Cycle with only liquid, no vapor?

[SES Utah]

Hey guys, I'm wondering if anyone has ever developed a refrigeration cycle that doesn't have a gas phase? We're developing a new technology, and one part of the system is a liquid with a very low vapor pressure that needs to be cyclically cooled.

It would be ideal if I could use this as the working fluid in a refrigeration cycle, but based on ph (mollier) diagrams it appears that in the subcooled liquid region the constant temperature lines are nearly parallel to the pressure axis, meaning expanding a subcooled liquid into a subcooled liquid will not cool it - it may actually raise the temperature!

Any work arounds?? Thanks!

[mad fridgie]

Hey guys, I'm wondering if anyone has ever developed a refrigeration cycle that doesn't have a gas phase? We're developing a new technology, and one part of the system is a liquid with a very low vapor pressure that needs to be cyclically cooled.

It would be ideal if I could use this as the working fluid in a refrigeration cycle, but based on ph (mollier) diagrams it appears that in the subcooled liquid region the constant temperature lines are nearly parallel to the pressure axis, meaning expanding a subcooled liquid into a subcooled liquid will not cool it - it may actually raise the temperature!

Any work arounds?? Thanks!

This is not the answer you want, but there are millions of these system, we commonlly use the term
"secondry refrigerant" the most common being water,
a sub-cooled liquid at atmosperic pressures.
A liquid is not compressable so can not expand.
You can look a phase change fluids with ( example "ice slurry")
mixture of solid and liquid, no vapour stage, but still relies on latent energy exchange, not just sensible.

[SES Utah]

This is not the answer you want, but there are millions of these system, we commonlly use the term
"secondry refrigerant" the most common being water,
a sub-cooled liquid at atmosperic pressures.
A liquid is not compressable so can not expand.
You can look a phase change fluids with ( example "ice slurry")
mixture of solid and liquid, no vapour stage, but still relies on latent energy exchange, not just sensible.

You are correct, that is not the answer I wanted. Thanks!

[mad fridgie]

Not sure what your question is?
Are you looking for a liquid that dramatically changes its properties under pressure (reverisble chemical change as an example with some form of exothermic reaction,)

[SES Utah]

Not sure what your question is?
Are you looking for a liquid that dramatically changes its properties under pressure (reverisble chemical change as an example with some form of exothermic reaction,)

I'm basically asking if I can use a liquid as the working fluid in a refrigeration cycle but never have it change phase. I thought since liquids are slightly compressible we could still heat it up with a high pressure pump, but when you run the liquid through the expansion valve it will not cool like it will when some of the liquid flashes to a vapor.

[mad fridgie]

I'm basically asking if I can use a liquid as the working fluid in a refrigeration cycle but never have it change phase. I thought since liquids are slightly compressible we could still heat it up with a high pressure pump, but when you run the liquid through the expansion valve it will not cool like it will when some of the liquid flashes to a vapor.

Standard working fluids (refrigerants) "NO"

[mad fridgie]

It has just twigged!!!!, you have understood that it more efficient to pressurise a liquid than is to pressurise a vapour.