During this month I was in charge of drawing the 3D structures of the vacuum tube solar collectors and some new products with AutoCAD. It's the first time that I use 3D-drawing software like AutoCAD, but it seems to be not so difficult.
Here's some experience of AutoCAD and a little discussion of solar collectors...
AutoCAD:
1) In AutoCAD, the different movements of mouse cause sometimes different orders: as "select", "fillet", "break", etc.
2) In general we can only draw the graphics in x-y plane, besides of the line. But sometimes when there's a line in any other plane, we can draw the graphic in this plane, like circle or cylinder. Selection of angle in rotation only can be done in the plane which you've chosen, so only the lines in the plane can be snapped.
3) When you print, select "line merge" instead of "line overwrite" for better quality. (But in my computer, I must change between the two each time. What's the matter is it?)
I find that, the word "professional" does not mean that you can reach the result that you want, but the time that you cost. Perhaps I'm never "professional" in music? And in science?
Solar collectors:
1) The silicium solar cell can reach a yield of 18%-20%. But a vacuum tube solar collector has a yield of 80%-90%. In north of France as here, Laval, The open system of vacuum tube solar collector can even reach 200°C. And it function quite well even when the weather is not fine and the light is weak.
2) The combination of solar cell and thermic solar collectors may solve the problem of high temperature of each other. Its principle is just like the multi-junction solar cell. But the rest of energy (most is IR) must get out from the solar cell. The thermic solar collectors can also function as an air conditioner for the top floor; in fact, it's already done it very well.
3) Why there's "electric cell" (battery, 电池) but no "thermic cell" (热池)? First, we don't need to stock the heat, it's easy to generate. Then, the heat has fewer usages than the electricity. But now, we need "thermic cell"! In summer, the vacuum tube collector cannot support the high temperature that it generates, but we can convert it for winter. In fact, there's already some thermic cell like "暖宝宝", but what we need exactly, is a rechargeable thermic cell. The idea can be some compounds with crystal water, which can decompose at 180°C-200°C, and react with water for generation of heat. (Like the CaO <=> Ca(OH)2, decompose at 580°C.)
4) The photosynthesis fixed only 1% of solar energy on earth, but what we use now, the fossil energy, is exactly the 1% of energy. We can find only one thing in it, that the chemical energy is the most storable. That's what a chemist needs to think of.
