I am trying to build a refrigerator?

Question

I am a senior mech. engineering student who wants to build my own refrigerator unit (about 36 cubic feet). I plan to do this with TEC devices. I could use some suggestions on the best ways to go about this (best thermal insulators, TEC suppliers, etc.). I have no problems with the mechanical aspects of the device (thermodynamics, structure, etc.), but I am a clueless on how to make a decent power supply. If anyone out there has any experience with any of this, and would like he help out, I would be very grateful. Thanks!

Answer 1

You don't need anything fancy for insulation, kaowool or styrofoam is just fine. You buy the Peltier junction that suits the type of need you have, whetherthat be to cryogencally cool something or just keep a beer chilled. Basically, you feed it low voltage DC, so you just select a power supply out of Digikey that meets the nameplate rating...don't worry too much about ripple current or noise, a Peltier junction could care less about that, so an El Cheapo power supply is fine.

The trouble with Peltier devices is that they are rather inefficient (3% or less), don't have much capacity (a few watts at best), are relatively expensive, and have a very steep Qlow versus delta T curve (a delta T greater than 10 deg C means your refrigeration "coolth" wattage goes way down). Also, make sure you have an adequate heat sink on the hot side or it's not going to work at all!

Gateway Electronicsand All Electronics have some surplus Peltier deivces you can play with for a lot cheaper than buying a brand new one. Good luck!

Answer 2

Guys are selling TEC/Peltier devices all the time for cheap on E-bay.

http://business.search.ebay.com/peltier_Electronic-Components_W0QQcatrefZC6QQcoactionZcompareQQcoentrypageZsearchQQcopagenumZ1QQfclZ1QQfromZR2QQfsooZ2QQfsopZ2QQftZ1QQftrtZ1QQsacatZ4659

Just get the biggest ones (300+Watts). They run off of any voltage up to12VDC.

You can actually use old PC power supplies, because they supply 5VDC and 12VDC. Here's how:

http://www.makezine.com/blog/archive/2005/12/how_to_atx_lab_bench_power_sup.html

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Answer 3

These web pages might get you started. Otherwise, just pull a power supply out of an old refrigerator.

Answer 4

You do not need power supply.
look at following link:
http://www.nh3tech.org/abs.html

Answer 5

use ice