|
|
re: is efficiency dangerous ? not for a drainback system
3 nov 2005
christian kaiser wrote:
>doesn't the water that comes down from the collectors reduce the power
>needed of the pump?
i think it could, if the downpipe is full. why doesn't someone try an
experiment with a kill-a-watt meter? or try out a uk shower pump with
2 pumps on one shaft, the downgoing one hooked up as a turbine?
>that is, only the first startup time, until all pipes are filled, are a
>problem to the pump (if the drainback reservoir is at the bottom of the
>system), or am i wrong? afterwards, it will not need more energy (or very
>little more) than with a pressurized system.
sounds good, with a pinhole somewhere for a slow drainback. do we really
need a 2-speed pump or 2 pumps in series?
>...here in the manual of the collectors it states that they should not
>be filled once they are above 40 deg c (which is very low).
to avoid steam or thermal shock? a little steam in an open system might
be ok. some thermal shock might be ok in a non-glass collector.
>this is a critical point of the drainback system then, if i would use
>these collectors, as the pump would need to transport water although the low
>temperature of 40 degrees (they do have this even in misty weather) will not
>allow me to heat up any reservoir. so a lot of pump energy is used for
>nothing...
that does seem like a waste, altho it's probably ok to let the dry
("stagnated") collectors get hot in the sun with no pumping, and
the pump might cycle on and off just enough to keep the collector
above the storage temp.
nick
|
|
