| 8 | “At sun radiation at 1 KW/m2 at 10% efficiency the 7m2 cell would provide 700W=1hp during daylight.” |
1. Your estimate of available solar energy is far too generous.
| SOURCE |
(%) |
(W/m2) |
|
|---|---|---|---|
| 1. | solar constant | -- | 1370W |
| 2. | atmospheric loss | 27 | 1000W |
| 3. | cloud loss | 21 | 790W |
| 4. | sun angle loss1 | 50 | 395W |
| 5. | night time loss2 | 50 | 198W |
| 6. | cell conversion loss | 90 | 20W |
| Source Notes: 1. Average for hour-angle, season and latitude (37º N). Increased atmospheric path length was not considered. 2. See link. Continental U.S. average sunshine is 4.8 kilowatt-hours/ square meter/day, or 200 watts/square meter. That value is nearly identical with total losses shown for items 1-5 above. |
|||
2. I realize the syntax used by the author was questionable, but since he spoke of "a seven-metre squared array", rather than "a seven square meter array", I feel pretty confident that the intended meaning was 49 square meters.
3. In testing the reasonableness of the author's energy claims, you can avoid any question or discussion about the automobile's horsepower (whether maximum rated horsepower or operating horsepower) simply by employing the following reasoning.
| gallons of gasoline saved per year (11,000 miles @ 30 per gallon) |
367 gallons |
| energy per gallon | 120E6 Joules |
| total energy savings per year | 44E9 Joules |
| energy savings per second (Watts) |
1,400 Watts |
| energy per second per square meter of fuel cell array | 28 Watts |
| solar energy available per sq meter (see above table) |
20 Watts |
In other words, Dr. Auty's claim that "a solar powered fuel cell array of 49 square meters that is 10% efficient, would produce enough energy to drive an automobile 11,000 miles", is fairly close to reality.
HOWEVER, WHAT IS NOT CLOSE TO REALITY is some of the related claims and fuel cell requirements.
First, according to the article, the conversion process relies on solar ultraviolet radiation, but since UV comprises less than 10% of the total solar radiation, how can he have a cell that is 10% efficient???
Second, there is no such thing as a low price glass that is highly transparent to UV radiation. Just how economic a process will this be when it requires acre upon acre of amorphous quartz (or something equally expensive)?
Third, based on my experience, I would be extremely surprised if they can make such an array cheaper than solar cells (which are not an economically viable source of energy) and those run in the neighborhood of $500 to $1000 per square meter.
If you got lucky and got an 8% interest only loan to pay the cost of capitalizing Dr. Auty's contraption, the fuel cost would not be the $1.80 to $3.00 per liter that Dr. Auty claimed, but rather it would be about $6.24 to $12.47 per liter. (The number of liters per year equals 44E9 J divided by 140E6 J per liter of H2. At a cost of $500 per square meter, capitalization cost for 49 square meters of fuel cell would be $24,500 and the annual interest would be $1,960.)
There is only one way that Dr. Auty's scheme can be made to be economically viable. If you can't lower your own costs, you've got no alternative but to cause your competitors prices to rise. And you do that through government interference with the free market place.
Raise the gas tax, raise the road use tax, and do it both at the state and federal levels. Restrict new drilling for oil. Institute ever more restrictive environmental controls. Don't allow new refineries to be built. Require the use of oxygenated fuels. Institute a carbon tax.
Oh, wait, we're already doing that! Welcome home Dr. Auty, your time has finally come.
--Boot Hill
Thanks for your informative discussion.:)
By the time this type of energy is perfected, someone will find a different way.
