Solar Experiment  

 

Setup

The solar experiment consisted of 4 Siemens 10W solar panels. The output of the solar panels was applied to one of two resistive loads or a battery. The battery was used to power a microcontroller which recorded the voltage generated by the solar panels across the resistive loads. The temperature was also recorded. Each solar panel was mounted facing a perpendicular direction. To reduce wind loading the panel was deployed facing approximately NW. The others faced NE, SE and SW. Data was sampled every 2 min and the average recorded every 30min, 24 hours a day.

Results

There was no observed snow accumulation of the solar panels. This is due to the hard, granular nature of the snow as well as the steep angle of the panels.

The following average power outputs were recorded under low resistance and high resistance loads:

Average Solar Power
Low Resistance Load
High Resistance Load
Average Maximum Power 6.3 W
Average Minimum Power 0.6 W
 
Average Maximum Power 4.6 W
Average Minimum Power 1.1 W
 
 

Maximum power is generated when the panel is facing the sun, while minimum power is generated when the panel is facing away from the sun (lit only by reflection of surrounding snow). On average only 1/2 of the panel's rated power was generated.

The average temperatures recorded were:
 

Average Temperature
External Temp -3.7 C
Internal Temp 15.9 C
 
The battery never needed external charging, despite operating continually for 20 days. This indicates that the solar panels produced enough power to keep it charged (the entire monitoring circuit used 2.2W continuously)

This shows the power output of all four solar panels over 24 hours. Notice that the output of each panel is roughly sinusoidal indicating the dependence on Sun angle to power output as the Sun clocks around the experiment.

Conclusions

The temperatures seen during the experiment were significantly warmer than the -20 C expected and designed for. The solar panels only produced 60% of rated output on the average. Peak powers of 10 or 11W were common. The average was brought down due to several days of cloudy weather. However, this provides a conservative bound of 60W/m2 of solar panels, instead of the 100W/m2 which the panel specifications would indicate. Reflectance from snow, while small, could contribute a few watts per square meter of solar panel. The snow in the Patriot Hills region was very granular, almost ice crystals. This is probably due to the dryness rather than cold temperatures. However, it did not stick to the solar panels at all, even though a few blizzards occurred during the experiment.

Back to Experiment Results.


Robotic Search for Antarctic Meteorites 1998
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This document prepared by Michael Wagner.