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Solar Year

The "Solar Day" and "Solar Year" windows calculate energy characteristics of the same collector system of the latest active 3D View window. They display warnings if there are no 3D scenes (if the last 3D View window was closed), or if the latest active scene does not contain solar collectors.

The "Solar Year" window shows how the daily energy characteristics of your solar collectors (including the self- and full-shading) vary during a year, and calculates their yearly sums and yearly average values. It calculates also the very important and useful characteristic of your system, its annual energy yield.

All the calculations are implemented according to the climate model of the scene. To specify the climate model of the scene, read the section "Create the climate model ... " of the topic "Solar Day" and use the "Climate & Irradiance" window.

To understand better the sense of the characteristics displayed in the "Solar Year" window, read the following general sections of the topic "Solar Day": "Basic formulas for calculations", "Comments", and  "Note the curves' overdrawing"

If you feel that the "Solar Year" works too slowly, try to simplify the scene following the advices of the section "Keep a reasonable complexity of scenes" of the topic "Create Architecture". See also the section "Simplify your scene if it is needed" of the topic "Visualize Shadows".

The "Solar Year" window

The name of the associated latest active scene is written in the title bar of the "Solar Year" window.

Pages:

1. Daily sum, kWh/m2

2. Daily shading, %

3. Daily system output, kWh

To switch pages, use the keyboard keys "1", "2", "3", or the right mouse click, when the window is active.

The argument of functions of all pages is the same: DOY -- the day of the year from 1 to 365.

To see the numerical values of the calculated function curves, use the "Solar Table" window.

There are no specific control elements or input data for the "Solar Year" window. It reacts on the changes provided in the latest active scene displayed in the latest active 3D View window.

Switch window modes with keys "M", "V", "N"

• "M" -- Switch between "month spline" and "constant moth" modes.
• "V" -- Switch between "100% clear sky" and "mean cloudiness" modes.
• "N" -- Switch between 12 and 36 control days of the year, by which the curves are drawn.

In the "constant month" mode (when "M" shows "const month"), all the monthly input parameters of the climate model stay the same within the corresponding months.

In the "month spline" mode (when "M" shows "month spline"), all the monthly input parameters of the climate model are parabolically splined. To see the parameter value of a particular day, transfer the climate model from the scene to the "Climate" window, open the corresponding input page of the "Climate" window (where the parameter is displayed graphically), and then open the "Solar Table" window.

The switch "V" between "100% clear sky" and "mean cloudiness" modes affects the curves of the daily characteristics (how they are changing during the year), but does not affect the yearly characteristics which are calculated always for the "mean cloudiness" mode.

The switch "N" determines the number (12 or 36) of the control days of the year, by which the curves are drawn. If N = 12 days, the control days are the 15th days of the months (so each month has only 1 control point). If N = 36 days, then each month has 3 control days (the 5th, 15th, and 25th days of the month). Although the shape of curves differs in these two cases, the yearly characteristics are calculated with rather good accuracy in both the cases.

Page 1: Daily sum

The page shows the direct, diffuse, and total radiation sums on the collector surface (remember that we assume Dif_S = Dif_H).

If there are no active collectors in the associated scene, then the irradiance is calculated for a horizontal surface.

The first line of the legend shows the system type and objects that constitute the collector system.

The second line of the legend shows the geographical latitude.

Curves:

• Dir_N -- the direct solar radiation sum on a normal surface, kWh/m2.
• Dir_S -- the direct solar radiation sum on the collector surface, kWh/m2.
• Dif_H -- the full diffuse solar radiation sum on a horizontal surface (including reflection between ground and sky), kWh/m2.
• Tot_S -- the total solar radiation sum on the collector surface, kWh/m2.

The line below the title "Yearly sum, kWh/m2" shows the yearly sum of the solar radiation components Dir_N, Dir_S, Dif_H, and Tot_S in kWh/m2.

For a scene without collectors, the corresponding values are calculated for the case of a horizontal surface, so the values of Dir_S and Tot_S are substituted by Dir_H and Tot_H.

On four screen shots above, you see one case of a scene without solar collectors, and three cases of the scene "s823 ..." with solar collectors for different variants of "V" and "N" switches. You see that for N = 12 and N = 36 days, the curves are slightly different but the yearly values are practically the same. Obviously, the results for N = 36 are more precise, but further increasing of N has no sense.

Page 2: Daily shading

The page shows the shading of the collector system. We distinguish self-shading (only by elements of the system) and full shading (a combination of self-shading and the shading by other objects).

If there are no active collectors in the associated scene, the page shows the warning.

The first line of the legend shows the system type and objects that constitute the collector system.

The second line of the legend shows the geographical latitude.

Curves: 

• Full -- the full shading by all objects (including the system).
• Self -- the self-shading only by elements of the system.

The line below the title "Yearly losses of Dir_S as % of the Tot_S sum" shows the yearly full shading and self-shading energy losses as the percentage of maximal possible value of the yearly sum of total solar radiation on collectors.

The final line "Annual energy yeld = ... " shows the value of the annual energy yield in kWh/kWp.

On four screen shots above, you see one case of a scene without solar collectors (where the warning is displayed), and three cases of the scene "s823 ..." with solar collectors for different variants of "V" and "N" switches. You see that for N = 12 and N = 36 days, the curves are slightly different but the yearly values are practically the same. Obviously, the results for N = 36 are more precise, but further increasing of N has no sense. Note also that there is no self-shading in the scene "s823 ...", so the corresponding curve overdraws the bottom coordinate line.

Page 3: Daily system output

The page shows the energy output of your collector system (the yearly profile of the daily output in kWh per day, and the yearly sum in kWh per year) for three cases: without shading, with full shading, and with self-shading.

If there are no active collectors in the associated scene, the page shows the warning.

The first line of the legend shows the system type and objects that constitute the collector system.

The second line of the legend shows the geographical latitude.

The fifth line of the legend shows the number of collectors, their dimensions, and their total area, m2.

The sixth line of the legend shows the efficiency of the collector system.

Note that you can set the efficiency calling the "Efficiency" dialog with the key "E" of your keyboard. You call this dialog, when the "Solar Year" window (but not the 3D View window) is active, and the dialog will change uniformly the efficiency of all the collectors of the associated scene, which name is written in the title bar of the "Solar Year" window.

Curves:

• "No shading" -- the daily energy output calculated without any shading, kWh.
• "Full" -- the daily energy output calculated with full shading by all objects, kWh.
• "Self" -- the daily energy output calculated with only self-shading by elements of the system, kWh.

The line below the title "Yearly sum in kWh and %" shows the yearly sum of the energy output of the system, calculated without any-, with full-, and with only self-shading respectively. The sum for the case without any shading is accepted as 100% for the calculation of the percentage values.

On four screen shots above, you see one case of a scene without solar collectors (where the warning is displayed), and three cases of the scene "s823 ..." with solar collectors for different variants of "V" and "N" switches. You see that for N = 12 and N = 36 days, the curves are slightly different but the yearly values are practically the same. Obviously, the results for N = 36 are more precise, but further increasing of N has no sense. Note also that there is no self-shading in the scene "s823 ...", so the corresponding curve for "Self" shading overdraws the curve for "No shading".