How to harness the sun without solar cells?

Related to your power production are methods to harness the heat of the sun: Solar water heating for a single house, trombe walls, greenhouses, cold frames.

It's a popular misconception that Solar PV isn't efficient; it can be more efficient than oil or nuclear. The internal combustion engine of a truck is around 20% efficient and a nuke plant is around 30% efficient. Many multi-crystalline solar cells are around 20% efficient and some solar cells that use concentrated sunlight (because their materials are very expensive) are around 40% efficient- beating out both nuclear and oil.

Solar towers are about 30% efficient because, just like nuclear, they heat water up to make steam, except to a higher temperature so they are a little more efficient than nuclear. There are also sterling dishes (that look somewhat like the old, large satellite dishes) and troughs that carry an oil mixture through a pipe in the center of the troughs. Then there's my favorite coming in at around 80% efficient- the solar hot water heater; cheap, easy to use, no moving parts, lasts for decades.

At this time, there are only two methods or technologies to convert solar energy into electricity. As you summarized, these are - broadly - photovoltaic and concentrated solar thermal. Within these categories, there are a variety of tracks. For example, within PV, there is the emerging "thin film" approach. The most interesting to me, as a utility employee, is where the concentrated solar energy heats thermal salts -- so-called molten salts -- which affords energy storage and generation after the sun has set, or even if it ducks behind a cloud. Perhaps you can come up with a third way to harness the sun.

2 parts to this answer.

1 efficiency: Solar cells are efficient, and compare favorably with other technologies. Their problem is really one of cost. Also since the fuel is 'free', its hard to compare efficiency to other energy sources. So what if its a few % lower or higher then some other process, if you pay for the fuel in that process, but sunlight comes free?

2 methods: It is important to remember that sunlight is still the prime source of energy on earth. It always has been. It powers all [well almost all] life on the planet. It keeps the surface of the earth warm enough to support life, it keeps the oceans liquid. It provides total lighting directly for 50% of each day planet wide. All of that in a totally sustainable zero cost manner. It is the energy source that drives winds and storms, that create rain and hence hydro power and waves too.

OK, so you might be thinking of how can we extract even more use out of this wonderful resource to replace some of the unsustainable energy sources we currently use?

Well, wind turbines, wave energy generators, even hydro power plants, bio fuel sources all are reliant on sunlight for their energy source albeit indirectly.

Using sunlight more directly comes down to 2 main processes, using the heat generated when the light is absorbed or using the light in a photovoltaic process.

Heating can be direct as in solar hot water systems or home heating, or via some concentration device. Mirrors or lenses. Concentrated light can be used to reach any temperature you like, including enough to melt steel!

A less well known method of capturing low temperature heat and converting it to electricity is to trap it in 'thermal ponds' of very saline water and to use a low boiling point fluid to power a turbine. The advantage is that the ponds are dirt cheap to construct and maintain and store lots of energy even during no sunlight periods. Being only a hundred degrees or so above ambient it requires far less insulation to keep its heat than a molten salt bath.

And here is a final different way of capturing solar energy...using it to trigger a chemical reactions directly, somewhat as plants do, but to produce high energy chemicals, which can then be used directly as fuels. This solves storage problems. It is possible to produce hydrogen for instance by the direct action of sunlight on water with the help of certain catalysts. [not very efficient, but room to improve if it is studied.]

The technology to trap solar energy and convert it to sustainable energy for human use is evolving all the time.

In time in line with hazard we can. The very nature of technological awareness and discovery is that there is often something to be chanced on and/or some greater effective thank you to do something. take a seem at desktops; we began with a working laptop or computing device that filled an entire room, used vacuum tubes, and ought to in basic terms do person-friendly algebra. we've what quantities to desktops that slot interior the palm of your hand! Scientists are consistently attempting to locate a greater effective, greater maximum economical, greater helpful answer to each thing, and that i could be prepared to wager a great form of money that interior the no longer-so-distant destiny we are going to see some variety of image voltaic panel that certainly has an performance close to that of vegetation. Or, in line with hazard, they'll improve some new technique that facilitates them to apply the solar to rapidly create fuels very like the fossil fuels we use as we communicate. As they say, "The sky's the shrink".

In addition to parabolic mirrors, there are also fresnel lens designs which focus the suns rays to heat up water/create steam to drive turbines or to heat up molten salts for storage and use when the sun is not shining....or used in conjunction with multi-spectrum solar designs.. Basically, it's the same principle of using solar heat energy.

Such designs or methods using fresnel lenses can also be used in cooking or distilling water...desalination.

http://www.nrel.gov/features/20110216_low-cost_sol...

http://en.wikipedia.org/wiki/Solar_thermal_energy

And there are more efficient PV designs being developed using thin-cell or multi-spectrum methods which are much more efficient than silicon based systems and could compete with oil, gas, hydroelectric or nuclear.Some alternative designs get upwards of 43 percent efficiency. Stirling engines are another alternative to PV designs.

A site with a variety of articles on solar energy systems and other topics...

http://www.greenoptimistic.com/category/solar-powe...

Multi-spectrum solar designs utilize more of the sun's rays wavelengths to create electricity...

http://www.lbl.gov/Science-Articles/Archive/MSD-fu...

http://www.ecoficial.com/new-multi-junction-solar-...

http://www.sciencedaily.com/releases/2011/01/11012...

"New Solar Product Captures Up to 95 Percent of Light Energy

ScienceDaily (May 17, 2011)— Efficiency is a problem with today's solar panels; they only collect about 20 percent of available light. Now, a University of Missouri engineer has developed a flexible solar sheet that captures more than 90 percent of available light, and he plans to make prototypes available to consumers within the next five years."

http://www.sciencedaily.com/releases/2011/05/11051...

Growing bio-fuels, such as ethanol.Can be used to generate electricity, but also power transport etc.

Solar electricity does not pollute the land like nuclear power stations.There is nothing to leak out or that has to be stored for thousands of years as it produces lethal amounts of radiation.

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yes i found an interesting wat to convert the suns power into sound

i was recently in dubi

i was with a tribe that was using the suns rays to torture a bloke they had tied down for two days

he was so sunburnt he screamed like mad