h a l f b a k e r yPoint of hors d'oevre
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,
|
|
|
The shaft from the windmill(/waterwheel) terminates in a paddle arrangement inside an insulated tank, that stirs a non-newtonian fluid solution. A heat exchanger sits between it and the regular hot-water storage tank.
The heat-exchanger is necessary to allow a higher temperature in the windtank than
injury concerns allow in the regular tank. It also mitigates sediment buildup in the tank.
The non-Newtonian working fluid's viscosity increases with windspeed. This translates rather neatly into an increased efficient power-transfer band that includes minimalization of static friction at startup, and governs the maximum RPM.
The more advanced model has retractable water-vanes or a clutch, also a generator/battery to take up any excess energy, power the heat-exchange mechanism, and overcome startup static-friction in very-low wind conditions.
For increased nift, the tank could be built as the widened core of a corkscrew VAWT.
------
All credit due [8th of 7], [pfperry] & [bronco] <link>. except the non-Newtonian fluid bit which is mine.
Post inspiration and anno promotions from
Windmill_20powered_20friction_20oven
[FlyingToaster, Mar 24 2012]
pre-girded_20loins
..does what is says on the tin [not_morrison_rm, Mar 25 2012]
http://books.google...v=onepage&q&f=false
Ram urine [not_morrison_rm, Mar 25 2012]
http://news.msue.ms..._prices_on_the_rise
...urea price per ton(ne) [not_morrison_rm, Mar 26 2012]
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.
Destination URL.
E.g., https://www.coffee.com/
Description (displayed with the short name and URL.)
|
| |
Ideally, use the windmill to do useful work (perhaps
gun-drilling), and use water to cool the machinery
and collect the waste heat. |
|
| |
Sweet. Is there an energy level difference between solid metal and metal dust ? |
|
| |
Yes - the difference is called the surface energy, and
is related to surface tension (which is more familiar
in liquids). |
|
| |
... But that energy difference is small; most of the work in milling metal is converted to heat. |
|
| |
This is, of course, a very old idea. Lord Kelvin himself equated heat with work precisely by stirring water and noting the change in temperature. It only took someone to think, hey, this mechanical means of heating water, I just realised, you could use it to heat water! Genius! Using wind power in particular to heat water (or oil) by stirring has been discussed for decades at least. One variant has contra-rotating concentric drums with a thin film of oil between. |
|
| |
There's a nice symmetry, though, in that you are coupling two fluids. That should make it easy to get the speed/power curves to match nicely - one of the challenges of wind turbine design. |
|
| |
Oh, and since you seem to be genuinely interested in home-baked water heating, my advice is to get an instantaneous water heater (also known as a flow heater). Make sure it's one that doesn't come on at all if the inlet water is already at a reasonable temperature. That way, you can add your wind/solar/whatever device upstream, and every single degree of heating you achieve will directly translate into an energy saving. |
|
| |
A heating element inside a storage tank ends up fighting your 'alternative' heating method, wasting energy, and is a really dumb idea. To understand why businesses will cheerfully promote and supply such systems, repeat this mantra: "They have no soul. They have no brains. They only want my money." |
|
| |
Add non-newtonian fluid for a variable viscosity that reduces system static-friction at startup, and governs speed without gears or mechanical devices, while maintaining full power transfer, at high speeds. |
|
| |
And if it's on a sturdy rooftop the whole thing could be built inside a spiral VAWT :-) |
|
| |
<awards self [+] based on the preceding two paragraphs, hint hint> |
|
| |
No custard! Bad toaster! The power delivered to plain water is already the cube of speed (assuming a high Reynold's number), which is precisely the relationship between power and wind-speed for a wind turbine. Making the power curve any steeper will slow the wind turbine too much, without making starting any easier; resistance of water asymptotically approaches zero as speed approaches zero. |
|
| |
Yes to VAWT, as it keeps it simple - potentially just 1 moving part. Roof-mounting is not necessarily the best idea, though. By the time you address all the structural, vibration, and access issues it can often be better just to build a separate tower. I've mounted a small (~1m diameter) HAWT on my roof; it worked, but even at that scale, there were problems. |
|
| |
[sm] From reading your posts over the years I can't help but think you've built yourself a very unusual anti-junkyard to live in. |
|
| |
Good call on the instantaneous heater instead of a coil built into a regular tank, for low-heat conditions. But for usual use, unless you wanted to incorporate the regular tank inside the windtank, it'd have to be a large surface area heat exchanger in order to heat a large flow. |
|
| |
(Come to think of it that's quite doable... and a better idea: make it concentric tanks... maybe put the instant-on burner in there as well). |
|
| |
// No custard!//
Heck with that ! It's staying: the only part of the idea that's actually mine; further... |
|
| |
Remember that power *delivered* is *also* going to be at cube of the windspeed. Increasing viscosity with speed allows a speed-control without wasting power or adding mechanical complexity... amount of usefulness depends on the design. |
|
| |
(external temperature is a factor for heat loss, so integrating the tank(s) inside the VAWT itself might not be such a good idea in extremely binary environments) |
|
| |
I like this I just can't understand why you wouldn't want to store energy in a flywheel to be drawn as needed. |
|
| |
Honestly, what's the down-side?
You can still have your VAWT. |
|
| |
I missed the point didn't I?
hmmmm |
|
| |
Just to be clear, my preferred hybrid design goes cold water -> storage tank (heated by wind or whatever) -> separate, conventional instantaneous heater (heated by town gas or whatever) -> end use. |
|
| |
The storage tank could use a separate fluid and a heat exchanger, but water is PDG already, and simplicity is good. My main point is, never put expensive energy into your cheap energy storage. |
|
| |
A 100gallon tank, as a flywheel itself, should be able to store over 0.1kWh in a strong wind: smooth things over in gusts and lulls. |
|
| |
... whereas 100 gallons of water, heated by 75 degrees, stores about 35 kWh. You're right to want to store the energy as heat. |
|
| |
(Aside) I hate units like kWh. Pretty much the only advantage S.I. has over imperial is the consistent way in which the units relate to each other. kWh just pointlessly multiplies the standard unit - the megajoule - by a factor of 3.6. My gas bills use megajoules, and my electricity bills use kWh! How messed up is that? When I wanted to compare the two, I had to ring the electricity company (because the bill used the ambiguous term 'units' for kWh), then do tedious calculations. None of which is your fault, of course. |
|
| |
One of the strong points of a closed system is that the heat-storage fluid can ramp up to waaay above the point where users will get 3rd degree burns by just looking at it. Another is that the working fluid need not be potable water: glycol could be added if it were for a cottage that could stand empty during cold periods; Lubricants for pump parts; custard for variable viscosity. |
|
| |
My druthers'd be for a solar(lunar)-mirror infested roof which feeds a greenhouse, home-lighting and a giant heat-tank in the basement for year-round free heating (accompanied by a giant cold tank, filled by winter weather, for the AC, fridge and freezer)...and an industrial-sized NG tank for the ng/diesel/electric hybrids in the driveway... future expansion to include clean (ng--> h2 + c) conversion to feed the stove, house fuel cell and vehicles. Not that I've thought about it much of course. |
|
| |
//heat-storage fluid can ramp up to waaay above the point where users will get 3rd degree burns// True; but it might just be cheaper to just make the storage tank bigger. That also means you can use relatively crude heat collection methods - you don't need sophisticated materials or construction to get a more modest temperature rise. |
|
| |
I set up a couple of 30 litre drums inside the roof space one summer. I mean, they were literally nothing more than that - just a drum, no solar collector at all. For almost 6 months of the year, they absorbed enough heat during the day for a perfect shower temperature in the evening. That's the problem I have with many solar installations. They are too expensive and sophisticated - and they _still_ use fossil fuels, even in summer! With a bit of thought, you can get huge savings for very little effort - low-hanging fruit and all that. |
|
| |
Another principle I advocate is that a small sacrifice of performance can provide a disproportionately large saving of energy. If you're prepared to put up with a lukewarm shower occasionally, your water heating costs can easily become almost non-existent. |
|
| |
I still like the concentric tanks idea. An electronic or simply bimetal-operated valve decides the mixture ratio between tank and unheated bypass. Then the stored house-side water can be as hot as the sump-liquid, increasing the overall capacity even more. |
|
| |
//Mechanical Hot Water Heating// |
|
| |
Anyway, shouldn't that be "cold water heating"? Not much point in heating it if it's already hot, dontcherknow... |
|
| |
"And your chosen specialized subject ?"
|
|
| |
"The Bleedin' Obvious ..." |
|
| |
I stand my ground on this one, he says looking at the instructions in the loin girding manual (made in China). See pre-girded loins link. Or don't. |
|
| |
... well if it were heating by cold water, it'd never get hot now, would it. |
|
| |
Where do you get mechanical water from, anyway? |
|
| |
By collecting the urine of a Hydraulic Ram, stupid ... |
|
| |
//... well if it were heating by cold water, it'd never get hot now, would it// |
|
| |
If you ran a heat pump on it, you could get hot water from cold water. |
|
| |
I'm sticking to my guns on this one (due to mishap with a tube of superglue, more than anything). |
|
| |
The new three-hundred and forty-four-millimeter
Lepage glue guns? I hear they can glue an entire
formation of bombers together in mid air. |
|
| |
Hmm, better filter than ram urine first, seems they get stones, see link, you'd also be taking the p**s as well.. |
|
| |
Is this the point where I traditionally mention the Pentagon, and of course Oval Tube station, neither of which actually resemble the geometric shapes they are named after? |
|
| |
I conclude the hot water heating is actually not the correct name, it is in fact cold water heating. |
|
| |
That's twice in a few days I've read the term 'taking the piss'.
Never in 43 years and then WHAM! twice in a week. |
|
| |
Where exactly does one take said urine to?
Is it inappropriate for one to leave some piss in order to replenish that which has been taken by others?
Would taking or leaving kidney stones be a faux pas? |
|
| |
//Never in 43 years and then WHAM! twice in a week.// |
|
| |
In 1996 I once devised an entire business model based around the lack of urinals in the pub area of central London with kiosk-like booths, each one drained into a tanker truck in the mornings, thence transported to a vertical tank where pressure would work the R/O filtering to separate the water from the other stuff simply so I could do the national TV adverts with me going, "Yes, I'm taking the piss". |
|
| |
Even had an incentive package, use the swipe card with each deposit and save up the points for a gift voucher, for the added jingle "don't spend a penny, make a penny!" |
|
| |
Unfortunately, urea is cheap to produce synthetically and it kind of undermined the business model.. |
|
| |
Synthetic urea is cheaper to manufacture than to extract from piss?
Well now your just pulling the wool over my eyes... |
|
| |
//The February 2011 approximate retail prices for major fertilizers per ton are: $494 for Urea (53¢/lb N)// see link |
|
| |
Love this idea, but it's missing a piece. Why just deal with heat? Electricity is more valuable, and you're wasting less entropy. Instead of a paddle, have your shaft attached to a sealed generator that's encased in oil. Then you get electricity from the wind, and hot water from your waste heat. If you need more heat than you're wasting, use an electric heater. |
|
| |
That's fine, as long as the total outlay for your fancy generator and the infrastructure to make good use of the electricity (grid connection, presumably, or some end use that can make good use of fluctuating input) is less than the value actually obtained from the electricity. |
|
| |
The trick with renewable energy is bang-per-buck, of course, rather than raw thermodynamic efficiency. |
|
| |
It's like the urea discussed above. If you get too involved - separate the urine, transport it to a processing plant, separate and refine the urea, truck it to where it's needed - it quickly becomes pointless, and you may as well just synthesize it. But pissing on your lemon tree makes perfect sense. |
|
| |
Clearly you need to refine out the urea in situ then, and send your trucks around to take only the value-added fraction of the piss. Now, attach a windmill to the top of your kiosk ... |
|
| |
//Now, attach a windmill to the top of your kiosk// |
|
| |
Erm, might not need it as there's possibly enough power from a water-wheel, although it's not exactly water... |
|
| |
<Windows 7 ate my linux partition, so typing this in Windows..I feel kind of ikey> |
|
| |
I just realized that this is one of those energy storage schemes where there's no gradient to work against: stir the water, even a little, and it gets hotter. |
|
| |