Unique potential WC project - opinions please!

[zer0signal667]

right... convection occurs due to the boyancy of an expanding heated fluid.

If I remember correctly the density of water doesnt significantly change until within a few degrees of freezing. As water nears freezing point it begins to condense to about 99.8% of its previus volume, but then when it freezes it expands to about 110% of its normal volume because of the way the molocules align. its been a long time since chemistry, so my numbers might be off... but thats the way I remember it.

also convection takes a considerable amount of space, in order for the heated fluid to be able to flow past the non-heated fluid.

and as far as I know, if a fluid cannot be compressed it cannot expand and condense because its properties dont allow conversion between density and heat. (thats more of an assumption on my part)

please, if I am wrong, prove it and explain it to me.

Water being incompressible by external application of pressure is unrelated to density change by thermal expansion. Solids exhibit both of these characteristics as well; you can't very easily compress a block of 100% dense aluminum, however it will still change in dimensions, and hence volume & density, when temperature is varied from the initial condition.

 

[rodsfree]

right... convection occurs due to the boyancy of an expanding heated fluid.

If I remember correctly the density of water doesnt significantly change until within a few degrees of freezing. As water nears freezing point it begins to condense to about 99.8% of its previus volume, but then when it freezes it expands to about 110% of its normal volume because of the way the molocules align. its been a long time since chemistry, so my numbers might be off... but thats the way I remember it.

also convection takes a considerable amount of space, in order for the heated fluid to be able to flow past the non-heated fluid.

and as far as I know, if a fluid cannot be compressed it cannot expand and condense because its properties dont allow conversion between density and heat. (thats more of an assumption on my part)

please, if I am wrong, prove it and explain it to me.

This is actually the basic principle behind canning with the old Ball / Mason Jars.
The jars are filled with whatever you want to preserve. Then placed in boiling water without lids on them. When the jars and their contents get near boiling temp - they are removed from the boiling water and the caps quickly installed. When the jars cool to room temp - the liquids inside the jars becomes more dense due to the decrease in temperture. Causing a vacuum to form in the jars.

To prove it to your self.
Get an empty plastic soda or water bottle.
Fill it up completely with hot tap water.
Cap it tightly.
Put it in the fridge - not the freezer. We only want to get it cold not frozen.
Come back in about 2 hours and see what the bottle looks like.

The sides of the bottle will be collapsed in from the change in volume of the water due to the change in temperture of the water.

Likewise - hot rodders want very cold air going into their engines. It is more dense and therefore carries more O2 per cubic foot into the engine. This is the reason we have intercoolers for turbocharged engines. And Nitros Oxide Systems also do 2 things for us - they add O2 to the engine in the form of NO2 and as it converts from a liquid to a gas it cools the intake charge and makes it more dense, therefore increasing power.

This principle works for just about everything on the planet. Solids, liquids and gases.
The hotter something is, the less dense it is and the inverse is also true (colder = denser)
There are some special cases like water that condense as they get colder and then actually expand as they solidify. But these are the exceptions to the rule.

Don't you love Mr. Wizard!!!

 

[smithj]

My 2 cents:

1. Water driven RHVT's have been proven successful (and problematic - 750psi input).
"R.T. Balmer. Pressure-driven Ranque-Hilsch temperature separation in liquids. Trans.
ASME, J. Fluids Engineering, 110:161–164, June 1988."

2. "nonlnear" is brilliant in noticing the potential economizing effect of RHVT in a heating/cooling system.

3. I am an RHVT nut. Please don't leave me hanging. Anyone with water based sucess OR failure please do tell. Anyone with a spare commercial VT please sell it to me cheap.

 

[spenny2112]

Sounds awesome. So the VT will be before the radiator? And the "hot" water that comes out of the VT and passes through the radiator will rejoin the "cold" water from the VT?