Vapour pressure and saturation temperature - Estimate qunatity

[nevinjohn]

How can we estimate the liquid quantity in a jug, by knowing its pressure and temperature?

[Brian_UK]

If by jug you mean a refrigerant cylinder then simply weigh it and subtract the tare weight to give the weight of the contents.

[nevinjohn]

Yeah, but how exactly do I know what percentage is liquid and gas? The PT chart would show the refrigerant within the saturation curve, but how can I estimate the liquid/gas percentage....

[seanf]

The way Ive seen it done is,

- Find the specific volume of the total contents -

v = Volume of cylinder / Mass of the refrigerant (vapour and liquid)

- Use the refrigerants property tables to find the specific volumes of the vapour and of the liquid at the saturation temp/pressure. -

vg - specific volume of the vapour
vf - specific volume of the liquid

- Find the Quality -

x = (v - vf) / (vg - vf)

- The mass of vapour is then found -

Mass of vapour = (quality) X (total mass (liquid and vapour))

You can work out the rest from that.

The above is given as an example in the book, Thermodynamics: An Engineering Approach, Çengel/Boles, 8th edition, page 129, Properties of Saturated Liquid-Vapour Mixture. More than likely to find it online for free.

[Brian_UK]

Or, tap the side of the cylinder with a small spanner moving slowly from the base up to the top. When the sound note changes then you have found the top of the liquid.

[r.bartlett]

This is a test or homework question not a out in the field one :-)

[nevinjohn]

Thanks a lot guys! I was just being curious whenever I see a liquid receiver. Now it makes some sense :-)

[nevinjohn]

haha... definitely not in field.

[Josip]

Thanks a lot guys! I was just being curious whenever I see a liquid receiver. Now it makes some sense :-)

Here you can read a little more all about: ... easy way ... all is within RE forums ;)

http://www.refrigeration-engineer.com/forums/showthread.php?4365-Liquid-receiver

http://www.refrigeration-engineer.com/forums/showthread.php?4436-Liquid-receiver-size

http://www.refrigeration-engineer.com/forums/showthread.php?46172-Volume-of-chiller-liquid-receiver



http://www.refrigeration-engineer.com/forums/attachment.php?attachmentid=14178&d=1466916864



best regards,

Josip