Any theoretical physicist or astronomers here?

[npita]

I'm confused. I thought that theoretical physics was about the math that develops the theory of the our existence?

Well, if anyone asks about those things, I'll be happy to answer.

[npita]

Originally Posted by GneissGuy

The Bloom box looks really interesting. There's no science fiction involved, either. However, it does use natural gas and produces CO2. The big questions for the Bloom box are initial cost, reliability, lifetime, efficiency, and long term economics.

So, to the best I can determine, (since Bloom Energy isn't providing info), the Bloom Box is a large box full of (expensive, at the moment) batteries that can be charged in whatever way you can hook up a power source to charge the batteries. The only advantage to using natural gas to power a generator (or whatever) to charge the batteries over using a generator directly, is that you can use a smaller generator (which is more affordable) to charge the box when you aren't home so that the box is charged when you are home. It still requires the same amount of energy to produced. For that matter, you could ``save'' money by using the power company to charge the box at off-peak rates if you use the most electricity at times when the rate is at its peak.

[npita]

Originally Posted by CaptainMidnight

I'm looking into an off-the-grid system for my hill country place west of Austin, primarily because I plan to build a house on top of a steep hill far from power lines.

Build your house into the side of the hill. Then it will be very well insulated and the walls will be held at the themperature of the surrounding dirt. That ought to reduce your electricity requirements by a lot. If I were starting from scratch, I'd make certain that the wasted heat from the refrigerator coils and ovens could be used to help heat the house in winter and not be cooled by the A/C in the summer.

[GneissGuy]

Originally Posted by npita

So, to the best I can determine, (since Bloom Energy isn't providing info), the Bloom Box is a large box full of (expensive, at the moment) batteries that can be charged in whatever way you can hook up a power source to charge the batteries. The only advantage to using natural gas to power a generator (or whatever) to charge the batteries over using a generator directly, is that you can use a smaller generator (which is more affordable) to charge the box when you aren't home so that the box is charged when you are home. It still requires the same amount of energy to produced. For that matter, you could ``save'' money by using the power company to charge the box at off-peak rates if you use the most electricity at times when the rate is at its peak.

The Bloom box is not a battery or an energy storage device. The Bloom box is a natural gas powered fuel cell. Natgas goes in, electricity and CO2 comes out. There's no significant energy storage.

It's essentially like having a natgas powered engine driving an electrical generator at your house. Except for being quiet, and (MAYBE) more efficient, cost efficient, reliable, and cleaner compared to a normal natgas powered generator.

The possible advantages of Bloom box vs. grid power is: 1) If the net cost of energy out of the Bloom box is less than the cost of energy off the grid. 2) Independence from the electrical utility company or extra reliability if you have BOTH grid and Bloom. 3) Less CO2 from natgas bloom vs. grid coal power source. 4) Not having to build more power plants, cooling ponds, power lines, substations, etc.

There's nothing new about the idea of a natgas powered fuel cell system. Bloom uses different kinds of materials in the chemical part of the fuel cell. If it works right, it may have advantages in initial cost, lifetime, efficiency, etc. It may also get produced in a "ready to use" package. Time will tell if the whole package really plays that well in the real world. The practicality will also depend a lot on availability and cost of natgas.

I'm not denigrating the Bloom box. It may save money and do good things for the environment. Time will tell.

[npita]

Originally Posted by GneissGuy

The Bloom box is not a battery or an energy storage device.

Fuel cell is a fancy name for battery. Batteries generate power from chemical reactions.

The Bloom box is a natural gas powered fuel cell. Natgas goes in, electricity and CO2 comes out. There's no significant energy storage.

That's probably the case. I was basing my comment on an article that said something about using solar energy with the bloom box, so I assumed that implied energy storage.

The possible advantages of Bloom box vs. grid power is: 1) If the net cost of energy out of the Bloom box is less than the cost of energy off the grid. 2) Independence from the electrical utility company or extra reliability if you have BOTH grid and Bloom. 3) Less CO2 from natgas bloom vs. grid coal power source. 4) Not having to build more power plants, cooling ponds, power lines, substations, etc.

All of those but (3) make sense. The end result of a reaction that produces energy from a hydrocarbon and oxygen is CO_2 and water (and if the original hydrocarbon contains radicals with other elements, like sulfur, that will be in the waste as well). If it's more efficient, the conversion will produce more CO_2. Inefficient processes just produce waste that contains other hydrocarbons.

I'm not denigrating the Bloom box. It may save money and do good things for the environment. Time will tell.

I really have no opinion beyond being skeptical of a company that has nothing to say (in the technical sense) about what it's selling. The articles about it are inconsistent with respect to claims about how it works and what that is supposed to accomplish. Either way, you're right. Time will tell.

[..]

Originally Posted by npita

I really have no opinion beyond being skeptical of a company that has nothing to say (in the technical sense) about what it's selling. The articles about it are inconsistent with respect to claims about how it works and what that is supposed to accomplish.

hehe, that's a litte bit unfair. it's an very advanced solid oxide fuel cell design. However the problem is -- from a tech POV -- even with pure methane (CH4) getting a solid oxide fuel cell to work is very, very tricky. (and full of problems that drive you almost crazy)

(for the interested, since i'm bored just a link: http://de.wikipedia.org/wiki/Festoxi...onsgleichungen )

Worse NG (nat gas) is a gas mixure with methane btwn. 70% - 90%. Thus the efficency of the boom box depends on how much methane is the NG.

Even worse, the remaing gases besides methane, introduce all kinds of problems (membrane pollution, etc.)

anyway they publish the specs (but it really depends on how much methane there is, thus they only claim efficency > 50%)
http://www.bloomenergy.com/products/data-sheet/

[..]

Originally Posted by GneissGuy

There's nothing new about the idea of a natgas powered fuel cell system.

i disagree. even building a fuelcell which uses pure methane is non-trival. NG as fuel is much worse!

Note also, the bloom box is a electrical phys-chem. system thus NOT governed by the carnot-cycle, yet with NG as fuel it's not more efficient than a well-designed heat combusion engine.

[John Bull]

It's claimed that the cells use 1/2 the natural gas that a normal generating plant uses per kwh. If that is so, that's the savings of CO2 in the atmosphere.
They are hoping to have residential type boxes in production by 2011 at a cost of approx $3k a piece.
The beauty as I see it is the fact that major companies are already using (and testing) large installations so this is definately not pie in the sky. This is a serious operation with lots of money behind it.
It will also use biogas but who has access to that?

[GneissGuy]

Originally Posted by npita

Fuel cell is a fancy name for battery. Batteries generate power from chemical reactions.

There are similarities, but nobody calls a battery a fuel cell, or calls a fuel cell a battery. In a fuel cell, chemicals flow in and out on a continuous basis and energy comes out. In a battery, the chemicals stay inside the battery and energy flows in and out.

Originally Posted by npita

That's probably the case. I was basing my comment on an article that said something about using solar energy with the bloom box, so I assumed that implied energy storage.

Maybe someone has a dual system where you power your home or business with solar when available and Bloom when the solar panels aren't producing enough power. The Bloom box consumes natgas, which costs money. A solar cell system in addition to a Bloom box makes sense because it cuts down on your natgas bill when the solar cells are working.

Originally Posted by npita

All of those but (3) make sense. The end result of a reaction that produces energy from a hydrocarbon and oxygen is CO_2 and water

Burning coal produces only CO2, no water. Coal is mostly carbon. It can't produce much H2O, because there's little hydrogen in the original fuel. Other fossil fuels have varying amounts of carbon, hydrogen, and oxygen. For a given amount of heat produced, various fuels produce differing amounts of CO2. Coal is among the worst. Hydrogen fuel produces only water, no CO2. Natgas probably produces the least amount of CO2 from any hydrocarbon because it has the highest percentage of hydrogen in the original fuel. Natgas will produce less CO2 than an equivalent amount of gasoline, oil, ethanol, or coal.

Originally Posted by npita

If it's more efficient, the conversion will produce more CO_2. Inefficient processes just produce waste that contains other hydrocarbons.

Not necessarily. Even if two devices consume the same amount of fuel and produce the same amount of the various exhaust gases, they can produce different amounts of electricity. In a conventional electrical power plant, you burn the fuel, and produce heat. Then you convert the heat to electricity. There are very big differences in the efficiency of the heat to electricity step between different power plants. Even if the burner produces the same amount of heat, the electricity output can vary.

Originally Posted by npita

I really have no opinion beyond being skeptical of a company that has nothing to say (in the technical sense) about what it's selling. The articles about it are inconsistent with respect to claims about how it works and what that is supposed to accomplish. Either way, you're right. Time will tell.

If you follow the info they've published, the basic science is pretty clear. It's a ceramic electrolyte natgas powered fuel cell. Other people have made ceramic fuel cells before. The exact chemicals of the cathode, anode and electrolyte may be secret. Several companies like Google are using Bloom boxes on a full time basis.

There's nothing all that new about the idea of the Bloom box. It's just a question of how it will play in the real world. Remember when Wankel engines were going to replace the piston engine? Or gas turbine engines? Or all-electric cars? No great mystery involved, just a question of real-world practicality and economics.

[..]

Originally Posted by GneissGuy

A solar cell system in addition to a Bloom box makes sense because it cuts down on your natgas bill when the solar cells are working.

solar cells are a) not efficient and b) expensive.

what you want is a a sun-collector hooked up with a closed cycle stirling engine.

[GneissGuy]

Originally Posted by John Bull

It's claimed that the cells use 1/2 the natural gas that a normal generating plant uses per kwh. If that is so, that's the savings of CO2 in the atmosphere.
They are hoping to have residential type boxes in production by 2011 at a cost of approx $3k a piece.
The beauty as I see it is the fact that major companies are already using (and testing) large installations so this is definately not pie in the sky. This is a serious operation with lots of money behind it.
It will also use biogas but who has access to that?

Some of the claimed savings may be from losses in the power distribution network, not the power plant vs. Bloom box itself. The savings could still be real.

I think there are a lot of bogus claims floating around about how much energy is lost in the power transmission network. Lots of people are claiming 50% loss in power distribution, which is flat out wrong.

I just hope it doesn't turn out to be the Duke Nukem Forever box instead of the Bloom box.

[..]

Originally Posted by John Bull

It's claimed that the cells use 1/2 the natural gas that a normal generating plant uses per kwh.

with the bloom box the efficency depends on how much methane is in the NG or biogas. (theor. limit of a "almost" ideal fuel-cell ca. 90% with a pure fuel, but practical e.g. with bloom-box and NG only > 50%)

----------------------------------------------------

for normal generating plant one needs to seperate 2 steps..
from fuel to mechanical energy: theor. limit ca. 60% efficency (carnot cycle)
practical 40% max. 50%

now from mechanical energy to electrical energy theor. limit max. ca. 80% efficency
practical 30% - 60%

--> thus a modern well-designed generating plant tries to use the execess heat (from the combusion step) for e.g. district heating

[Marcus Aurelius]

Cold Fusion In 1989, researchers in the United States and Great Britain claimed to have made a fusion reactor at room temperature without confining high-temperature plasmas. They made an electrode of palladium, placed it in a thermos of heavy water (deuterium oxide) and passed an electrical current through the water. They claimed that the palladium catalyzed fusion by allowing deuterium atoms to get close enough for fusion to occur. However, several scientists in many countries failed to get the same result. But in April 2005, cold fusion got a major boost. Scientists at UCLA initiated fusion using a pyroelectric crystal. They put the crystal into a small container filled with hydrogen, warmed the crystal to produce an electric field and inserted a metal wire into the container to focus the charge. The focused electric field powerfully repelled the positively charged hydrogen nuclei, and in the rush away from the wire, the nuclei smashed into eachother with enough force to fuse. The reaction took place at room temperature. ; http://science.howstuffworks.com/fus....htm/printable

A thermos sized fusion reactor will do fine.

[GneissGuy]

Originally Posted by Marcus Aurelius

Cold Fusion In 1989, researchers in the United States and Great Britain claimed to have made a fusion reactor at room temperature without confining high-temperature plasmas. They made an electrode of palladium, placed it in a thermos of heavy water (deuterium oxide) and passed an electrical current through the water. They claimed that the palladium catalyzed fusion by allowing deuterium atoms to get close enough for fusion to occur. However, several scientists in many countries failed to get the same result. But in April 2005, cold fusion got a major boost. Scientists at UCLA initiated fusion using a pyroelectric crystal. They put the crystal into a small container filled with hydrogen, warmed the crystal to produce an electric field and inserted a metal wire into the container to focus the charge. The focused electric field powerfully repelled the positively charged hydrogen nuclei, and in the rush away from the wire, the nuclei smashed into eachother with enough force to fuse. The reaction took place at room temperature. ; http://science.howstuffworks.com/fus....htm/printable

A thermos sized fusion reactor will do fine.

You posted this 6 hours too early.

[winemaker]

There are many problems with Silicon based photovoltaics. First, they are an in-direct bandgap semiconductor, meaning they need a phonon mediated transfer mechanism ( lattice vibrations ), the band gap is approx 1.4-1.7eV which means it really only absorbs light in the orange/red spectrum. The second big problem is the spare bonds, it requires hydrogen passivation to "tie" up the loose dangling bonds, otherwise electrons may "leak" / tunnel into the substrate. These bonds tend to get fractured under UV light, thus the aging problem with Silicon photovoltaics. As they age, they get less effecient due to leakage.

CIGS is more promising ( Copper Indium Gallium Selenide ), but the shit is damn toxic, and Gallium isn't really a plentiful material for world power generation. Its more of a direct bandgap, meaning it can directly absorb the photon, however, its bandgap is similar to Silicon, absorbing only limited bands of sunlight.

The most promising is organics, their conjugated hydrocarbons have enormous potential to absorb a very wide range, due to the delocalized nature of there orbital wavefunctions.

BTW, Natural gas has many issues with thermal composition. Its has a good mix of isopentane, isobutane, methane, propane, as well as a hideous amount of supercritically dissolved CO2. So the thermal decomposition will vary from source, and time, and thus the electrical power extracted will vary as the thermal units shift due to composition.