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Peltier Cooler/Heater - Pooling Brainpower

I recently acquired a thermoelectric mini fridge. As a fridge, it doesn't work so very well - it will get down to ~50 degrees with an ambient temperature of 70. So, I took it apart. You know the saying: "If it ain't broke - fix it until it is." So I now have a peltier effect cool/heater. I put my meat thermometer on the cold side with the fan off - and it gets down to freezing (probably a bit below). On the hot side, with a big sink and fan - it seems to be ~85 at it's warmest point (this sink is about half a square foot and an inch deep). Ideas on where to use? It's 110 service.... It literally almost killed me a few days ago when I touched a transistor sink that was part of the rectifier circuit while holding a plate that was grounded (I got knocked out for a few seconds) I've got a couple ideas, I just figured I'd pool brain power and see what happens :p

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zeeshanudsd2 years ago
hi '
i want to make a peltier heater but there is a problem if i used for cooling i placed a heat sink on cooling side but if i used for heater what will i do?
whiteoakart8 years ago
Hi trebuchet, it just so happens that I work with Peltier units as an industrial designer. I have created oodles of products and product proposals with these little beauties.

I can not give away any proprietary ideas, but here are a few I can throw your way:

First you need to control the output. Build a box with the sides isolated. Duct a small computer fan to the waste side (the temp that you don't want).

1a. Personal automotive A/C. Power with a converter and run off car's power port. Duct the cool or warm air to you, the less desirable air to the floor under the seat.

1b. "Desktop A/C". Same idea, just use it at your desk and run it off good 'ole 110V .

2. On your custom box, cut a hole about 4 inches DIA directly in front of the face of the cooling fins. Mount an aluminum (aluminum conducts heat and cool really well) cup directly to it. The more physical contact, the better. You now have a drink cooler. It will keep your beer cold for hours. You still have to blow/duct off the hot air from the reverse side. Put an aluminum sleeve on both sides and you can flip it over to warm your coffee. Use a baffle to direct the fan over the cool side for this.

3. "Battery Warmer". If you have battery powered tools that you use outside or in a garage, you know how coldness kills your battery life. Make a battery storage box with the warm side of the Peltier unit facing in. Keep your spares in here while you are working outside in the Winter. You will have a nice fresh, fully charged battery to switch out when the time comes.

NOTE. This particular unit is set up to cool. that is why the fins on the heat side are so huge. If you can remove the heat side sink and replace it with one like that on the cooling side, it will be much more efficient to switch between heat and cool. This is pretty easy to do. On a Peltier unit, reversing the polarity changes which side is hot and which is cool.

If I think of more, I will send them your way.

David
Hi David, I was wondering if you are still active in this field. Thanks, Joe
I am a complete novice and dont understand your explanation I am interested to find a way to install an AC in a very small car Could you please explain "very simply" step by step what is the parts required and how to install it I would also be open to the idea of someone building a unit for me Thank you for your patience and assistance
A traditional AC unit uses a closed refrigerant loop. It has a compressor, radiator, condensor, and dryer. You could install this your self, however, based on that fact that you don't know how to install a TEC system, this is out of your grasp. A simple way to install a tec system is, assuming your cars engine is liquid cooled, is to route an extra pair of hoses into the cabin area, which are connected to your cars cooling system in parralel. The hoses connect to a waterblock, which cools the hot side of the peltier and removes the heat to the outside of the car. The coolside can have a heatsink and fan attached which can blow air towards you by just building a baffle.
 hey man, u r thinking-wt i am thinking :D !!! depends on wt the car has it right now! actually the Conventional A/C produce more BTU's then a similar ( with all accessories ) size unit. also its going to drain your battery. However if you have a small car lets try it..!! i know how conventional and Peltier  units work. so i think i can help. but you have to do the craftsmanship ok ! let me know if u r interested. TC bye..
 Hi David, I was trying this crazy idea to Cool down a PC (Desktop) with this. with a primitive setup. ( i am not a Pro like u :D ) anyways. thinking to put the cold side inside the PC casing and hot outside (obvious). well this wont help u with overclocking your Processor but will cool it down if u dont have a A/C house. let me know what you think.  
zihanjj, Your application should work well.  I have seen Peltier units get frost on them in normal room temperature conditions.

You will need to vent the hot side with a small fan, so I am not sure you would be saving anything there.  Perhaps you could make some kind of passive chimney instead to create an updraft over the heated fins, instead of a fan.  You would have to experiment to see if you can get enough airflow to cool it passively.

As mentioned below (by member, night), you should also be concerned about condensation on the cool side.  Last thing you need is water puddling inside your PC case.  The amount of condensation would be proportional to the amount of humidity in the air.  Atlanta, Georgia in the Summer...Bad.  Phoenix, Arizona...good.  It may be possible to create a tray that catches any drips under the cool side and drains them out to a reservoir.  Well, maybe not just possible...perhaps mandatory.
 Hey Bro, Thax for the advice. for the past few weeks i was experimenting only with the module. this is what i have done upto now.

I put a 8cmx8cm sink and same size fan on the hot side. and 6cmx6cm Fan and Sink on the cold side. TEC Qmax 63w. my question is how to calculate the BTU inside the PC when its working? can i calculate it just with a Thermo. it vl give only a reading in Celsius.

Thinking on ur advice wt i thot was to make a bigger casing to put the PC in. bcz in a normal casing it is designed to have high ventilation, thus will push all the cool air that i am trying to circulate out. Specially with the Power Unit Fan.

Only issue is getting external devices connected to the CPU through my NEW Casing (Monitor,Keyboard,Pointing, etc.

Let me know what u think..

 



trebuchet03 (author)  zihanjj6 years ago
Temperature (Celcius) is an instant measure of energy...

What you need is Watts - Energy over time

You can probably get this thermal data from the manufacture's specs (check their website?). Alternatively, you can look up the ratings of the heat sink offerings for your chip (but this might be confusing as sinks are rated by  °C/W as sink thermo performance varies with temperature).

In your case, if your chip puts out less than 63W - it should work (how well is another story). At the end of the day, however, it will be far less efficient than a solid heat sink and fan :(
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