Peltier elements

[crandf]

Anyone interested in cooling by peltier elements.

Peltier elements - a solidstate thermoeletric device that creates temperature gradients when current is supplied. Fans or watercooling on the hot side will help to dissipate the heat.
Usually used for cooling PCs, but also used in some aquarium chillers

Any thermodynamic expert can calculate the wattage needed to cool per gallon water?


Discussion
http://fins.actwin.com/nanf/month.9907/msg00207.html

Product using peltier elements
http://www.coolworksinc.com/more_about_ipac1.htm

Prices
http://www.americool.com/moduleprices.htm
http://www.kryothermusa.com/NewProductsHE.htm

But seems hard to get here.
Maybe order online, but anyone willing to order in bulk with me?

[tawauboy]

why rush into buying peltier elements so soon?
have you thought through what are other components needed yet and how to acquire them?
what heat exchanger do you intend to use?

[crandf]

Well, I would prefer being able to buy just 1 low wattage one to experiment with, but if cannot get, then have to resort to overseas shipment. Even so I'll prefer ordering in 2 batches, first a small batch to test things out, followed by larger batch if things work. Thus looking for people to share costs with. I think VPOST-USA may reduce shipping costs significantly, but not sure by how much.
But frankly, all this may be wishful planning on my part, becos if shipping costs too much, then might as well buy small fridge, drill 2 holes and pass filter tubing thru, as suggested in petfrd or is it arofanatics

Heat exchanger?, you mean cooling device on the hot side? I think the average type of fans may work, but need to experiment first loh. I'm going to salvage from my old CPU cooling fans if possible. As for larger heat dissipation plates, maybe I try those aluminium bar thingys I always see around construction sites, hardwares stores etc etc.
If can find Aluminium box, then maybe can try dipping the enclosed end into the water, stick the peltier element at the bottom, and then place fan to draw out hot air or maybe should be blow in room temp air.

[tawauboy]

heat exchanger is a device to add or remove heat. you idea of the aluminium box is the heat exchanger. however, it is not a good idea as it will be very inefficient and takes up space in your tank. you need to move tank water through a heat exchanger and the heat exchanger will be the weakest link. you need something which works like a car radiator. search for something called a cold block. it will have to resist corrosion and non-toxic to tank inhabitants.

heat sink is the right technical term and is used to cool devices. doubt you can find these in construction sites and those used for cpu are usually too small. what is required here is maximum possible surface area from whatever mass of material used because you are cooling by either convection or forced convection.

basic construction will be sandwiching the peltier elements between the cold block and heat sink. fans will blow on heat sinks to remove heat while water will be cooled by cold block. the clamping force is critical for good heat transfer.

[vinz]

There are 2 chillers on the market using peltier. IceProbe and a local brand, Eido (or Eidos, i forget).

IceProbe is for small tanks only... starting with as small as 10gals. Use multiple units for larger capacities.

The Eidos one is rated for 4ft tanks.

So far it seems Peltier chillers are too slow at bring the temperature down.

[crandf]

If cannot get peltier, then will never know for sure its feasibility.

Very OT now, but cannot resist. Its on using refridgerators.

First there is the theoretical proof against fridge cooling
http://www-2.cs.cmu.edu/~cap/raid/ch...dge/index.html

Then there is the contradictory empirical proof http://chiller.nickperkin.com

Wonder whats favouring the actual operation.

And perhaps many of you know this already http://www.kingvinnie.com/aquaria/diy/
Tons of Diy plans at this site.

[kersian]

If you guys are interested in 226W peltiers, let me know...

I can get them for you guys...

[tawauboy]

explain how having the peltier will enable you to know whether it is feasible. peltier will work but whether it will cool a tank fast enough is another question.

the heat exchanger is the main problem, both sourcing and design.

[crandf]

tawauboy, I meant that as a general statement. Peltier elements will work, yes, but need to know how much each watt can lower temp by. This will depend highly on the heat input from environment, the contact design for the transfer of heat from the tank water to the peltier's cold side, as well as the cooling installation on the hot side.

And kersian, how much the cost!, pray tell? If expensive, then got lower cheaper wattage or not? PM me.

[MdmBudak]

[quote:dcfb661a5e="kersian"]If you guys are interested in 226W peltiers, let me know...

I can get them for you guys... [/quote:dcfb661a5e]

You either need a really big heatsink and fan to cool the hotside or use watercooling man.

Also, you need a seperate PSU.

[tawauboy]

to check whether it is feasible, you can do some calculation.
look for btu, energy required to heat or cool 1 pound of water by 1 deg f.
you know your tank volume and how much you want to cool down by. so you can calculate the wattage required.
however, the wattage required will most likely be about 300++ watt for a 4' tank.

[crandf]

hehehe,
http://www.stud.ntnu.no/~arnesen/peltierbeer/index.html