One of the most important parameters when developing a roof-mounted project is the near shading impact due to objects on the roof and outside of the roof. For that purpose, the shading analysis can be used.
To start, we will open the Shading Analysis by clicking on its button:
Once opened, we will see two different tabs:
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Irradiance data analysis; this analysis will take irradiance data obtained from the selected location and from PVcase Yield to provide us with shading loss percentage and irradiance data from every module in our layout.
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Shading projection; this analysis will provide us with the projection of the shadings on a desired date and time for the selected location.
Now we will explore both types of analysis on a project.
Irradiance data analysis
We will start by opening the irradiance data analysis tab by clicking on it:
Next, we will need to set the location where we want to obtain the irradiance data. We can either click on the globe and set it manually or enter the latitude and longitude in their respective fields.
To continue, we will click on the Run new irradiance analysis button to request the meteorological information from the PVcase Yield software. It will take a few seconds to fetch the data. Meanwhile, you will see the following window:
Once the data from the desired location has been obtained, we can display the information for the PV areas we want. To do so, we'll need to click on the Select PV area(s) button prompted after successfully retrieving the meteorological data:
In this example, we have 4 different PV areas, each for a separate slope of the roof, and we will proceed with selecting them all:
Once the PV areas have been selected, we will see that the Irradiance data analysis window has changed, displaying the two different types of information.
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Yearly shading loss: This analysis will provide us with a percentage value of the yearly losses due to shading.
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Yearly in-plane irradiation: This analysis will provide us with the values of the yearly irradiation received by each module.
Within both analyses, we will be able to display the values along with a heatmap or color gradient to get a fast visual understanding of the effects of the shadings on our layout.
Note: If, at any time, the layout is modified, it will be necessary to rerun the irradiance data retrieval so that the information for the new position of the modules can be recalculated.
Yearly shading loss
In this section, we will be able to display the yearly shading loss values for every module as a percentage value, as a color gradient, or both simultaneously. This analysis is particularly useful to identify the most shaded modules and get an idea of the impact resulting from having them on the layout.
Additionally, just by opening the window, we can quickly understand our layout. For example, in this layout, we can easily see that my minimum shading loss percentage is 0.1% and the maximum is 11.1%.
Also, we can filter out the modules affected by a desired loss percentage. To do so, we need to scroll the bar from the minimum or maximum to locate the affected modules. Another option is to manually input the shading loss percentage value we want in the minimum or maximum fields. In this example, we have set a minimum loss percentage of 7% and left the maximum value as it is:
To see the frames within our desired range, we will need to click on the Apply filter button. Afterwards, we will be left with the affected modules.
On top of that, we can also delete those modules within our analysis by clicking the Delete modules in this range button, which, in this example, will represent a total capacity of 5.3 kW.
Yearly In-Plane Irradiation
With the irradiance data analysis tool, we will do a similar analysis as we did for the Yearly In-Plane Irradiation. The main difference is that we will be analyzing yearly irradiance and the units will be kWh/m2.
To start, we will open the Yearly In-Plane Irradiation tab:
Now we will see the two available display settings. They can be shown independently or all together by turning on and off their respective switches:
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Show module values (kWh/m2);
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Show color gradient.
In this example, we will display both simultaneously:
Next, we will use the display range filter to identify those modules receiving less than 1,600 kWh/m2, and apply the filter:
As can be seen, the capacity within that range is 2.3 kW.
If desired, we could click on the Delete modules in this range to erase those modules from the layout.
Shading Projection
The shading projection analysis from PVcase Roof Mount is a tool that can be used to display the shades generated by objects on and around the roof at a specific location, date, and time of the year.
To start, we will open it by clicking the Shading Projection tab:
Next, we will set the location by either selecting it on the globe or by setting the latitude and longitude in their corresponding fields.
If we choose to set it manually by clicking on the globe, we'll need to click on the globe icon and type the name of the town where the project is located:
Once the project is properly located, we need to set the date and time when we would like to generate the projection of the shades. In this example, since the project is in the northern hemisphere, we will choose solar noon on the winter solstice - December 21st, 13:12 hours (Local Time).
Once defined the date and time, we will click on the On button to display the shading lines:
From these results, we can differentiate between two different scenarios:
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When modules are not shaded by other modules or by shading objects; in this case, the shading line will be represented as a simple fuchsia polyline.
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When modules are hatched in fuchsia; this happens if the shadow generated by a nearby shading object shades the module:
Comparing Results
If we take our analysis a step further, we can overlay the yearly shading loss with the shading projection. We will therefore see that for both analyses, modules affected by the shadings are the ones located near shading objects - object blocks on the roof.
The main difference between the Irradiance data analysis and the Shading projection is that the former takes values throughout the year, while the latter captures a snapshot at a particular moment of the year.