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

[Stormin Mormon]

If air could get in, there wouldn't be enough propane to matter.

[Stormin Mormon]

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

. . wrote in message

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.

[clare]

The explosive range for propane is relatively narrow (and low) at 2.1 to 10.1% by volume at 20C and atmospheric pressure.

Gasoline is 1.4 to 7.6 BY VOLUME - Stoich is about 14:1 BY WEIGHT.

[clare]

describe (for your opinion of the only possible way) does happen.

Not on a functioning system - most will shut down before that happens because that means a very low charge. Perhaps some home units may get that low - I don't have much to do with them - but I've never seen an automotive system get anywhere NEAR that low.

[clare]

OK Smartass. Mercaptan. You've never mis-spelled a word? Ethyl Mercaptan - the odorant in propane and natural gas

[clare]

pounds of propane.

Any idiot who will fill a leaky system without evacuating and repairing it deserves to have his double-wide join the international space station in orbit. Propane or not.

Good start for the Darwin awards.

[clare]

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.

[The Daring Dufas]

That's what the fuel/air delivery systems in gasoline engines strive for. ^_^

TDD

[Stormin Mormon]

[Stormin Mormon]

Perhaps some home units may get that low - I don't have much to do with them -

[Home Guy]

Are you just clowning around, or have you really never heard of mercaptan?

It's what they add to natural gas to make it smell like rotten cabbage so you can smell gas-line leaks.

They apparently also add it to refrigerant-grade propane.

And by the way, propane is apparently approved for use in commercial refrigeration plants.

The way things are going with the drive to increase energy efficency in consumer devices and appliances, it's really only a matter of time when residential AC units are going to start using propane. I mean jesus christ - natural gas is already being pumped into and combusted in millions of homes, in furnaces, water heaters, stoves, dryers. It's not like we don't know how to handle flamable gases in residential appliances.

The amount of gas circulating in a residential AC system is a pittance anyways, and anything short of a burst pipe is not going to be a hazzard.

[clare]

I do know MINE won't - it shuts off to protect itself if pressure is either too high or too low.

[grumpy]

Comon Chris the word is few other it's cool man, do you digit man you need to to NYC bronx section.

[grumpy]

[grumpy]

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....

[Home Guy]

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:

=============

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. ==============

[trader4]

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?

>

[Home Guy]

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?

[trader4]

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?

[grumpy]

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.

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?