White roofs have the double effect of significantly reducing the air conditioning load within the building. This reduction in power consumption will probably reduce global warming by avoiding CO2 emissions as much if not more than the direct reflection effect... The peak power demand days in California are during the summer because of all the air conditioning.
One study found that there was between a 15% and 60% reduction in cooling power use just by applying a white roofing compound.
One problem with this is that high albeido (white-ish) pavement doesn't stay that way for very long because concrete ages and gets dirty. You can read more about this here.
There is a video of the WVU team doing a pit practice here. These are college kids, probably engineers and not mechanics. A real pit crew could do it in much less time.
If this is heat rejected from a server farm, it'll be too low grade to do much with it other than heating. You might be able to heat the premise hot water a tiny bit...
Absorption chillers, the common way to do waste heat to cooling, want medium grade waste heat a lot hotter than what's coming from a server farm and steam generation is totally out of the question.
As with anything written by a reporter, engineering details are all f'ed up.
"The project is expected to produce up to nine megawatts of power for the local community."
No, the project will probably pipe 9MW of heat from the server farm over to the housing complex. Hopefully they can use 9MW of heat continuously, summer and winter.
âoeThe energy savings will equate to boiling 3,000 kettles continuously,â
Um - that's a really funny way of thinking about saving energy. 9Mw/3000= 3kw/kettle. That's a hell of a kettle.
For anyone who thinks that running a computer in their house to heat it is clever, you would do a lot better (price AND CO2 wise) just running a furnace or your heat pump. Resistance heating is the WORST way to heat a house.
If you're going to be producing the heat anyway and can find a use for it like this, please do! Don't think that because you CAN use a computer for a heater means that it makes sense.
Not sure where you got the 50~60k battery replacement, because it's simply not true
The state of charge of the battery in a prius is carefully kept between 45% and 75% in order to give the battery pack a long life. And by long I mean that the prius taxis used up in Vancouver with 200k+ miles on the clock still haven't failed a pack.
The only packs that have failed in service are those that have been damaged in accidents or those that have been tampered with by "tuners".
but the questions become: what problem are we trying to address by using hydrogen in vehicles, and is this the best way to address this problem?
If you are addressing the problem of "criteria" pollutants (CO, NOx, SOx, HC) this is a very good way to move the pollution away from the tailpipe.
Yes, hydrogen CAN be produced all the ways that you mention above, but IS it? The answer for now is no. Most hydrogen is produced by steam reformation of natural gas. The above methods are either much more expensive (electrolysis) or are stil in the early development phase (photolytic).
If the problem you are trying to address is CO2 emission, you are better off using your methane in power plants to offset coal based generation. Coal is such a bad actor that as long as we are burning ANY we should do everything in our power to turn off those plants.
Though it is possible to pontificate about the potential "green" sources of hydrogen production, it is still useful to think of the big picture problem that you are trying to solve.
None of the existing fuel cell vehicle prototypes work this way.
This idea, properly called on-board reforming, was floated as a way to get around the problem of lack of fueling infrastructure. Unfortunately reformers are fussy, high temperature devices that are not good at load-following.
Your efficiency numbers are way off too. IC engine vehicles are about 15% efficient and fuel cell vehicles are about 40~50% efficient on a well-to-wheels basis.
One of the problems is that hydrogen has a very low energy density. So low that by transporting liquid or 5000 psi hydrogen more than 150 miles in a diesel truck, you've used more energy than you are transporting.
All of these cars will be using compressed hydrogen, just like all of the current prototype vehicles.
Planned installations chasing incentives are a far cry from power plants installed to meet grid needs.
24h power (storage and retrieval of energy) is unnecessary system complexity when you are not looking to replace the current grid, and at their current level of deployment (nil, pretty much) this is not a concern. You might want to co-fire with natural gas to avoid thermal cycling of your plant like they do at Kramer Junction in CA, but that's beside the point.
Furthermore, there is a strong disincentive to producing 24h, and that is the overnight bulk rate for electricity - maybe $.06/kwh vs more than $.20 at peak when you have the solar resource.
So, for anyone who knows about low temperature difference stirling engines, they know that one cylinder engines are not self starting. This looks like a one cylinder engine, so you'd probably have to open up your computer and give it a spin to make sure it starts.
I wonder how much power this actually dissipates. Most recent desktop processors I've seen need at least a 80mm fan running pretty fast or even a 10cm fan and shrouding. This is a gimmick. A cute gimmick but a gimmick nonetheless.
Back at the turn of the century there were oil burning stirling powered fans. There is a company that makes them now, but these are inherently sensitive machines to work on a low temperature difference. This translates to expensive parts... Most are about $100~200, though you might be able to do it for less, it won't touch the price of a cpu fan.
It might be splitting hairs, but most of our hydrogen comes from steam reformation of methane, not from electrolysis of water.
Your point about electric cars I don't really get. Sure you have a longer tailpipe with an electric car, but if your thermal efficiency and CO2 or whatever pollutant you care about per mile is less, you are still winning. There are other technical challenges for electric cars, and a lot of people might not see that you have to look at the bigger picture, but even when you do EVs look pretty good.
and yes I recognize that is an EV advocacy site, but their point is correct. IC engines have a thermal efficiency of about 15% or less. It's not hard to beat that with a stationary plant.
Now, about the present article - I'd like to see some analyses that say that you can actually fly a supersonic plane a good distance on hydrogen, and how the hell you think you can make that economical.
But grad school is often all about things like this. Never mind that it would take 8000 years to recoup the initial investment, IT IS CLEVER (sort of).
We most certainly are able to make the deaf hear with cochlear implants. This isn't even uncommon; a friend of mine who adopted a child who was deaf at birth already has a cochlear implant. The quality supposedly about as good as a fuzzy AM radio, but it works!
As for making the blind see, this is not yet FDA approved, but it has been put through FDA testing. It's pretty impressive actually check it out.
I understand the frustration with medicine, but don't be too cynical. There is a lot of pretty unbelievable technology out there.
You got it there; this is NOT a feasible technology for wide scale applications: it is only for solving two problems: battlefield waste and battlefield power demands. Think of the trash as fuel extender; you already have the trash, you already have the generator, this is just a generator that you can throw your trash into.
It is undoubtedly dirtier than hell...
If this ever becomes an actual technology, don't expect to see it anywhere other than at overseas bases. No way in hell would this fly stateside.
If your actual battery volume is low, then you have a lot of surface area of the container and vs. a conventional battery all of the volume of container, interconnect, and everything else will take up (proportionally) a lot more of the space. Think about it.
Since power is proportional to volume (length^3), scaling laws for a nano-scale battery are VERY unfavorable. I'm not sure how they will get over this hurdle.
Just like nano-sized heat engines, nano sized batteries have a big problem in this department. There may be advantages in internal resistance or peak current, but the power density of such a battery, not to mention the cost, seem unfavorable.
The other issue, as far as I can tell, is the bad rap that diesel engines have because of their dirty ancestors.
Even the current generation of ultra low sulfur diesel with particulate traps there is still the issue of particulate and NOx emissions to be dealt with; they're dirtier than gas engines even when done 100% correctly with best available technology. Now, whether NOx is actually a problem in a lot of areas remains to be proven; smog formation is VOC limited in a lot of areas, so a little more NOx doesn't make a difference in the long run.
I think that poor economy and engine durability is another killer when it comes to gas turbine engines in a car. While regeneration can increase efficiency, at the scale of automotive engines there are a LOT of losses.
There were actually some turbine powered serial hybrid diesel electric locomotives built back in the 1970s, but you're right; if a gas turbine was the best engine, it would be in widespread use...
You can get these up at harbor freight for about $3 and they're worth every penny. They'll save your nice scissors from being used to cut wire, staples and cardboard. I couldn't find them on the HF website but I got a pair up there two weeks ago.
You need to look up the laws for your state. In California judgements are enforceable for ten years, and they are renewable for another 10 years after that. On top of this you accrue 10% interest on the settlement every year it goes uncollected.
This can add up to a tidy sum. So, if you still have your paperwork and your state has laws similar to California you are in luck. Now, if your roommate still has no money you might be out of luck, but there are ways of getting money from them. Look it up for your state; in California there are a lot of ways to force payment of a settlement.
I'm not sure where you're getting this information.
The energy density of metal hydride storage is huge compared to chemical batteries - you just can't make a practical electric car with any kind of range because chemical batteries are just too heavy for the power they store.
The energy density of a metal hydride storage tank that you can buy today from Ovonics is about 2 or 3 times better than a lithium ion battery in terms of energy density (both volumetric and specific). I would not really call that a huge advantage. Sure, this is about 1% H2 storage and the projected limit is 8%, but I would not call that huge. Batteries will advance as hydride technology advances, and will likely advance more quickly. By contrast the energy density of a gasoline tank is orders of magnitude higher. On top of this you have to consider conversion efficiency. Combustion of hydrogen is a joke - you spend too much energy making hydrogen to use it in anything as inefficient as an otto cycle. The tank from the ovonics site I am looking at weighs 127kg and carries 1.7kg of hydrogen; by most people this is considered to be equivalent to about 1.7 gallons of gas. 127kg!
If you make the metal into suitably small glass-encased spheres, you can transport it using the existing infrastructure for gasoline. Building the additional electrical distribution infrastructure to replace what we have would take decades - we'd have to triple what we have now.
I've never heard of any scheme for transporting and exchanging hydrides. The hydride storage that I have heard of is the standard ovonics metal hydride tanks with hydrogen added and removed as a gas. There are schemes to use sodium borohydride as a chemical carrier, but I've never even heard of what you are proposing here. Again, metal hydrides are REALLY HEAVY. You don't want to ship them around. I've also not heard that we would need so much additional transmission capacity in order to move our automotive fleet to electricity - if you look at the diernal cycle of power demand, there is a LOT of excess capacity at night. Conveniently this is when we aren't driving very much. It is dubious to imply that trucks full of hydrides are cheaper or more efficient than stringing up more power lines.
Metal hydrides are a very safe way to store power densely. Batteries (and liquid fuel, of course) are very dangerous in a fire. I wouldn't want to store the power to run my house overnight in chemical batteries, and that's a big drawback to going all-solar.
Again, I'm not sure where you're getting this. Most metal hydrides are reactive when exposed to air. They are not that much more energy (or power) dense than existing batteries, and you are going to be throwing away at LEAST 50% of your energy in losses in your electrolyzer and fuel cell (assuming you are using a fuel cell - best case). If you are using a hydrogen ICE it gets even worse. The round-trip efficiency of batteries (about 90%) totally KILLS metal hydrides for storage of energy in stationary applications. The only reason that hydrides are being considered for H2 storage for cars is their safety and potential for improved power and energy density over gaseous or liquid H2.
It's the big picture that makes hydrogen make sense. Plus, by using the existing gas infrastructure the oil companies still make money, so it's politically viable.
I would argue the opposite. Hydrogen is a distraction. We replaced battery electric vehicles that cost $60K and could be recharged anywhere with minimal infrastructure cost with fuel cell (and H2 ICE) vehicles that cost a million or more each (optimisitcally $300K with mass production) and have to be refueled at hydrogen stations that do not exist with hydrogen that will optimistically cost $14/kg (that is equivalent to a gallon of gas). If you use compressed hydrogen you have already used 10% of the energy in the H2 just to compress it to 5000psi (the usual pressure, for 10K psi it is even worse).
Slashdot Mirror
White roofs have the double effect of significantly reducing the air conditioning load within the building. This reduction in power consumption will probably reduce global warming by avoiding CO2 emissions as much if not more than the direct reflection effect... The peak power demand days in California are during the summer because of all the air conditioning.
One study found that there was between a 15% and 60% reduction in cooling power use just by applying a white roofing compound.
One problem with this is that high albeido (white-ish) pavement doesn't stay that way for very long because concrete ages and gets dirty.
You can read more about this here.
This is how it was done in SAE formula lightning.
There is a video of the WVU team doing a pit practice here. These are college kids, probably engineers and not mechanics. A real pit crew could do it in much less time.
If this is heat rejected from a server farm, it'll be too low grade to do much with it other than heating. You might be able to heat the premise hot water a tiny bit...
Absorption chillers, the common way to do waste heat to cooling, want medium grade waste heat a lot hotter than what's coming from a server farm and steam generation is totally out of the question.
As with anything written by a reporter, engineering details are all f'ed up.
"The project is expected to produce up to nine megawatts of power for the local community."
No, the project will probably pipe 9MW of heat from the server farm over to the housing complex. Hopefully they can use 9MW of heat continuously, summer and winter.
âoeThe energy savings will equate to boiling 3,000 kettles continuously,â
Um - that's a really funny way of thinking about saving energy. 9Mw/3000= 3kw/kettle. That's a hell of a kettle.
For anyone who thinks that running a computer in their house to heat it is clever, you would do a lot better (price AND CO2 wise) just running a furnace or your heat pump. Resistance heating is the WORST way to heat a house.
If you're going to be producing the heat anyway and can find a use for it like this, please do! Don't think that because you CAN use a computer for a heater means that it makes sense.
How is a mac mini different from what you want?
CONSTITUTIONAL SMACKDOWN!!!
Not sure where you got the 50~60k battery replacement, because it's simply not true
The state of charge of the battery in a prius is carefully kept between 45% and 75% in order to give the battery pack a long life. And by long I mean that the prius taxis used up in Vancouver with 200k+ miles on the clock still haven't failed a pack.
The only packs that have failed in service are those that have been damaged in accidents or those that have been tampered with by "tuners".
They have one of the first implemented license plate recognition "tollboothless" toll systems.
I remember reading about it- they use SGI boxes to do the recognition and databasing.
but the questions become: what problem are we trying to address by using hydrogen in vehicles, and is this the best way to address this problem?
If you are addressing the problem of "criteria" pollutants (CO, NOx, SOx, HC) this is a very good way to move the pollution away from the tailpipe.
Yes, hydrogen CAN be produced all the ways that you mention above, but IS it? The answer for now is no. Most hydrogen is produced by steam reformation of natural gas. The above methods are either much more expensive (electrolysis) or are stil in the early development phase (photolytic).
If the problem you are trying to address is CO2 emission, you are better off using your methane in power plants to offset coal based generation. Coal is such a bad actor that as long as we are burning ANY we should do everything in our power to turn off those plants.
Though it is possible to pontificate about the potential "green" sources of hydrogen production, it is still useful to think of the big picture problem that you are trying to solve.
None of the existing fuel cell vehicle prototypes work this way.
This idea, properly called on-board reforming, was floated as a way to get around the problem of lack of fueling infrastructure. Unfortunately reformers are fussy, high temperature devices that are not good at load-following.
Your efficiency numbers are way off too. IC engine vehicles are about 15% efficient and fuel cell vehicles are about 40~50% efficient on a well-to-wheels basis.
One of the problems is that hydrogen has a very low energy density. So low that by transporting liquid or 5000 psi hydrogen more than 150 miles in a diesel truck, you've used more energy than you are transporting.
All of these cars will be using compressed hydrogen, just like all of the current prototype vehicles.
Low temperature cells of the type that would be used in this camera usually run on METHanol, not ETHanol.
The cells you are thinking of are borohydrate/borohydride with alkaline electrolyte and are (were?) manufactured by a company called medis.
You used to be able to get them at treostore.net but they don't seem to have them in stock there any longer.
They were pretty much a curiostiy - a VERY expensive ($20/use) disposable battery.
..and I'll believe it when I see it.
Planned installations chasing incentives are a far cry from power plants installed to meet grid needs.
24h power (storage and retrieval of energy) is unnecessary system complexity when you are not looking to replace the current grid, and at their current level of deployment (nil, pretty much) this is not a concern. You might want to co-fire with natural gas to avoid thermal cycling of your plant like they do at Kramer Junction in CA, but that's beside the point.
Furthermore, there is a strong disincentive to producing 24h, and that is the overnight bulk rate for electricity - maybe $.06/kwh vs more than $.20 at peak when you have the solar resource.
So, for anyone who knows about low temperature difference stirling engines, they know that one cylinder engines are not self starting. This looks like a one cylinder engine, so you'd probably have to open up your computer and give it a spin to make sure it starts.
I wonder how much power this actually dissipates. Most recent desktop processors I've seen need at least a 80mm fan running pretty fast or even a 10cm fan and shrouding. This is a gimmick. A cute gimmick but a gimmick nonetheless.
Back at the turn of the century there were oil burning stirling powered fans. There is a company that makes them now, but these are inherently sensitive machines to work on a low temperature difference. This translates to expensive parts... Most are about $100~200, though you might be able to do it for less, it won't touch the price of a cpu fan.
It might be splitting hairs, but most of our hydrogen comes from steam reformation of methane, not from electrolysis of water.
Your point about electric cars I don't really get. Sure you have a longer tailpipe with an electric car, but if your thermal efficiency and CO2 or whatever pollutant you care about per mile is less, you are still winning. There are other technical challenges for electric cars, and a lot of people might not see that you have to look at the bigger picture, but even when you do EVs look pretty good.
reference on EVs here
and yes I recognize that is an EV advocacy site, but their point is correct. IC engines have a thermal efficiency of about 15% or less. It's not hard to beat that with a stationary plant.
Now, about the present article - I'd like to see some analyses that say that you can actually fly a supersonic plane a good distance on hydrogen, and how the hell you think you can make that economical.
Probably polygenesis, not plagiarism.
If you want, you can read more about this here on wired:
Wired magazine article
But grad school is often all about things like this. Never mind that it would take 8000 years to recoup the initial investment, IT IS CLEVER (sort of).
As for making the blind see, this is not yet FDA approved, but it has been put through FDA testing. It's pretty impressive actually check it out.
I understand the frustration with medicine, but don't be too cynical. There is a lot of pretty unbelievable technology out there.
You got it there; this is NOT a feasible technology for wide scale applications: it is only for solving two problems: battlefield waste and battlefield power demands. Think of the trash as fuel extender; you already have the trash, you already have the generator, this is just a generator that you can throw your trash into.
It is undoubtedly dirtier than hell...
If this ever becomes an actual technology, don't expect to see it anywhere other than at overseas bases. No way in hell would this fly stateside.
If your actual battery volume is low, then you have a lot of surface area of the container and vs. a conventional battery all of the volume of container, interconnect, and everything else will take up (proportionally) a lot more of the space. Think about it.
Since power is proportional to volume (length^3), scaling laws for a nano-scale battery are VERY unfavorable. I'm not sure how they will get over this hurdle.
Just like nano-sized heat engines, nano sized batteries have a big problem in this department. There may be advantages in internal resistance or peak current, but the power density of such a battery, not to mention the cost, seem unfavorable.
The other issue, as far as I can tell, is the bad rap that diesel engines have because of their dirty ancestors.
Even the current generation of ultra low sulfur diesel with particulate traps there is still the issue of particulate and NOx emissions to be dealt with; they're dirtier than gas engines even when done 100% correctly with best available technology. Now, whether NOx is actually a problem in a lot of areas remains to be proven; smog formation is VOC limited in a lot of areas, so a little more NOx doesn't make a difference in the long run.
I think that poor economy and engine durability is another killer when it comes to gas turbine engines in a car. While regeneration can increase efficiency, at the scale of automotive engines there are a LOT of losses.
There were actually some turbine powered serial hybrid diesel electric locomotives built back in the 1970s, but you're right; if a gas turbine was the best engine, it would be in widespread use...
You can get these up at harbor freight for about $3 and they're worth every penny. They'll save your nice scissors from being used to cut wire, staples and cardboard. I couldn't find them on the HF website but I got a pair up there two weeks ago.
RBC=Royal Bank of Canada = US Federal laws don't apply...
right?
You need to look up the laws for your state. In California judgements are enforceable for ten years, and they are renewable for another 10 years after that. On top of this you accrue 10% interest on the settlement every year it goes uncollected.
This can add up to a tidy sum. So, if you still have your paperwork and your state has laws similar to California you are in luck. Now, if your roommate still has no money you might be out of luck, but there are ways of getting money from them. Look it up for your state; in California there are a lot of ways to force payment of a settlement.
Good luck!
The energy density of a metal hydride storage tank that you can buy today from Ovonics is about 2 or 3 times better than a lithium ion battery in terms of energy density (both volumetric and specific). I would not really call that a huge advantage. Sure, this is about 1% H2 storage and the projected limit is 8%, but I would not call that huge. Batteries will advance as hydride technology advances, and will likely advance more quickly. By contrast the energy density of a gasoline tank is orders of magnitude higher. On top of this you have to consider conversion efficiency. Combustion of hydrogen is a joke - you spend too much energy making hydrogen to use it in anything as inefficient as an otto cycle. The tank from the ovonics site I am looking at weighs 127kg and carries 1.7kg of hydrogen; by most people this is considered to be equivalent to about 1.7 gallons of gas. 127kg!
I've never heard of any scheme for transporting and exchanging hydrides. The hydride storage that I have heard of is the standard ovonics metal hydride tanks with hydrogen added and removed as a gas. There are schemes to use sodium borohydride as a chemical carrier, but I've never even heard of what you are proposing here. Again, metal hydrides are REALLY HEAVY. You don't want to ship them around. I've also not heard that we would need so much additional transmission capacity in order to move our automotive fleet to electricity - if you look at the diernal cycle of power demand, there is a LOT of excess capacity at night. Conveniently this is when we aren't driving very much. It is dubious to imply that trucks full of hydrides are cheaper or more efficient than stringing up more power lines.
Again, I'm not sure where you're getting this. Most metal hydrides are reactive when exposed to air. They are not that much more energy (or power) dense than existing batteries, and you are going to be throwing away at LEAST 50% of your energy in losses in your electrolyzer and fuel cell (assuming you are using a fuel cell - best case). If you are using a hydrogen ICE it gets even worse. The round-trip efficiency of batteries (about 90%) totally KILLS metal hydrides for storage of energy in stationary applications. The only reason that hydrides are being considered for H2 storage for cars is their safety and potential for improved power and energy density over gaseous or liquid H2.
I would argue the opposite. Hydrogen is a distraction. We replaced battery electric vehicles that cost $60K and could be recharged anywhere with minimal infrastructure cost with fuel cell (and H2 ICE) vehicles that cost a million or more each (optimisitcally $300K with mass production) and have to be refueled at hydrogen stations that do not exist with hydrogen that will optimistically cost $14/kg (that is equivalent to a gallon of gas). If you use compressed hydrogen you have already used 10% of the energy in the H2 just to compress it to 5000psi (the usual pressure, for 10K psi it is even worse).