Boeing to Mass-Produce Industry's Most Efficient Terrestrial Solar Cell

[Gold Metal Flake]

http://pddnet.com/news-ap-boeing-to-mass-produce-industrys-most-efficient-te-112210/

SYLMAR, Calif., Nov. 22, 2010 -- The Boeing Company today announced that Spectrolab, a wholly owned subsidiary, has started mass production of its newest terrestrial solar cell, the C3MJ+. With an average conversion efficiency of 39.2 percent, C3MJ+ will be the industry’s highest-efficiency cell.

The concentrator photovoltaic (CPV) cells -- used for renewable energy -- draw on Spectrolab's 50-year history of manufacturing solar cells for space and terrestrial applications and are an improvement on the C3MJ cells currently in production, which convert 38.5 percent of the sun’s rays into energy.

"These more efficient cells are drawing interest from a number of current and potential customers," said Russ Jones, Spectrolab director of CPV Business Development. "Last year we set a new world record for efficiency with a test cell that peaked at 41.6 percent. We now have entered production with essentially this same technology and plan to deliver the first of these 39.2 percent efficiency cells in January."

Spectrolab has introduced mass production of a new series of solar cells with increased energy-conversion efficiency each year since 2007. The current C3MJ series entered production in mid-2009. More than 2 million C3MJ cells have been sold to customers around the world.

[Gold Metal Flake]

1. To be clear, these are not silicon cells used on flat panel installations.

These are multi-junction cells similar to those used in space and on the Mars Rovers. Terrestrial versions are used in concentrator systems on sun trackers which are mostly used by utilities at this point. As solar expands on the rooftops of factory and business building I think concentrator systems will expand into private use.

[kristopher]

2. Cool.

But perhaps that is a poor choice of words since one of the issues with concentrated PV has been accumulated heat. I'd like to know more about their product if you find something.

Thanks for posting.

[Gold Metal Flake]

3. Heat is not an issue, it is a design consideration.

Heat sinks of moderate mass are sufficient. The smaller the cell, the less an issue heat is. Multiple cell arrays use smaller cells from .3cm2 to 1cm2.

[kristopher]

4. I'd phrase it that heat is an issue *and* it is a design consideration.

I'd like to know the specific way they have dealt with the problem, that's all.

[Gold Metal Flake]

5. I've told you.

It's not rocket science.

[kristopher]

7. No you haven't.

Saying it isn't an issue isn't an explanation. If it is the design of the focusing device, I'd like to know what it is. If it is a transport mechanism, I'd like to know the specifics.

Take the chip off your shoulder.

[kristopher]

9. OK, I got it. They use a ceramic substrate.

That has expansion characteristics similar to the similar to the solar cell. The entire unit is designed to withstand temps up to 180C with an operational range of -40C to 100C.

[Gold Metal Flake]

11. I'm not going to give specifics or confirm theories.

I have limitations. I will say that I know of a customer that is throwing 1000 suns on a cell and is running 30C above ambient which is perfectly reasonable. Keep in mind that MJ cells do not suffer due to heat as much as silicon. CPV will work very well in the Arizona desert in summer where the performance of silicon will degrade.

[OnlinePoker]

8. Answers are here

http://www.spectrolab.com/pv/support/Sherif%20et%20al%20paper%202006%20European%20PV%20conf,CONCENTRATOR%20TRIPLE-JUNCTION%20SOLAR%20CELLS%20AND%20RECEIVERS%20IN%20POINT%20FOCUS-%20AND%20DENSE%20ARRAY%20MODULES.pdf

"In this model, the heat spreader has dimensions of
5cm x 5cm and its thickness is 2mm. Heat removal from
the back of the heat spreader occurs by natural
convection (i.e., passive cooling) with the heat transfer
coefficient assumed to be 100 W/m2-deg C, which is
typical of natural heat convection."

[DCKit]

10. I'll assume because nobody could figure out any use for all that "waste" heat?

Free hot water, anyone? Sheesh.

[Gold Metal Flake]

12. Active cooling has it's own problems.

Miles of pipe. Leaks. There are other ways.

[DCKit]

13. In huge installations, I might agree.

On single/home systems, it would pay huge dividends.

Not using the "waste" heat is a wasted opportunity.

[eppur_se_muova]

6. K&R nt