A temperature difference of 130 K is not unusual with a solar system. Winter nights with temperatures of -30°C and sunny days with collector temperatures of about 100°C mean enormous strain fo a solar collector.
Besides the low-iron soda lime glass and the copper heat pipe, only high-quality materials are used with the OEG 4flex® heat pipe. High-quality EPDM rubber flanges insulate and protect the glass-metal seals.
Other tubes in the market only have thin rubberized end flanges to cover the mechanical glass-metal seal.
