Crazy ægreen machinesÆ 1

[KENAT]

I thought I’d start a thread for people to suggest some ‘green machines’ following on from my post about exchangeable battery packs for vehicles.

I know not everyone, or even most members believe it’s necessary but lets ignore that temporarily and pretend we all think it’s a good idea to reduce the use of fossil fuels, especially oil.

What cunning machines, techniques, systems, mechanisms etc do you have for saving energy or generating it in ‘cleaner’ ways, and to keep it on topic ones that could be realized (at least in prototype/proof of concept form) in the next 5 years.

Obviously if you think it’s a really good idea you may want to save if for your patent application, since once on this board I suspect anyone could use it although I’m no expert on patents or copyright law etc.

Try to think outside the box a little, ideas that aren’t receiving much if any attention at the moment, perhaps do a quick internet search before you post just to check.

So for starters, wind turbine powered ships. Especially a vertical axis wind turbine powered ship.

The direction of travel would be completely independent of the wind direction, you wouldn’t even need to tack.

If a two blade ‘H’ configuration or egg beater configuration were used then in port auxiliary power could be used to avoid any dangers of collision with the turbine locked for and aft.

Once at sea the turbine could be unleashed.

Classically ‘H’ vertical axis wind turbines have problems with peak power being provided n times a rotation for an n bladed turbine.

This can cause problems with a torque tube as well as being non optimal for driving a generator.

This can be alleviated by ‘twisting’ the blades around the axis but using this would complicated stowing the turbine for and aft as above.

On the ship maybe a ‘power smoother’ could be used. Perhaps a hydraulic pump at the hub connected to a hydraulic motor for the propeller via an accumulator to smooth the rotation.

This is about the only thing I could find which isn’t quite what I’m thinking of.

http://www.memagazine.org/supparch/pejun04/ebursts/ebursts.html

So obvious problems and flaws with the idea.

Or have any of you got your own ideas that you think Engineering might explore in the next 5 years?

 

[KENAT]

Well Greg, looking at a couple of posts in other related threads you could be forgiven for thinking that some might at the very least not care if we increased use, even if they don't positively encourage it. Also I'm sure all the petrochemical guys don't want to see use cut too much .

Some nice ideas, I think we'd have to get a communist or similar government to really get some of them running though! I’ve always thought the refrigerator/air conditioning situation was kind of dumb.

Here’s one, modular integrated offshore power generation. I understand two of the major costs for off shore wind/wave/tidal power projects are:

1. Cost of laying transmission lines back to land.
2. Cost of rigidly anchoring the system/unit to the sea bed (if required, a lot are now looking at floating platforms which minimizes this)

So if you’re going to spend all that money why not at least maximize the power generation at each ‘anchor point’. I’m thinking a platform that has not just a wind turbine but also wave power generators and tidal/current power generators mounted on it. It would be modular so in a site which really wouldn’t justify one of the generators, e.g. an area with very low tides/currents, you could leave those components off.

Also the energy from the 3 sources could perhaps be integrated before being transformed into electricity reducing the number of generators and perhaps using power smoothing techniques (maybe the hydraulics & accumulators I mentioned before) to get a steadier out-put.

It would allow use of sites which are perhaps sub optimal for any one energy source but from a combination of 2 or 3 are economically feasible.

Also hopefully this would lead to higher production rates which in turn would allow prices to drop, opening up more opportunities.

 

[sms]

Cooling the oceans and the atmosphere, and causing the next ice age..... ;-)

Sorry Kenat, just had to throw that in. Off shore wind turbines are being done now, adding a wave generator and using the same lines makes sense.

We pipe natural gas back to shore from platforms as long as they aren't too far out or too deep, no reason why we can't bring electricity back as well.. except capital investment and ROI.

-The future's so bright I gotta wear shades!

 

[Jabberwocky]

http://www.geocities.com/mariner767/where.htm

Vertical axis turbine! I liked this movie...

 

[davefitz]

I am not sure we need to invent new devices to make a big difference- changing behavior or employing new energy management schemes would make a large difference in the next 5 yrs.while using existing technology.

In terms of energy used in vehicles, urban traffic use would employ more mass transit or more hybrid vehicles. For highway traffic, use of the new diesels ( Toyota Yaris gets 75 mpg with a common rail diesel)could cut highway fuel use in half. Other management schemes that use the internet to post ride sharing boards ( as well as means to improve security of ridership- ID schemes)could be used to reduce fuel consumption in rural areas.

In terms of reducing energy use in homes, there are schemes used in europe that seem to work- heating costs can be reduced by use of radiant floor heating as opposed to conventional hot air systems. A/C costs can be reduced by passive solar measures and use of solar screens on south and west facing windows. For apartment buildings, use of micro turbines with heat recovery for building heating or absorption Air conditioning would yield an 85% energy efficiency, vs the 50% efficiency for gas fired combined cycles.

 

[dcasto]

davefitz is correct. Now the tough love part, how do we change the behavior. Nobody in the US is going to buy a 1500 pound car because they are afraid the 6000 pound SUV beside them will run them over. So, instead they buy a 7000 pound super SUV and onward. Behavior modification needs outside forces. The price of fuel and/or taxes are the only way.

 

[0707]

For big green energy machines go to

http://www.aip.org/tip/INPHFA/vol-10/iss-5/p20.html

For the first wind-hydrogen production ship go

http://www.hydrogen-challenger.de/index_english.htm

and see the video.

 

[monkeysolder]

Probably not crazy enough, but when I used to live in an apartment that was sunken into the ground by about 3 feet, it greatly reduced the amount of heating and cooling needed. The ground acted as a natural temperature buffer. If a house were built mostly underground, I imagine it would stay very nice year round with no air conditioning/heating (although probably somewhat humid in certain climates).

 

[Schipperus]

Like these houses in Tunesia...

We slept in one of these houses, nice and warm while it was freezing outside. The romans also had undeground houses when they lived in Tunesia.

http://home.tiscali.be/f.vanlil/Tunesie/Matmata.htm

http://www.galenfrysinger.com/matmata_tunisia.htm

IJsbrand

 

[davefitz]

Unerground houses were proposed in the late 1970's , but were later found to be problematic regarding buildup of radon gas. This radon problem can be mitigated by use of a visqueen plastic liner plus vented subfloor.

 

[Jabberwocky]

Not so much a machine, but pretty crazy:

Along the lines of the underground house, my idea consists of a buckyball dome mostly embedded into the side of a hill. I guess the closest analog would be a hobbit-hole? This way you save on heating and cooling, are immune to most natural disasters (providing you're geographically distant from earthquakes and volcanoes), and you can use all of the above ground side as your yard!

I had an idea to have a skylight as well, maybe with a retractable cover? Also said yard could easily accomodate solar and/or wind turbines, again depending on locale.

For the (future) wife's sake, you could even build a facade of a normal looking house for the entrance, it would just appear much smaller than your actual place.

Finally, sorry to keep bringing up movies, but I'm pretty sure that the Tunisian Matmata houses were shown in the first Star Wars, ostensibly for the same purposes of cooling in a desert.

 

[Schipperus]

JabberWocky,

true, we slept in the very hotel where the movie was shot.

And, for people who live in flat countries:

http://www.de12ambachten.nl/ondergrondsbouwen.html

(sorry it's in Dutch, but the pictures will tell the story)

IJsbrand

 

[Jabberwocky]

That Dutch site is great! Toss a couple of wind turbines and/or solar cells up top and I'm sold!

It also reminds me of this article I saw on wired:

http://www.wired.com/wired/archive/14.09/noaa.html

as well as when I was growing up in Oklahoma we visited the 911 call center (emergency services) and their HQ was underground as well to prevent tornado damage. They also told us it was on springs to prevent earthquake damage and has escape hatches in case of fire. Pretty slick.

 

[Schipperus]

Another cool 'Green design':

http://www.unibail.com/corp/pdf/CpPhare271106_uk.pdf

IJsbrand

 

[electricpete]

I have a half-baked idea for an energy saving device. Or maybe it's not half-baked... you tell me.

The public water supply system delivers to my house water at a pressure Psupply which is more than enough pressure than I need to get it to come out of my faucet at a satisfactory rate (Pminimum=mimimum acceptable pressure).

Psupply >> Pmin
Psupply = Pmin + Pextra
Pextra > 0

So I open the faucet and the water comes out with certain kinetic energy that is wasted and some throttline losses in my faucet that are wasted.

The amount of energy wasted is Pextra * V where V is the volume of water that I draw out.

What if I had some kind of turbine wheel in the water supply to my house that extracted that extra energy (pressure drop) that I didn't need. Perhaps it could be remotely adjustable from inside so that when I need more pressure, the turbine wheel extracts no energy (no pressure drop), but when I have pressure to spare, the turbine wheel extracts all that extra energy.

So I get the extra energy. Also I don't think the city needs to expend any more energy to deliver my water. Again it is a savings in that throttling loss and extra wasted kinetic energy of water coming out of the faucet.

Seems like a sound theory to me (what do you guys think?).
I would have to sit down and think about the total volume of water and the pressures invovled to discover what the magnitude of the potential savings are. Off the top of my head I'm thinking they are pretty small.

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[GregLocock]

In my house I use 300 litres (75 gallons) of water per day. Guessing that it has one atmosphere of excess pressure then that comes to 300*10^5 J, =30 MJ. Sounds like a lot. that's around 300W continuous, which is ridiculous. Therefore my conclusion is that the excess pressure is only a few psi. Interesting.

So, what you need to do is run your system from a header tank, and feed that from the mains with a turbine in it.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[KENAT]

I like the idea, it’s the crazy kind of stuff I wanted to encourage.

Instead of throttling the water by restricting it at the stopcock you doing the same thing with a turbine.

I’m thinking it would only generate power while water was flowing so I’m not sure what you mean by continuous Greg.

I'm not sure you'd be able to extract a significant amount of energy, I believe most turbines only extract a relatively small % of the total energy.

 

[GregLocock]

That's why I was proposing a header tank, to average it out over 24 hours. UM,by the way, notice that I was misled by the SI system. The proper unit of volume is m^3 not the litre, so on average (24 hours a day) one atmosphere of excess pressure supplies a measly 0.3 W, which I am going to completely fail to get excited about.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[dcasto]

I couldn't get my company interested in a turbine letting down a liquid from 1000 psi to 200 psi at a rate of 180,000 pounds per hour, not only would it have generated 800 HP, it would have saved another 800 HP in refrigeration in the plant. They were afraid the technology wouldn't be reliable. This said, look at the needle valve in a refrigeration system, a turbine would recover the work and generate additional refrigeration.

All large refrigeration system should do this.

 

[electricpete]

I checked Greg's numbers for 75 gallons per day, 15 psi extra pressure (seems pretty generous).

I agree that's a pidly 0.3 watts. In a day 27,000 Joules or 7.5 watt-hours.

It would take about 4 months to get a kw-hr, worth about about 20 cents, retail.

Of course as Kenat pointed out we assumed 100% efficiency, while fluid machines are typically way lower.

Thanks for bursting my bubble, Greg ;-)

dcasto - why is there a double-benefit in applying this in a refrigeration plant?



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