Thermal imaging and spot temperature measured in infrared.


Panel temperature has been monitored during a solar-AC water pumping experiment by the USDA-Agricultural Research Service. Using 6 years of average monthly panel temperature data, the solar panel performance during winter was estimated to be at rated power, but the solar panel performance during the summer was estimated to be only 93.5% of rated power. In addition, the water pumped on a hot day considered at 36oC / 96.8 Fahrenheit was shown to be 7 to 10% less than on a less warmer day (20oC / 68 Fahrenheit), the entire performance loss was attributed to higher panel temperatures. To monitor and identify solar panel temperature we need instruments as monitoring guns in infrared or simply spot on infrared thermometers allowing us to inspect solar panels temperature from up to 6 feet distance with an accuracy of +/- 2oC / 35.6 Fahrenheit and to identify those panels which are overheating. 

Determining the exact number of solar-PV (photo-voltaic) panels needed to pump water from a water well at a specific pumping depth for watering livestock it is a very important task. If too few solar-PV panels are purchased, this could result in the rancher having to haul water to the livestock. However, if too many solar-PV panels are purchased, then that will result in having more power available than the pump motor can utilize resulting in the rancher having wasted money on unused available solar panel power. Data was collected at the USDA - ARS laboratory on a solar-PV  installed system using AC water pumping equipment. That experiment has spanned over a 6 year time period and it was consistent with assessing following data elements: intensity of solar radiation, water flow rate, power (DC and AC, DC electricity from solar-PV panels converted to AC electricity by a controller), solar-PV panel temperature, wind speed.