Cooling panel sends excess heat back into outer space | Hacker News Reader

Cooling panel sends excess heat back into outer space

venturebeat.com

25 pointsjoshwa14 comments

It works well until it gets dust on it. They should read some of their own papers. The biggest challenge to reflection is that it only works when the surface is still reflective. If you lose 10% of reflection the system goes from cooler to heater.

Places like Phoenix if you have a dust storm while you are out of town the next day your Grandma dies of heat stroke because the "AC" is out.

I'm certain there are applications for this tech, but not as a replacement for AC in most locations.

What's the downside of cleaning it? Is it irreparably damaged by dust? Or does a micron-thick layer of dust render it ineffective?

We built windshield wipers to clean car windows. I think we can manage something to clean these automatically. In the meantime, putting on a pair of work shoes and getting out the ladder once a week/month to polish the mirror hardly seems like a downside given it might be able to cool a medium-large home at no cost.

"putting on a pair of work shoes and getting out the ladder once a week/month to polish the mirror hardly seems like a downside"

I also wonder about why cleaning isn't a solution but, if it is to be a solution, then that solution must be automated.

An automated system would be cost effective, dependable and conserve water. In the hottest places, where water is naturally scarce, the water would need to be reclaimed, filtered and reused in an efficient manner.

These are basically super mirrors. Have you ever tried cleaning the mirror in your bathroom to a spot free shine? Now imagine you had that outside, and you had to do it with bird poo, and dust, but you couldn't scratch the mirror, you couldn't use anything that would streak, and you have to be able to do it quickly enough that you don't interfere with the cooling...

Perhaps nanotechnology can provide a transparent, repellant surface?

Even if it's prohibitively expensive for say your bathroom mirror, this would be a good application for justifying cost.

It's not just that you have to clean it. It is that if you don't you have a heater instead of an airconditioner. So if you have a rain followed by 110F you have a very bad day.

And I can buy a lot of AC for $60 an hour that I would pay someone to get on my roof.

I can't (quickly) find the original Google paper, but here's a report of their report, which says Google worked out it's worth cleaning flat-mounted solar panels, but andgles ones (at least at SF's latitude) are adequately cleaned by rain (again, assuming Bay Area rainfalls).

http://www.etcgreen.com/industry-news/solar/should-you-clean...

As for cleaning it, it will work no matter how you point it, so put it vertical, aim it at the neighbors you like the least (or you could aim it at an angle into the sky as well).

But you can't reduce the cost and danger of that monster significantly :

* a quartz : ?

* SiC : not exactly cheap in large panels, but ok

* MgF2 : this substance is NOT welcome in my house (you can't safely touch it, and if it gets vaporized or granulized in a fire or because someone puts a drill to this thing, people will start dying), also : expensive.

* TiO2 : very very expensive

* Ag : silver. Surprisingly cheap.

This thing has the same problem as nuclear power. Solid state, yes. Easy, powerful and (probably) lasts hundreds of years. But it can turn a small misstep into a neighborhood extinction (exaggerated, but then so is nuclear power's dangers)

According to the Wikipedia, MgF2 is not harmful to touch, only if inhaled or swallowed. But so are lots of materials used in construction.

And I don't think TiO2 is very expensive, it's used all over as a pigment. Even sunscreen has it.

Couldn't you have an automated system for cleaning it?

I was going to say "Yes", but while searching for another answer, I found this:

http://www.google.com/patents/US8240320

"Disclosed is a method for cleaning solar panels by means of a washing apparatus (1) which can be displaced on the solar panel (2) and applies rinsing water to the surface of the solar panel (2) and washes the surface with the help of washing nozzles and/or brushes. The washing apparatus (1) embraces the solar panel (2) in the edge region in such a way that the washing apparatus (1) is guided in a longitudinally movable way directly on the solar panel (2)."

Yeah, cleaning something with water and moving nozzles and brushes. That's pretty novel and un-obvious...

This is a challenge, but the benefits create a massive incentive to find a solution. Commercial solar has a headstart, and while not perfect, http://solutions.3m.com/wps/portal/3M/en_US/Renewable/Energy... seems to be a start.

How does this work with conservation of energy? It seems like free cooling?

I'm no scientist but it seems its not destroying the energy, its just reflecting it out into space

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