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A/C MAX
26-05-2009, 03:09 PM
Hello to all

I wondering about the smallest practical applications for the CO2, Danfoss and Bitzer, for example have some fractional compressors, but where they are used?

its the enviromental safety the only benefit of using CO2 in small refrigeration devices?

Thanks in advance

Pierre

Sandro Baptista
26-05-2009, 03:44 PM
Even the small compressors of BITZER and DORIN can with R744 (CO2) and working in a cascade system easly give about 50 kW for the cold stores (-25C) due the fact of the properties of the CO2 (very high specific volumetric latent heat). For the same swept volume it gives about 6-10 times higher capacity comparing withe the other common refrigerants (R404A, R507, NH3, etc.). Of course the motors must have high mechanical power.

They can be used to operating in the transcritical conditions with pressures up 120 bar.

They can be used in the defrost systems of bigger plants, usinng them as hot gas pump to the evaporators.

In plants where you need evaporating temperatures lower than -40C, more or less, the COP of the plant would be higher comparing with conventional solutions, and the difference will be higher as much you lowering the evaporating temperature.

Regards

NoNickName
26-05-2009, 03:59 PM
Modern literature agrees that CO2 is not an option against traditional fluorinated gases, when operated mainly in transcritical cycles. That includes all countries within +/- 40C latitude

A/C MAX
27-05-2009, 03:00 AM
Gentlemens,
thanks for your advice, Its clear to me now, an intersting application without a doubt, maybe the tight enviromental regulations can be another reason to go with transcritical refrigeration.

Many thanks

D.D.KORANNE
22-06-2009, 10:56 AM
BOCK have developed further bigger models