east/west or south orientation

[namor]

we have an apartment with a flat roof oriented 350° north and wonder if it is better to install 5 kw east/west even when we calculated that we will gain 13% less based on the calculation here: https://www.regreen.it/Liguria/Genova/producibilita_fotovoltaico. we that about an angle of 15 or 20 °. if we would cover all of the roof it would make sense to install east/west. but if we want to maximize efficiency with a limited budget, we're unsure. we will add a battery somewhen in the future. we use the energy during all the day. in the winter we use it for the heat pump. thanks for your advice.

 

[SeaGal]

we have an apartment with a flat roof oriented 350° north

Not sure how a flat roof can be oriented in any direction

Do you have any shading?

 

[kc130up]

If the roof is flat and you can put up a ground mount in any direction, you can have the panels face any direction. Here is a calculator that will help find the best angle, azimuth, etc. for your location.

Then the question becomes "how many panels will fit" in the orientation that I want!

 

[Chicat]

You can put solar panels on an apatment?

 

[kc130up]

You can do almost anything with the landlords permission.

The OP is in Italy. In some places what we call condo's in the US are called apartments.

 

[BarracudaBob]

Then the question becomes "how many panels will fit" in the orientation that I want!

You got it. I am finding SE and SW seem to be the best but trees, shading, and wife dictates where it will go.

 

[Brucey]

we have an apartment with a flat roof oriented 350° north and wonder if it is better to install 5 kw east/west even when we calculated that we will gain 13% less based on the calculation here: https://www.regreen.it/Liguria/Genova/producibilita_fotovoltaico. we that about an angle of 15 or 20 °. if we would cover all of the roof it would make sense to install east/west. but if we want to maximize efficiency with a limited budget, we're unsure. we will add a battery somewhen in the future. we use the energy during all the day. in the winter we use it for the heat pump. thanks for your advice.

Doing east/west can give you a longer but shallower solar day. That may end up being an advantage if you dont have batteries to begin with than if it was south facing, where you may get a little more overall in the day but peaking at solar noon with less in the morning and evening.

 

[namor]

Not sure how a flat roof can be oriented in any direction

Do you have any shading?

no shading

as there will be more people putting solar panels on the roof, we would like to orient them to the walls. one side is about 170° azimuth.

 

[namor]

You can do almost anything with the landlords permission.

The OP is in Italy. In some places what we call condo's in the US are called apartments.

yes. most people in italy live in so called condominios.

 

[namor]

Doing east/west can give you a longer but shallower solar day. That may end up being an advantage if you dont have batteries to begin with than if it was south facing, where you may get a little more overall in the day but peaking at solar noon with less in the morning and evening.

plus there is the argument that you can put up more panels with east/west on a flat roof. if cost is not the most important argument you can generate get more energy out of an east/west layout, right?

 

[Brucey]

plus there is the argument that you can put up more panels with east/west on a flat roof. if cost is not the most important argument you can generate get more energy out of an east/west layout, right?

No for maximum annual production you want all south facing. But east/west arrays may not be far off especially if you arent far north or south.

 

[kc130up]

Being above the equator, you want as much south facing as possible. E/W is ok, but S is best. N is worst, but it works facing north, just not as good as the other 3 directions.

 

[SeaGal]

You would need to do the calculations, but east-west could have higher panel density than south-facing - so more panels for same area, important if area is limited.

 

[bladerunnerpv]

You might find pvgis useful too for estimating pv yield in your location.

https://joint-research-centre.ec.europa.eu/photovoltaic-geographical-information-system-pvgis_en

 

[bladerunnerpv]

Think there's a version you can do an east west system estimate at pvgis.com, you have to register there if I remember correctly

 

[SeaGal]

Or... you could just do the estimate for the East orientation and then again for the West orientation and sum the results.

 

[namor]

one additional reason to switch to an est/west installation might be the max. 6 kW rule for single phase installations. again you could put more panels on the roof and you could "earn" more energy, right?

 

[namor]

if we would like to get most out of our solar installation during winter time, we should put them up southwards, right?

 

[kc130up]

South is always the best, year round. The perfect panel angle varies between seasons, but south facing is always the winner.