Confused

[SRE]

Ok, I bit the bullet and bough PvSol, now I'm trying to design 2 systems on it - PC about to go out the window

Can't figure out how to add the panels onto the roof (already identified panels and inverter and roof size and boundaries)

Did a test report and the yield is way below anything else suggest eg:

PvSol - 2503 kwh
PvGis - 2950 kwh
SAP 2005 - 2900 kwh
SAP 2009 - 2987 kwh

All for Sharp NU185E, SE facing and 18 degree pitch.

I have a sinking feeling I've paid for PvSol to provide a more professional report and I'm not going to dare using it because the yield is so low! I've checked my yield so far against PVGIS and it's been quite accurate.

Any suggestions??????

 

[SolarCity]

Where have you set your climate data for? If its for anywhere north of Sheffield then you will find that the yield will drop.

Is it PVSol expert that you are using?

 

[SRE]

PvSol Pro - just as well really because I'm find that hard enough Climate data for the English/Scottish Border

 

[SolarCity]

Can't really help with PVSol Pro as I've never used it - placing panels on PVSol Expert is all done in 3D so is a little different.

What size system are you designing? I wouldn't be surprised if the results do come out lower by using the climate data from that area.

 

[SRE]

Using 21 x 185CP Solar Black for a slate roof. I've got 22 Sharp 180's and they are performing at PVGIS levels not PVSol (about 15 miles away from the job I'm pricing) - think I need to make a phone call tomorrow .....

 

[SolarCity]

I get similar results to you so I'm sure you're not making a mistake.

Remember, the PVSol figures are based on figures gathered over 20 years and that has to be far more accurate than the SAP figures. Frankly, I think that the SAP figures are a joke.

 

[SRE]

I agree about SAP but I thought that PVGIS was supposed to be pretty acurate as it uses more up to date info. I know that my own system is performing month on month at the same rate as PVGIS - that's almost 20% more than PVSol. PVGIS works on data from the last 10 years while PVSol works on data up to 2000 - do you think that would make 20% difference?????

 

[SolarCity]

I've not used PVGIS, to be honest. Is it a similar set up to PVSol in that it considers roof angle, orientation and geographical position?

 

[SRE]

PV potential estimation utility# Here's a link, it's really simple and i'm led to believe that a lot of the bigger solar firms have been using it for years. It's quite good because it goes down to postcode area.

 

[SolarCity]

Looks like a handy tool. And I get similar results to yours when I use it. A big difference between this and PVSol, however, and I'm struggling to work out why.