15.07.2015   EuroSun2008-7

Solar thermal plant

Three days with different conditions have been simulated and compared with measurements. Table 2 summarizes the results by comparing the energy measured and simulated for the different days:

Table 2: Summary of the measured and simulated results of the solar thermal plant

Qsol

Qcol_m

Qcol sim

Qload m

Qload_sim

Dev. col

Dev. load

kWh/m2

kWh/m2

kWh/m2

kWh/m2

kWh/m2

%

%

10th May

8.38

4.69

4.55

4.04

4.47

3.1

10.8

5th July

8.04

4.32

4.17

3.92

4.04

3.2

3.1

11Th July

4.93

2.57

2.27

2.10

2.08

11.4

0.8

2.1.1. Collector loop

The results show a good agreement between measured and simulated values with an acceptable deviation. Nevertheless, it should be mentioned that when the irradiation is fluctuating, the results are not so good (11.4% deviation in comparison to measured values). This might be explained by

the fact that the values used to perform the simulation are mean values over 5 minutes-period. The values of volume flow rate and irradiation are therefore not “real”, that is why one can observe these peaks in the collector outputs when the volume flow rate is lower. These problems can easily be avoided by using instantaneous values and by reducing the time step.