cap line

[epion2985]

Why exactly does it need both liquid and gas to work properly? What happens if you only have liquid in it?

[johann]

As far as I know you want liquid only in the captube, if you have gas in there it means your condensor is not condensing all the gas into a liquid state propperly.

I may be wrong...

[targ]

between the condenser outlet and the evap, the system should be full of liquid.

if not then you could have problems.

targ

[godmod]

in the cap the refrigerant is liquid. in the evap it becomes a gas and after the comp it gets pressured and becomes liquit again in the condensor. after that the refrigerant flows through the cap into the evap again....

you see ... liquid -> gas -> liquid...

[Bergo]

Hence "Phase Change"

[Gray Mole]

Actually i'ts pretty rare you'll ever see a liquid head to the captube entrance.

That's part of the reason that subcooling on these systems is so important, as the final complete condensing takes place in the captube itself.

If you put a sightglass just before the captube, it's very likely you'd see bubbles in there. There's liquid coming out from the condensor yes, but it's a mix of saturated and superheated refrigerant.

The reason? Well I'm not sure about that, and Gary Lloyd isn't here to answer that unfortunately :( but it just is what it is.

If you installed a sightglass and tuned the charge for a full liquid head, it's very likely your compressor would blow as it would be returning a substantial amount of liquid to the compressor.

The how has been covered many times in previous threads about the fact that these systems we make don't have a full liquid head in the cabtubes, only for cpev/pev etc.

The why I've never really known, and to be honest I don't really care all that much. It works, and that's what matters most.

Gray

[e_l_f]

Actually i'ts pretty rare you'll ever see a liquid head to the captube entrance.

That's part of the reason that subcooling on these systems is so important, as the final complete condensing takes place in the captube itself.

If you put a sightglass just before the captube, it's very likely you'd see bubbles in there. There's liquid coming out from the condensor yes, but it's a mix of saturated and superheated refrigerant.

The reason? Well I'm not sure about that, and Gary Lloyd isn't here to answer that unfortunately :( but it just is what it is.

If you installed a sightglass and tuned the charge for a full liquid head, it's very likely your compressor would blow as it would be returning a substantial amount of liquid to the compressor.

The how has been covered many times in previous threads about the fact that these systems we make don't have a full liquid head in the cabtubes, only for cpev/pev etc.

The why I've never really known, and to be honest I don't really care all that much. It works, and that's what matters most.

Gray

Just thinking a little about it right now but the high pressure side is basically a closed space filled with some fluid partly gas and partly liquid at about the same pressure and having a temperature gradient produced by the condenser; in this compartment liquid is in the low temp extreme and this temp is a little over ambient, how much depends upon heat transfer caractheristics of condensor and flow rate. As vapor and liquid are the same substance and are at the same pressure, in the interface between them they are always at the boiling point temperature; so the only way to have a solid liquid line before cap is to have refrigerant condensing at temperature much over ambient, then you have pressures in a really high range.

Pressure is the same save for the gradient that maintains flow from compressor exit to capillary entrance and this should be a small one; bigger gradient is inside capillary (that is precisely capillary function: producing a pressure fall to get a low boiling temp and/or low gas temp so evaporation in the evaporator takes place at a really low temp)

:rolleyes: Not all very clear to me either, but this may trigger someone's further insight.

[epion2985]

well the reason I ask is because it makes sence that having only liquid will only be a good thing, but:

Capillary tubes need both gas and liquid present at their inlets to operate effeciently. A reciever is nessassary for teh TXV to maintain a liquid column but not on a Cap tube..