IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration
Subtask A Report, Date:…
5 Analyse of the monitoring data
5.1 Collector efficiency
The collector efficiency can be calculated and followed every two minutes thanks to an
efficient monitoring. It is then possible to draw the collector efficiency during one day.
The Figure 1 shows the collector efficiency of the Chambery installation on the 6 th June
2010.
Figure 1: Collector efficiency of the Chamberry installation on 06/06/2010
During this day the solar collector field is working properly as the installation is running in
stationary state between 10:30am and 4:30pm, the collector efficiency is around 0,45 which
is a correct value with regard to the expected performances.
However, when the calculation is performed during the whole day, solar irradiation is
184,13kWh while solar energy received is 59,77kWh: the whole day collector efficiency is
then 0,32.
This difference between the collector efficiency function of the time of observation can be
explained because in the morning and in the evening, when the solar radiation is low, solar
collectors can’t work at they full potential. Anyway, a collector efficiency value of 0,32 for the
entire day is still a correct value.
The calculation for one month follows the same principles.
For the period between 01/05/2009 and 31/10/2010, the monthly collector efficiency is
showed on Table 2.