Instructables

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

Picture of Peltier Cooler/Heater - Pooling Brainpower
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zeeshanudsd7 months 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?
whiteoakart6 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)  zihanjj4 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 :(
Using this to cool a computer is a waste of time and money. Considering the amount of airflow normaly going through a computer thereis no comparison to the amount of heat disipitated. Peliters/TEC are very innefienct. It takes roughly 100 watts of electricity to move 100 watts of heat, making it so you have to dissipatate 200 watts on the hot side. Coolit systems manufactures tec water coolers for computers. But they are realy a waste of time. If you want to get sub ambient, go for a phase change system. They are much more efficient and can handle a much larger load. They are much larger though. What you are speaking of is a chill box. Basicly you take a evaporator froman a/c unit and put it inside a sealed computer case or cooler, With a lightbulb so you can quickly heat it up to room temperature if neccesary. These can get down to -20 c or colder.
night6 years ago
how about cooling your pc, it seems huge so maybe a pc case cooler with the cold heat sink in the case the hot one outside, you could then maybe remove some internal fans and make it a silent pc, just a thought, might have problems with condensation though,
they wouldn't work to cool a whole pc, but people do use them to cool single parts, usualy the processor, which has a waterblock on the hotside of the peltier.
zihanjj night4 years ago
 Hey night, I am just ahead of you. just checking if anyone had the same idea as me. (obvious i cant be the genius who thot of ths first right :D ) well let u know how it turns out ok..  
asourcelabs3 years ago
I see this is an older thread, but I was wondering about the power generation capabilities of a peltier junction? With lots of copper tubing (possibly pump-driven, fluid filled) the cool side buried, and the warm side black and in the sun, could I generate (even with multiple units) any kind of substantial current? Or what they pale in comparison to solar/wind/water?
They pale. The best a Peltier element can manage, in pretty well ideal conditions, and with high quality devices is barely 5%

Steve
magganrchy5 years ago
Just a thought...Why not make a peltier device that has the hot side in the water of a swimming pool...and the cold side cooling the room (piping the air away a little bit so it doesn't just re-cool the water... it's efficiency would depend on the water temp and air temp... but it might be a good way to mantain temperature in the room and pool....I'm gonna test it (i have an indoor pool...so spoiled haha)
I do not think you could get enough heat to warm a large amount of water, unless you had a gigantic Peltier that sucked Megawatts of power.  Water acts as a huge heat sink to start with and it loses heat very quickly through evaporation, so you will be fighting a losing battle.

Peltiers are better at heating or cooling small enclosed areas.  Their efficiency drops way off at bigger scales.  But if you had one of those small refrigerator types, it is probably worth trying.
Mike sr5 years ago
Disconnect all the electronics until you end up with only the cooling unit and the two wires that come out of it. Heat the side that doesn't have the cooling fins with a candle, kerosene lamp or hot exhaust and it will make electricity. you will get enough to charge some AA rechargeable batteries and might also run the fan if it is a DC fan. The cooler you make the "cold" side in relation to the hot side, the more voltage you will get out of it. I don't know how much heat it can stand so I wouldn't put the flame right on it, just kinda close to it.
NachoMahma6 years ago
. You may be able to tweak the power supply to up the voltage a little bit. It should pump more heat, but will have a shorter life. . Notice the foam seal at the sink/cold interface - don't disturb this if you can help it. This seal reduces the amount of condensation. . How many Watts does it use?
trebuchet03 (author)  NachoMahma6 years ago
Naaw, I don't want to mess with the PS - I just want to re-purpose with the same specs. According to the sticker on the case... The whole unit draws 75W
. PM mufngruf.