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Charts - Solar charts: Difference between revisions
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We measure [https://en.wikipedia.org/wiki/Solar_irradiance Solar Irradiance] as the power per unit area received from the Sun in the form of electromagnetic radiation as measured in the wavelength range of the measuring instrument (your solar sensor of your weather station). ''CumulusMX'' stores this in [[Standard_log_files|the monthly logs]] as the value of the ''Solar Radiation'' (field nr 19) at that moment. It is the momentary solar power in W/m<sup>2</sup>. | We measure [https://en.wikipedia.org/wiki/Solar_irradiance Solar Irradiance] as the power per unit area received from the Sun in the form of electromagnetic radiation as measured in the wavelength range of the measuring instrument (your solar sensor of your weather station). ''CumulusMX'' stores this in [[Standard_log_files|the monthly logs]] as the value of the ''Solar Radiation'' (field nr 19) at that moment. It is the momentary solar power in W/m<sup>2</sup>. | ||
The Solar Insolation for a given time period is the integration of the measured Solar Radiation values. Or as the wiki says: | The Solar Insolation for a given time period is the integration of the measured Solar Radiation values. Or as the wiki says: | ||
''Solar irradiance is often integrated over a given time period in order to report the radiant energy emitted into the surrounding environment (joule per square metre, J/m2) during that time period. This integrated solar irradiance is called solar irradiation, solar exposure, solar insolation, or insolation.'' | ''Solar irradiance is often integrated over a given time period in order to report the radiant energy emitted into the surrounding environment (joule per square metre, J/m2) during that time period. This integrated solar irradiance is called solar irradiation, solar exposure, solar insolation, or insolation.'' | ||
So if we take R for Radiation (which we sample in field 19) we get for a time period of a day: | So if we take R for Radiation (which we sample in field 19) we get for a time period of a day: | ||
<math>\int{R} \, dt</math> | <math>\int{R} \, dt</math> | ||
=== Using Numerical Integration === | |||
But because we do not have continuous measurement we have to approximate this by taking the samples of the ''Solar Radiation'' we do have for the sampling interval we use (1, 5, 10 etc... minutes). We use the theory of [https://en.wikipedia.org/wiki/Numerical_integration#Quadrature_rules_based_on_interpolating_functions Numerical Integration]. Assuming equal distance <math>\Delta t</math> between the samples and a not too disruptive radiation function we get an approximation for the integral as: | But because we do not have continuous measurement we have to approximate this by taking the samples of the ''Solar Radiation'' we do have for the sampling interval we use (1, 5, 10 etc... minutes). We use the theory of [https://en.wikipedia.org/wiki/Numerical_integration#Quadrature_rules_based_on_interpolating_functions Numerical Integration]. Assuming equal distance <math>\Delta t</math> between the samples and a not too disruptive radiation function we get an approximation for the integral as: | ||
<math>\sum_{0}^{\sum_{\Delta t}} ({field19} \times \, \Delta t)</math> | <math>\sum_{0}^{\sum_{\Delta t}} ({field19} \times \, \Delta t)</math> | ||
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#If the interval is larger then 30 minutes the gap is too large and the value is skipped, no addition is made, the calculation is restarted at the next entry. | #If the interval is larger then 30 minutes the gap is too large and the value is skipped, no addition is made, the calculation is restarted at the next entry. | ||
#The Energy over the interval is calculated as <math>{SolarRad} \times {Interval} \times 60</math> to get the energy in Ws and summed up to the total for the day. | #The Energy over the interval is calculated as <math>{SolarRad} \times {Interval} \times 60</math> to get the energy in Ws and summed up to the total for the day. | ||
#At the end of the day the total energy in Ws is converted to KWh by <math>the energy sum \div {3600 \div 1000}</math> | #At the end of the day the total energy sum in Ws is converted to KWh by <math>{the\ energy\ sum} \div {3600 \div 1000}</math> | ||
NOTE: during this process the actual calculation of the solar hours is also executed. All calculation are done in one pass. The creation of the actual charts data consists merely of the selection of the data from the resulting list. | |||
== Monthly Insolation statistics per year == | == Monthly Insolation statistics per year == | ||
[[File:Monthly insolation statistics per year.jpg|thumb|right|Monthly insolation statistics per year]] | [[File:Monthly insolation statistics per year.jpg|thumb|right|Monthly insolation statistics per year]] | ||
The chart is analogue to the previous chart for all years. | |||
[[Category:CumulusUtils]] | [[Category:CumulusUtils]] | ||