Open Project to Develop Renewable Energy System

rohar writes "We have been working on a system that combines some existing indirect solar technologies to build a location independent, renewable, reliable and economically feasible indirect solar electrical power generation system. The idea is to 'roll-your-own' geothermal source by capturing heat from the ambient air with a solar powered absorption heat pump, store it underground and generate electricity from the air cooling convection. When the air is cooler the stored heat is then used in a reverse process to generate electricity by transferring the heat back to the air when it is cooler (at night or seasonal). There are many additional benefits including clean water capture from the "dehumidifier" effect of the air cooling, construction from common materials and thermal storage that may be incorporated into dwelling heat systems." After reading over their description, how likely do you think it is to work?

Comments

How Likely?

[Umbral Blot]

37.62% according to my calculations. But I haven't taken quantum effects into account yet, so I may be slightly off.

Re:How Likely?

[Da_Weasel]

It is clearly 37.61% before quatum effects are taken into account!

Some people are sooo stupid, I swear!

Re:How Likely?

[RareButSeriousSideEf]

Is that with or without a Heisenberg compensator?

hmmm

[Swimport]

This sounds too good to be true. And you know what they say about things like that....

Re:hmmm

[kfg]

This sounds too good to be true.

The problem is that I don't see any reason why it shouldn't work; and there are plenty of people who don't understand that just because something works doesn't mean it's not too good to be true as well.

KFG

Re:hmmm

[shmlco]

"The problem is that I don't see any reason why it shouldn't work..."

Think harder. The logic seems to be that we pump ambient heat from the air into the ground... which is where things seem to fall apart. For example, just how MUCH heat can we gather and store in the ground? What's the differential? How much can we get back?

More to the point, how do we keep the heat we pump into a point in the ground from radiating away and disapating?

Re:hmmm

[tacocat]

Effectively speaking, you can't store heat in the ground. If you could, then heat pumps today wouldn't work. And plumbing in the north would fail every year. The ground temperature much below 3-6 feet stays a relatively constant temparature all year round. I think between February and August it might vary 10F if that.

The point being that if it takes 6 months of weather on the surface to effect a 10F change in the ground, you won't be able to create a heat pump powerful enough to make this project work. The earth has the property of being a massive heat sink with a reasonable thermal conductivity. This allows heat pumps to pull heat out of the ground in winter and push it into your house. They become inefficient at very low temperatures because the heat transfer freons don't work very well, not because the ground runs out of heat.

It might be more possible to do this if you had an insulated/isolated storage of water and used that as the heat source for storage and retrieval. You could also do it with air and stone. But in every case, you have to provide a means of thermal isolation between the earth and the storage facility. Also, it would be far more efficient to store the heat by means of thermal exchange pipes (solar heated pools) than trying to pump the heat into place.

The convection tower concept isn't new. I think someone came up with that in Australia about five years back. But the storage of heat for later retrieval is.

Re:hmmm

[rohar]

Drake Landing Solar Community is an example of seasonal thermal storage.

Re:hmmm

[salec]

So, if I understood you well, in a way, we have this "thermal ground" similar to "electric ground" by its constancy (of temperature instead of potential). The way to use it then would be to find the depth where the temperature is constantly in the middle of daily temperature extremes above ground, so that there is no need to "store" and "retrieve" heat, provided such "middle temperature point" exists in the ground, that is.

Re:hmmm

[b4upoo]

It won't work. Air has little ability to store heat. Commercial products already exist that store energy in the form of cold water. Water is an efficient heat storage medium. One other problem in looking at some of their drawings is that when water is pushed into a tower top it tends to evaporate and travel upwards. Their idea is that the air will travel down the tower. Take a look at a common, industrial AC water tower and you will notice that the air flow is aided in its upward direction.
                    If you had the money to build an insulated storage tank roughly the same size as your home and chill the water within by use of solar cells driving a refrigeration coil you could actually cool your home easily. Regions that have cold winters could easily chill the storage area down to freezing temperatures and if the block of ice is large enough it is obvious that air conditioning would be efficient.

Re:hmmm

[kfg]

Think harder.

I thought at least hard enough to write this:

". . .because something works doesn't mean it's not too good to be true as well."

In other words; it won't work in any real world, practical sense. It's too good to be true.

For example, just how MUCH heat can we gather and store in the ground? What's the differential? How much can we get back?

Enough to attract investors; not enough to accelerate a paradigm.

More to the point, how do we keep the heat we pump into a point in the ground from radiating away and disapating?

Blueboard and builder's foil ought to be sufficient. . .for the demo.

KFG

Re:hmmm

[tacocat]

That looks pretty neat! It would be great except I think Americans would be to quick to start bitching about the fat neighbor who runs around in skivvies all winter in his house of 90F because he's sucking up someone elses heat.

It appears as if they are sinking most of the heat into a large volume and not worrying about the thermal loss to the earth. I would consider some kind of isolation to better insulate the storage but it might not be worth it.

Re:hmmm

[m0rph3us0]

I think you mean Californians, not Americans, most American's wouldn't care because they know that person would be paying his share of the heat he used.

Re:hmmm

[nmos]

The way to use it then would be to find the depth where the temperature is constantly in the middle of daily temperature extremes above ground, so that there is no need to "store" and "retrieve" heat, provided such "middle temperature point" exists in the ground, that is.

It's possible but I'd think it would be pretty expensive to drill down that far and lay collection pipes etc. In practice what people do is only go down a few feet and use a heat pump. How well that works depends a lot on what the ground in your area is made of though. In general moist soil is good, rock is bad.

Re:hmmm

[PermanentMarker]

Wel simply why it doenst work good...
why should warm ground air prefer to go trough a tube to cold areas?
If it simply can bypass it and go from everywhere outside the tube up or down, with less friction. The same goes for the oposite direction.


But no wories there is realy enough energy on this planet....
you only have to dig a hole in the earth, as Lava is quite hot you know, and even without such deep holes, below earth there is enough heat energy stored which make oil and uranium look like a joke. Its only politics of some oil & electric companies who dont want the masses of people to know that. Whenever you go to iceland you see it can be done with not that much engineering (okay their place is ideal, but it can be done everywhere if you have some enginering skills, the start of such projects will cost something but he energy was never for free...) A bit strange we dig a hole from france to england but going down is momre difficult ????

Thin Air

[Bargearse]

So you're going to generate electricity and clean water out of think air. Next you'll be turning lead bars into gold :)

Re:Thin Air

[Anonymous Coward]

And i suppose you think that generating electricity from wind turbines or solar panels is impossible too?

Generating electricity from a heat difference is entirely possible, its just a matter of how efficient the whole process is as to whether its worth it. Actually if your after more information on that (it works both ways too!), then have a read here: http://en.wikipedia.org/wiki/Peltier-Seebeck_effec t

And the water thing is just a by-product http://en.wikipedia.org/wiki/Condensation :)

Jacko

Re:Thin Air

[kfg]

And i suppose you think that generating electricity from wind turbines or solar panels is impossible too?

I suppose you think it's impossible to turn lead bars into gold?

KFG

Re:Thin Air

[Soko]

So you're going to generate electricity and clean water out of think air.

Hmmm... think air...think air... *SNAP* Hey, Al gore invented the Internet and is all about green energy, maybe I should think like him. Here goes:

With Global Warming, we've got a lot of extra heat in the air - meaning that the atmosphere is both warmer and wetter than would be before we stared using energy stored in hydrocarbons to power our economy and release all the trapped CO2 back into the air. On first glance the method in the article looks to be at least a plausible way to recover some of that excess latent heat, with the side effect of removing water vapour from the cooled air as well. The benefit to the Dwelling heat system is that it puts the excess heat back underground from whence it came - like an oil well - and provides long term storage in a safe and relatively cheap manner. If they can work out all the problems sufficiently this just may work in a way beneficial to us economically and environmentally.

So, yeah - electricity and water from the think air. Thanks Al Gore!

Soko

Re:Thin Air

[networkBoy]

Not impossible, but highly impractical. Lead bars are far too thick. Lead ribbon, now you're talking. Just need *free* energy and we're all set to ruin the metals markets :-)
-nB

Re:Thin Air

[yada21]

Natural gold has intrinsic value. Artificial gold is by definition a fiat currency, and henceforth is worth no more than the paper it's printed on.

Re:Thin Air

[networkBoy]

Assuming I have limitless energy I can make the metal atomically correct. After bombardment I can seperate the gold atoms by density, and re-bombard the light ones with neutrons, the heavy ones with protons to the point they fission (or should I manage to capture enough positrons I can smack those around to lighten it), and the random other bits can be used to operate my antimatter reaction vessle :-)

Point I was making is that once it costs less than gold to make gold, then the market for gold (as currency) will be broken.

-nB

Re:Thin Air

[Calinous]

You will take some of the heat from the outside air, and even generate some clean water using condensation - but the heat will only move from the outside air into the ground. The only positive point is that, creatively using the energy transfer, you get (hopefully) energy independence (thus reducing the heat others would put in the air to generate your electricity).
      I hope it will work - but you are starting from a very low temperature differential, and you are bound to get only small results

Re:Thin Air

[Calinous]

Mod parent up - this is too true, and too sad

Re:Thin Air

[Anonymous Coward]

Point I was making is that once it costs less than gold to make gold, then the market for gold (as currency) will be broken.

And I think the point KFG was making was a parallel one, that alternative sources of energy, right now, net so little gain in comparison to the fossils fuels that there's little point. And when the fossil foils become horribly expensive unfortunately so will all the the alternatives, since producing and maintaining them depends on a rather nontrivial amount of fossil fuels. It's easy for people to shrug off fossils fuels as just another energy source but really, think about what they are... millions of years of condensed, stored, solar energy, with a dash of geothermal thrown in too. And we're burning through that million years of energy in decades. When the oil is gone, I think our descendants (assuming any survive the bloody resources wars) are going to be absolutely furious with us that we just burned the stuff.

Re:Thin Air

[Oligonicella]

Foo. Our descendants will reap the benefits of the technology that was developed utilizing ff. Bloody resource wars will only occur if we fail to become a space-faring race. We will graduate beyond them (fossil fuels) and our progeny will be grateful we did. Unless you think they'd rather be living in caves.

Re:Thin Air

[Anonymous Coward]

Yes, because no civilization has ever completely failed because the critical resources they depended on simply ran out. Oh, wait. That happened to most of the civilizations throughout history. There's being an optimist, and then there's being rational.

Re:Thin Air

[kfg]

Maybe I should just hire you to follow me around to smooth out the turbulence I leave in my wake. Ya done real good.

Reagan used to have people like that - "What the President meant was. . ."

Ok, maybe that's a bad example. At least I hope it is.

In any case, the reason for my post is that I'm not entirely sure that wasn't something like OP's point either. It has the whiff of my "let's not fill space with nuclear radiation" post about it. He even put a smilely at the end of it in an attempt to avoid gang rape. Well, at least it kept the crowd small.

It's good to know that my suffering at least serves as an example to others. Now if I were only smart enough to learn from it myself.

KFG

Re:Thin Air

[Em Adespoton]

Sounds great! Current estimates say that it will take 20-50 years for FFs to become more energy expensive to extract from the environment than there will be energy gained from using them.

Should I appoint you as the person in charge of making us a fully space-faring race that doesn't depend on FF anymore? Can you get it completed within the next 50 years?

Personally, I think FFs will last longer than 50 years, but I DO think that we probably only have around that amount of time before sending large objects into space becomes cost prohibitive. What we need is a space elevator that can be completed within that timeframe; after that, there should still be enough fuel around that we can run the thing until our asteroid mining camps can be set up.

But if we miss that window....

Re:Thin Air

[cbacba]

Hey, the stuff is there. It just depends on how many dollars you're willing to spend for a gallon of water.

Actually, our air conditioner produces a fair amount of h2o.

As for those towers, I'm thinking they're at least twice as tall as any manmade structure ever built. I'd think that costs/efficiency considerations would probably trash the whole plan when compared to plain old wind generation and they're still a bit more expensive than more traditional means despite the absence of paying for fuel.

Economics always controls progress. And, it's the total package, cost of production of the capital equipment, maintenance and longevity of the capital equipment, fuel costs, costs to society (pollution), unintended consequences and time to break even on operation.

Also, considering that short term climate change (not necessarily global) can also affect such things. What might be effective at an average 50% humidity (for h2o extraction) might be unworkable at 45% average humidity.

When an idea is developed by those who are enamoured of the idea rather than by the goal of what was the end result to accomplish can result in a failure of the design evolution to adapt to new information and new conditions (a fatal darwinian flaw in an otherwise intellegent design approach).

That towah' of powah' appears like it might suffer from this problem. It requires building a 3000 ft tall chimney to heat up air with solar energy so it rises and turns a couple of generators when the sun heats up the chimney. That is a lot of structure (hence capital equipment cost) there to extract what is essentially a man-made breeze.

Rather than a new worlds record for a structure, why not take those two generators and put them horizontally out somewhere that is breezy. One could probably do 6 or 8 generators a couple of hundred feet up for the price of two in the tower and probably producing 2 to 4 times the energy - if not 16 times the energy of the chimney. All of a sudden, it's a totally different idea, most likely a far better idea. Best guess is that the windfarm is probably still several percent more expensive - but tax incentives can help bridge the difference.

The one question that should always be asked of such alternative approaches is why hasn't someone else done it already to get rich off of the profit. Even if the answer is as simple as no one else ever thought of it (very unlikely), it still can bring one through the process of anaylizing the hidden costs and technological problems associated with it. Perhaps with some new technology, it can be a viable idea. Then again, perhaps it's BS with inferior capabilities and higher expenses.

something interesting I saw a while back...

[mwilliamson]

here's a project using solar heat to drive a ammonia absorption cycle freezer. [PDF]

Re:ThinK Air

[lostguru]

yup

we just get the air to think really hard and then we use that thought energy to power our cars

just give the air some perl to trace and we'll have energy forever

Wind turbine

[Technician]

After looking at the diagram, it is evident the math is not done. A few things come to mind. The most glaring is the wind turbine. Anybody you know of put a turbine in the fireplace flue to get electricity from the heat draft? This is a draft with a large heat change. How much draft do you expect to get from the day/night differential. Don't expect enough juice to power the water pump in a water cooled PC.

Getting the heat to provide the high pressure ammonia to feed the expansion valve is also a problem. Time to do the math.

A good place to start is Modern Refrigeration and Air Conditioning.
http://www.bizrate.com/technologybooks/modern-refr igeration-and-air-conditioning--pid4254146/

Instead of trying to get high pressure ammonia, look up continious cycle absorption cycle refrigeration. The key is using vapor pressure to your advantage. Day/night cycles are not going to provide the requried amount of pressurised liquid ammonia for the job.

Study and learn continious cycle absorption cycle refrigeration then redesign and eliminate the expansion valve, & turbine. Add a light weight inhert gas to the entire system to make distilation of ammonia possible and stop uncontrolled reasorption into water.

Re:Wind turbine

[dbIII]

Getting the heat to provide the high pressure ammonia to feed the expansion valve is also a problem. Time to do the math.

OK - I have not read the article but I will point out that a century old kerosene refrigerator uses a wick and not a great deal of fuel plus a bucked of water to handle expansion and condensation. Solar thermal has potential and scales up - things will be practical given a large enough size, and practical things become smaller given a larger heat differential.

Re:Wind turbine

[Technician]

OK - I have not read the article but I will point out that a century old kerosene refrigerator uses a wick and not a great deal of fuel plus a bucked of water to handle expansion and condensation.

Early kerosene refrigerators used a single cycle sytem where the ammonia boiled or evaporated as it was absorbed into water. To get the ammonia back and the water, the cold side was stuck in the bucket of water and the room temprature water chamber was heated by the kerosene flame to seperate the ammonia from the water. Do a Google search on "iceballs ammonia" for a version that still entertain people today who build their own.
Before you build your own, remember this runs on high pressure during regeneration, and uses ammonia, a relatively hazardous material.

http://www.ggw.org/~cac/IcyBall/crosley_icyball.ht ml

Simple day/night tempratures will not complete the regeneration cycle. The temprature is too low. Even though very little kerosene is burned in those refrigerators, the burning kerosene did provide the required tempratures to complete the regeneration cycle.

So...

[CookieOfFortune]

So this relies on a difference in ambient temperatures. You could also drill a hole deep into the ground and send in heat pipes, since it's pretty hot underneath the ground. The issue here is economics, how much power you get out compared to how expensive it is to build the system. Drilling a deep hole probably isn't cheap, and I don't think building a tower is either. At least you don't have to worry about temperature swings underground (sure it could happen, but I'd think air temperature would change more drastically). I think the issue is pretty much based on economics, there are cheaper ways to get energy, and the concept of using ambient temperature isn't new.

Re:So...

[noigmn]

Their idea was storage using heat pumps so you can use the energy at night rather than use battery storage. It wasn't claiming a new form of power production.

As for production of energy if they wanted to not store it then ground/air temperature difference during the day would probably be similar to day/night air temperature difference.

Re:So...

[Sub Zero 992]

Drilling deep holes can cause earthquakes:

http://www.swissinfo.org/eng/front/detail/Geotherm al_project_shakes_Basel_again.html?siteSect=105&si d=7407138&cKey=1168104002000

I'll let you know...

[advocate_one]

just as soon as I get back from the patent office...

The analogy to Linux

[Scareduck]

They cite a mistaken analogy to Linux as one of the reasons they feel their project could succeed, but in fact the problem is that such a system will require capital to run. This in fact makes it the opposite of the situation obtaining with Linux, when one of the key ingredients, low-cost commodity PCs, helped drive and unify development.

Re:The analogy to Linux

[Anonymous Coward]

The analogy to F/OSS has been applied quite nicely to architecture http://www.architectureforhumanity.org/ hardware http://en.wikipedia.org/wiki/Open_source_hardware .

The absence of capital does not seem to be a prerequisite for the success or usefulness of this model.

Re:The analogy to Linux

[dbIII]

They cite a mistaken analogy to Linux as one of the reasons they feel their project could succeed,

Which is really bizzare becuase open source software is just a subset of the sharing of knowlege that got science to the point it is today.

Probably going to need active cooling

[Anonymous Coward]

After skimming over the design, my gut tells me that the system is also going to need an active cooling component. For the steam turbine to operate efficiently, he's going to need to cool the working fluid below its boiling point. Otherwise a lot of energy is wasted pumping the working fluid in its gaseous form. To operate continuously without an active cooling system, the cold reservoir will need to always be below the boiling point of the working fluid. Now this works in the winter when the air cools off and the system is using air as its cold reservoir. But since he's transferring heat from the ground, we must assume that the ground is above the boiling point of the working fluid. Therefore he runs into the problem that the ground won't cool the the working fluid below its boiling point when the system is operating in reverse, with the ground as the cold reservoir and the air as the warm reservoir. As a result, he'll need to either replace the working fluid when the system starts using the ground as the cold reservoir or integrate an active cooling system.

Re:Probably going to need active cooling

[networkBoy]

Yes, but as he points out as long as there is a gradient there is energy to be had. The wider the margin, the better the efficency, and possibly you could design in two or three working fluids that can be switched as appropriate? It should be nominally more expensive to introduce a decent vaccume purge cycle to minimize contamination?
-nB

All I know is that I applaud his making it "free". Likely if he had tried to make money off of this tech it would fail, but now enough tinkerers may pick it up that it has a hells chance (kinda like the EV).
-nB

Geothermal..

[Anonymous Coward]

This design seems to be a complicated form of utilizing geothermal energy. I don't see any reason why the geothermal energy shouldn't instead simply be used for space heating instead of electricity generation, especially in areas with low levels of geothermal energy availability.

In areas such as Iceland or Hawaii, this technique would be more feasible, but simply using the more abundant geothermal energy sources to drive steam turbines without the use of refrigerants or air turbines would probably be more efficient.

When considering alternative energy sources, we need to be careful to exploit the most abundant and economically feasible first. In the same way that we did not begin investing in hard to refine oil sands or deepwater oil before we exhausted all the easily available sources of light sweet oil, we should not invest in capital that is designed for diffuse, "use it anywhere" sources of energy before we install windmills in all the major windy mountain ranges and coastal areas, solar panels in all the worlds equatorial deserts, and hydroelectric plants in all the worlds damable rivers.

Doing so would be like buying 2% yeild bonds when 10% yeild bonds with even lesser risk are available.

Re:Geothermal..

[Anonymous Coward]

I agree with the previous post about geothermal heat. It efficient and is already in real use in several locations, and very common for instance in Sweden. They actually save quite a lot of oil and are simple to install in single houses. The hole you drill is not that deep and not likely to cause earthquakes!!

Have a look at these at wikipedia for more information:

http://en.wikipedia.org/wiki/Geothermal_power

http://en.wikipedia.org/wiki/Geothermal_exchange_h eat_pump

Re:Geothermal..

[dbIII]

I don't see any reason why the geothermal energy shouldn't instead simply be used for space heating

I do - however it is over 30C here in a house built for the climate and it is after 10pm at night. Hot water is a different story.

Re:Geothermal..

[wisdom_brewing]

To be fair your final analogy is flawed. It would be more like buying 30 year bonds with 10% coupons but low yield as opposed to buying 5% coupon 5 year bonds with a higher yield. You dont know how much time will push up the cost, and the 30 years can outperform the 5 years if things happen in a certain way (as with everything in life).
 
Im not an environmentalist, but investing in power which doesnt require much outside input to generate is something Im for. I feel that we are suffering undeservedly due to a bunch of retards who got too many people scared of nuclear power, which in my opinion is the best option in the medium term and even long term.
 
Youd have to invest in "renewable" sources for the prices to come down, the technologies would mature with time, become more cost and space efficient (up to a certain level) and you cant tell me that the first computer ever built was a waste of time, and I can bet you that there were more than enough people that could add up several hundred times faster than it took to input the question at the time and see where we are now...

Re:Geothermal..

[Anonymous Coward]

Seeing as Hawaii rarely gets below 60F or above 85F year-round, Hawaii doesn't really need heat or cooling, unless you live at a high enough elevation near the top of the volcanos.

Lemme Ask Lord Nemesis

[abesottedphoenix]

Lord Nemesis, how do we get this to work?

Where it is theoretically something that's feasible, I'd have to say that you'd have to scale things very, very small indeed. Of course, this is theoretically possible to me on the same level that it's theoretically possible to capture all of the hot air from a committee meeting. On the other hand, with emerging nanotech, they might be able to invent something that can easily power a small gadget. It still looks like it would be least effort to employ either wind or solar in the meantime, though.

For this, hell no.

[Khyber]

There's too much energy transfer/transformation to make this very feasible. Just stick with solar energy/cooling for fuck's sake.

You still need nuclear in the mix

[Anonymous Coward]

Renewables are really a good idea but if you truly want a reliable energy supply you need to have a base load energy source such as nuclear. All the others have problems such as Coal with its CO2 and other greenhouse gas emissions not to mention the radioactive elements that it releases. Hydro with its damage to the surrounding environment's fish and wildlife (there is even talk of the draw down of the dam causing CO2 emissions due to plant die off). Wind's problem with efficiency and not being a reliable resource. Solar with similar problems of Wind in that it still isn't efficient and not very reliable. Tidal sounds interesting but there isn't any practical applications out there yet. Fusion power isn't going to be viable for a number of years if ever. Natural gas has CO2 emissions and can't last much longer from a resource standpoint. Fossil fuels are going to eventually peak and are terrible for the environment.

What does that leave? Nuclear. I know there is the problem of storage of the waste from these plants but with the new fast breeder reactors coming online within the next 20 years and fuel reprocessing many of these problems should be minimized. Safety isn't as big an issue as it used to be. Many of the new generation reactors have built in safeguards that prevent thermal runaway from occurring. In fact more people die from any of the other energy producing technologies than from nuclear. If you are worrying about non-proliferation, well that is an issue but investingating technologies such as Thorium reactors which do work today (they have an experimental one up and running in Europe). Thorium for those who are interested can be used to create a sub-critical reactor that requires an external neutron source in order to sustain the reaction (ie. No thermal runaway is possible). The Uranium 233 that is created in the reaction is increadibly hard to process to create nuclear weapons so this technology is proliferation resistant (it's probably easier just to buy a nuke on the black market).

I've also heard that the waste from a thorium reactor would go to the radioactive level of coal potash after a period of approximately 500 years so it should be easier to store than uranium would.

Re:You still need nuclear in the mix

[deadlock911]

"need" Do you have any idea how many countries DON'T use nuclear power? Boy, they must be all be warming their homes by rubbing sticks together....

Re:You still need nuclear in the mix

[bestiarosa]

In Italy, we don't use nuclear power. Instead, we buy electricity from France which built nuclear power stations just across the border.

Solar PV Cells

[Keebler1175]

Isn't the most viable alternative energy available today solar PV cells? Already proven technology and now even affordable!

Re:Solar PV Cells

[dbIII]

It doesn't scale up - double the area and you only get double the power. This is why nuclear likes to compare themselves with photovoltaics - just about any thermal solution built big enough will pull ahead of photovoltaics eventually - the only exception I've heard of was the Superphoenix fast breeder which could not even win such a rigged contest at any scale due to reprocessing problems.

Re:Solar PV Cells

[Keebler1175]

I'm not sure that thermal is the ideal candidate to support existing home construction for alternative energy, but I believe that PVs coupled with some sort of storage solution is the best choose for that segment of the market.

Perpetual motion

[flyingfsck]

hmm, just wait with that one till I get my perpetual motion generator set to work...

Things like that do exist

[de_valentin]

In Germany there are several different projects and ways found to build a 'zero emission' house. Most of which use a combination of solar, wind and water energie, in ways that are to say the least very creative but they work and that is the point. So why wouldn't this work in most cases it is a delicate combination and even small bits of energy like draft coming from night and day differences could make the difference.
I for one hope they succeed even if it takes them several years and more 'crazy' ideas

http://www.hartmann-hauss.de/turm.html (zero emission office in germany)

Re:Things like that do exist

[abdulwahid]

In Germany there are several different projects and ways found to build a 'zero emission' house.

I don't think that it is fair to say there is such thing as a 'zero emission' house. Most of the equipment used in such houses such as turbines, solar panels etc are all built in factories and from materials extracted and manufacturered from processes that are using fossil fuels.

In fact, most of the green fuels we have today are in fact products of fossil fuel because their supply chains rely on fossil fuels. For example, Brazil has successful ethanol production where the ethanol is produced from sugar with a positive energey returned on energy invested (EROEI) ratio. However, the claims on the EROEI forget to mention that the distribution vechicles and agricutural vechicles used to produce the ethanol are using fossil fuels. If they were not the EROEI would be considerably lower and perhaps even negative.

Re:Things like that do exist

[Anonymous Coward]

As far as the Zero Emission Solar Panels are concerned, in Germany there is a Zero Emission solar panel factory too, in Freiburg. The trick is that they use Rapeseed oil to power their plant.

Re:Things like that do exist

[abdulwahid]

Well that sounds like a nice project, but still far from a 'zero' claim due to the supply chain issue. All this says is that the first level of the supply chain e.g. he panel factory uses a renewable source. However, at the end of the day the supply chain is still heavily relying on fossil fuels for agricutural equipment, distrubition, raw material extraction and other equipments and proceses.

Anyway my point is not to be argumentative about the definition of 'zero' but rather to highlight that even with the most promising renewable sources we are still stuck relying on a supply chain and distrubution network that relies on fossil fuels. So the idea of a transistion to a complete reweable structure is a bit of a pipe dream at the moment and it is unclear weather with exisitng technology it can be carried out at mass scale with a positive EROEI.

Re:Things like that do exist

[Chris Burke]

Anyway my point is not to be argumentative about the definition of 'zero' but rather to highlight that even with the most promising renewable sources we are still stuck relying on a supply chain and distrubution network that relies on fossil fuels. So the idea of a transistion to a complete reweable structure is a bit of a pipe dream at the moment and it is unclear weather with exisitng technology it can be carried out at mass scale with a positive EROEI.

Well, yes, our distribution infrastructure (and many other aspects of infrastructure) rely on fossil fuels rely on and will continue to rely on fossil fuels for quite a while.

However any time we take a truck that used to be shipping a heating/generation component that was created using non-renewables and once installed is fueled by non-renewables, and replace that same shipment with a component created using renewables and which operates on renewables, then we have a net reduction in the amount of non-renewable energy used.

Which has the happy side effect of making our non-renewables last longer, so that our distribution infrastructure can run for longer before we have to make the painful and at this point purely hypothetical switch to a replacement. It is exactly because we are stuck relying on fossile fuels for our supply chain that we should avoid using fossil fuels everywhere possible.

My point is that you are absolutely correct, yet this should not be used in any circumstance as an argument against using alternative energy sources. Rather the opposite -- that we will need fossil fuels for the forseeable future means that it is all the more urgent that we don't unneccessarily stress our supply. You weren't arguing the point, I realize, but it is typical for anti-conservationists to seize upon examples like this to claim that things like solar panels made from rapeseed oil are no better, so I'm heading them off at the pass.

might work with large heat differences

[abdulwahid]

This might work in some places where there is a large difference in temperature from day to night. Where I am living on the edge of the Saharah desert we have hot temperatures all year around but the temperature does drop considerably at night. However, the places like this that have such differences generally need the electricity during the day for cooling rather than at night for heating. So the system would need a good way of storing the energy for day time use and I am not sure of the best way of doing that.

Re:might work with large heat differences

[Anne Thwacks]

While living in Nigeria in the 1970's I proposed a system similar to this, and tried to patent it when I returned ot the UK. However, the company I was using to licence my ideas "Cambridge Intellectual Properties Ltd" (Cambridge, England) appeared to have stolen my idea and sold it to an organisation in Spain, who actually built it as I described it to CIP (as opposed to my actual proposal, which I did not disclose).

The spanish organisation built one, and it worked for at least 7 year to my certain knowledge (hint: Google is your friend).

The way to store the heat/cold is very simple - black bin-bags full of water on the ground under your solar collecting surface.

The limitations of this technology have been extensively discussed in academia. My proposal is considerably more efficient than any of these proposals in TFA, and addresses the known limitations directly, but I am in active negotiations about patenting it with more honest partners, so I will not disclose it here.

And for those who are rabid anti patent people

A) I am not against the GPL, but its not the solution to everything.

B) Yes I do work as an energy consultant as my day job.

C) There are people in Australia working on a huge energy tower, several miles high

Re:might work with large heat differences

[Znork]

"This might work in some places where there is a large difference in temperature"

You dont really need that much of a temperature difference to generate electricity; there are model stirling engines that work off the difference between the heat of the air and the heat of your hand.

Of course, you still do need enough of a total stored energy diffrential to actually generate the electricity needed, so at low diffrentials you may need larger initial storage generators or storage volume.

Re:might work with large heat differences

[Anonymous Coward]

Actually people in your part of the world first built towers like this (as far as we know). Now I am not saying they produced electrity with them. Current consensus is they were strictly for water production and worked well enough to connect underground aqueducts to them. Similar towers have also been used to cooling with the water production as a side effect. Installing turbines in them to take advantage of the air/gas flow through them is maybe a new "invention" and maybe not. Even belching smokestacks could be used to produce electricity in a similar manner. Our systems allow lots of energy to go to waste worldwide. Much of it going to "waste" is naturally occurring. Any research into practical applications for making use of that waste is nice to see, especially if its open sourced or put in the public domain, either way it can be widely adopted by anyone.

Re:might work with large heat differences

[nasch]

C) There are people in Australia working on a huge energy tower, several miles high

These people? "The tower will be over there," Davey says, pointing to a spot a mile distant where a 1,600-foot structure will rise from the ocher-colored earth. "Several miles high", even if "several" means three, would be over 15,500 feet. According to Wikipedia, "Currently, the tallest standing structure is the KVLY-TV mast near Fargo, North Dakota, at 629 m (2,063 ft)." I don't think anyone is planning anything seven or more times taller than the current tallest structure in the world.

And you're right, Google is my friend. :-)

What a fazinating idea

[Knutsi]

It may be that this particular case will not work, but the idea is great. Roll it yourself systems developed, improved, forked and tested online through an open source ideology... great stuff (: One has to admire the potential social consequences of the open source ideas, both in technology, law and governance.

Sadly for some, this also applies to warfare.

(this blog speaks of, amongst other things, how "open source warfare" (OSW) is the key behind the insurgency success in Iraq. The methods applied by what is essentially guerilla groups testing wildly different approaches across the nation, then learning from their success, contrary to a carefully planned and centralized military system)

Re:What a fazinating idea

[Knutsi]

Actually, check the post from Friday, December 08, 2006 for a general introduction to the concepts.

Re:What a fazinating idea

[zCyl]

It may be that this particular case will not work,

That seems like the likely outcome.

but the idea is great. Roll it yourself systems developed, improved, forked and tested online through an open source ideology... great stuff (:

Hmm. Perhaps they should consider putting the design under a wiki which specifically encourages original research, and see what happens to it.

Re:What a fazinating idea

[Knutsi]

Such things could possibly also stimulate more interest in engineering and science, and work as great comunity-competence building worldwide. If enough components are available at low price, it may be very usefull things for developing nations as well.

It's a matter of dimension vs efficiency

[JHWH]

how likely do you think it is to work?

I think that a per-house solution could not be feasible. I'd rather see a per-quarter or a per-village solution with larger plants and, maybe, higher efficiency.
Moreover the materials involved in this project are not all 100% safe. In a bigger plant you could spend more money for safety.

Re:It's a matter of dimension vs efficiency

[Anne Thwacks]

I think that a per-house solution could not be feasible.

Why? Do you have any data?

Or do you support the Victorian concept that the mill owner should own everything? Or maybe the communist idea that the state should own everything? Or the Italian idea that the Mafia should own everything? (Just kidding ;-}

Firstly

[deadlock911]

I haven't finished reading this/thinking BUT in the diagram of the "Down Draft" step they forgot to connect the pink line... Back to the article!

Basic Thermodynamics - 2nd Law

[Anonymous Coward]

Someone didn't do their math...

For a reversible power cycle operating between a cold sink at temperature Tc and a hot sink at temperature Th, the maximum possible thermal efficiency nmax is given by:

nmax = 1 - Tc/Th

Where n = Wcycle/QH. Wcycle is the net work (energy) being extracted from the cycle, and Qh is the amount of energy being transferred from the hot sink to the cold sink.

There are only two sinks in this system: the ground and the air. It is easy using the Carnot cycle above and an amount of enegy to be transferred Qh to determine the maximum possible output of such a system. The actual mechanical implementation, however, reduces n far below nmax, and the particular implementation described is prohibitively complex....

Clearly the author has no understanding of basic thermodynamics. You could choose a case of ground temperature and air temperature based on published data and do the calculations very easily...

Re:Basic Thermodynamics - 2nd Law

[Anonymous Coward]

A feasibility/efficiency study of a down draft tower is here: http://www.ecmwf.int/about/special_projects/czisch _enrgy-towers-global-potential/

The Carnot efficiency of the possible energy captured from wind turbines from cooling ambient air in such a tower is around 2%. The thing is that Carnot efficiency is more relevant in non-renewable systems, because the supply of ambient temperature air is unlimited and by using a solar powered cooling system, there isn't energy expended in cooling the air.

The fact that the wind turbines can only convert 2% of the heat energy in the air into electricity isn't a consideration except for the physical construction costs of the tower. Once the tower is built, at least that portion of the system is little-to-no maintenance.

Utilizing a solar powered absorption heat pump increases the ROI of the solar panels by using the heat collected to move up to 20x the direct solar heat (the additional heat comes from the ambient air). The more air that has to move through the system, the better and the 2% Carnot efficiency isn't all that important.

When all you have is a hammer....

[DerekLyons]

After reading over their description, how likely do you think it is to work?

Not very likely at all - because the creator doesn't really have any idea how steam engines, or refrigerators work. Also, like most armchair engineers he's really, really light on the math.
 
I find this part particularly amusing;
 

2. The principles and project management of Linus Torvolds with Linux and the many other contributors to Open Source and Free Software has shown such success with large projects.

3. There are many people with good ideas and a willingness to help, but Mechanical and Electrical Engineering and Physics are not their field. The project is based on bringing people together to work on something that has benefit for everyone.

I think the creator quite misundertands how F/OSS works - he somehow thinks that people who aren't programmers get together and somehow create the programs, and that the same magic wand will work for making this kludge a reality.
 
Then he makes laughable statements like this:
 

In the capital investment for energy sources that are renewable, the capital investment is not important. Once the system is built and producing electrical power, it doesn't run out.

I guess in his world structures and machinery aren't subject to wear and tear - but here in the real world they are.

Re:When all you have is a hammer....

[TubeSteak]

I guess in his world structures and machinery aren't subject to wear and tear - but here in the real world they are.

The miracle of modern technology is that consumer grade stuff just works, with very little extra input required. I'd submit that is why someone can seriously suggest such a project without factoring in maintenance.

Other than a car, I can't really think of many consumer grade pieces of 'equipment' (which people regularly interact with) that require regular maintenance.

Even newer cars don't require the same level of maintenance that they used to. Modern diffs, transmissions, bearings and spark plugs can all (supposedly) go for ~100k miles... Radiators don't really need to be flushed anymore. Heck, you don't even need to change your oil every 3,000 miles (RTFM, YMMV).

Re:When all you have is a hammer....

[dbIII]

I think the creator quite misundertands how F/OSS works - he somehow thinks that people who aren't programmers get together and somehow create the programs, and that the same magic wand will work for making this kludge a reality.

It really isn't all that hard - it only took me four years of intensive education to get a grasp on engineering and a bit of experience to get more of a grip. A lot of the education is available on line now and there are ways to get experience even in remote areas. If they out in enough work they will get there in the end and perhaps pick up some very experienced mentors along the way. There is currently a cutting edge solar water purification project being run by a retired physicist - perhaps they'll attract the intrest of some people with some time and no wish for payment that can point them in the right direction.

A good start would be some thermodynamics textbooks - most of the mathematics isn't hard.

Re:When all you have is a hammer....

[drinkypoo]

Radiators don't really need to be flushed anymore.

WRONG. Please do not dispense your automotive advice, you will be directly responsible for the destruction of other people's cars.

I will now tell the assembled populace the truth, so that they do not believe you. I have received ASE certification in automotive heating and cooling systems - the only certification I bothered to get. I could have easily passed the automotive electrical exam, as I aced the class, which was a six unit class. These are my credentials, the following is my knowledge.

Automotive coolant is made up of two things; distilled (we hope) water, and antifreeze. Antifreeze is made up of a bunch of things but it's mostly poly-ethylene glycol or PEG, which is used because it is highly stable at a very wide range of temperatures, including very high ones. Antifreeze has three jobs; it lowers the temperature at which the coolant freezes, it raises the temperature at which it boils, and it helps prevent corrosion. Another element in the cooling system is the radiator cap, which also raises the boiling point; IIRC it's 1 degree centigrade for each 1 PSI at your radiator cap. Most of your older (1960s era) vehicles have a very low pressure cap, usually about 7 PSI. Modern vehicles might be anywhere from 10 to over 20 psi.

However, coolant does not last forever. If you regularly run the car at high temperatures, coolant breaks down faster. If there is intrusion of any kind into the coolant, such as from a gasket leak, the coolant goes bad very fast, but that's not so much what we're talking about here. However, other things can cause coolant to go bad. For instance, if your vehicle has aluminum heads on an iron block, the combination of coolant and the two metals creates a dielectric which results in a voltage potential, which in turn produces current flow. This causes anodization of one of the metals (I always forget which metal becomes the anode in this relationship - I'm not a physicist and my memory is for shit in some areas) which in other words is corrosion. The result is that the oxidized surface (I believe it's the iron) will lose particles of its oxides into the coolant. This decreases its effectiveness and makes it more conductive, leading to further oxidization.

As such, you can actually check your coolant with a voltmeter. Put one lead on a ground and dip the other end in the coolant in the radiator. If you measure over 0.1V, your coolant is bad and should be replaced as soon as it is convenient. If it is 0.2V or higher, your coolant is actively causing damage to your cooling system and must be replaced as quickly as possible.

With all that said, coolant does go bad much more slowly in any engine which features all the same composition; iron block with iron heads, or like many modern vehicles (Especially small imports) alloy block with alloy heads. However, just the coolant pump itself typically contains multiple metals and you also have the radiator itself to deal with (usually alloy these days) and the heater core (probably alloy, but could still be copper) not to mention any additional piping like you see on some poorly designed vehicles from Ford :)

You should also be aware that GM's red coolant "Dexcool" is a horribly destructive fluid that DOES go bad (although GM claimed you could leave it for ten years or more) and when it does it doesn't just eat metals, it eats plastics too. It has been known to destroy entire cooling systems, requiring replacement of the radiator, heater core, and coolant pump, and complete flushing of the entire system. Anyone with a GM vehicle that says "USE ONLY DEXCOOL" or has a similar message should drive as fast as they are legally permitted to a non-dealer shop that will, upon request, put some kind of coolant in there that will not destroy your vehicle.

Please, save your misinformation for someone else.

On the topic of eng

Re:When all you have is a hammer....

[drsquare]

3. There are many people with good ideas and a willingness to help, but Mechanical and Electrical Engineering and Physics are not their field.

If they don't know anything about mechanics, eletrical engineering or physics, how helpful can they really be? Anyone can come up with ideas.

Re:When all you have is a hammer....

[syukton]

"Consume grade" machinery doesn't require maintenance because it has a tendancy to just up and break rather often, requiring repair. Toaster ovens, microwaves, blenders, all manner of home appliances will inevitably fail, possibly just outside of their warranty period. Washing machines are another great example of a "consumer grade" piece of equipment that will just mysteriously stop working, usually due to a motor shorting out or a similar electrical problem. Anything with an engine or motor is generally under-engineered, which can lead to sudden failure.

It's the tradeoff between predictable downtime and unpredictable downtime that really gets me. Especially in a power generation scenario, it seems imperative that you know when your system be unavailable for power generation as it may be relied upon for mission-critical systems such as medical equipment.

I, personally, would rather regularly maintain my blender than have it just unexpectedly die on me in the middle of a smoothie. Unless I build it myself (or get one of those absolutely insane blendtec units) though, my blender unexpectedly dying on me is inevitable.

Re:When all you have is a hammer....

[treeves]

Some corrections to your correction:

Engine coolant has three main ingredients, not two: you forgot corrosion inhibitors. They passivate the metals in the cooling system and prevent the galvanic corrosion you mention without naming.

And it's ethylene glycol (or propylene glycol), not POLYethylene glycol as the other ingredient besides water.

The radiator cap allows the pressure the in the cooling system to increase so far before it relieves pressure. It is the increased pressure which raises the boiling point. BTW, it's closer to 2C/psi for water.

Re:When all you have is a hammer....

[drinkypoo]

Engine coolant has three main ingredients, not two: you forgot corrosion inhibitors. They passivate the metals in the cooling system and prevent the galvanic corrosion you mention without naming.

Actually I wasn't trying to go through the laundry list of ingredients in antifreeze; the product that you put in your radiator up to 50/50 in normal places or 70/30 in seriously fucking cold ones is still called "antifreeze".

And it's ethylene glycol (or propylene glycol), not POLYethylene glycol as the other ingredient besides water.

Sorry, I was just going through a whole thing on chemicals in beauty products the other day and it stuck with me. :)

The radiator cap allows the pressure the in the cooling system to increase so far before it relieves pressure. It is the increased pressure which raises the boiling point. BTW, it's closer to 2C/psi for water.

We're not using water, though :D Actually some people DO use water as a coolant in racing, and it's flushed out in between races to prevent corrosion, because while water+antifreeze has a higher boiling poing than water alone, water alone is better at transferring heat, both from the engine and to the radiator vanes which are then air-cooled. (Just being complete.) You can buy various products to go with your water in small quantities, like Water Wetter.

Re:When all you have is a hammer....

[mianne]

Honestly, I think that is the point. If you are a mechanical engineer, you have a solid understanding of stress tolerances, friction, waste heat, MTBF, etc. Ergo, anytime someone proposes a perpetual motion generator, said engineer can probably find a dozen reasons why said system won't work. That said, don't discourage the dreamers!

Sure, there will be all kinds of hare-brained schemes dreamt up by people with nary a clue how the real world operates, and convincing these people otherwise will be difficult, if not impossible. -- Part and parcel of being a dreamer.

OTOH, many an idea with potential merit has been created by dreamers, not engineers. In terms of alternative fuels, a couple examples would be power generation from scrap tire recycling and biomass fuel from livestock waste.

So, in that sense, I can see how a F/OSS approach to alternative energy could be effective. Some folks can bring ideas to the table, experts within a specific scientific discipline can determine the feasibility. Folks from other fields of knowledge may spot "out of the box" solutions to a proposed, but inefficent idea, or conversely, point out potential pitfalls (legal, environmental issues) that weren't readily apparent.

The point being, as long as this community of dreamers, sages, and pragmatists are bound neither to a single idea nor especially to one specific industry's financial interests; it may be the best hope for discovering a viable (as in cost-effective, able to meet demand, and safe) alternative to fossil fuels within the foreseeable future.

Re:When all you have is a hammer....

[DerekLyons]

I guess in his world structures and machinery aren't subject to wear and tear - but here in the real world they are.

The miracle of modern technology is that consumer grade stuff just works, with very little extra input required.

The reality of modern consumer grade technology is that, yes, it just works - until the day it doesn't. (Kinda like my washing machine which recently required repairs.)
 
 

Other than a car, I can't really think of many consumer grade pieces of 'equipment' (which people regularly interact with) that require regular maintenance.

There problem is, you are responding to a strawman of your own creation - because I didn't mention (regular) maintenance. I adressed the (false) claim that the machinery will not wear out - and that capital investment is thus preserved. In the real world, machinery of any grade eventually requires either corrective maintenance or outright replacement.
 
 

Even newer cars don't require the same level of maintenance that they used to. Modern diffs, transmissions, bearings and spark plugs can all (supposedly) go for ~100k miles... Radiators don't really need to be flushed anymore. Heck, you don't even need to change your oil every 3,000 miles (RTFM, YMMV).

That's news to me - got a cite? (IOW, bullshit.)

Re:When all you have is a hammer....

[Anonymous Coward]

most companies offer a 100,000 mile powertrain warranty (diffs, axle bearings, transmission, etc) because that's the rated lifespan of the parts that they're using.

radioators used to need flushing every few thousand miles, nowadays it's done once or twice during the lifetime of a modern car.

go talk to a mechanic about that stuff

if you've never heard of 100,000 mile spark plugs or 5,000/7,500/15,000 mile oil, you should go to an auto-parts store and see it for yourself.

Not Yet.

[WindBourne]

Isn't the most viable alternative energy available today solar PV cells? Already proven technology and now even affordable!

At this time, Solar provides the least amount of energy of all of the alternative systems. Hydro, wind, geothermal, and methane generation currently provide more energy than does solar. In addition, they do it cheaper.

But long term, homes will probably be better off using a geothermal heating/cooling combined with electricity from pv systems

Re:Not Yet.

[Keebler1175]

I know the current state of PV is limited, but I believe it's the most likely to increase in usage for home users.

Secondly...

[deadlock911]

OK, i had a big post written explaining that there is going to be a serious lack of air circulation through that tower, definitely not enough to power those turbines you have in there.
BUT i wont post it because i had an idea, what if you replaced those turbines with FANS!
Now before you laugh i know that fans would use up some of the power you are generating BUT it would greatly increase the thermal exchange in your air heat exchange. This would increase the power generated by the "steam" engine and increase the speed at which you can generate power.
I KNOW this will decrease efficiency, BUT its not like your going to use up all that heat anyway ;P

Gold from human shit.

[cheekyboy]

http://cat.inist.fr/?aModele=afficheN&cpsidt=34076 62

Sewage sludges from German municipal wastewater treatment plants possess high gold concentrations (280 to 56,000 g/kg in dry matter) similar to some ore deposits which are being mined for gold. In addition, the sludges exhibit elevated platinum (10 to 1,070 g/kg) and palladium values (38 to 4,700 g/kg), and low osmium (3 to 51 g/kg), iridium (0.6 to 26.5 g/kg), ruthenium (2 to 390 g/kg), and rhodium contents (2 to 352 g/kg Major amounts of these metals are already present within the wastewater solids before the raw sewage reaches the treatment works. Sludges from industrial areas tend to possess higher precious metal values than those from rural regions. Thus industrial discharges contribute significant quantities of precious metals to municipal wastewaters and sewage sludges. However, elevated precious metal contents in sludges from rural areas show that additional sources are present which remain to be determined by future studies

Re:Gold from human shit.

[drsquare]

Sewage sludges from German municipal wastewater treatment plants possess high gold concentrations (280 to 56,000 g/kg in dry matter)

So 1kg of dry shit contains 56kg of gold? Fetch a fishing net and a pair of rubber gloves, I'm going to make myself a millionaire.

Re:Gold from human shit.

[njh]

You don't think it's just a few random wedding rings that fell down the toilet? (Where's your muse when you need them?)

If you are interested in this stuff :

[Anonymous Coward]

I advise you to buy this book now!

Ecohouse2 - A design Guide.

http://books.elsevier.com/uk/architecturalpress/uk /subindex.asp?isbn=9780750657341&country=United+Ki ngdom&community=architecturalpress&ref=&mscssid=ME J825X2A5M08HHFFWHR0L2NDV0W0GU0

I have had a copy since 2004 and would not be without it.

On the right track...

[GrahamCox]

I think the idea is flawed but on the right track. Direct solar energy to electricity conversion is currently about 10-15% efficient, so you need very large areas to get a decent output. On the other hand, absorbing solar energy as heat in a medium such as water is vastly more efficient, but the problem is to get useful energy out of the heat. Using a Stirling engine and an ordinary alternator could be one practical way, and you'd still end up with overall system efficiencies (maybe up to 50%) that direct solar conversion engineers can only dream of. What surprises me is that it's not being more actively researched, as far as I know. Stirling engines are a very old concept that have not been given the refinement work that they might deserve - certainly in theory they could yield good efficiencies, if only someone would throw a few million in their direction (internal combustion engines started out pretty poor but they are now working at close to their theoretical maximum efficiencies after 100 years development).

Re:On the right track...

[Calinous]

You might get some "energy capture" efficiency of 100% from solar energy into water - however, keep in mind that any thermal engine is restricted by the Carnot efficiency (1-Tcool/Thot, with temperatures in Kelvin). For a not-so-dangerous temperature differences (using a frozen pond in winter) of freezing-point - to boiling-point (273Kelvin to 373Kelvin), efficiency (max, theoretical, when using a gas) would be about 25%. This is where you start

      Photovoltaics have extraordinary efficiency, coupled with zero (close to zero) maintenance. They might cost (both in dollars and environmental impact), but are better than thermal anything in small scale electricity generation

Rough efficiency

[clare-ents]

Assuming a hot temperature of 70C (black plate in strong sunshine) and a cold temperature of 20C, the theoretical efficiency limit is (343-293) / 343 or 14.6% - assuming a perfectly efficient generator and a very large capacity foe the 85% waste heat capacity.

At night, it's going to be more like 30C -> 0C which is down at 9.9% efficiency.

Even cheap solar cells do better than that, you'd be better off just buying solar cells.

Re:Rough efficiency

[Anne Thwacks]

As the efficeincey of PV cells is generally less than 5%, I think not. Also, the cost per watt of capacity for PV cells is way higher, so your post supports the concept quite strongly, rather than opposing it.

Re:Rough efficiency

[Anonymous Coward]

Note that the Carnot efficiency figures for the above post are for maximum theoretical efficiency. When you start adding in mechanical and thermal losses on the system, actually efficiency drops much lower.

Re:Rough efficiency

[clare-ents]

I can't see any costs on the site so I don't understand how you can possible make an assertion about this being cheaper.

An amorphous silicon cell is typically 6-8% efficient, lots of commercially available cells are 14-16% efficient - more efficient than this scheme can possibly be.

I respectfully refer you to Homer Simpson, 'In this house we obey the laws of thermodynamics'.

Re:Rough efficiency

[rohar]

I don't quite understand what the efficiency of Solar PV at night is supposed to conclude.

15% efficiency of Solar PV with no input source for 1/2 of the 24 hour cycle (NM cloudy days) and the silicon shortages mean that for Solar PV to become feasible for anything more than supplementary power generation, they have to become way more efficient at capturing solar energy when the sun is shining. A feasible power storage system needs to be implemented for it to be reliable. These two factors make Solar PV at best a supplementary energy source.

ethanol and biodiesel.

[testadicazzo]

From the article:

Renewable and portable energy products like Ethanol and BioDiesel now take more fossil fuels to produce the input crops than if the fuel was burned directly.

This has nothing to do with their method, but I think that claim is a bit misleading. From the wikipedia article on ethanol:

For ethanol to contribute significantly to transportation fuel needs, it would need to have a positive net energy balance and the U.S. Department of Energy has concluded that it does, stating in a recent report "the net energy balance of making fuel ethanol from corn grain is 1.34; that is, for every unit of energy that goes into growing corn and turning it into ethanol, we get back about one-third more energy as automotive fuel."[33] The report also indicates that using a crop with a higher sugar content than corn, such as sugar beets, would result in production with a much higher positive net energy balance. Some scientists[34] argue that the energy balance is negative when all factors are considered. Professors Tad Patzek and David Pimentel are the most well-known academics to make this argument. These arguments have been challenged in a report from the U.S. Department of Energy as being based on decades-old data and not considering recent advances in production or the use of more efficient source crops for ethanol fermentation. [35]

With ethanol being produced in such large quantities, such as in Brazil, I don't understand how this is subject to debate. Couldn't one just measure the fossil fuel use of an ethanol producing farm, and compare it to the amount of ethanol produced? Anyone know of a study that lays this issue to rest?

Re:ethanol and biodiesel.

[abdulwahid]

With ethanol being produced in such large quantities, such as in Brazil, I don't understand how this is subject to debate.

The debate being that working on a Sugar plantation producing ethanol, like where I am working, we can produce Ethanol with a positive ERORI.....BUT, there is so much of the infrastructure, resources, supply chain and distribution network that still relies on fossil fuels that the whole measurement of the EROEI is a bit misleading. Yes, we have a positive ERORI while we have fossil fuels to support it but it is unclear what would be the situation in a post carbon world. With present technology it seems that bio-fuel production would not have a positive ERORI without fossil fuel support.

Re:ethanol and biodiesel.

[Oligonicella]

Just being pedantic here. I think you meant a post petroleum world. Ethanol is carbon based too.

Re:ethanol and biodiesel.

[rohar]

Renewable and portable energy products like Ethanol and BioDiesel now take more fossil fuels to produce the input crops than if the fuel was burned directly. The point I was trying to make is that if agriculture was moved towards using cleanly generated electricity and away from fossil fuels, it lowers the amount of fossil fuels required to produce and deliver consumer Bio-Diesel and Ethanol. I understand that everything from equipment manufacture, fuel delivery and even the transportation of labour to the farm currently requires fossil fuels, but the point is to "fix" agriculture first and as more Bio-Diesel and Ethanol are produced, the required fossil fuels for the rest of the supply chain will eventually lower.

It is a solved problem

[IMustBeNewHere]

I don't know about the part of his design that is above ground.

The underground bit however, works well in practice, at least in the Swedish climate.

Extracting heat from a temperature differential with a heat pump and storing it in the ground, is in wide commercial use here, and you can save money on it.

In a quick search in the Swedish yellow pages, I found hundreds of contractors to choose from.

There has also been plenty of research conducted in this field in various Swedish universities. The article author would probably save himself a lot of time if he looked some of it up. Here are a couple of abstracts (in English and Swedish):
http://www.lib.kth.se/main/stems_projektrapporter. asp?subj=vp

Re:It is a solved problem

[Anonymous Coward]

"Extracting heat from a temperature differential with a heat pump" is a widely used technique in sweden due to benificial geological properties (a particular type of granite) cold winters and subsidised installs. But the "and storing it in the ground" part is afaik non-existant here and non of the abstracts linked indicates that this technique was used (if you have links to a common type of installation of this sort in sweden or even a single large one feel free to provide links).

Re:It is a solved problem

[Mysticalfruit]

I actually see a problem that nobody has mentioned yet.

Anhydrous Ammonia is used to make methanphedamines, hence you're going to have a couple of problems.

Firstly, any chemical company that's going to sell you the required quantities (I think) has to report these sales to the athorities (which won't be an issue when they show up and you show them that you're working on a renewable energy system (and you've got all the proper permits, etc))

Secondly, I suspect that you'll be a target for meth dealers who will want to steal your ammonia.

With that all said, it does look like an interesting system however the feasibility is yet to be seen.

Re:It is a solved problem

[daeg]

Lace your ammonia with rat poison and you won't have a problem.

What? It works for garbage cans to get rid of raccoons!

Re:It is a solved problem

[mr_mischief]

Actually, rat poison is sometimes one of the ingredients in the mix to create crystal meth. You may be making their job easier for them if you lace it that way.

With rat poison, starter fluid, and anhydrous ammonia being ingredients and mixing being done in wooden shacks and moldy basements, is it any wonder this stuff kills people?

Please, if you're going to do illegal drugs, people, at least get something grown in the ground or made in a lab by people with training as chemists. Don't let "Three-tooth Junior" sell you something he made in the toilet of his grandparent's broken-down RV out behind the trailer park.

Re:It is a solved problem

[mspohr]

Farmers and industry already use large amounts of anhydrous ammonia (farmers for fertilizer, industry for refrigeration and as a chemical component). The sale, storage, and use of this chemical is common and your home use of this chemical should present no regulatory problems.

Re:It is a solved problem

[Anonymous Coward]

Ammonia is already widely used as a refrigerant in industrial settings.

Re:It is a solved problem

[Anonymous Coward]

Boreholes are also in use in the US, though not as frequently as in Europe. It is not usually thought of as heat storage, but as an almost unlimited source/sink for heat pump operation that has a much smaller temperature range than the ambient atmosphere (heat pumps don't really work for heating below 20F or so). Often, heating and cooling loads do not match across seasons, and you end up derating the source/sink due to the fact that your operations will gonna be heat up or cool down the ground on average. Getting heat directly from the ground is not easy, due to the small temperature differences, except in places like Iceland, wherer there is volcanic activity heating up the ground. Therefore, amost all of therse systems use some sort of heat pump to drive the heat flow into and out of the ground. TFA seems to only be suitable for very large installations, and in my mind, it has dubious ecomnomic value, since high temperature differences are hard to obtain from solar (needs fancy concentrators), and hard to store in the essentially uninsulated ground (think ground water moving through to take away the heat).

Post carbon world

[Anonymous Coward]

Microbrain rejoices, the ugly bags of mostly water are gone!

Re:Gold from human shit - numbers are off?

[Elrac]

(280 to 56,000 g/kg in dry matter)

So, in units people feel comfortable with, there's at least half a pound of gold in two pounds of shit? And under favorable circumstances, shit is 5600% gold? Something smells around here, and it's not fishy.

Micrograms, perhaps?

Re:might work with large heat differences ---

[meburke]

--- or more air volume. I was discussing this type of idea with an architect who wanted to build large multifamily housing of good quality in Houston, TX. His idea of having hollow walls between units (for fire protection, utility access, component upgrading and modularity and thermal cooling, plus a "wind farm" of vertical windmills at the corners, plus a large vegetation plot on the roof (similar to the Ford plant in Michigan), plus heating and cooling control by having chambers of eutectic salts around a large swimming pool, could easily be augmented by having this type of system embedded in the hollow walls.

FWIW, the economics of the housing project are not feasible at this time. Many of the components are too expensive when compared to existing technology, but I have no doubt that someday he will build a project with similar standards designed to provide quality housing for a hundred years or more.

This project may get legs. I've seen some projects developed and spread by the "Mother Earth" types in the 70's and 80's. The final product may not look quite the same, but the community may be very active and efficient because of the project's appeal. When it does look good, the Design Science License doesn't seem to prevent someone from making the product and distributing it commercially, it just prevents them from locking it up.

one notable piece

[way2trivial]

look down, what are you typing on.... is it maintenance free?

That's right, make fun of science!

[Anonymous Coward]

All this is is a plan to generate energy from heat. Guess what happens when you burn gas in your car? Heat! How far Slashdot has fallen, when I can see a simple science concept proposed and see mostly jackasses braying at it. But, wait, I forgot, your precious 401(K)s are all based on Oil and Microsoft stocks, so every idea involving alternative energy sources or free software has to be booed down.

I'd sooner rob the dead than accept the filthy money from where you people get it.

It isn't about efficiency of the system

[Colin Smith]

It's more to do with cost per kiloWatt. While it may be more efficient to put in photovoltaic cells or a ground source heat pump for space heating, it may not be cheaper.

OTEC up in the air?

[ZonkerWilliam]

Sounds like what they've been trying to do with extracting energy from the ocean's, with little success. http://www.nrel.gov/otec/electricity.html

I Am Listening

[LifesABeach]

I just got a bill for $320 for using 1,300 kWatt hours, last month it was $280 for using 1,200 kWatt hours. I have been looking at how to reduce my dependence on the electric company. But I have yet to find a solar solution that is not priced at break even amounts of money. Where should I look? Also, in my community, this is a non-community-type-issue, I am alone in this quest.

Re:I Am Listening

[nmos]

But I have yet to find a solar solution that is not priced at break even amounts of money.

Normally when people are looking into this what they want to know is "How long is it going to take for this investment to break even?". The underlying assumption is that after break even you'll continue to generate a positive return even after maintence costs etc.

What just about everyone who seriously considers solar electricity finds out is that the initial cost to supply their current usage requirements is so high that break even is likely to occur sometime after their dead. At that point they either give up the idea or they realize that if they could reduce their consumption by something like 25-50% then the numbers look a lot better. It's not just about the cost of solar cells but also about the cost of more batteries, larger capacity inverters etc that really drives up the cost. The first year or two after deciding to pull the trigger on a solar electric arn't going to be spent buying/installing your system but rather trying to reduce your consumption to the point where a reasonably priced solar system can supply your needs. You may even find that reducing your consumption alone is easier, cheaper, and offers a better return than installing a solar electric system.

bought a corn stove

[codepunk]

I got real pissed off last year and decided that I am no longer gonna be subjected to
swings in the fuel market. I bought a corn stove and installed it, best thing I ever did, so far
this year heat has cost me less than 1/3 of what it normally does. Much simpler system than what is described here, corn in and heat out. My stove is also multi fuel if corn goes high I can buy wood pellets, barley, cherry pits etc whatever is running the cheapest.

Re:bought a corn stove

[LetterJ]

So, with corn up 60% over last year, what *are* you burning in it?

Dean Kamen(of Segway fame) is on it....

[CrankinOut]

Dean Kamen's research organization DEKA is using this technology to produce electrical generators already in demonstration projects in Bangladesh where the fuel is the heat generated by animal manure. Instructions read "Just add S#!t" (No kidding!)
Here's his core technology (http://www.dekaresearch.com/coreTech.html).
He's developing technology that can produce energy with 1) available fuel, 2) no supply consumption, and 3) no harmful materials. He also has developed a water purification system that literally can take sewage and produce potable water. He gives a very persuasive presentation on the benefits of the simple and limited capabilities in the vast areas of this planet where neither energy nor clean water is readily available.

Re:Dean Kamen(of Segway fame) is on it....

[Anonymous Coward]

While that is 'interesting' that Dean wants to burn Dung, there are others who are building heilostats with Stirling engines. (That means you don't have to go gather dung for power.)

Whispergen is shipping engines, has test dishes, Solo was selling some a couple of years ago for sub-10,000 euros.

And these people were at one time claiming a $89 price point for a 1hp engine if you bought 'em in 40 foot container lots.

Dean's looking like the looser on the stirling race.

Re:Dean Kamen(of Segway fame) is on it....

[CrankinOut]

Good to see!
However, in a lot of places on this planet, cow dung is more available than sunlight!
By the way, DEKA's prices on these machines are in the $2K-3K range, as I recall. That's a price range that allows charitable organizations (think Non-Governmental Organizations) to fund and deploy them.
These designs fit more with the concepts described in Small is Beautiful by E.F. Schumacher.

Call me prejudiced, but...

[FlyingSquidStudios]

I have a hard time taking seriously an energy generation project that uses pot smoker slang like 'roll your own.'

Re:Call me prejudiced, but...

[wintermutex]

To be fair, "roll your own" is not pot-smoker slang, it refers to rolling your own tobacco cigarettes in lieu of buying packaged pre-rolled cigs. It's a lot cheaper and sure, could be seen as 'pot chic' to do, but the term's been around about as long as cigarettes have been manufactured.

Re:Call me prejudiced, but...

[Anonymous Coward]

OK, you're a prejudiced butt.
Not only that, but you're grossly misinformed, as well.
In addition to 'roll your own' being a tobacco smoker's term as stated in the parent, it is also used within the computer world when one is compiling a binary from source or kludging together a custom distro.
In addition, might I suggest that you stop caring so much what others choose to do with their bodies and minds. If people like you ruled the world the world would still be flat, the Renaissance would have never happened, Carl Sagan would have been an accountant and rock music would still be "sock-hop" crap.

Re:Call me prejudiced, but...

[Yfel]

Hello Prejudiced,

I think you're jumping the gun a bit with your critique. What implies that they're necessarily using pot smoker slang? People rolled tobacco cigarettes well before marijuana joints came into popularity. Plenty of completely-sober technical people use that phrase (e.g., "roll your own linux distro") without meaning to imply anything about illegal drugs. As a point of evidence, look at the google results: the first 100 hits are invariably about software, tobacco, or sushi. As of the time of this posting, the words "pot", "joint", and "marijuana" do not appear in the summaries of the first 100 google results.

Thermodynamic specifics

[CodeShark]

I have been studying a variation on this exact problem for some time and have reached a tentative conclusion: that the energy and cost of such a system is economically prohibitive, not scientifically prohibitive.

By which I mean I did the math using the available solar insolation figures for the metro area closest to the middle of the US as a sample, the Carnot equation for thermodynamic efficiency [Max efficiency of a heat engine before losses = 1 - the ratio of the low temp/high temp in absolute degrees (Kelvin or Rankine) -- the formula works the same way]. Assuming a big rooftop as a heat source, and 90% efficiency in gathering all of the heat and 90% in the engine itself the system would produce -- are you ready?

About enough power to run the lights and light appliances in an average home, but not near enough to contribute to the heating and/or cooling loads in the home -- which are the main power consumers. Meaning that the economic payback for even a successful mass-produced system (which assumes a production figure of around 1/5 the cost of a custom built system) would most likely be measured in decades, not years. And that the manufacturing heat cost of building the system will use more energy than it will produce in a lifetime.

Re:Gold from human shit - numbers are off?

[Zerth]

Slashdot ate his mu :)

more data

[zogger]

Is that primarily for heating/cooling? If so your best bet is more insulation/better windows, etc. buck for buck you can't beat it, for most climates and most purposes, without really trying to paint with too broad of a brush. "Payback" on insulation is really superior for most people though before chucking money at electrical supply. If that power bill is for running electrical devices-too many variables there. You'd have to decide what is more valuable, and what devices could be economically exchanged for a lower demand device, etc.

How alternative energy companies work is sorta simple but very important. You need a full energy audit of all your requirements in the home and how your home is built, etc., along with what is called a site survey to determine how to proceed. There is no one size fits everyone there, again, too much variance.

    Energy independence is best achieved by working both ends towards the middle, reduce your demand--/--increase your (personal and local)production. Eventually those lines cross at the independence point (of the exterior power company).

When I was in this business before we used techniques like infared photography, we'd take exterior shots of the house to determine where heat loss and gain was the worst, then proceed to fix that. Houses are different, you never know. One house may have had the leakiest wimpiest roof, so we'd primarily fix that, others because of how they were situated and with window placement and quality of winjdows, that was the big energy hog-it all just depends. Some have walls that are compromised, I've seen homes where the insulation was borked from water and insect and rodent damage, even though the owners thought it was OK, they never looked behind the drywall. Some folks are better off just getting rid of their old furnace and going to a ground effect heat pump deal, others.....See? There's a lot to look at. But the basic rule of thumb is insulation *works*, efficient devices work. The more you can reduce your demand, the cheaper the alternative energy production part becomes.

  If you just think of an ice chest for camping, then think of your house like that, it makes it easier. A good ice chest with heavy walls that is thick and seals good will work well with a small amount of ice, a cheap 3 dollar thin one and your ice won't last one afternoon out camping. Same deal really.

Wait a minute!

[StarKruzr]

How does the Heisenberg compensator work?!

(Fishing for Okuda's stock response here)

Re:Wait a minute!

[Viper Daimao]

How does the Heisenberg compensator work?! Very well, thank you.

Re:Wait a minute!

[Barryke]

How does the Heisenberg compensator work?!

(Fishing for Okuda's stock response here) answer: snippet from http://en.wikipedia.org/wiki/Heisenberg_compensato r :

When asked "How do the Heisenberg compensators work?" by Time magazine on 28th November 1994, Michael Okuda, technical advisor on Star Trek, famously responded, "They work just fine, thank you."

Re:Wait a minute!

[StarKruzr]

::applause::

Sure

[Scareduck]

But architecture is essentially the building of plans, not the development of actual physical buildings. My point is that there's no such thing, and never will be, as an open source oil company.

alt.energy.*

[_iris]

Check alt.energy.* for more practical, proven ideas that are cheaper and easier to do for your home.

Here's an idea

[SnarfQuest]

I'm going to hook up my dog to one of those retractable leashes, and attach that to one of those generators used for the OLPC. Then, when a squarrel runs across the lawn, I'll generate enough electricity to run most of my appliances. Should work, as long as the supply of squarrels doesn't run out.

What are the large-scale effects?

[FiloEleven]

More importantly, if it works well and catches on, has anyone looked into what it'll do to the surrounding climate and weather? Or would even vast stretches of urban sprawl built with this system have negligible effects?

Re:What are the large-scale effects?

[rohar]

I think it's not really possible to build a system that is "large-scale" relative to the earth and sky. I think that if you could build a system that could actually influence weather, that would really be interesting.

Noticed one inaccuracy.

[Anonymous Coward]

>> They are building an electric car that goes 0-60 mph in 4 seconds and has curb appeal, but having someone else burn fossil fuels to charge the batteries isn't economical, convenient, environmentally friendly or even more efficient than using existing fossil fuel engines.

This line alone tells me that they don't know what they are talking about. Coal can be used instead of oil, and we won't reach peak coal for a long time after we reach peak oil.

Additionally a central coal fired power plant is between 3-4 times more efficient at converting fuel into electricity and the same factor less polluting than the internal combustion engine they are talking about. Energy efficiency of a motor is entirely the difference in the temperature they can create compared to the temperature of the environment they are in and how much of that energy they can capture as the heat moves from the high to the low.

Re:Noticed one inaccuracy.

[rohar]

The author lives in Saskatchewan where there is an estimated 3.9 billions tonnes of coal. At the current rate of extraction, it will not run out for 390 years. The efficiency of electric vehicles with power generated from coal versus traditional gasoline or diesel engines is more to do with infrastructure and transportation of electricity than with the coal fired generation. If you have to increase the vehicle weight (batteries) over comparable horsepower from a gasoline engine, it is by definition not as efficient. If battery technology gets to the point where equivalent energy per pound of battery weight weight is close to gasoline, the efficiency of driving an electric car will make more sense. Until that happens, generating the electricity from a renewable source removes the amount of fossil fuel required to carry the batteries around, and makes it carbon neutral.

Saskatchewan Coal Info

It a bit of a tough sell to build a high capital investment clean energy system in an area that has that much coal.

Re:Noticed one inaccuracy.

[lisaparratt]

Of course, when the day comes when you can only build things ohut of mud and sticks because you no longer have the chemical feed stocks to manufacture anything more modern, you'll rue the day you were so shortsighted as to waste fossil fuels on energy when other alternatives were available...

PV links :

[Anonymous Coward]

National Renewable Energy Lab http://www.nrel.gov/

Sandia National Labs http://www.sandia.gov/pv

Solar energies association http://www.seia.org/

Solar Trade Association - Solar Energy, Energy for a Cleaner Environment http://www.greenenergy.org.uk/sta/solarenergy/cont ent.htm

PV-UK http://www.greenenergy.org.uk/pvuk2/

Solar design associates http://www.solardesign.com/experience.html

PV power resource site http://www.pvpower.com/

PV Materials Efficency http://www.iea-pvps.org/pv/materials.htm

Solar Cell Technologies http://www.solarbuzz.com/Technologies.htm

Sounds well suited for desertic zones

[Anonymous Coward]

Sounds well suited for desertic zones where temperature delta between day and night are known to be large (and water quite rare).

Uh...

[Anonymous Coward]

"pot smoker slang like 'roll your own.'"

Uh, dipshit, it's a term that originated with tobacco smokers.

So get off of your high horse and walk with the rest of us primates.

The Real Question

[rohar]

First, thanks to the /. editors for accepting the submission, the increase in email inquiries and interest in the project since the story was posted have been phenomenal.

The design methodology of the project has been to research the deficiencies in current energy sources and to attempt to design a system that overcomes these problems, but the project is still very much in the concept stage.

The real question is, "This is what they have so far, what enhancements to the design are needed to make this feasible?"

lost cause

[alangelov]

Not a chance. It doesn't seem efficient, however it's interesting.