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Thread: freon 410 problem in iraq
08-25-2012, 02:50 PM #14
08-25-2012, 08:13 PM #15
08-25-2012, 10:26 PM #16
Yes you need water source units.
08-26-2012, 02:07 PM #17
08-26-2012, 02:07 PM #18
08-26-2012, 04:42 PM #19
08-26-2012, 04:46 PM #20
08-26-2012, 06:18 PM #21
An R-22 has a critical point temperature of 205.6 degrees F and loses about 6% of capacity for every 10 degrees above 95 degrees OSA.
An R-410A has a critical point temperature of 162.5 degrees F and loses about 7.5% of capacity for every 10 degrees above 95 degrees OSA.
Both refrigerants lose about 2% of capacity on a condenser for every 1000 feet of rise in altitude.
The performance of both R-22 and R-410A is influenced by condensing temperature – R410A is slightly more sensitive to condensing ambient temperature than is R-22 up to around 45°C. Above this temperature (equivalent to a condensing temperature of around 60°C) the refrigeration capacity of the R-410A system starts to fall off more rapidly. At this temperature the relative drop in capacity exhibited by R-410A systems is around 10% greater than that of an R-22 system.
08-30-2012, 11:14 AM #22Professional Member*
- Join Date
- Jan 2005
The reason your having problems with the new R-410A systems is due to the characteristics of the refrigerant and the outdoor temperatures your experiencing. R-410A is not designed for air cooled equipment at the temperatures you indicated.
If we go back to the principles of refrigeration, the way we cool is to send a liquid refrigerant to a heat exchanger where it boils. The only way to boil a liquid is to add energy to it, in our case HEAT. As we remove the energy surrounding the coil to boil the refrigerant we cool the area. This energy is now trapped in the refrigerant vapor and we need to release the heat energy to return the refrigerant to a liquid state to be used again to absorb more energy. And this goes on over and over. Pretty simple process.
In your case the problem is your outdoor temperature.
In order to condense a refrigerant vapor we compress it to increase its temperature above the ambient surrounding the heat exchanger coil. With the temperature of the refrigerant climbing above the ambient air (normally 15- 25 degrees “F”) the heat naturally flows out of the vapor and condenses the refrigerant.
I think in degree “F” so let’s convert. 60C = 140F, 70C = 158F. Using this information, a system operating in a outdoor condition of 60C will need to condense between 155F to 165F depending on the equipment (remember condense 15-25 degrees above ambient), in a outdoor condition of 70C will need to condense between 173F to 183F depending on the equipment (remember condense 15-25 degrees above ambient) This would be considered normal for the conditions.
The characteristics of R-410A are that it has what they call a Critical temperature of around 162F. This means that R-410A can’t exist as a liquid above this temperature no matter what the pressure is, as a matter of fact it will be a vapor no matter what the pressure needs to be. If you look back at the condensing temps at your temperatures at 60C you MIGHT condense if the condensing unit is designed for a minimum rise above ambient. At 70C it’s NOT going to condense.
The reason R-22 worked is the critical temperature is around 204F which would allow it be able to condense at the conditions above.
I hope this helps to explain why your having problems with an air cooled R-410A system in your location.
08-30-2012, 12:24 PM #23
08-30-2012, 01:30 PM #24Regular Guest
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- Aug 2012
- Toronto, Canada
08-30-2012, 08:07 PM #25Professional Member
- Join Date
- Apr 2008
08-30-2012, 10:29 PM #26