Shane

@dtarin Thanks for the response. I appreciate it, I'm new here so I don't know about the forum categories.

@dtarin Thanks for the response. What could be the proper justification to make negative values zero? secondly, I didn't fully get your last sentence's meaning, can you elaborate?

Hello Bruno!! Thanks for your message, the negative irradiance values come from actual data from the Finnish Meteorological Institute. Yes, you are right! and it is hard for me to interpret, but do you know any formula (with reference) I should use or is there any drawback of this formula? any suggestions/interpret? Thanks in advance

Hello all, I have an odd question to ask, I'm using the below information to generate a PV profile for one day, however, I have negative values and I'm a bit confused about what to conclude from these values. I'm using Matlab to generate the plot Formula: PV = 1/1000.* (et.*Av.*Ir .*(1-0.005.*(Tou-25))), where Tou is the outdoor temperature, Ir is the solar irradiance, et is efficiency (20%), Av is the area=1.6 meter square, 1/1000 to convert into kw. The solar irradiance and outside temperature are given by, noting that the location is in the south of Finland. Ir= [ -1.6 -0.8 -1.0 -1.0 -1.2 -0.8 -1.3 -0.5 6.9 27.6 43.9 38.8 15.9 2.1 -1.6 -1.3 -1.1 -1.1 -1.5 -1.4 -1.3 -1.7 -1.7 -1.4] Tou=[-20.3 -19.4 -18.6 -18.4 -18.0 -17.5 -16.9 -16.0 -15.3 -14.9 -14.5 -14.6 -14.6 -13.6 -12.4 -11.6 -11.3 -11.2 -11.0 -10.9 -10.9 -10.7 -10.5 -10.7]