home A/C and R-22 - cost per lb

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Please explain to me again, that the toothless home owner with the ten big dogs tied out front, using propane for his AC system. That sleeveless, truck driving wonder who calls his wife by blowing the horn on the truck "musical rendition of Dixie" will evacuate to 400 microns, using two stage vacuum pump, digital micron gage, and full flow ports with valve core remover? Is that before he farts a few bars of "anchors aweigh" or after? . Christopher A. Young Learn more about Jesus www.lds.org . .
But if there is air in the system the owner has other problems. That's why a system is "evacuated" before recharging - with ANY refrigerant.
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On Sat, 27 Apr 2013 21:25:37 -0400, "Stormin Mormon"

Which is why in Canada it is technically illegal to open a refrigeration system without a licence - which requires training.
Used to have mine for automotive AC but let it lapse many tears ago.
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You could not be more wrong

Yes some of replacement Refrigerants use some mixture of propane/beuteen etc whatever, the Refrigerants are approved by OSH that is all one needs to know! And yes are whole lot more efficient then old 22,12,and 502, and specially over 134 and 410, 410 is efficient on high pressure but very lousy on low pressure/temperatures....

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grumpy used improper usenet message composition style by unnecessarily full-quoting:

Oh really?
==============Journal of Environmental Science and Engineering Dec 2010, Volume 4, No.12
A Comparative Study on the Performance and Environmental Characteristics of Alternatives to R22 in Residential Air Conditioners for Tunisian Market
Abstract: This paper presents the simulation results of a 9000 BTU/h air conditioner with some selected fluids that have been assessed for their suitability as alternatives to R22 for air conditioners. Only those refigerants with zero Ozone Depletion Potential (ODP) are considered.
Ther performance of 11 refigerants were comparatively studied using the simulation software NIST Cycle_D. R134a, R290, R600, R404A, R407B, R407C, 407D, R410A, R410B, and R417A are considered in this study.
The thermal performance obtained with R134A and R290 (propane) are very close to those of R22. The power consumption of the units operating with R404A, R407C, and R410A are higher in the range of 22-31% with respect to R22. For units operating with 407A, R407B, R407D, R407E, and R410B, the electric consumption is higher in the range 10-23%. For R600, the power consumption was in the range 6-8%.
For all the fluids, the COP (Coefficient of Performance) is lower by 7-24% compared to R22 except for R600 for which the COP is higher by 7-9% and R134A and R290 which exhibit the same COP as R22. When considering the thermal and environmental parameters, R290 (propane) is identified as the best candidate for R22, provided safety aspects of using R290 are addressed. ================= I was wrong about R22 having better efficiency than R134a (it has the same efficiency / COP) but R410 (A or B) is a big loser in terms of electrical efficiency and COP compared to R22. R410a is what you will get when you install a new A/C system these days.
But clearly, propane (R290) is the way of the future for residential air conditioning, as a drop-in replacement for R22 and R12.

Again, R22 is (was) one of the most efficient working fluids - equivalent to R134. Not sure how it compares to R12. R12 probably has a higher COP than R22, but it's a major ozone killer compared to R22.
See also:
============http://www.hychill.com.au/pdf/cpohcr.pdf
Conclusion: Hydrocarbon refrigerants have environmental advantages and are safe in small quantities. R290 (propane) can replace R22 and HC mixtures can replace R12 and R134a in applications using positive-displacement compressors.
HC refrigerants are completely soluble in and compatible with hydrocarbon lubricants. HC liquid absorbs only trace amounts of water, like R12, so HC refrigerants are completely compatible with R12 driers. HC refigerants with appropriate vapor pressures are drop-in replacements for CFCs on equipment using thermostatic expansion valves. =============
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Exactly!
My 22-year-old central air unit used to draw about 16 amps and my new 18 seer Goodman only draws 10. With the current price of electric I'm glad I replaced it.
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wrote:

Did you really run the numbers? You have to have *very* high electricity rates for the really high SEER units to pay for themselves. BTW, current draw doesn't tell the whole story (either in "efficiency" or energy used). By itself, it's a meaningless number.
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On May 8, 8:39 am, snipped-for-privacy@attt.bizz wrote:

You also need high usage of the AC to make them come out ahead. When I replaced mine 2 years ago, I took a look at the options. The cost went up a lot when going from 14 SEER to 18. My electric cost is 18c kwh and I concluded that with my usage it would take a long time to recover the extra cost. And you'd have to be confident that the unit will last long enough too. I went with the 14 SEER. Part of the cost differential may have been due to the fact that it was a 5 ton, there are less high efficiency units in that size.
Also agree that the current draw by itself doesn't mean much. Biggest potential there for a difference would be if the two systems were not of the same capacity. You could replace a 4 ton with a 3 ton, for example. And you're also comparing an old 10 SEER, which probably isn't running as efficiently as it did when new, with a brand new unit. But achieving an overall savings of 38%, which is what he's implying, seems reasonable.
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On Wed, 8 May 2013 06:18:19 -0700 (PDT), " snipped-for-privacy@optonline.net"

All things being equal, the difference between SEER 18 and SEER 14 is just that; 22% (that's really the bottom line). From everything I've seen, 14 is about the optimum price point. As you point out, the up-front cost skyrockets above that.

Right. In addition, a lower efficiency unit may have a lower PF, increasing the current further for the same KW used. It likely wouldn't be 40% but it could easily be noticeable. Current is a lousy thing to measure where watts is what is important.
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On 05/08/2013 03:50 AM, Anonymous wrote:

I just replaced my 29-year-old central A/C. Efficiency of the new unit is more than twice that of the old one.
--
Mark Lloyd
http://notstupid.us
  Click to see the full signature.
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wrote:

That may be true, though you may have saved even more money by not replacing it or replacing it with a lower efficiency unit. Like may such decisions, neither the up-front or the recurring costs tell the entire picture alone.
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d

You do realize that your source is a study of using R134A and R410 in OLD R22 based systems, don't you? It's being used in systems that were never designed for it. It says nothing at all about the efficiency when used in new systems that are designed for R410. If the efficiency is so lousy, how is it that we had 10 SEER R22 systems that are being replaced by new 14 to 18 SEER R410 systems?

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" snipped-for-privacy@optonline.net" wrote:

Assuming 40 degrees evaporating temperature and 105 degrees condensing temperature.
R410A gauge pressures will be 344 head and 119 suction R22 gauge pressures will be 211 head and 68 suction
R410A compression ratio calculation:
344 + 15 (14.7 psi atmospheric rounded up) = 359 psia 119 + 15 = 134 psia
359/134 = 2.67:1 compression ratio, R410A
R22 compression ratio calculation:
211 + 15 = 226 psia 68 + 15 = 83 psia
226/83 = 2.72:1 compression ratio, R22
Practically a tie. So in terms of compressor work-load, it's pretty equal. The higher pressures in the R410a system require a thicker compressor shell, and the long-term durability / cost-of-ownership of the entire system has yet to prove itself. The lubricating oil used in R410a absorbs more water than the mineral oil used in R22, so that's another factor.
R410a will also be phased out (or phased down) so who knows if owners who have switched from R22 to R410 will again face the cost of switching in 10 years (to R600?).
The compressor is one of two components responsible for maintaining a pressure difference in the refrigeration circuit. The other component is the metering device at the inlet to the evaporator. For residential air conditioning, a target indoor evaporating temperature is around 40 degrees F. What OEMs have been doing for some time now when playing the SEER game is to lower the condensing temperature, which would concurrently lower the head/discharge pressure. With evaporating temperatures/pressures fairly constant, a lower condensing pressure lowers the compression ratio of the compressor, which in turns reduces energy required to run the pump.
Until R410 came along, OEMs kept making larger and larger condensing units for the same nominal tonnage ratings to reduce head pressure for R22 systems. Not only was that the goal, but the larger coils made for better subcooling of the condensed liquid so there would be a corresponding gain in net refrigeration effect in the evaporator (how much actual refrigeration occurs after the refrigerant is cooled immediately downstream of the metering device).
One thing to consider is the difference between ECM and PSC motors and their effect on SEER ratings, which have nothing to do with what the working fluid in the AC system is.
I could replace the HVAC blower and condenser fans on an R22 system with ECM motors and raise the SEER of the system.
Are any compressor motors ECM these days?
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Does all of the above mean that you agree that the R410 systems that are being sold are in fact as efficient or substantially more efficient than the R22 systems they replace and that using R410 is not a significant issue from an efficiency standpoint?
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I ca not comment on whole but perhaps the answer to you question if current 410 systems are more efficient ten the old 22 systems my answer would be yes but not as is giving to people by industries. The reason that is more efficient is because condensers are made more efficient so that heat can be removed much quicker, any system depend on transfer of heat. Maintenance R410 will never be able to compete with R22 of cost and easiness for service.
wrote:

Does all of the above mean that you agree that the R410 systems that are being sold are in fact as efficient or substantially more efficient than the R22 systems they replace and that using R410 is not a significant issue from an efficiency standpoint?
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nt

yes

What answers exactly are "industries" giving that are false? Pretty much what I've heard is that the R410 systems are safe for the environment because of the R410 and that the systems are a lot more energy efficient than the typical older systems they replace.

be

Sure, that's part of it. They've also changed and improved other major components too. Larger evaporators, ie N coil instead of A, scroll compressors, etc.

What do you think the cost differential is between what R410 costs and what R22 used to cost prior to the phase out? Allowing for inflation over the last decade, I don't see it as being a huge difference. R410 is probably a little more expensive. But in the overall cost of a repair bill when you need to add enough to matter, it shouldn't make a big difference. Not sure what the issue is that you're referring to with ease of service.
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" snipped-for-privacy@optonline.net" wrote:

All the parts of a 410 system must be built to handle the higher working pressures. That makes it more expensive. Leaks that happen because of higher working pressure will reduce system efficiency over time.
Comparing the heat exchanger size and design of 410 vs 22 is disengenuous - you could have just as easily (and more cheaply) built more capable heat-exchangers for r22 systems.
I'd like to see a comparison (real dollars spent by real home owners, real dollars saved over time, etc) if someone takes a 15 to 25 year-old R22 system that needs a recharge and instead of replacing it with a new r410 system, charge it with R290 (propane).

R410 effect on ozone is nil (that is true) but as a greenhouse gas, it's not that good. R410 will be phased down in 10 or 15 years, probably will be replaced with r600.

Again, from a carnot-cycle point of view, and from real-world working pressures and compression ratio analysis, there is no difference between the two systems. If you replace a small A-frame r22 with a larger N-frame R410, you can't say that your increase in system efficiency has anything to do with the r410 circulating in the lines.
And again I ask -> does the use of ECM motors (plenum fan, condenser fan) get factored into SEER ratings?
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I don't see that in the installed cost of a new system. The systems today are about the same cost as the ones that they replace, adjusted for inflation. That is if you take an entry level system from 20 years ago, which was 10 SEER and compare it to a 14 SEER system today. Factor in utility rebates, govt rebates, and lower operating costs and they are less expensive than the old ones they replaced.

Nonsense. If a pipe or component is going to fail, it's typically from corrosion, a bad braze joint, etc. And I'd say the probability of that isn't dependent on the system pressure. And if you get a leak, it's not really an efficiency issue, because before very long with a typical leak, it's not going to run anymore.

But who cares? It's that the new R410 systems are a lot more efficient that's the bottom line. Exactly how they got there doesn't matter to the consumer.

You could try it and tell us. If it works you could have a new business. Of course the problem is that a 20 year old system that needs recharging, probably has a serious problem that caused it to need recharging.

Who cares? It's not like a car or power plant that's BURNING fuels that release CO2. Any release of R410 is going to be so small, it's irrelevant, except maybe to an environmental nut.
 R410 will be phased down in 10 or 15 years, probably

I never claimed that it did. Nor do I recall seeing manufacturers make that claim. What I see them usually saying is that R410 is environmentally friendly, R22 is phased out, and that the new systems using R22 are a lot more efficient than the old systems.

I guess you could address that to the folks that do the ratings. AFAIK, the only ECM motors used would be for the blower motor in the furnace, if it has one.
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wrote:

What answers exactly are "industries" giving that are false? Pretty much what I've heard is that the R410 systems are safe **************************************************** Yes R410 is safer as to what defiantly not regarding pressures, yes it is safer as to Propane R290 and it is Environment friendly because it does not have chemicals in it, that effects the atmosphere, as to other studies we will have to wait for few years before truth comes out. The efficiency does not come from Refrigerant regardless of type it comes from design at hole package. Note; from experience I got compressors on R134 and R410 do not hold up as good as on 12or 22. I have replace few on the brand new equipment that came directly from OEM so the sales pitch from suppliers don't work with me. Ratting is big mish mash there is no NBS anymore so the manufacture doing they own rattings just like cars, have any one ever got gas milege according to manufacture addvertisment, do I need to say more!!!
for the environment because of the R410 and that the systems are a lot more energy efficient than the typical older systems they replace.

Sure, that's part of it. They've also changed and improved other major components too. Larger evaporators, ie N coil instead of A, scroll compressors, etc.

What do you think the cost differential is between what R410 costs and what R22 used to cost prior to the phase out? Allowing for inflation over the last decade, I don't see it as being a huge difference. R410 is probably a little more expensive. But in the overall cost of a repair bill when you need to add enough to matter, it shouldn't make a big difference. Not sure what the issue is that you're referring to with ease of service.
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e

Nice edit, completely changing the context of what I said.
"What answers exactly are "industries" giving that are false? Pretty much what I've heard is that the R410 systems are safe for the environment because of the R410 "

No shit Sherlock. I've been saying that from the start. The point is that you can get a system today that uses R410, is a lot more efficient than the typical system it replaces and adjusted for inflation, they cost about the same. In other words, all this bitching about R22 vs R410A doesn't matter.

If you have more than a rare failure on brand new compressors, either you're using crap eqpt or you're doing something wrong.

You don't need to get the exact MPG the manufacturer claims to believe that cars that get 25 highway get significantly better mpg than those that are rated 18 mpg.

n

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it matters because if "they" didn't outlaw R22 you could get it at a decent price and that would in many cases be the most economical choice if you have an existing R22 system that needs repair.
the only reason switching to a new system is more economical is because of the artificially high cost of the R22.
the point is that there is no INHERENT economic advantage between R22 and R410A but yet we are forced to update
Which brings me to my question...
If you top off an R22 system with R290, do you have to remove all the R22 and replace it with R290 or can they be mixed?
Mark
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