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Simon Butler
10-05-2010, 09:59 PM
Hi, I've been asked to look at building a one off piece of lab equipment which require two walls about two foot high which atmospheric particles will pass through and freeze.
One wall needs to be colder than the other, one at -60C and one at -40C the temperature needs to be very even from top to bottom.
Also it needs to be cheap!
I was thinking of flooded evaporators to give the even spread, the heat load is very low as the chamber will be well insulated with just a small amount of air being injected into it.
What are your thoughts on getting -60C, can it be done with a single circuit (space is also an issue as it needs to be used on a plane).

Thanks.

mad fridgie
10-05-2010, 10:49 PM
Hi, I've been asked to look at building a one off piece of lab equipment which require two walls about two foot high which atmospheric particles will pass through and freeze.
One wall needs to be colder than the other, one at -60C and one at -40C the temperature needs to be very even from top to bottom.
Also it needs to be cheap!
I was thinking of flooded evaporators to give the even spread, the heat load is very low as the chamber will be well insulated with just a small amount of air being injected into it.
What are your thoughts on getting -60C, can it be done with a single circuit (space is also an issue as it needs to be used on a plane).

Thanks.
I have done similar types of work, you combine 2 different types of refrigeration effect.
-40C by vapour compression (normal say using R404a) for both plates, then you cascade thermoelectrics on to one of the plates to make your -60C (or colder if required) Bad timing I was in Manchester last week would have shown how, back in NZ now