PDA

emcoasthvacr
12-05-2006, 06:28 PM
From a post in R&I on this site, I think it's likely that these so called higher SEER R-410a residential units actually cost more to run than lower SEER R-22 units due to the higher pressures.

Since you need more amperage to run a compressor at higher pressures in a R-410a unit, your electrical cost will unequivocally be higher.

beenthere
12-05-2006, 06:51 PM
If a 12 seer r22 was more efficent then a 13 seer r410a.
Then the r410a wouldn't be 13 SEER.

Your confusing higher pressure reading, with compression ration.

The pressures are higher on both the vapor and liquid line, but the compression ratio is lower, so it takes less amps to run the compressor.

hvaclover
12-05-2006, 07:02 PM
HHHmmm.. I always thought it was watts and power factor that determined final cost of operation

beenthere
12-05-2006, 07:07 PM
Originally posted by hvaclover
HHHmmm.. I always thought it was watts and power factor that determined final cost of operation

Sort of like 12 seer, 12 btu's to the watt.
And 13 seer, 13 btu's to the watt. :)

emcoasthvacr
12-05-2006, 07:25 PM
Thanks for your input.

He basically said that your just operating at a higher pressure level -- but higher pressure level means more Force to maintain at a constant working level.

In addition, my 95 Dodge Diesel truck runs at a much higher compression ratio than the newer Dodge Diesel trucks, but I get more mpg (same displacement & horsepower). Diesel is more efficient than gas due to the higher compression ratio, thus more thermodynamically efficient -- how do you reconcile that?

Originally posted by beenthere
If a 12 seer r22 was more efficent then a 13 seer r410a.
Then the r410a wouldn't be 13 SEER.

Your confusing higher pressure reading, with compression ration.

The pressures are higher on both the vapor and liquid line, but the compression ratio is lower, so it takes less amps to run the compressor.

[Edited by emcoasthvacr on 12-05-2006 at 07:38 PM]

snewman24
12-05-2006, 07:43 PM
> Diesel is more efficient than gas due to the higher compression ratio, thus more thermodynamically efficient -- how do you reconcile that?

One reason is that a gallon of diesel fuel contains 139,000 BTUs, and a gallon of gasoline only 124,000 BTUs.

mark beiser
12-05-2006, 07:44 PM
It takes the same amount of energy to compress 1 pound of vapor from 1 psia to 10 psia as it does to compress 1 pound of the same vapor from 10 psia to 100 psia.

Its all about the compression ratio relative to the absolute pressures.

emcoasthvacr
12-05-2006, 09:39 PM
snewman,

I'm comparing the higher compression diesel to the lower compression diesel -- same engine, but much lower compression ratio due to the newer government mandated diesel emissions.

My engine has 20% higher mpg at the same cost. This doesn't include the 40% higher engine cost that I can't recover over the life of the engine or truck -- I think the same thing applies to AC units when you compare the costs.

Originally posted by snewman24
> Diesel is more efficient than gas due to the higher compression ratio, thus more thermodynamically efficient -- how do you reconcile that?

One reason is that a gallon of diesel fuel contains 139,000 BTUs, and a gallon of gasoline only 124,000 BTUs.

[Edited by emcoasthvacr on 12-05-2006 at 09:48 PM]

emcoasthvacr
12-05-2006, 09:41 PM
only in an adiabatic process, which never occurs in reality.

Originally posted by mark beiser
It takes the same amount of energy to compress 1 pound of vapor from 1 psia to 10 psia as it does to compress 1 pound of the same vapor from 10 psia to 100 psia.

Its all about the compression ratio relative to the absolute pressures.

travistee
12-05-2006, 10:39 PM
They only prove their effiency in ideal (laboratory) controlled conditions. Don't fall in line with the SHEEPLE.

The thing thats gets me

More effiency but more controls to go down in the life of a unit. Sure save hundreds on paper effiency but spend more on actual maint. cost.

beenthere
12-05-2006, 10:40 PM
Originally posted by emcoasthvacr
Thanks for your input.

He basically said that your just operating at a higher pressure level -- but higher pressure level means more Force to maintain at a constant working level.

I

Originally posted by beenthere

[Edited by emcoasthvacr on 12-05-2006 at 07:38 PM]

The pressure you and I read on the guages, is referenced to Atmosheric pressure.
But neither an r22, or r410a compressor is sensing atmosheric pressure, they only move gas in an enclosed eviroment attempting to move x amount of refrigerant.

hvaclover
12-06-2006, 01:27 AM
Originally posted by travistee
They only prove their effiency in ideal (laboratory) controlled conditions. Don't fall in line with the SHEEPLE.

The thing thats gets me

More effiency but more controls to go down in the life of a unit. Sure save hundreds on paper effiency but spend more on actual maint. cost.

Don't crab, that's job security.

mark beiser
12-06-2006, 01:40 AM
No, relative to absolute pressure. You figure compression ratios with absolute pressures.
Remember, its not just the head pressure that is higher, the suction pressure is higher too, it is the ratio between the pressures that determins how much work the compressor has to do. The compression ratio between the low and high side of a R410a system is lower than with R22, so the compressor is actually doing less work, even though the pressures are higher.

gevans
12-06-2006, 10:25 AM
SEER=Seasonal Energy Efficiency Rating.
This rating is all about the power consumption to btu ratio.
Yes, the 410a systems operate at higher pressures.
Yes, they also are typically more efficient in that they consume less energy (electricity) per btu produced.
If one unit is rated 12 SEER and the second 13 SEER, the second unit is more efficient, regardless of refrigerant type.
However, maintenance/longivity issues should also be considered.

dash
12-06-2006, 10:31 AM
IMHO,Puron/R410a systems have proven ,since the late 1990's to be at least as reliable if not more so,then Freon/R22 systems.

See http://www.410a.com