Installation of a variable-angle spectrometer system for monitoring solar radiation

We report on the design and installation of a spectrometer system for monitoring solar radiation in Cochabamba, Bolivia. Both the light intensity and the spectral distribution affect the power produced by a photovoltaic device. Local variations in the solar spectrum (especially compared to the AM1.5 standard) may have important implications for device optimization and energy yield estimation. The spectrometer system, based on an Ocean Optics USB4000 (300-900nm) spectrometer, was designed to increase functionality. Typically systems only record the global horizontal radiation. Our system moves a fiber-optic cable 0-90 degrees and takes measurements in 9 degree increments. Additionally, a shadow band allows measurement of the diffuse component of the radiation at each position. The electronic controls utilize an Arduino UNO microcontroller to synchronizes the movement of two PAP bipolar (stepper) motors with the activation of the spectrometer via an external trigger. The spectrometer was factory calibrated for wavelength and calibrated for absolute irradiance using a Sellarnet SL1-Cal light source. We present preliminary results from data taken March-June, 2013, and comment on implications for PV devices in Cochabamba.


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For more information, go to:
Installation of a variable-angle spectrometer system for monitoring diffuse and global solar radiation - Appropedia: The sustainability wiki

Download the paper here:
https://www.academia.edu/26042563/De...s_preliminares

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MOST,

Interesting design for the spectrometer monitor. I learned something new today about air mass coefficient and "AM1.5" being almost universal when characterizing power-generating panels. I planned to learn more about this.

Last year I installed a 100 kWh/day PV solar system on an area of our lower property with perfect southern exposure and on a 40 degree natural slope. Based on what I have observed so far the ambient air temperature seems to have a major impact on the efficiency of the PV generation in addition to the quality and duration of the sunlight. The month of May had shorter daylight hours than during days in mid-June to mid-July (the longest daylight hours) but the month of May had significantly greater electric generation due to lower air temperatures in the 70's degrees F and clearer mornings (no significant marine layer) vs. the high 80's and 90's degrees F.

Thank you for the posting,
Paul Jones

$2000 sensor attached to a $20 micro...
Sounds about right.