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2009-06-23 20:01:52

Defrost in CO₂ system

Hi,

I have some expertise in refrigeration with Ammonia and Freon, but I don't really know the world of CO₂, does the system can use the same way to defrost as the other refrigerant?

RE: Defrost in CO₂ system

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Hi Frederick
It depends on the application you running if it is sub critical on a ht application you can defrost off cycle
If you are running a trans critical on ht or lt it depends on the evaporating temp. If you are running on lt you can have electric defrost

Andy

RE: Defrost in CO₂ system

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Hi Frederick
I agree with Andy about the defrosting MT coils by off cycle. You can also use hot gas defrost on the low stage. If you have no time issues you can use the superheat of the discharge gas to defrost the coils and if rhere is a time issue and in plate freezers you can use dedicated hot gas defrost compressors. There are many ways to do it but basically you can use a lot of the know how from the ammonia systems. Just bear in mind that the gas is not as hot as ammonia discharge gas

Alex

RE: RE: Defrost in CO₂ system

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you can use any way in your expertise for defrost ing,  or sometime, some systems were used heat recover loop (glycol) for defrosting