The system has been teste in summer temperatures between 15 and 40 deg C and in winter between -10 and 20 deg C It works a little bit better in winter because the ambient air is drier. It has not been tested in snowing conditions, but adding more heat to the system is easy. It is getting enough air through the grain that was the big challenge. One way to add more heat is to increase the self regulating heaters underneath the solar collectors capacity.
The solar collectors heat the air the same way as a solar water heater would. No electronics or electrical equipment in the solar collectors. When dirty you wash them with water.