David Hansen wrote:
On Thu, 28 Feb 2008 05:10:59 -0800 (PST) someone who may be
wrote this:-
Agreed. Vacuum tubes have the edge in cloudy conditions, but
commercially supplied flat panels will do almost as well in bright
sunshine.
I'm not sure where you get that from.
It's common knowledge,
Flat panels yield far more output per area and per cost in bright
sunshine, basic physics tells us that.
Common belief doesnt make something accurate. That belief comes
from comparing systems rather than comparing equal collector
cost or equal collector area. I'm sure you'll have noticed that tube
and flat panel systems tend not to be comparable cost-wise or
performance design-wise
FWIW old systems are always flat panel, and modern are mostly
tube, and much more expensive systems too. Its no surprise that
a higher cost system with better specs can produce more return, .
but it would be unsound to conclude vac tube gives greater ROI
than plate. It isnt that simple. We havent even started on the
significant variation in flat plate designs and performance.
NT