Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE credits
One argument against the usage of PV system is the low energy density. Another common
argue is the bad possibility to match energy generation and the energy demand in time. A
solution for these problems could be to use bifacial PV modules. A bifacial PV module can
generate energy even from the rear side. With this technic more energy can be generated
per area. In this thesis simulations with bifacial PV modules has been performed for three
different locations in Sweden. Different tilts, mounting heights and azimuth angles have
been simulated, all in combination of varying albedo. These cases simulated are Borlänge,
Jukkasjärvi and Linköping. In Linköping there is a PhD project about bifacial PV modules
going on. The test field used in that project has been simulated in this simulation study to
later be compared with measured results.
In this thesis the simulation tool Polysun was used. Polysun is a user friendly tool and with
the latest update it’s possible to simulate bifacial PV modules. For all three cases a
reference system has also been simulated using monofacial PV modules.
The simulated result suggests that bifacial PV modules should be mounted with the same
tilt as monofacial PV modules. The orientation should be towards south, the output
becomes evident decreased if the bifacial PV modules are facing east-west compared to
south.
Polysun seems to only take ground reflected radiation into account when calculating the
rear side energy output when simulations is performed with bifacial PV modules. When
the albedo is 0 there won’t be an extra output from rear side for all mounting
combinations. If the bifacial PV module is mounted 0m above ground, there won’t be any
energy output from the rear side either. This are big limitations in the program.
In Polysun the simplification is made that it’s the same albedo all year around. It’s not
possible to do simulations with different albedos. In reality the natural albedo will change
with the season, especially in Sweden. But those conditions are not possible to simulate. A
good idea for bifacial modules would be to secure as high albedo as possible by paint or a
bright canvas.
2016.