>I need to test a product at hot and cold temperatures. Can anyone 
>suggest a
> cheap alternative to an environmental chamber?
>
> A small freezer would probably be fine for the cold, but what is a 
> good
> solution for hot (50C)? I think a toaster oven would be too hot.
Marcel's answer sounded excellent if you need a large chamber size.

For smaller sizes a Peltier device will provide both heating and 
cooling. You can buy 50 to 100 Watt DC input 'modules' for modest 
prices (around $US10 AFAIR) and mount as many of these as needed. 
Adequate ambient airflow over the external heatsink is probably a key 
requirement.

50 C on the hot side should be easy with a Peltier device and you can 
easily supplement the heating with resistive heating if desired. At 
low Wattages even a bank of off the shelf 5W or 10W resistors may 
suffice and you can find 250+ Watt  surplus resistors at minimal 
price.

If you need to go VERY low then a Peltier device may not have enough 
power. What is your target temperature range?

Actual temperature control is easy. Discuss that here if needed once 
you sort out how to do the heating/cooling.

If you can tolerate a $US400 odd price tag then the off the shelf (eg 
Costco) Colemans Stirling cooler would have more power and be more 
efficient than most alternatives. While it can notionally also cool it 
probably isn't intended for that and adding resistive heating would be 
cheap and effective.

Having too much heater power is not a problem if you can control it 
OK - having too little is.



        Russell

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