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Quote:

Originally Posted by Pazuzu (Post 8741901)

That seems to fly in the face of every fluid dynamic rule out there, but we'll ignore that.

We won't ignore that he also made it clear that the pressure change is attributed to the temperature change across 12-15 feet of hose...which is something that you hold near and dear to your heart, and would NEVER refute, right?

"It doesn't seem possible.."

Seems to me that if you take a 55 gallon drum filled with refrigerant, set it on a block of ice and build a fire on top the pressure will be equal throughout.

Other than the minor effects from frictional resistance to flow how does 12-15 feet of hose differ?

Quote:

Originally Posted by wwest (Post 8742054)

I think it's different in two ways. The shape of the 55 gallon drum is different from a 3/4" hose 14 feet long, and there is a pump at the end of that hose providing relative suction. The effects are small but the pressure difference is small too.
Thanks
Dave

Quote:

Originally Posted by DaveMcKenz (Post 8742107)

I guess the base question is:

Why would the molecular density of the gas be different at one end of the hose vs the other?

The temperature at the inlet side of the rear lid condenser varies pretty dynamically from the temperature at the inlet to the R/D, so would you say there is a pressure different in accordance with temperature change?

Brain-twister..

How is it possible for refrigerant pressure to EQUALIZE so quickly THROUGHOUT the system before the low side (evaporator, etc) WARMS to OAT nor the high side COOLS to OAT if BOYLE's law prevails?

Quote:

Originally Posted by wwest (Post 8743258)

1) How quickly does it equalize?
2) Just because the pressure equalizes within the system, does not mean that it equalizes to a corresponding pressure that would be found at OAT
3) Once fluid flow ends (shut off compressor) the gas within the hose will reasonably quickly stabilize to a constant pressure (from transfer of actual atoms from high to low pressure regimes). However, that stable pressure will be based on averaging pressures within the hose, and will require that some gases heat up and some cool down. The final static pressure will have some final static temperature, and that will NOT be OAT. NOT. NOT. NOT.
4) Don't forget the fluids in that hose! Half the system has hot pressurized liquid even when you shut off the flow. Hot pressurized liquids do not follow the ideal gas law. LIQUIDS. LIQUIDS.
5) Your silly 55 gallon drum misses one key element that our A/C system has, and that is FLOW. FLOW. FLOW. Sometimes I think you miss words, so I will repeat the key ones. FLOW.