September 29, 2020, 05:27:18 AM
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Topic: Homemade Air Conditioner Help  (Read 655 times)

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Offline phkc070408

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Homemade Air Conditioner Help
« on: May 17, 2020, 05:12:08 AM »
I work night shift a 24-7 office.  Unfortunately, we get forgotten about in the summer and the AC is often turned off, or is set to an unbearably high temperature.  I've talked to my manager about the situation several times but it nets zero results.

Since I can't find one for purchase, I'm trying to build a mini-table top AC for my desk.  Lots of companies make ones that work off of evaporation, but that doesn't help on a humid night.  I'm thinking about building this:

https://www.youtube.com/watch?v=_h8SeC_iUJc

I was wondering if there were any liquids that I could use other than Ice Water that would result in a colder temperature.

I looked at the sites:
https://www.engineeringtoolbox.com/boiling-points-fluids-gases-d_155.html
https://www.engineeringtoolbox.com/freezing-points-liquids-d_1261.html

While some chemicals appeared in an ideal range of boiling and freezing points, they looked really bad to have in an office.

I considered denatured alcohol, but a quick google search shows that evaporates really quick in an open system.
White Vinegar, while very safe, appears to freeze above 0 C.

Can any of the chemical experts recommend something that I can use to run through the copper pipe colder that 0 C?  Remember, it has to be office safe.  Also, my only source of chilling the liquid is a kitchen freezer, about -20 C or so.

Offline Borek

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Re: Homemade Air Conditioner Help
« Reply #1 on: May 17, 2020, 01:40:43 PM »
Water and ice are the cheapest option (and actually one of the best in general, water having very high specific heat).
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Offline Enthalpy

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Re: Homemade Air Conditioner Help
« Reply #2 on: May 18, 2020, 05:23:23 AM »
The cooler in the linked video lets ice met. You could just put the ice in some tank with added ribs and suspend the tank under the roof. More silent, more reliable.

If you replace melting by evaporation, you will have a vapour in the room. Do not use alcohol, as the explosion risk is strong, and it's a poison. Vinegar has only drawbacks over water. As a melting solid, water ice would be my choice too.

Your kitchen freezer has at least its heat sink outside the room I hope? If the whole freezer is inside, it will produce more heat at its sink than it absorbs heat from the water it freezes.

If significant modifications are conceivable, you could transform a (cheap old used) fridge into an air conditioner. Its heat sink must be outside and its cold part must communicate with the room, possibly by removing the door and blowing air in it.

I suppose you already tried a ventilator?

Offline RIKRIK

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Re: Homemade Air Conditioner Help
« Reply #3 on: May 19, 2020, 06:13:29 PM »
Im a electrical engineer but asked a question on another forum. But adding salt to water will lower its freezing point. You would however need a pump to move the liquid. Or it is going to freeze up.

The easiest method would be a regular fan blowing over some ice.

Another option may be window tint film. Used for privacy but it will also reflect heat.

Now i could go into lots but nothing is going to beat shorts and a tank top with the windows open thats if your boss allows it. Also drinking cold fluids.

As metioned below, you can use T.E.C's peltier coolers. With a heat sink and fan. They run off 12v and are used in alot of electric coolers.also i dont know how well they work but you can buy tshirts with fans in them.


Offline Borek

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Re: Homemade Air Conditioner Help
« Reply #4 on: May 20, 2020, 03:56:43 AM »
adding salt to water will lower its freezing point

But it won't change the heat balance.

Quote
You would however need a pump to move the liquid.

There is a pump in the setup already.

Quote
As metioned below, you can use T.E.C's peltier coolers.

Nope, nobody mentioned peltiers. And for a reason. Putting both the cold and hot end of an AC inside you can only heat up the room, not cool it down.
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Offline Corribus

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Re: Homemade Air Conditioner Help
« Reply #5 on: May 28, 2020, 02:04:45 PM »
Nope, nobody mentioned peltiers. And for a reason. Putting both the cold and hot end of an AC inside you can only heat up the room, not cool it down.

Not 100% related but this discussion reminded me of Toaster vs Freezer.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

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