If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#51
|
|||
|
|||
~^Johnny^~ wrote:
> On Sun, 26 Sep 2004 14:58:07 -0400, Threeducks > wrote: > > >>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. > > > > 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. > 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? > > [Now I'm gonna sound ridiculous, to prove a point:] You've already sounded quite ridiculous. The only thing you've proven is you know nothing about refrigeration. |
Ads |
#52
|
|||
|
|||
~^Johnny^~ wrote:
> On Sun, 26 Sep 2004 14:31:59 GMT, wrote: > > >> 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. > > > > 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. No they don't. And it's not semantics. It's just wrong. > Even the 1911 unabridged Webster's dictionary included both definitions for > the term "heat", altough more modern dictionaries seem to have dropped the > former. > I stick with what the rest of the thermodynamics community has agreed on as the correct terminology. > 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. 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. > It was pointed out to me, that heat (even > latent heat) can only move across a non-zero temperature gradient [thank you, > Daestrom]. > 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. > 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. Which textbook? I have plenty of thermodynamics textbooks and none of them say something so ridiculous. > 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. > It's not the same thing. > You are all acting like a bunch of 10-year-olds! > Only because certain people don't know enough about thermodynamics to know they don't know what they're talking about. > 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! > > |
#53
|
|||
|
|||
[original post is likely clipped to save bandwidth]
On Tue, 05 Oct 2004 21:05:59 -0400, Threeducks > wrote: >~^Johnny^~ wrote: >> On Sun, 26 Sep 2004 14:31:59 GMT, wrote: >> >> >>> 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. >> >> >> >> 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. > >No they don't. And it's not semantics. It's just wrong. > >> Even the 1911 unabridged Webster's dictionary included both definitions for >> the term "heat", altough more modern dictionaries seem to have dropped the >> former. >> > >I stick with what the rest of the thermodynamics community has agreed on >as the correct terminology. 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 -- Personal home page - http://gogood.com gerry misspelled in my email address to confuse robots |
#54
|
|||
|
|||
gerry wrote:
>>I stick with what the rest of the thermodynamics community has agreed on >>as the correct terminology. > > > 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? |
#55
|
|||
|
|||
|
#56
|
|||
|
|||
On 7 Oct 2004 03:00:42 GMT, "Tegger®"
> wrote: >Sparky > sprach im . net: > >> ~^Johnny^~ wrote: >> > >>> 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! >> >> 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/ |
#57
|
|||
|
|||
Tegger® wrote:
> Sparky > sprach im > et: > > >>~^Johnny^~ wrote: > >>>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! >> >>Excuse me, is this the argument clinic? > > If you want an argument you have to pay a dollar. But you're arguing with me, therefore I must have paid you. There, I've run rings around your logic! |
#58
|
|||
|
|||
On Fri, 08 Oct 2004 05:07:32 GMT, Sparky > wrote:
>Tegger® wrote: > >> Sparky > sprach im >> et: >> >> >>>~^Johnny^~ wrote: >> >>>>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! >>> >>>Excuse me, is this the argument clinic? >> >> If you want an argument you have to pay a dollar. > >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/ |
#59
|
|||
|
|||
On Tue, 05 Oct 2004 20:52:58 -0400, Threeducks > wrote:
>~^Johnny^~ wrote: >> On Sun, 26 Sep 2004 14:58:07 -0400, Threeducks > wrote: >> >> >>>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. >> >> >> >> 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. >> > >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. Uh, I was being facetious. Believe me, I am NOT confused. I led. I am confused about your post! :-) >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. Of course. Ignoring friction losses. Of course, I was being a smartass. I am having fun! Are you? >The >energy contained within the fluid does not change as it passes through >the valve! Where would it go? =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. >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? > >> >> [Now I'm gonna sound ridiculous, to prove a point:] > >You've already sounded quite ridiculous. The only thing you've proven >is you know nothing about refrigeration. Bull****. 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. -- -john wide-open at throttle dot info |
Thread Tools | |
Display Modes | |
|
|