas flame instead of mechanical motion.

the mechanical pump has the advantage you can put as much power into it as you like.

it is hugely wasteful to burn diesel to get rotating motion, then lose efficiency to convert that to electric, then lose efficiency to convert that to rotating motion, to power your phase change pump.... eliminate the electrical stage, and lose all those problems associated with starting electric motors under load, always a dumb idea if you can avoid it.

lister - petter still do a roaring trade today making small 1500 rpm units direct driving A/C units for truck trailers that are refrigerated.

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

without wishing to be coming accross as anti american.....

yanks are blessed with vast resources, as a result, it's harder for them to think small.

my start-o-matic is rated at 2.5 kw ac electric output (ok it is built to take over rated output and power factor unity etc etc)

be honest, 2.5 kw ___is____ enough, IF you make everything else fit, eg flourescent bulbs instead of filament, electroluminescent for background lighting etc etc etc.

when pushed, such as arctic bases and spacecraft, americans can do this stuff.

when not pushed, hell, buy a 15 kw head, not enough? buy a 25 kw head

you don't *have* to sit there and say 5kw head and one 6/1, that's my limit, now how do I do this? and go looking for efficiency.

that's a shame, you lose out on a lot because of it.

a 1970 muscle car with a 440 etc etc is cool.

but

a 1970 MG midget with an 80 cube 4 pot can be one hell of a lot of fun too, and it will do the same journeys, just in a different way.

I always get the feeling in here that some of you are buying 40 year old MG midgets, and working on them to make them quarter milers, with the way you deal with lister(oids) when the real beauty was keeping the MG as standard and working on your other alternatives to get the same result.

none of you NEED more than 5 KW.

you only consume more than that now because efficiency is your lowest priority.

go on an efficiency drive and make everything work within that 5 KW and peak oil or not, veg powered lister or not, economic crash or not, you are going to learn a hell of a lot, and save a hell of a lot of money, year on year on year, even if you never fire up a lister again.

sometime I'll show you an picture of my domestic heating unit. it may surprise you.
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Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

jimmer

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Re: Jury rigging your A/C
« Reply #6 on: April 01, 2006, 06:44:47 PM »
a 1970 muscle car with a 440 etc etc is cool.

but

a 1970 MG midget with an 80 cube 4 pot can be one hell of a lot of fun too, and it will do the same journeys, just in a different way.

I always get the feeling in here that some of you are buying 40 year old MG midgets, and working on them to make them quarter milers, with the way you deal with lister(oids) when the real beauty was keeping the MG as standard and working on your other alternatives to get the same result.

none of you NEED more than 5 KW.

you only consume more than that now because efficiency is your lowest priority.

go on an efficiency drive and make everything work within that 5 KW and peak oil or not, veg powered lister or not, economic crash or not, you are going to learn a hell of a lot, and save a hell of a lot of money, year on year on year, even if you never fire up a lister again.

Well said.

Good grief!! I agree with GuyFawkes!

jim

solarguy

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Re: Jury rigging your A/C
« Reply #7 on: April 01, 2006, 07:25:17 PM »
Yup, Guy is right.

Conservation is EVERYTHING.

Don't even talk to me about solar electric or small scale hydro until you have pushed the conservation/efficiency trick just as far as you can push it.

Homepower magazine (which is a fabulous periodical by the way) gives the rule of thumb that you will save 4-5 dollars on photovoltaic panels and equipment/batteries for every dollar you spend on conserving electricity.

Good luck and have fun!

troy

Stan

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Re: Jury rigging your A/C
« Reply #8 on: April 02, 2006, 12:01:52 AM »
Those old "coolers" using evapouration to cool you are/were called "swamp coolers".  You can still buy them for houses, but they are most efficient when the outside air is below 40% humidity. (of course ::))
Stan

sid

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Re: Jury rigging your A/C
« Reply #9 on: April 02, 2006, 02:09:29 AM »
a/c are already built to use the consensation from the evaportor to blow back on the condenser and be more efficient//they use a slinger on the condenser fan blade to pick up the condensation in the bottom and spray it back thru the coils/ lowers pressure. some old styles even used a belt to pick up the water// other used a vortex mounted in the bottom/ it made the air swirl and pick up the water//sid
15 hp fairbanks morris1932/1923 meadows mill
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hotater

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Re: Jury rigging your A/C
« Reply #10 on: April 03, 2006, 12:42:59 AM »
I'm laughing myself silly at folks not knowing about swamp coolers.  They're sold in Home Depot here.  It's rare to see regular AC in an old building in the west.
  In FACT, I have a portable unit I bought at a flea market to cool the shop. It runs a 1/3 HP fan and a 1/10 HP water pump and can bring down the temperature ten degrees in just a few minutes.

Most swamp coolers are metal boxes with grass mats for three sides.  The bottom is a water pan about three inches deep that's fed by city or a well water supply through a float valve to maintain level.  The water is pumped from there into a three sided manifold that trickles water through the fibre matting and back into the pan.  The forth side of the box has an outlet for the 'squirrel cage' turbine fan that is mounted inside the box over the water pan.
   The largest I've seen are in the older shopping malls in Colorado and Utah and have about a thousand square feet of mat and multiple three HP fans, but most home units are one HP and 50 square feet or so.  Most are extremely effecient.
   The downside is they're not 'instant on' or dependable to supply a certain temperature air at all times.
In highly mineralized water the mats are junk in a month, but I can run two summers on my well water without having too much calcium/lime/manganese/etc interfer with air flow.  Mats are cheap at $.10 a ft2.

  To go into an old place in the low desert made of adobe and native rock with pounded earth and varnish floors and pole beam ceilings and a swamp cooler is to enter the finest of comfortable summer quarters.   A cold beer is appropriate to celebrate it.

Most of the ranchers and native travelers around here have a canvas bag of water hanging off a mirror bracket or hood ornament.  It's teeth-hurting cold on the hottest of days as long as the truck is moving.  The fabric is designed to 'sweat' just enough to cool the bag.  Old time western 'hotels' had burlap window screens and a pan of water and a dipper to throw it with....

One more....in the "Magic Valley" of Idaho and much of the west, much of the field laborers are Mexican or Central American. On the hottest of days, one hundred plus and no shade, they wear a Levi jacket with wool lining and a felt hat.  It mystyfied me for a while, but a local friend and sugar beet grower that hires a lot of field help told me that during the day you'll see one or more go to the nearest irrigation ditch and dip the hat and jacket in the water and go back to work.
    I tried it last year....I don't work hard enough to stay warm!!!
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pa73

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Re: Jury rigging your A/C
« Reply #11 on: April 03, 2006, 08:52:50 AM »
For Guy’s information, there is a huge London building which was designed in the late 1950’s. It draws 1 billion imperial gallons of Thames river water through heat exchangers in the building, which in turn cool air for circulation throughout the office areas.

The tunnels which carry the pipes to two sumps (inlet & outlet) under the Thames are half the size of the Northern line tunnels.

Such a system is now prohibited, as nobody is allowed to warm the Thames in an artificial manner. However, this example of conservation saves millions of KwH every year.

Doug

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Re: Jury rigging your A/C
« Reply #12 on: April 04, 2006, 07:13:52 PM »
The city of Toronto has a few large office buildings cooled this way from deap lake Ontario water...
This is "New Technology" here.

Doug

Stan

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Re: Jury rigging your A/C
« Reply #13 on: April 05, 2006, 03:47:34 AM »
Large office buildings in Toronto have to be cooled.  I worked in the TSE and the 3 large office towers had no heating, only air con....The activities in these buildings overheated them even in the winter.
Stan

hotater

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Re: Jury rigging your A/C
« Reply #14 on: April 05, 2006, 05:51:03 AM »
Quote
The activities in these buildings overheated them even in the winter

I've been to a few of those partys!!   ;D
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.