crazy 3rd-world idea: aircon from small fridge

[Darshi]

Dan
NO unfortunatly they are over size for he application.On a second thought ,I may be able to use the evaporator as a condensor perhaps. I am looking at using air con blower motors to have smooth speed control and also manage the pressure drop across the evaporator coil without getting into too much of calculations.
I also plan to use wind shield washer pump for indirect evaporative cooling of exhaust air by saturating it to near the ADP. That way ,we have 100% fresh air .
The latent heat removed by the evaporator is converted to condensate and I plan to use the condensate to pre cool the fresh air after the heat recovery module but before the evaporator. I expect 20 to 30% saving in the capacity of te cooling unit at the steady state conditions.Here again I plan to use wind shield washer pump for direct evaporative cooling,above the system ADP.The pump will go off automatically ,when the ambient dew oint is higher than the space dew point.

Please give suggestions to improve my thinking .I will have the protos ready in 2 months or so and will surly post the images on our site .

[US Iceman]

Why not knock a hole in the wall the size of the fridge, stick the fridge in it so the coils are on the outside, open the door off the fridge and place a fan in front of it. You can still use as a fridge when not needed to cool the room

That is about the same as telling someone to live in a reefer container to have air conditioning.

[Darshi]

what motive power the farmers use in this area?
Oxen ,Horsesor tractors?

[cold stratum]

Watering the condensor will scale it up, if you use untreated water, within weeks!

I think you don't have enough cooling capacity, you will build just a de humifier with this setup.

The superheat will be to big, and therefor it will cool the compressor unefficient.

Sorry i don't see it work, in the conditions you set.


cold stratum.is1a.JPG

[Darshi]

Head board air conditioning strikes me as ingenious, Darshi. I would love to see some pictures or sketches of it someday. What automotive parts are you going to use, the evaporator and condenser?

Dan,
Thanks for the encouragement
My bed air con was assembled last week .
I will be doing some trial runs for an other week .
Should be able to post pictures and some performance data .
look forward to help from every one on the RE , for improving it further.

[TSK]

Domestic fridges work at freezing temperatures, so the simplest suggestion I can think of is to strip several down as someone as already suggested and place the evaprators in an insulated tank of water, if there is enough capacity in the fridges you have available the water should start to freeze around the coils making blocks of ice. The ice would provide stored cooling effectivly. You would then need an old blower coil from a small coldroom to pass the water through. Limited effective running time but that depends on how large the tank is and how many fridges you can get hold of and manipulate the tubing, domestic fridges tend to have aluminium pipes which break easily. Best of luck.
Have you got a stream nearby that you could build a water wheel to drive an open type compressor from a comercial type unit, then you would have a much better chance with lots of btus at your disposal.
People in England are adapting water wheels to power homes, bit radical but if you have water power you might as well use it.

[Lan1]

If the idea is for a sleeping area then two fridges hacked and joined would make a sleeping area, approapriatly vented with pre cooled air with light and escape built in it should be a comfortable sleeping bag

Doug

[Lan1]

the idea about pulling water sounds good, small electrical conduit would be suitable for this with a pond pump or similar the Asian electrical conduit I have used was very thin but would be usefull , you may need to aquire the glue from somewhere else though as my experience is that glue as not used in Asia (Indonesia)

[fridge doctor]

As our USA friend Pethereshy (apologies if name is wrong) suggests, stick to the water cooling principle. If as the last post suggests most people cope during the day and can manage with a cooler sleeping area, then storing cold water during the day is the answer. You can use any number of old fridges (stripped) and dunk their evaps into whatever tank you can lay hands on in order to pump the tank water through a fan coil of some sort (old car radiator, old fridge condenser... whatever). Glycol may be a problem for you, if so use the cheapest alcohol to enhance the water properties. Key points to remember are

• Keep the fridge compressors cool - trickle droplets of water on them if you have to (away from the electrics of course)
• Likewise the condenser, if the exit of the condenser (opposite end from where the compressor discharges) is hot, you need help. Cool it down to at least lukewarm. Use the chimney principle mentioned elsewhere, or water again (depending upon your water situation).
• Insulation - The tank you choose.... Insulate it, and the pipes leading to/from the cooling coil. Use whatever materials are available... Old woolens if you must, Get the tank up to 10 inches thick and the pipes at least 5 inches.
• Keep the cooled space small, and as well insulated as is practical.

If your tank is big enough, you can always add another fridge or two as they become available at the right price, and as needs dictate.

Finally, just a thought which may not be relevant...

The usual method of cooling draught beer or dispensed soft drinks, is by passing the beverage through a 'flash cooler'. Small fridge unit, sits behind bar, or larger unit located in storage area. Perfect for the job, already contain all the ingredients you need, water tank, circ pump, cooling coil etc... just add fan coil and water pump and you're in business. These things are thrown away with abandon in some parts of the world, but I suspect not where you are.. Good luck.

[Sledge]

I would lie the fridge on its back, plugging up the drain holes.
-First carefully move the compressor so that it will sit upright before the fridge is laid down. Be careful not to break the pipes
-Move the condensor onto one side of the fridge and refasten it there. If the condensor is the type that is built inside the outer shell (so that it is inaccessible) I would put a couple of sleepers down, and lay the fridge on that. This will allow some air flow around the condensor under the fridge
-leave the evaporator in place
-disconnect the fan and all the electric controls, wire the compressor direct to a plug/source.
-Fill the fridge with water.
-Hook up a pump that will draw the water out of the freezer section and pump it through an air coil with a fan in the room you want to cool, and circulate the water back to the fridge.
-Keep the door on the fridge and close it to keep out the heat.

One fridge will not have the capacity to achieve what you want, so do this with a lot of fridges, and fan coils.

The important issues will be
-dont break the pipes
-plug all the holes well
-good water circulation...freezing the coil is not what you want, ice is an insulator, aim for lots of water moving around the evaporator
-the condensor must be kept cool as possible, so shade would be good, air movement important, or ...perhaps put condensor in its own containor full of water, if available, (pond)
-

[Sledge]

If you decide to try this, I would do one thing different;

Draw the water as far from the evaporator as possible, and direct the warm return water directly at the evap, to try and keep the evap from freezing up.

[Darshi]

Excellent Sledge!
You can add 10% glycol to the water so that it does not freeze.Now you can keep the fridge "on" without fear of freezing.
It will also act as Thermal Storage .

[theboss]

heat gained = heat lost is the principle of energy. A fridge compressor even charged with R290 will take days to lower temp by few degs.

[kubae]

I've been building Ice block makers for awhile now. First as a Graduate student, and now as a business. Your climate is more humid and thus less friendly than even Nigeria. Whist this last idea is theoretically beautifully, it can't work using a fridge "as it comes". Reason: I use 2 (two) 2HP compressors to build ice (about 320 liters of water). In the first say, hour of operation, I noticed that the compressors were being overloaded. They survived if there was no power cut since the suction cooling kept coming. If there was a power cut, the internal components overheated and overloaded causing compressor failure. So I increased evap temp to reduce the load (BECAUSE I DESIGNED THE SYSTEM). Your case seems more complicated as the idea is that your evap sits right inside your water (thus drawing ALL the heat it could) yet you are using already designed evap temps.
Your water (what quantity will fill the fridge?) will enter the fridge initially at above 100F???. The evap will have to transfer the heat through the compressor (fridge = 1/x HP compressor) which will definitely overload.
But if you could reduce the evap temp so that there is less heat transfer, you might be able to keep the compressor alive. Note though that this means you make your ice slower or you start with already "iced" water. Plus if you really utilize the fan and cooling pipes, your returning water will be at much "hotter" temp adding to a really small compressors load. If you have power cuts, this idea won't last one summer day.

[Dr._Fleck]

The only way i think could work is mount the evaporators horizontally on the ceiling with the compressors and condensers on the floor above(or attic/loft).
This way you don't need fans, the cold air simply drops off the evaps. To get enough capacity the ceiling will have to be plastered with evaps.
The compressor mortality rate will be high though... in fact very high.

[theboss]

you can gut a swamp cooler with a small refigeration system so the water being used is much cooler than ambient and will make a difference. Don't try to cool a water reservoir or something that will be very inefficient and over load compressor. Instead use a small heat exchanger at water pump outlet. Water is cooled in this heat exchanger and sprayed onto cooler pads.

For you interest a fridge compressor is rated between 500-1700btu depending on the size of refrigerator it came from. That capacity is only good to cool your pockets.

[Darshi]

you can gut a swamp cooler with a small refigeration system so the water being used is much cooler than ambient and will make a difference. Don't try to cool a water reservoir or something that will be very inefficient and over load compressor. Instead use a small heat exchanger at water pump outlet. Water is cooled in this heat exchanger and sprayed onto cooler pads.

For you interest a fridge compressor is rated between 500-1700btu depending on the size of refrigerator it came from. That capacity is only good to cool your pockets.

One could use an indirect evaporative cooler instead of a swamp cooler. It reduces enthalpy instead of adiabatic cooling by adding moisture.

You get lower temperature too.

[Sinke]

...I have one smart idea...
...I see here is many people from the rich west...
...so just collect the 500$ for man...

[IceMan08]

wow, just found this thread and finding it extremely interesting-especially the barrel trick LMAO!!!
Also just a thought,if there is a supply for water could this not be pumped to roof level and dispersed acroos the surface? this may lighten the load of any fridgte ac setup you may have?
Evaporation=cooling!
not a massive amount I agree but, not to rip off the supermarket slogan, every little helps!!

[dddon]

Hello to all!! I am from "Minne-soda" .. where we have much more problems with cold !
I would like to suggest this: .. If you go below the ground a few meters, I believe the temp is constant ..a dwelling below grade is therefore cooler than the ambient .. If there are reasons that a dwelling below grade is not possible ,say flooding or rodents or?/ then perhaps a "duct" that carries air ,so any air directed through the duct will be cooler. a fan in the would probably move enough air to be really helpful.
dddon

[dddon]

Hi again.... had another thought ... I know that it may sound simple, but if you have 1 (one) arm or foot cool.. the human body is "comfortable ... there have been people that subjected the majority of their body to very cool conditions ,whilst one hand or foot was warm, and they had little discomfort ... for an example of this effect, that I experienced ..I arrived home from work one afternoon years ago, when my sweetie was due in two weeks with our fourth child.... we had no a/c ,and the outside temp was over 100 F , she was like a boiled lobster ...RED!! so I quickly soaked a bath towel with cool water and wrapped it around her arm , and got a pan of cool water to put her feet in ... she was already "comfortable" before i got the pan of water ready!! so perhaps to take the idea to the simplest form in the case of a small fridge ... an inclosure that can cover the feet of the sleepers and contain the cooling output of the tiny refridge would allow a "comfortable" sleep.
really worth a try!!
dddon

[wilks]

I think the idea of storing "cold" as ice and circulating it when needed is the best idea.

Now, this thread reminded me of the time when someone in Survivor (a video system benchmark) improvised an evaporative "A/C" by using an empty coconut shell to fetch water from a nearby lake and pouring the water on themselves. Then they either relied on the wind or used some object as a makeshift fan.

me too ,,