h a l f b a k e r yYou want a piece of this?
add, search, annotate, link, view, overview, recent, by name, random
news, help, about, links, report a problem
browse anonymously,
or get an account
and write.
register,
|
|
|
Consider an ordinary tap (faucet). The water pressure in the pipes leading up to it is at maybe a few bar. The pressure as it exits the tap is basically atmospheric. There has been a pressure drop: work has been done pushing fluid through the resistance of the tap, and as a result the temperature of
the water and tap has slightly increased.
Mitxela Mechanical Heating Co. has decided to capitalize on this effect. A modest upgrade to your plumbing may be required before switching your water supply to us, as our standard pressure for water delivery is 40,000psi. When you turn on your tap, the cold water magically, and instantaneously, turns hot.
The genius of this system, if we may say so, is that unlike any other hot-water-to-the-home system there is absolutely no heat-loss on the journey from the power station to your sink. So what are you waiting for? Toss your boiler today!
The Joule-Thomson effect for liquid water...
http://www.madsci.o...959891423.Ph.r.html
[mitxela, Feb 08 2015]
Major-General Sir Colin McVean Gubbins KCMG, DSO, MC
http://en.wikipedia.../wiki/Colin_Gubbins
Originator of the Gubbins sabotage /demolition charge, a most delightful and entertaining confection. [8th of 7, Feb 09 2015]
94,000 psi water pump
http://www.flowwate...pumps/hyperjet.aspx
[scad mientist, Feb 11 2015]
Please log in.
If you're not logged in,
you can see what this page
looks like, but you will
not be able to add anything.
Annotation:
|
| |
Afraid not. No work is done during a throttling process so
the energy content of the fluid doesn't change. The water
temperature will be the same upstream and downstream of
the tap. |
|
| |
Incorrect. You are thinking of gasses. |
|
| |
A liquid and a low Mach number gas behave similarly.
Where are you suggesting the energy comes from to raise
the temperature of the fluid? |
|
| |
Ultimately the power station. |
|
| |
Temperatures do change during throttling - how else would refrigeration work? Liquid water is basically incompressible, and its Joule-Thomson coefficient is negative. |
|
| |
I think [mixtela] is right. If the nozzle at the tap is
very small, then a large force (ie, water pressure) is
needed to get the water through it at a decent flow
rate. And since the water is moving, this force acts
through a distance. |
|
| |
The power being delivered to the water will be: |
|
| |
where A is the cross-sectional area of the pipe
(before the throttle), L is the *linear* flow rate of the
water in the pipe, and P is the pressure in the pipe.
This is the amount of power you would have to supply
to a piston driving the water. |
|
| |
The only place this power can go is into the water or
into the metal around the narrow orifice. Some of it
will end up as kinetic energy in the water (ie, the
emerging jet will be fast), but this can be recovered
by baffles. Therefore, apart from the small amount
of energy lost to the nozzle metal, all the power will
go into heating up the water. |
|
| |
The emerging jet will cut your hand off, or you know
cut metal, but I suppose that's another story. |
|
| |
And yeah, the upgrade from a 15 psi design to a
40kpsi on plumbing might take a bit of thought. |
|
| |
Yes, leaks in the street would be fun! |
|
| |
Indeed, each household would be required to protect its own family Joules against rupture. |
|
| |
.... especially if you wanted to use the water to clean The Last Turkey
In The Shop ... |
|
| |
I have consumed only white wine. The cost of a
single cup of tea will depend on whether you're using
a teabag or leaf tea, on the cost of said tea, etc. |
|
| |
In theory, this system could have a lower energy
consumption than a kettle to produce said tea.
Moreovermore, it need not waste any water. |
|
| |
Of course, if you include the capital cost of the
system, the cost for a single cup of tea will be steep. |
|
| |
Where did the water wheel come from? |
|
| |
I think you should return to this idea post-vin. |
|
| |
How about splitting the water into hydrogen and oxygen at the pumping station, and delivering it in twin gas lines? The hot tap could have a combined nozzle and spark igniter. |
|
| |
[bigs], you're entirely correct, but about the wrong
thing. |
|
| |
The idea (that thing, top left, lots of words in order)
is about pushing water through a small orifice at
wonderfully high pressure. There are no waterwheels
involved, nor significant fallage. |
|
| |
Also, you promised personal insults and I'm still
waiting. |
|
| |
[bigs], such a system can raise the temperature of
water to any desired level, at least in theory. |
|
| |
Power = A x L x P where A=area of the main pipe,
L=linear flow rate along the main pipe, and P is the
pressure. |
|
| |
By making the nozzle at the end sufficiently small,
whilst keeping A and L constant (say, sufficient to
eject one teapot's worth of water in 10 seconds), the
pressure can be made arbitrarily high, and hence so
can the power delivered. |
|
| |
I just come here to watch the egos anymore. Enough Joules can be found with the general rise in air temperatures. |
|
| |
Yes indeed so, by varying the pressure. |
|
| |
It's not the size of the nozzle that counts but how you use it... |
|
| |
// Enough Joules can be found with the general rise in air
temperatures. // |
|
| |
"How many halfbakers does it take to make a cup of tea ?" |
|
| |
// [bigs], you're entirely correct, but about the wrong thing. // |
|
| |
//If you have a smaller nozzle, your L goes down.// |
|
| |
I don't get yor argument. This idea would work, absolutely. Silly quibbles about practicality are surely just detail scoping for others to worry about later. |
|
| |
As to the issue of a given supply pressure necessarily only being able to deliver a given temperature outlet - surely the solution to this is two or more supply streams. One with 50Ksi+ or whatever pressure is required to deliver ~100 degree water, and a lowe pressure stream to then post-nozzle mix back to the desired temperature. |
|
| |
In fact, in-home steam cleaning of floors and kitchen surfaces is beginning to become quite popular, so perhaps the high pressure supply would actually need to be much higher pressure, in order to deliver superheated steam? I wonder what the nozzle would look like, that facillitates conversion of rather high pressure liquid water into superheated steam? |
|
| |
The nozzle would look like an old fashioned tap with a four-pronged turner. All the gubbins would be concealed inside. |
|
| |
A good starting point for the design of the internal
gubbins/Gubbins be a Tesla valve oriented in
reverse of the expected direction. For a pressure
as high as we're talking here, it seems like the
Tesla valve might need to be pretty long to drop
the pressure that much. That unfortunately gives
a lot of area to loose heat. We can combat that by
having the valve inside a water jacket so most of
the heat loss is recaptured in preheating the
water. |
|
| |
I really like this idea. It's just too bad that the
pressure needs to be so high. |
|
| |
Ill advised - tribal lore has it that the Grand Canyon was created by a failed " Going up? First floor, geosynchronous orbit". |
|
| |
Good news. I found a 94,000 psi water jet cutting
system <link>, so that means the pressure is "easily"
achievable. Of course their nozzle is inappropriate
since it is designed for maximum output velocity
(Mach 4 in this case) rather than maximum
temperature rise. |
|
| |
//it is designed for maximum output velocity (Mach 4 in this case) rather than maximum temperature rise// |
|
| |
Just aim two of them at each other then. |
|
| |
I was going to suggest aiming the nozzles at each
other as well, but then I realized that very little of
the energy would be converted to heat. The
collision would mostly just make the water spray out
into a plane perpendicular to the water jets. |
|
| |
I think we need to drop the pressure gradually
through a turbulent path. That way the water
velocity never gets high enough to wear out
Gubbins. |
|
| |
Why does the whole house need to be upgraded when the cylinder can just be a big piston with associated pressure regulators? |
|
| |
I'm with Maxwell, there is no upper limit on what
temperature a friction nozzle might achieve given
limitless pressure. The energy will go someplace with
the challenge being to keep it within the water. I
suggest that the water must be made to impact itself
by meeting from opposite directions. |
|
| |
Does it have to be the nozzle? Could the pipe, close to the tap, have a bit of shape change ability to allow the pressure to friction the water.
The tap, of course, would be constantly hot. Maybe, too noisy. |
|
| |
hmm, would forcing water backwards through a Tesla valve have a similar effect? |
|
| |
Yes, if the valve had the same flow resistance as a
fine nozzle. |
|
| |
With the thought that heat is simply vibrations of the
molecules, or something like that, then the valve could
be like an ultrasonic whistle. |
|
| |
With the added advantage that one could train a pet dog
to indicate when tea break is coming up. |
|
| |
Could we use the water pressure to compress and
decompress a reservoir of air instead? With a bit of heat
exchange you could have heated or chilled water. |
|
| |
/backwards through a Tesla valve/
// if the valve had the same flow resistance as a fine nozzle.// |
|
| |
Could such a design be incorporated into a construction substantial enough, say on the Hoover Dam-ish scale, so that the outflow of water escapes as steam?
Would the electrical generation potential to the turbines be increased enough to warrant the cost of the change in architectural geometry? |
|
| |
hmmm, also, could vortex rings of steam, like those produced in the Copenhagan art installation (link), which vary in rate of speed and rate of rotation, use prevailing winds at different altitudes to fairly accurately deliver precipitation to optimal farming areas by targeting cloud seeding.
(Yes I know cloud seeding hasn't been proven 100% effective, but this might allow for controlled atmospheric moisture level tests to determine just what works best with the least collateral impact on the environment.) |
|
| |