Author Topic: Bedroom cooling ideas (Read 516 times)

David HK · « **on:** February 17, 2009, 06:06:07 AM »

Summer will soon arrive in Hong Kong and with it will be humidity of around 70% on average. In the middle of the summer 30 - 33 degrees Celsius is the all day and night average temperature.

I have now provided a 12 DC power supply to the bedroom and the main window is fitted with a mosquito screen. The 220 volt AC unit remains in its port.

I would like to have a go at sleeping without the AC unit consuming my pension dollars so any ideas readers may have about a cooling or air moving system would be read with interest.

Oscillating fans immediately spring to mind and perhaps I could convert an existing 200 volt AC unit into a DC motor driven machine.

I have also thought about 12 volt DC box fans ganged together. Power consumption by these units is quite low.

It is also possible for me to change the power supply to 24 volts DC.

Regards,

David HK

thirteen · « **Reply #1 on:** February 17, 2009, 12:25:06 AM »

a swamp cooler also somes to mind but the high humidity may be to much. A small fan blowing would help maybe a computor fan or a couple of them might help and they don't use much power, sleeping in a hammock with the open mess could be good, drink water not beverages, maybe an open matteress would help. Blowing air over ice or thru it. a large turning fan pulling the air up. Just some ideas to use or laugh at. Maybe use some solar or wind for power.

MtMnRoy

Basil · « **Reply #2 on:** February 17, 2009, 05:19:12 AM »

Make a ceiling fan like I did with one of those 38 volt dc motors. I seen ac units for the foot of the bed that blow under the cover for sell on the net. Wife like lots of cover and a fan next to the bed with the ac wide open. Lot of wast there but that's her. I am getting a 12 volt small blower to blow under the cover at our feet. I will run it off my solar. I plant to put a speed control on it. Hope I can get her to like it so she will cut the ac down.

clflyguy · « **Reply #3 on:** February 17, 2009, 09:26:27 AM »

David,

I don't know how much you are willing to do for free cooling, but take a look in my

files at "offgridsolarabsorbtion.pdf". I live in N.E. Florida (US) with high humidity and heat also. This is how I plan to cool my house. -Gus

hvirtane · « **Reply #4 on:** February 17, 2009, 10:17:01 AM »

Once upon a time there was a stirling fan.

It worked for example by heating it below by a candle.

It was first developed in Germany I've heard. Many of them were made in India. The last ones I've heard about in the olden times were made in Pakistan.

Nowadays you can still buy them, but they are very costly. Please see for example:

http://gyroscope.com/d.asp?product=THERMALENGINE

You can get drawings to make them for example here:

http://www.jerry-howell.com/Menu-1.html

I hope that someone would start manufacturing them cheaper.

- hv

BigBreaker · « **Reply #5 on:** February 17, 2009, 10:17:23 AM »

Make yourself a reverse electric (heater) blanket. Route your cold (and dehumidified) air under your blanket / sheets. It will take a very, very small amount of cool air to do the trick. That may let you use a much cheaper, smaller, alternative tech A/C.

spinningmagnets · « **Reply #6 on:** February 17, 2009, 12:04:23 PM »

I know water-beds are cheesy, but I had one in highschool (class of '77), and they will keep you suprisingly cool in summer.

Box them in and install a plastic liner, it is only a matter of time before the bladder springs a leak that must be patched.

If you use cold water in a garden or for some other non-pressurized reason, you could pass cold water through the water-bed on its way to the garden (or to a holding tank that is lower than the bed)

Also, in winter, you can set a flat electric heating panel under the bladder and very cheaply stay warm all night.

Very easy to drain, unbox, and set-up a conventional mattress for the half-year you don't need cooling.

Also, perhaps set out plates of dessicant in the closed room (RV enthusiasts do this) to dry the air, this will make the ceiling fan and skin-sweat provide better cooling. Just a thought...

electrak · « **Reply #7 on:** February 17, 2009, 12:30:03 PM »

Water beds work very well for cooling, they were developed for burn victims, it fact you will have to use the heater or a few blankets between you and the bladder or it will be too cold.

30-33C (86-92) day and night avg? what is the day high and night low?

scottsAI · « **Reply #8 on:** February 17, 2009, 02:37:16 PM »

Desiccant cooling. Good call spinningmagnets.

Many inexpensive clays can be used a desiccant.

10 cents/lb (USA) Small quantities more.

The clays releases moisture at lower temperatures, 110F and up.

Do not leave as powder! What a mess!

Use the Sun to dry during the day, blow air over at night.

Fan -> Desiccant -> you for best effect.

To make this work more reading is required.

Water bed looks like a good option, fun too.

Be cool,

Scott.

wooferhound · « **Reply #9 on:** February 17, 2009, 03:50:02 PM »

I have been using a forced filtered ventilation system like this for 30 years. Not much good when the outside temperature gets up over 90 F (32 C).

http://www.fieldlines.com/story/2008/7/8/12123/01961

But I think that the best Idea is to pull air into your room through a window that is well shaded with lots of plants.

http://www.fieldlines.com/story/2007/6/5/4912/23050

wooferhound · « **Reply #10 on:** February 17, 2009, 03:55:41 PM »

I could'nt get your PDF file to load. What website is it on?

wooferhound · « **Reply #11 on:** February 17, 2009, 04:00:25 PM »

Yes

My water bed is great in the summer with the heater turned off and a fan blowing on me under just a sheet. Plus the heater is wonderful in the winter, the house can be freezing and the water bed is perfect. If you change the temperature on a water bed it will take at least 24 hours before the change is complete.

richhagen · « **Reply #12 on:** February 17, 2009, 04:34:19 PM »

It strikes me that the reason that a waterbed is great for cooling is that the beds material conducts heat away from you more rapidly than traditional bedding materials. I don't know what other materials would do this well though, as I don't think sleeping on top of copper plate would be very comfortable. Some types of cloth are likely better conductors and worse insulators than others though. I am not sure how one could work heat pipes into a bedding design. Rich

hvirtane · « **Reply #13 on:** February 17, 2009, 04:49:26 PM »

I think that a water bed is good,

because you can put there cool

water inside and it needs large

amounts of hot air to heat it.

Maybe the good way would be

to keep inside the room a big water

bed with 20 degrees C water.

And not to sleep on it to

avoid health problems, but just

to cool the room air with the bed.

- hv

clflyguy · « **Reply #14 on:** February 17, 2009, 05:36:47 PM »

Woof,

I can't remember the websight as I was at work when I sent it in, but I am at home

now, checked the board, saw your prob., went to it in my files and it downloaded for

me in about 3.5 to 4 seconds. The only thing I see that could be a prob is that I

didn't use the entire name when I described the .pdf, having left out the word

"ammonia" assuming you would navigate to my files and i.d. it visually.

Try again, it should work unless the prob is on the Board and not your browser,

best of luck.. Gus

dnix71 · « **Reply #15 on:** February 17, 2009, 05:54:24 PM »

www.free-energy-info.co.uk/P13.pdf

is pictures and plans for a solar ice maker using ammonia. It's too big to put in someone's bedroom.

David HK · « **Reply #16 on:** February 17, 2009, 06:13:46 PM »

Thanks for all the replies, they are very interesting and need some careful thought.

The water bed is probably out for weight load reasons, and the ammonia job sounds risky.

I'm surprised no one suggested a beautiful woman waving a fan over me.

Thanks to all.

David HK

jonas302 · « **Reply #17 on:** February 17, 2009, 06:38:01 PM »

Well if the waving ladies don't work out more ideas..

http://www.fieldlines.com/story/2007/3/10/23942/1876

http://www.fieldlines.com/story/2008/6/25/164450/707

clflyguy · « **Reply #18 on:** February 17, 2009, 07:19:16 PM »

dnix-

Come on buddy, think it through.... The whole thing doesn't go in the bedroom,

now does it?

A source of coldness, insulated lines in & out, small car radiator in a 12v or

24v computer fan or fans air handler.... Man, I can think of 4 different ways to

build that right off the top of my head. Probably depends most on property

orientation and shading

thirteen · « **Reply #19 on:** February 17, 2009, 08:18:25 PM »

I don't know the place your in but if there is a basement you could use the cooler air down stairs for cooling your bedroom maybe using a fan and some flex piping. Maybe. cover the outside walls with blinds or an exterior shad paneling about 6 in. from the outside wall. The wall will not get as hot as if in direct sunshine. They could roll up under the eves.

richhagen · « **Reply #20 on:** February 17, 2009, 08:53:50 PM »

It should take somewhere around 1.1 KWh to raise the temperature of about 200 liters of water by about 5 degrees Celsius. That is a lot of water to change out periodically unless you are only wanting to moderate the temperature in unusually warm or cold periods of short duration. Rich

BigBreaker · « **Reply #21 on:** February 18, 2009, 08:20:45 AM »

Skin temperature is around 85-90F. As long as the water is below 85 it will feel cool. 70 degree air feels neutral because of the heated air pocket close to our skin. An 85 degree bath feels neutral to cool.

The "coolth" also does not add moisture to the air which is handy - the water is sealed up.

If you can't come up with a mostly passive way of keeping water under 85F after visiting this forum... you are not really reading it!

TomW · « **Reply #22 on:** February 18, 2009, 08:29:47 AM »

David;

Been kind of loosely following this and I had a probably weird idea that you could use one of those bed canopies like they use to keep skeeters out combined with the dessicant method or a small AC window unit to just blow drier air into the "tent" or whatever they call it?

Seems an easy way to limit the cubic space to keep dried and therefore lower the energy needed?

Just a thought.

Good luck with it.

Tom

David HK · « **Reply #23 on:** February 18, 2009, 04:06:34 PM »

Thanks chaps,

As usual there is more to it than I thought.

I shall probably give the 12 volt DC box fans a go in the first instance because I have plenty of power available.

Will report back in about two months.

David HK

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Author Topic: Bedroom cooling ideas (Read 516 times)