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runce
24-10-2003, 03:52 PM
I am currently involved in a university project to produce a domestic water chiller. The unit has a tank of approximately 2 to 3 liters (there is a little flexibility in this). Doesn't sound too difficult yet does it?! However, to keep cost down we are trying to utilise solid state refrigeration (ie thermoelectric) to cool the tank, as appose to a vapour cycle system. The tank is to be cooled to 15C below ambient. Does anybody have any experience of thermoelectric chilling of water or any suggestions? I am familiar with vapour cycle refrigeration but have virtually no experience of thermoelectric systems.

runce
24-10-2003, 03:57 PM
Further to what I've said above, could thermoelectrics be used to generate any significant electrical current from a cold water (5C) / hot water (95C) temperature difference?

Argus
24-10-2003, 05:39 PM
You may be looking for Peltier Effect heat pumps.

Try the link below, also, as I recall, RS Components had a data sheet on their use some while ago ? though I cannot say if it is still available.

http://www.hawco.co.uk/news_details.asp?NewsID=62

Also search Peltirer effect on Google


Argus
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DaBit
27-10-2003, 11:56 AM
I have been working with peltiers/TECs. These do work for your application, but you have a tradeoff: either use a single TEC near it's maximum rating, and experience a low COP, or use multiple TEC's at a fraction of their maximum rating, and experience a higher COP. The latter way is as expensive as a small vapour compression system.

You might want to check out the design software from Kryotherm.

About generating electric current with a TEC: when a temperature difference is applied, a voltage will appear. However, this voltage source has a fairly huge internal resistance, so actually drawing current from it is hardly possible.

dude
16-02-2004, 02:16 AM
I have seen a canned whip cream chiller based on peltier that looks like a small plastic drum in a supermarket. It is apparently provided by the whip cream vendor as the whole thing is decorated specifically for the product.

It doesn't hold that many cans of whip cream. The usable space is rather small and the whole thing sits on what I would guess to be a hollow plastic cylinder.

There's a pair of fans whirring at the top.