h a l f b a k e r y
Not the Happy Cuddle Club.

meta:

account: browse anonymously, or get an account and write.

 user: pass:
register,

# PiVNuRT the pool heater

PV work heats your pool water
 (+1, -1) [vote for, against]

The principle is thus: A large air-filled balloon, flexible but inelastic, is powered down to the bottom of the pool. The work performed on the gas inside by the increased pressure/decreased volume causes the air to heat up.

Leave it down there until the temperature equilibrates with the water.

Haul it out of the water quickly and completely. It will be very cold, due to work performed BY the gas, so leave it flapping in the breeze until it warms up to air temperature.

Dunk it again.

Refinements: Heat transfer will be faster underwater, so have one down and ten up, all strung along a steel cable. Run them around conveyor style. Use the bouyancy of the upwards-going one to partly offset the force required to sink the downwards-going one.

Happy winter swimming.

 — GutPunchLullabies, Mar 15 2007

The water in your pool would have evaporated, along with all the water on the planet as well as everything else on the planet when the sun exploded before you were able to obtain a 1 degree rise in the temperature of the water in the pool.
 — jhomrighaus, Mar 15 2007

Yeah, but eventually we can all go swimming... Somehow I thought 10 m = double the pressure = double the temperature. But that just isn't realistic.
 — GutPunchLullabies, Mar 15 2007

 I think this is very slick. Use the depth of the pool to facilitate heat transfer. It would work. One would need some math to figure out how well it would work. I think it would work better than [jh] does.

One could use a body of water to cool a building in this way, by venting the newly emerged balloons into the dwelling.
 — bungston, Mar 15 2007

 All right, I ran some numbers just to see what we were talking about. With 10, 24.5 Liter balloons(1 mol of air ea), a 10 meter round by 3 meter deep pool the change in temperature of the ballon will be 1.2 degrees, which is equivalent to 28 Joules, It takes 4178J to raise 1kg of water 1 degree so to raise the entire pool 1 degree would require 1,017,266,960 joules.

 That means you would need to perform 36,330,962.9 compression cycles to raise the temperature 1 degree. So at 5 minutes to equilibrate per cycle and 10 balloons being used we would arrive at the following numbers;

 It would take;

 302,758 hours = 12,614 Days = 1,802 weeks = 35 years

 to raise the temperature of the pool 1 degree.

 There is also another small issue, if you proceed as you have shown and you maintain a constant temperature above the pool then you can never raise the temperature of the water more than 1.2 degrees(the temperature due to the pressure /volume change) which means even with 1000 balloons the temperature will never rise above 1.2 degrees of the ambient temperature of the balloons, EVER.

So no the sun will not meet its fiery doom before this works but it just wont do what you think it will.
 — jhomrighaus, Mar 15 2007

Deeper pool. Bigger balloons. Faster cycles. We have the technology.
 — bungston, Mar 15 2007

 Want to go swimming THIS decade? Try PiVNuRT v.1.1!

 Okay, how about two big wheels, like a ferris wheel except not perfectly in parallel. In between ten points on these circles are connected semi-sealed pistons. As each piston circles, it is compressed by the offset between the wheels. The maximum compression coincides with the time it is in the water. It pauses there, the metal quickly conducting heat into the water (it has fins for surface area).

 When it reaches pool temp, the piston is vented, the bubbles having little effect before they reach the surface. The cycle continues. The piston gasps in a new breath of air above the surface, and the cycle continues.

And it runs on a GIANT windmill.
 — GutPunchLullabies, Mar 15 2007

Sorry, but isn't all the work that is done here heat "invested" when we force the baloon into the water? Conservation of energy seems to require an energy source and I highly doubt that the heat engine powering the dipper will be more effcient than, say, running two rough pieces of metal against one another inside the pool.
 — WcW, Feb 09 2008

 Thanks for resurrecting this idea, I always liked it. The idea isn't so much about efficiency, and certainly is not an attempt at free energy or perpetual motion or anything like that. If I wanted efficiency I would just use resistive heating like every other pool heater.

The energy source is the electricity driving the motor.
 — GutPunchLullabies, Feb 11 2008

there are some other problems that occur to me, the first being evaporation which would eat up all of your gains and more unless this somehow doesn't cause evaporation. I would be disapointing to have a system that actually did the opposite of what you intended.
 — WcW, Feb 12 2008

 [annotate]

back: main index