UFC 3-440-01
14 June 2002
(c) Total number of collectors (N).
(d) Number of collector banks.
(e) Number of collectors per bank (4 < B < 7).
(4) Array piping. It is critical to system performance that the piping layout
satisfies the reverse-return criteria of equal lengths for any possible flow path. This list
presents the steps necessary for proper sizing of the array piping based on the
geometric layout. It is necessary for the designer to know the design flow rates in all
branches of the array - calculation of branches should begin from the bank manifold
diameter (collector internal manifold diameter) and work outward to the array supply
and return manifold diameters.
(a) System flow rate (AFR = CFR x N).
(b) Bank flow rate (BFR = CFR x B).
(c) Row flow rates (if applicable).
(d) Pipe sizing criteria to be satisfied.
NOTE: The ratio of manifold pressure drop to riser pressure drop for any branch must be
less than 0.3 (around 0.1 is preferred); and the fluid velocities must be below 5 ft/s (1.5
m/s) (Refer to Figure D-1).
(e) Collector internal (bank) manifold diameter.
(f) Row manifold diameter(s) (if applicable).
(g) Array supply and return manifold diameter (@AFR).
b. Storage Sub-System
(1)
Storage tank volume.
(a) Minimum storage tank volume = 1.5 gal per square foot (61.1 L per
square meter) of total collector area.
(b) Maximum storage tank volume = 2.0 gal per square foot (81.5 L per
square meter) of total collector area.
(c) Standard sized storage tank volume within above constraints.
(2)
Storage subsystem flow rate.
(a) Storage subsystem flow rate = 1.25 x (AFR).
D-5
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