Written by:
stankelly
10/9/2008 8:32 AM
When someone hears the term solar power, one of the very first things that they think of is the use of photovoltaic cells. But in the world of solar technology research, while some effort is geared towards the solar cell, the vast majority is on solar thermal technologies. There are many reasons for this but the most important one is the difficulty to manufacture silicon crystals versus their efficiency in regards to the use of the sun’s heat at more than double the efficiency.
Truth be told, solar thermal technologies have been around for a longer period of time then that of the photovoltaic cells. The vast majority of solar power plants all around the world is in fact solar thermal and not based on light collection. Furthermore, there is currently more research being done in the other uses of solar energy such as cooking and cleaning out water supply.
While solar cells are being researched, right now the research being done is to find new, cheaper and easier methods of manufacturing the needed crystals as well as research on the development for concentrated photovoltaic panels. Basically its been found that the same centuries old technology used in the solar thermal process can work in photovoltaics; but solar cells degrade in efficiency as the heat increases. The concentrated PV cells are specially designed to be used in concentrators like parabolic dishes and troughs and also can have efficiencies upwards of 40-50%. However if you think the standard PV panel is expensive, then you definitely do not want to know how much a concentrated PV panel costs.
On the other hand you have solar thermal which basically uses a concentrator, much like a parabolic dish you would use for cable television. This can be as a dish or even as a trough depending on the scale of the power production needed. Capable of concentrating the heat given off by the sun’s rays of light to more than 500 times, solar concentrators collect pure heat with a single collector running upwards of 1000°F.
The biggest issue with solar power to date is that of storage which in terms of solar cells means batteries. With solar thermal though, plants are now capable of storing the heat in a molten salt bath that consists of a mixture of sodium nitrate and potassium nitrate. This molten salt melts at almost 500°F and stays in its liquid form which has the consistency of water, at about 550°F. A large enough container can store enough heat to produce 100 megawatts of energy for up to 4 hours.
If you go to places like India, the uses of solar technology are very different as they use them for cooking and drinking. Using the same concept of thermal concentration, they are able to open community kitchens that produce enough steam on a daily basis to cook food for more than 100,000 people. This same heat concentrated by the sun can also be used in the purification of water both as steam distillation as well as evaporative-condensation purification.
With so much energy being researched in the field of solar thermal, it is no wonder why PV panels are still expensive. But then again going with the safest bet which is technology that is centuries old will never let you down.
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7 comments so far...
Re: The focus of solar research
Thank you so much for the information in this article. I was not aware that there are two things being looked at and that one solar power has been around much longer than the other one. I appreciate the fact that you have taken the time to explain and name the different sources of solar and how they both are used.
By attagirl on
10/11/2008 10:46 AM
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Re: The focus of solar research
I've read many articles about using solar concentrators along with a sterling engine to produce a virtually free energy device. I say virtually because the sterling engine and solar collector large enough to produce a great deal of electricity is beyond the means of an average person. This molten salt pond is an interesting concept and sounds like it could easily be accomplished
By Taki on
10/11/2008 10:19 PM
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Re: The focus of solar research
The molten salt pond is a different idea and am sure it will give good results. Actually the government must be ready to invest more in this aspect as this is the source of energy in the future. Solar collectors must be build in a better way and must be expanded so that maximum energy can be tapped.
By descorpio on
10/12/2008 1:31 AM
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Re: The focus of solar research
this article is very informative. and i agree with descorpio. this i a very important source of energy and will be used for future purposes. the government should give so much attention to this and prepare everything that they will need for it.
By Maylin on
10/12/2008 7:37 AM
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Re: The focus of solar research
"I've read many articles about using solar concentrators along with a sterling engine to produce a virtually free energy device. I say virtually because the sterling engine and solar collector large enough to produce a great deal of electricity is beyond the means of an average person. This molten salt pond is an interesting concept and sounds like it could easily be accomplished"
What great comment here. I appreciate that you went to work on this one and provided this. I agree with you 100 percent on this. If I knew how to do this I would do it. Anyway to get the cost of power down in today's economy. With prices on everything so high and wages so low, it is not a bad idea to do this.
By attagirl on
10/14/2008 2:11 PM
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Re: The focus of solar research
Guys we must understand that we live in the most dangerous world these days. Everyday we keep poluuting our environment. Because of which there is no proper rains, climatic changes. The best example is where i live. No rain in the past one year. Also no proper wind speed because of which hydro electric projects could not produce electricity and the same case for wind mills also. The result is we have a power cut of 5 to 6 hours every day here. So make your advancements in tapping the sun energy.
By descorpio on
10/18/2008 11:03 PM
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Re: The focus of solar research
Even i have got the same question as the author. With so much of advancement in technology, still why the PV cells are expensive. And its a great news that Indians have the community kitchen where they utilize the energy and prepare food for 100000 people. Great amount of energy is being tapped then. Others must learn a quick lesson from them.
By cogbuddy on
10/20/2008 1:00 PM
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