Cost of Collector
Comparing the purchase price of the collector alone is
NOT useful. The final installed cost and expected annual
energy output for the specific application should be
considered in order to make a sound choice.
FP installation cost can be higher if hydraulic lift platform
(cherry picker) is required due to the size and weight of the
ET collector components are lightweight and can be
carried up a ladder. Flat Plate is heavy single components
so may require lift platform.
Low Temp Applications
FP collectors are suitable for domestic hot water
applications (<600c />1400F) as heat loss at higher
temperatures results in poor solar conversion efficiency.
High Temp Applications
ET collectors are suitable for both domestic and industrial
high temp applications (<1200c />2500F) with high solar
conversion efficiency even at higher temperatures.
FP collectors perform poorly in cold conditions.
ET collectors perform well in cold conditions due to the
Both ET and FP collectors can be installation in the
vertical orientation, but note also the installation angle
requirements for the ET collector is 20-800 range.
ET collector can only be installed with the evacuated tubes
in the up-down orientation, not left-right.
FP can be installed in either orientation.
Et must be 20-800 to ensure optimum heat pipe
operations. FP can be installed at 00 (vertical) or 900
(flat), although these are not ideal for best solar exposure,
as angle should ideally be close to latitude.
ET and FP can withstand hail of < 25mm / 1” in diameter,
however FP is stronger.
If a tube is damaged by extreme hail or branch failing on
the roof, individual tubes can be replace.
If a FP is damaged the whole panel must be
Because of the small diameter of the riser copper pipes in
the FP collector, limescale may block the pipes more
easily than the ET collector which has a large diameter