8
Solar Collectors - APOLLON
MAXIMUM OPERATING PRESSURE, PRESSURE DROP,
The maximum operating pressure - taking into account the increase in pressure due to the water’s expansion - must
not exceed 400 kPa. The ideal water flow in a central system is 40 lt/m
2
h to 70 lt/m
2
h and the pressure drop per meter
of installed pipe (supply and return to the collectors) is 30mm of water. This is the data that is used for calculating the
dimensions of the circulation pump in each installation.
NOTE:
To the pressure drop of 30mm of water per meter of installed pipe one must add 10mm of water per square
meter of installed collector.
A basic factor in the optimum performance of the system is the correct selection of angle and orientation, in relation
to the installation site and the period during which we want the maximum yield. The solar system must be oriented so
that the collecting surface faces the geographical south for the northern hemisphere (and the geographical north for
the southern hemisphere), i.e. it should always face the equator. Any deviation in the orientation means a drop in the
system’s performance. If a deviation from the correct orientation cannot be avoided, then the system’s performance
must be corrected by increasing the collector surface, after study and evaluation of the particular circumstances. As
the solar radiation’s angle of attack changes over time and in relation to the system’s installation site, the collector’s
angle shall have to be equal to the site’s latitude ±5°. At this angle the maximum yield is achieved on an annual
basis. The system must not be shaded by trees, buildings or other obstacles so as to ensure 4 hours of unimpeded
exposure of the collector area during the midday hours.
MEANDER AL GRD MDR
Mass flowrate [lt/h]
Pressure drop [Pa]
800
700
600
500
400
300
200
100
0
0
50
100
150
250
200
300
