IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask C2-A, November 9, 2009
By comparing the calculated and the measured outlet temperatures for the atypical
conditions day, when the overall solar radiation fluctuated constantly, it can be seen that the
model very accurately predicts the outlet temperature for the whole day, whatever the
amplitude of the solar radiation fluctuations and the maximum error is always below 2°C but
the model does not show any time delay with respect to the measurments.
In these first two cases, the model correctly predicts the collector outlet temperature under
different radiation conditions but for storage load. The next step in the validation procedure is
to study the model’s response to a desiccant cooling load, i.e. storage in the morning, with
regeneration in the afternoon.
Day 3:
1000
900
Solar global radiation -jour 3-
90
Outlet temperature -Day 3-
Experimental
Model
800
Radiation [W.m -2 ]
700
600
500
400
300
Temperature [ C]
80
70
200
100
0
0 100 200 300 400 500
Time [min]
60
0 100 200 300 400 500
Time [min]
Figure 12: comparison of the predicted outlet temperature of the collectors with the measured
one for good radiation conditions and a desiccant load (storage in the morning and
regeneration starts in the middle of the day)
Under typical desiccant cooling load there is remarkable agreement between the predicted
and the measured outlet temperatures, for both storage and regeneration periods even for a
sever transition period at t=300 min.
These three typical days show the capacity of the model to predict the outlet temperature of
the collectors with a negligible error.
page 40