Hello,
Always in my research concerning the power of a solar oven, there is a question that I ask myself: this value of the sunshine of 1kW / m² which everyone uses to make the calculations of oven power, is- what it is a value that we can take for the whole world, or is it precisely the value that we find on the maps of sunshine and that varies with the latitude at which we find?
Because where I ask where this value comes from, I am told that it is a value that everyone takes, which is always taken everywhere and commonly accepted. But I would really like to find a place where it is written black on white ...
Thank you in advance for your answer, I know you are always very fast!
sunshine value in France and worldwide
Re: Sunshine value.
mageflor wrote:Hello,
Always in my research concerning the power of a solar oven, there is a question that I ask myself: this value of the sunshine of 1kW / m² which everyone uses to make the calculations of oven power, is- what it is a value that we can take for the whole world, or is it precisely the value that we find on the maps of sunshine and that varies with the latitude at which we find?
Because where I ask where this value comes from, I am told that it is a value that everyone takes, which is always taken everywhere and commonly accepted. But I would really like to find a place where it is written black on white ...
Thank you in advance for your answer, I know you are always very fast!
It is a reference value.
In fact it is a kind of international "standard", which does not necessarily correspond to reality (in practice, depending on whether you live in Finland or in the Sahara, the average solar power perceived annually varies ... significantly ), but that everyone uses history to work on common benchmarks.
Similarly, we use a reference solar spectrum (called AM0 for the solar spectrum outside the terrestrial atmosphere, and AM1.5 for the terrestrial solar spectrum. See on the NREL website for more information.). Here too, these are reference spectra which are not necessarily those that you will measure at home.
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Uh I don't really understand why you recreated a subject ... We already answered you here:
Solar-thermal / power-of-a-solar-oven-t3454.html
(solar world map)
1 kW / m2 is the average value admitted on Earth of the solar flux (without cloud) after we could have fun making a more precise calculation with the world map of the other subject ...
Here is a map for France:
More specific here: Solar-thermal / card-precise du radiation-solar-en-France-dni-France-t7232.html
Solar-thermal / power-of-a-solar-oven-t3454.html
(solar world map)
1 kW / m2 is the average value admitted on Earth of the solar flux (without cloud) after we could have fun making a more precise calculation with the world map of the other subject ...
Here is a map for France:
More specific here: Solar-thermal / card-precise du radiation-solar-en-France-dni-France-t7232.html
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Do a image search or an text search - Netiquette of forum
answer
hi christophe and all of you
1000w / m2 is used to test the solar collectors to know the performance of each. (this is a laboratory test) !!
then there is the reality the sun sends 1340 w / m2 in space .. the earth turns on itself !! (you know!) which means that at night she receives nothing! so you have to calculate an average, then there is the reflection of the atmosphere, then clouds etc etc ...
here are some more realistic values:
south France in SUMMER, we receive 5.44 Kwh per m2 and per DAY !!
North France in SUMMER, we receive 3.83 Kwh per m2 and per DAY !!
south france in winter: 2.44 kwh / m2 / d
north france in winter: 1.09 kwh / m2 / d
I'm going to work in the sun !! I give you here real figures to allow calculations.
there is another important factor: the number of hours of sunshine per city etc ...
a ++
1000w / m2 is used to test the solar collectors to know the performance of each. (this is a laboratory test) !!
then there is the reality the sun sends 1340 w / m2 in space .. the earth turns on itself !! (you know!) which means that at night she receives nothing! so you have to calculate an average, then there is the reflection of the atmosphere, then clouds etc etc ...
here are some more realistic values:
south France in SUMMER, we receive 5.44 Kwh per m2 and per DAY !!
North France in SUMMER, we receive 3.83 Kwh per m2 and per DAY !!
south france in winter: 2.44 kwh / m2 / d
north france in winter: 1.09 kwh / m2 / d
I'm going to work in the sun !! I give you here real figures to allow calculations.
there is another important factor: the number of hours of sunshine per city etc ...
a ++
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Thank you and other issues: efficiency of a solar oven?
The thank you box
In fact, it is true that with Christophe's maps, if we do the calculations, we can find the value of average sunshine in France. So thank you very much! Indeed, you had already answered my question.
Simply, do you know or can we find on the web the formula that you gave me for the calculation of the power of a solar oven: sunshine * surface * yield? And do you know how we calculate the efficiency of a solar oven? What is it due to?
Goods.
In fact, it is true that with Christophe's maps, if we do the calculations, we can find the value of average sunshine in France. So thank you very much! Indeed, you had already answered my question.
Simply, do you know or can we find on the web the formula that you gave me for the calculation of the power of a solar oven: sunshine * surface * yield? And do you know how we calculate the efficiency of a solar oven? What is it due to?
Goods.
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I am also interested in solar ovens, but with the aim of turning a turbine to transform thermal energy into electrical energy.
The yield is the same for all production systems, you divide your transformed energy (example: if you cook water, you get it with E = m * c (4180) * (t2-t1)) by your energy received (here: solar power * surface * time).
Then you multiply by 100 -> you get the return.
I hope I answered your question and that you weren't waiting for a more detailed answer ^^.
The yield is the same for all production systems, you divide your transformed energy (example: if you cook water, you get it with E = m * c (4180) * (t2-t1)) by your energy received (here: solar power * surface * time).
Then you multiply by 100 -> you get the return.
I hope I answered your question and that you weren't waiting for a more detailed answer ^^.
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