How to assign thermodynamic properties after splitting two phase into gas and liquid

[Gary]

Maybe you missed my point so I will try again. We have removed gas at the 8 bar line and so this gas is no longer cooled by flashing liquid, similarly the gas at 4 and 2 bar are seperated and they also need no further cooling. In a standard TXV system all the gas is cooled to the evap temp so we have saved some energy here. The question is - is it enough to help and then we have the side streams of gas.

Got to replace the mainsail so the diagram will come later.

Chef

I'm confused. Does the liquid cool the gas?... or does the gas cool the liquid?

[chillerman2006]

I'm confused. Does the liquid cool the gas?... or does the gas cool the liquid?

Hi Gary

If I have followed properly, the liquid is cooled by the drop in pressure after the condensor, before the vessel, (constant pressure valve) the flash gas removal, does not affect 'p' or 't' but increase's mass to txv

Regards Chillerman

[Gary]

Hi Gary

If I have followed properly, the liquid is cooled by the drop in pressure after the condensor, before the vessel, (constant pressure valve) the flash gas removal, does not affect 'p' or 't' but increase's mass to txv

Regards Chillerman

Actually, on a drop in pressure part of the liquid flashes into vapor and heat from the liquid is transferred to that vapor... the gas cools the liquid.

[chillerman2006]

Actually, on a drop in pressure part of the liquid flashes into vapor and heat from the liquid is transferred to that vapor... the gas cools the liquid.

Hi Gary

Thankyou Sir,

Dont know what I was thinking trying to educate you, duh!

The info hit a reverse cycle valve & miss-directed

But still got you thinking, mate & now we both understand,

R's chillerman

[Chef]

Actually, on a drop in pressure part of the liquid flashes into vapor and heat from the liquid is transferred to that vapor... the gas cools the liquid.

So a small experiment is due here I feel. I pour lighter fuel on my hand and as it evaporates it gets cold, if I blow on it it gets even colder as more evaporation takes place. So you are telling me that the gas after evaporation is cold and in the time available before it disperses in the atmosphere it has time to transfer it coldness to the liquid. Yeah right I beleive that. If you wish you could provide a useful referance to support your comments.

In the PH diagram I posted there are 3 places where we propose to strip the gas away and pipe it off for its own process. The first split is at 8 bar which is 31.4C so the gas remains at that temp in its side pipe.

If we had left that gas with the rest of the refrigerant as in a standard TXV system it would need to be cooled down to -26C which is the evap temp in this case.

So we are going to need to cool that gas and the only source of 'cold' is the liquid hence my comment the liquid will cool the gas. The JT effect is not enough on its own. It is the phase transition that does the cooling.

But you say the gas cools the liquid so by dropping some gas from 8 bar to 1 bar it will cool in a process that not not only cools itself but has enough (negative) energy to also cool some of the liquid. ????

Chef