I need a heat sink like this one, please help?

I have been looking to find a long heat sink like this one: http://www.anglia-live.com/products/kw/LAM-4-150-05-V/774353001_HEATSINK-FAN-150MM-5VDC but I can't find one that is cheaper or similar (Other than other models of this). I basically want to make a thin air conditioner with about 18 peltier units. I want one of those heat sinks on the hot side. I then want to do the same thing on the cold side or I want to use a bunch of mini 40x40mm fans on each cold side of the peltier units. Please let me know if you know any similar heat sink designs or if there is a name for this kind of design.

Also, if there are no similar heat sinks, could I just go to Home Depot and buy a hollow aluminum square pipe and add a mini PC fan instead of this? I would assume it wouldn't be as effective because of the less surface area, but, it would be cheaper I think.

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-max-2 years ago

As mpilchfamilay said, peltier units are better heaters that they are coolers. You could probably hack a CPU heatsink (they go for as little as $15). searching active (as opposed to passive) heatsink pull up many similar results, but also many CPU heatsinks.

I do not see that a aluminum pipe will do a great job with heat transfer. Looking at the heatsink in the URL provided, it has a thermal resistance of 1.1*C/W. without the fins there to increase surface area, this resistance will be noticeably higher., which will probabaly lead to poor performance.

Peltier units are no good as an air conditioner. They are great for cooling a CPU or other hot running electronic devices. They even a nice novelty item for those 12 oz soda can USB coolers. The produce a lot of heat and pull a lot of power of relatively low return on the cooling.

But you won't find any nice extruded aluminum heat sync like that for any less than that. That isn't a bad price for that heat sync and fan. Any chunk of copper or aluminum will be good at drawing the heat away form the peltiers.The more surface area you have the better faster it can pull the heat away. The key will be isolating the hot and the cold sides.

People are always wanting to use peltier units for some sort of personal AC but they quickly learn the limitations of the, So get one unit and see what you can do with it before scaling up.

knexpert1700 (author)  mpilchfamily2 years ago

I was thinking of that as well being inefficient for how much energy it uses and the lack of heat it produces on the cold side. I found a great deal of $1.48 for each. I will buy 18 and have some fun with them whether or not they will work well for an air conditioner. I was thinking about a hand usb power bank that uses your body heat to charge a power bank and the air & a heat sink to create a different in temperature. Maybe you could hold it in your hand and it would charge or something. Thanks though for the reply.

You need much more heat than your hand can provide. Now there are products out there now that have peltiers integrated into kettles and whatnot for camping so you can charge your devices while boiling water. Though the efficiency of it drops dramatically as the water heats up since it's relying on the water for the cooling of the peltier while it generates power.

knexpert1700 (author)  mpilchfamily2 years ago

Well I was considering that. I would only need about 0.9-1 volts so I could hook it up to this: http://www.ebay.com/itm/161154360120 and then hook that up to a USB power bank or maybe some rechargeable batteries.

In order to boost 1V to 5V you have to sacrifice current. The peltier isn't going to provide nearly enough current for that. For example most device need at least 200mA from a USB port. Even if the converter is 100% efficient the peltier will have to produce 1A. Unfortunately the peltier is vary inefficient. So much so that it would be better to use a heat source to boil water and run a small turbine than is would to heat the peltier and try to produce power that way. A solar panel would be more efficient than a peltier.

knexpert1700 (author)  mpilchfamily2 years ago

What about multiple peltiers? Say 5?

You'll have to play with them. Just keep in mind you'll need to maintain about a 40 degree C difference in temp to maximize their output. So while you may get say 9V out of them the current will be vary vary low. The more you have the morre currnt you can get as a whole and make them useable.

knexpert1700 (author)  mpilchfamily2 years ago

In winter, I can probably get about half of that at 20°C if one side were at 96°F and outside it were a little below freezing point (Which is common in New England).

petercd2 years ago

I needed a custom heatsink for my LiPo charger and it was much cheaper to build it myself. I used 15mm dia al tube with thermal paste between the sections as well as the transistor mount. The gaping hole is for airflow and to isolate the heatsink from the rest of the circuit, the tab wasnt at ground potential.

The formula and folded aluminium concept here.