A
Flat Plate is flat and therefore, it requires the sun to be directly
overhead to
operate properly. Evacuated Tubes, however, can collect sunlight earlier and later in
the day, when the sun is at lower angles. Since there is a larger
collector (aperture) area, the efficiency of the collector is dramatically
better than it would otherwise be in lower light conditions.
A
Flat Plate is flat and therefore, it requires the sun to be directly
overhead to
operate properly. 