11
Design configuration and sizing
Piping
Material
The piping material used for the solar
circuit shall be approved for use in solar
heating systems as per EN 12975. We
recommend using copper or stainless
steel piping with connectors that form a
metal-to-metal seal. All solder connec-
tions shall be hard soldered.
The materials and connections used
shall be guaranteed to withstand tem-
peratures of up to 270°C. They shall
also be rated for use with the heat
transfer fluid and be weather resistant.
The warranty becomes null and void if
collectors are damaged as a result of
using unsuitable piping.
Sizing
The required pipe diameter is shown in
the table on the left. The table is valid
for the solar pump group 65.
Pipe diameter and flow resistance shall
be individually calculated for large sys-
tems or for very long pipe runs and be
matched to the circulating pump design
specifications.
Pipe size shall be selected to ensure
that the heat transfer fluid flow rate
remains between 0.5 m/s and 1.0 m/s
per second.
When choosing the pump, keep in mind
that the heat transfer fluid pressure
drop is greater than the pressure drop
for water.
*The actual pressure drop across the collector panel depends strongly on the
flow velocity and temperature of the heat transfer fluid.
Rule of thumb:
Pressure drop (heat transfer fluid) = 1.5 x pressure drop (water)
Cop-
per
Stainless
steel
corrugated
tube
Number of collectors (AURON 20)
with pipe lengths 15 double metre
1
2
3
4
5
6
7
8
9
10
DN 13
DN 16
x
x
x
x
DN 16
DN 20
x
x
x
DN 20
DN 25
x
x
Cop-
per
Stainless
steel
corrugated
tube
Number of collectors (AURON 20)
with pipe lengths 25 double metre
1
2
3
4
5
6
7
8
9
10
DN 16
DN 20
x
x
x
DN 20
DN 25
x
x
x
DN 25
x
x
x
= design operating range
x
= maximum limit
