Build a Pump-less Recycled AC With an Old Fan.





Introduction: Build a Pump-less Recycled AC With an Old Fan.

It's hot outside again, and fans just don't quite cut it. The purpose of this instructable is to show you how to take a fan that you would normally be using and make it much more efficient, by reducing the time you need to run it while increasing its cooling power.
I've been looking around on this site, and most if not all of the air conditioning units require some sort of pump, but to run both a fan and a pump does not save much electricity.

Below is a finished ac unit.

Step 1: Gather Tools/Materials

As far as cost this was free because i used only materials I had around the house.

1. A styrofoam cooler
2. Fan
3. Aluminum cans Cans
4. paper cups
5. saw (or something to cut stryofoam)
6. utility blade
7. screw driver
8. pen/marker
9. Duct Tape
10. Ice

Step 2: Attach Fan to Cooler Lid

For this step we need to do a couple of things,

1. Place fan on lid and trace with a marker.
2. Cut out a box inside of the traced area
3. Round out edges.
4. Place fan on the lid and tape it
5. Check for air leaks, and seal them with tape.

Step 3: Heat Transfer

Now the lid is complete! Next we have to make the heat sync(s).

Aluminum is excellent at transferring heat, so we'll be using cans to help transfer the cold of the Ice to the air. Latter we'll fill cans with ice to make them chilly.

1. we first need to cut of the tops of the cans, so we can fit the ice cubes in them.

Next we need to help improve airflow through the cans.

2. Cut slits in the side of the cans.
3. using a screwdriver widen the slit.
4. use sand paper to smooth out the tops, so you do not cut yourself.
5. recycle the cut off tops.
6. put the cans in the cooler bottom.

Step 4: Make Vents in the Cooler Bottom.

The air needs somewhere to go.

1. compare the size of the can and poke a hole about 3/4 the height of the can.
2. The power of the fan will determine how many holes you need in the side, just as long as it does not feel like there is air kicking back at the intake it is fine.
3. Test the airflow.

Step 5: Add Ice.

the More Ice the better so, fill your ice trays, i even put little paper cups in the freezer to make more ice.
Put the ice in the cooler, both in the can and surrounding the cans.

Step 6: Turn It on and Enjoy.

Now its time to turn it on, the air coming out of the box should be cool. If you don't think there is enough air coming out you can always make the holes bigger.

I hope this helps you! It made my room much cooler. I would have been running the fan anyway, so the addition of the ice has increased the cooling capacity of the fan, and I run it less often saving electricity.



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    20 Discussions


    5 years ago

    Would adding rock salt make this last longer?

    Keeping your refrigerator full actually helps increase energy efficiency because there is less air to cool when space is taken up. The same goes for your freezer.

    I will expect lots of humidity and end result not so appealing

    This is a great idea especially in an area where a convential airconditioner will not work. Using freezer gel packs would store more cold and thereby make the solution work longer. Remember, there is a carbon footprint cost to this solution. Usually we think that the freezer is already running so making ice or cooling gel packs does not cost anything. However the the cost of making the ice in your freezer probably increases your carbon foot print more tha you think.

    I've seen these before but nothing quite so big - this one looks like you would feel the benefit of it quite quickly. But with all of these, the key question is "where are you making the ice?" The overall effect of this system is to move heat out of the space the unit is into the room your freezer is in. In making your freezer work harder there's an additional amount of heat generated there through electrical inefficiency. L

    7 replies

    The freezer is in the cellar, while my room is two stories up. In terms of the overall effect of the system, I would be running both the fan and the freezer anyway so, for me there is a zero net gain/loss of how much electricity I use, but overall it is less electricity than an a/c unit in my window.

    Yeah, I can see how this works, but consider this: you are the pump. Moving ice and water between the cooler and your room is replacing the pump. It's good because human effort is taking the place of an electrical pump. But your cellar will get hotter (through the extra effort of producing ice) L

    Not sure if anybody touched on this in any of the upcoming steps, so bear with me. But I was under the impression that running your freezer when it's empty takes more energy than if the freezer is full. If there is nothing in the freezer to trap and hold on to the energy (cold air) than that energy is wasted. Containers of water can be used to take up the empty space in your freezer. And if you need room in the freezer, take one of the frozen containers and put it in your fridge to help cool the fridge some. I realize initially it may take more energy to get things to freeze, but I think in the long run it will save energy. Anybody have any thoughts on this?

    If the freezer is vertical and you open the door, all the cold air "falls out" and is refilled with warm air. This is why having it fuller is better: less cold air to lose. This is also why chest (horizontal) freezers have an advantage (the cold air stays in) and upright freezers tend to have drawers / sections.
    Filling it up with water is a bad idea, lumps of expanded polystyrene in plastic bags is better - it's air-displacement not cold-retention.


    My airconditioner involves riding a stationary bike to drive a compressor.

    So the thing cools you down while you're getting hot & sweaty exercising? Where do you pump the heat to - outside? L

    well water is prone to leak from this after a while, but as long as the water won't leak anywhere near the computer i think it should be fine. I would not use this as a method for cooling your pc.

    'jlombard1390 (author) says:
    I would not use this as a method for cooling your pc.'

    nah, was thinking with the added moisture in the air if it could negatively affect a pc?

    I've done something simular to this idea, in a bath tub at night after work. I would bring home 3 five gallon buckets of ice from work (free) lay a piece of plywood over the tub with two holes in it, one for the fan, and an exhaust hole for the cold air. I would also throw in some 2 liter and 3 liter bottles of ice to extend the time. In the morning, unplug the fan, remove the bottles and put them back in the freezer, stick the plywood in the closet until I am ready for the next night.
    I was only home to sleep at that time, went to engineering school full time days and worked evenings full time. Get home, do homework, while the improvised air began to strip the humidity and heat, go to sleep after I was done with my homework and start another day. I also had extra jugs freezing in the freezer if I needed them.

    Nice job for a portable unit you've posted here.

    I am really liking this version becuase I've always found genius in simplicity, and I like the fact you are removing the pump and taking the air directly to the ice, instead of moving the cold to the fan. It also reduced the need to include water to pump through a system, leaving more room for more ice. also, you can supercool the whole system by adding salt to the ice I have a few questions: how long does this system work without replacing the ice? How long does it last with respect to the more traditional fan and pump system? Do you need to isolate the ice in the cans, or can you just use ice cubes (in other words, do you need the space for the air to circulate and cool properly?

    1 reply

    also, how big is the room you use it in, and do you have any idea of the temperature difference? and if you were to use a funnel to direct the air into a coil of copper tubing surrounded by ice, would that serve as an effective replacement for the multiple cans?