Often the solar collectors used in
large solar collector fields have moisture trapped in the collector boxes, see
the figure below. The humidity inside the collectors might affect components of
the collector with reduced lifetime as a result. The moisture might also
decrease the efficiency of the absorber.
Consequently, it is important that the moisture content inside the
collectors is reduced to a minimum. Most likely, the moisture content will be
low if the collector is rain tight, if the collector is equipped with suitable
designed and sized drain holes and ventilation holes.
A literature study on humidity in solar collectors is
Experiment with six identical solar collectors at the
test field of DTU Civil Engineering, see photo below, are carried out with
differently designed ventilation systems. The solar collectors are examined
during a long period. The influence of the weather and of the ventilation
system on the moisture in the collector is investigated.
Damages of the collectors caused by the moisture are
Recommendations for suitable ventilation systems are given
based on the findings.