Duluth, MN
Annual Average Daily Solar Radiation

Latitude: 46.83 N Degrees
Longitude: 92.18 W Degrees
Elevation: 432 Meters
System Tilt: Latitude
Annual Total BTU's per square meter (10 tubes): 3,859,912

Please read the Collector Tube Efficiency and System Sizing sections before using this chart.

This page provides solar radiation values for Thermomax Solar Collectors and expected gallons of water raised by 60 degrees F. Radiation figures are from the Solar Radiation Data Manual, WBAN NO. 14913.  Thermomax collector (average) efficiency of 70% (based on Florida Solar Energy Center, Solar Collector Test Report No. 97005) is used for this chart.