Posted by Gary on October 14, 2004, 7:35 pm
Long runs of collector will result in higher average collector
temperatures. This increases the temperature of the water coming out,
but also increases losses (particularly from unglazed collectors).
So, I think that long runs are bad if you want good efficiency.
Several parallel runs that produce a modest temperature increase
should be more efficient.
If you want to look at numbers, this link has free pool simulation
If you use the "pro" version (still free), it allows you to change the
configuration of the collectors -- you should be able to run series
and parallel arrangements and see how big the differences are.
I think that you will need to download a TMY weather file for your
area, or some similar area. This NREL site:
has files for the US.
This site seems to have a lot of pool heating info:
Posted by N. Thornton on October 18, 2004, 1:47 pm
It depends what youre comparing.
If you compared the same flow rates /within each section/, which does
mean very different rates at the pump, then what you say would be
true. But IRL we want to compare the 2 layouts with the same pump, not
series with small pump vs parallel with big pump. For a given pump
flowrate, the gain would be the same with either configuration. That
means a lower flow rate in each parallelled bit.
The only thing that will change the relative efficiency of the 2
setups is flow rate, and parallel will give you higher total flow rate
with the same pump, as the parallelled flow resistances are less.