How to temporary chill a car with non-working AC.

Save us all some time and simply go **** yourself, asshole.

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'

HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Free Temperature / Pressure charts for 38 Ref's http://pmilligan.net/pmtherm/

 

No, it's not.

Please explain where the "heat" goes when the working fluid in a
refrigeration cycle is throttled through a valve.

 

New Jersey ?

Or perhaps it is transferred from outside ( warmer ) to inside
( cooler ) the system, through the evaporator, due to the change in
pressure ..... just a wild guess ......

What's being argued here is the sematics of saying 'thermal
energy' vs 'heat energy', and while the former is perhaps more
correct, the later does perfectly well.




Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'

HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Free Temperature / Pressure charts for 38 Ref's http://pmilligan.net/pmtherm/

 

Your intellect is a shining beacon, a brilliant burst of light across
the morass of stupidity that is the world. I hope you always wear your
seatbelt and don't smoke cigarettes, for all wisdom and knowledge shall --
alas, lackaday -- die with you.

 

A 700W home air conditioner? Haha!
The car has outlived its usefulness if it isn't worth fixing. Replace it.
Or fix it if you just like the car. Summer will come again next year, you
know. Or you could just go without air conditioning. I recently owned a
Honda Civic with non-existant A/C. How I hated that car (not just because
of no A/C). And yes I live in the south. So long as you don't need to
wear business attire or shuttle people around, it works just fine for short
distances. You can get one of those cheap plastic fans to plug into your
cigarette lighter. You can probably get one with a blue LED these days for
the tuner look.

Rodney

 

Nope. There is no heat loss when you pass a fluid through a throttling
expansion, but there is a significant temperature drop. Now it's
becoming clear that you don't really understand how a refrigeration
cycle works.

Well, "thermal energy" isn't really correct, either. Internal energy
and enthalpy are the two correct terms used to describe the amount of
energy contained in a fluid.

 

Man, we got some real rocket scientists in here.

 

I recommend that you do fix the AC if you feel it's a problem..there
are always used units online or at ur local junk shop that can easily
used to replace it..if not just go ahead and drive with ur windows
open hahaha...

 

It's rare that I find myself agreeing with Paul.
But he has a point. While technically incorrect to refer to enthalpy as
"heat", due to teh dynamic nature of heat, it is ridiculous to split hairs
over semantics, as many textbooks use the two terms interchangeably.
Even the 1911 unabridged Webster's dictionary included both definitions for
the term "heat", altough more modern dictionaries seem to have dropped the
former.

One can argue that since heat is *generated*, it has to be moving -- going
somewhere -- therefore, it is a dynamic phenomenon. A change of enthalpy
constitutes heating or cooling. It was pointed out to me, that heat (even
latent heat) can only move across a non-zero temperature gradient [thank you,
Daestrom].

However, the concept of "heat" being synonymous with "enthalpy" is going to
remain in the minds and textbooks of many, rightfully or wrongfully so, for
many tears to come. It's preposterous to go on and on and on about it, when
it is clear that we are are really talking about the same thing.

You are all acting like a bunch of 10-year-olds!

This kind of reminds me of a classic Looney Tunes dialog:

Bugs: I tell you it did!
Sam: Did not!
Bugs: Did, too!
Sam: Did not!
Bugs: Did, too!
Sam: Did not!
Bugs: Did, too!
Sam: Did not!
Bugs: Did, too!
Sam: Did not!
Bugs: Did not!
Sam: Did, too!
Bugs: Ok Doc, if you say so!

 

You mean expansion valves, orifices, tubes, and the like don't cause a
negligible friction loss?

Shame on you!


All joking aside, throttling (metering) does indirectly cause a heat loss of
fluid to air, as it forces condensation of the working fluid (latent heat),
and there is resultant desuperheating and subcooling (sensible heat) involved
as well.


[Now I'm gonna sound ridiculous, to prove a point:]

(well, _two_ points)

1) Without substantial throttling, little useful heat would be pumped,
since there would be no real compression.

2) And since no system is 100% efficient, throttling definitely *does*
cause heat loss.


But a little bit of heat is lost across the metering device, as well as in
the piping, coils, etc. <g>

Do you see where we could go with this? It's ludicrous, after awhile.

Of course Paul does know how refrigeration works.
But he's still a jerk most of the time.

 

You seem to be confused. The system of interest is a working fluid
passing from upstream of the orfice to downstream, not the rest of the
cycle. The change in enthalpy of a fluid as it passes through a valve
is zero and you can look that up in any thermodynamics textbook. The
energy contained within the fluid does not change as it passes through
the valve! Where would it go? How do you explain your concept of
"heat" in this context where we have a large temperature drop, but no
change in the amount of energy contained by the fluid?

The valve does not cause condensation, that is done in the condenser,
which is before you get to the valve. When you drop pressure with a
valve (or orfice), you vaporize part of the working fluid. How do you
expect to condense a fluid by reducing its pressure?

You've already sounded quite ridiculous. The only thing you've proven
is you know nothing about refrigeration.

 

No they don't. And it's not semantics. It's just wrong.

I stick with what the rest of the thermodynamics community has agreed on
as the correct terminology.

Or a change in pressure, or change in specific volume, or a change in
chemical composition, or chemical reaction. It is easy to have a change
in enthlapy without a change in temperature or a change in "heating and
cooling."

Explain where the "heat" goes when you pass HFC-134a through a valve.

Don't get offended if I don't take you seriously, but if you just
learned this, you don't know diddly about what you're talking about.

Which textbook? I have plenty of thermodynamics textbooks and none of
them say something so ridiculous.

It's not the same thing.

Only because certain people don't know enough about thermodynamics to
know they don't know what they're talking about.

 

[original post is likely clipped to save bandwidth]

Humor: - Now try and get folks to stop using the term "silver solder"
which was dumped by the alloy vendors and industry decades ago because it
wasn't solder! There is material correctly called silver bearing solder
and brazing material with silver content.

gerry

 

or "standard transmission" instead of manual transmission.
I had to pay extra for a manual for my car.
My wife's car wasn't available with a stick... how could it be standard?

 

Excuse me, is this the argument clinic?

 

If you want an argument you have to pay a dollar.

 

Does not.



Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'

HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Free Temperature / Pressure charts for 38 Ref's http://pmilligan.net/pmtherm/

 

But you're arguing with me, therefore I must have paid you. There, I've
run rings around your logic!

 

Gee, I never saw a micro-ring before ....



Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'

HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Free Temperature / Pressure charts for 38 Ref's http://pmilligan.net/pmtherm/

 

Uh, I was being facetious.
Believe me, I am NOT confused.

I led. I am confused about your post!

Of course. Ignoring friction losses.
Of course, I was being a smartass.
I am having fun! Are you?

=Whooosh!= It sailed right over your head, my friend.
I was intentionally splitting hairs. You can't argue against friction loss!
When a fluid flows through a capillary tube, there is (almost) sunstantial
friction loss! And with a TXV or TEV, there is turbulence, possible
cavitation, etc.

Bullshit.

YHBT, YL
(You have been trolled, you lost).

I have designed and built numerous systems for a living.
What have YOU done? Flame me? **** you.

Go soak your head.