What is the difference between the evacuated solar tubes more efficient than flat plate systems?
The evacuated solar tubes are the better system. The differences are as follows: Evacuated tubes are strong, long lasting, and should one be broken, inexpensive and easy to replace. If a flat plate collector panel is damaged the whole panel must be replaced. Due to the high efficiency absorption of solar radiation even during overcast conditions, combined with excellent isolative properties of the solar tube, solar tube collectors can heat water all year round (backup from gas and electricity is still required). Due to the cylindrical shape of the evacuated tube, the solar tubes are able to passively track the sun throughout the day. Flat plate collectors only provide peak energy output at midday when the sun is perpendicular to the collector’s surface. Air is evacuated from the solar tube to form a vacuum. This greatly reduces conductive and convective heat loss from the interior of the tube. As a result wind and cold temperatures have less effect on the efficiency of the evacuated tu
