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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 in kWh/kWp -- the annual productivity of each one installed kW of the peak power.

 

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 of solar radiation", "Comments", "Note the curves' overdrawing ", "Fresnel reflection and the Relative Fresnel Transmittance (RFT)", and "PV-strings, bypass diodes, and MPP-tracking".

 

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

 

We assume that reading this text you see the "Solar Year" window on your screen, so we explain and comment just what you see now.

 

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

 

Pages:

 

1. Daily radiation, kWh/m2

2. Daily shading, dimensionless units and %

3. Daily productivity, 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.

 

Use keyboard

 

The keyboard keys of the "Solar Year" window have the same meanings as it is described in the section "Use keyboard" of the topic "Solar Day". However, the corresponding switchers work independently. For example, you can switch the "Solar Day" window to the "Self" shading keeping the "Full" shading in the "Solar Year" window.

 

There are some minor differences between windows:

 

Curves cos(i) and RFT are displayed on second page.

 

 

So the "V"-switch of the "Solar Year" window has only two modes "clear sky" (100% clear sky) and "mean sky" (mean cloudiness). The switch "V" affects the curves of the daily characteristics (how they are changing during the year), but does not affect the yearly characteristics that are calculated always for the "mean cloudiness" (mean sky) 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. So you can use the fast variant of N = 12, switching sometimes to N = 36 only to control the accuracy.

 

Page 1: Daily radiation

 

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 is common for all pages. It shows general data for the entire PV-system or a chosen PV-string. Now you see the system data of the scene "s623": four PV-strings, fifty one PV-modules, installed power = 8.415 kW (peak).

 

The second line of the legend shows the list of names of the displayed curves. Colors of names correspond to the colors of curves.

 

Curves:

 

 

Below the curves you see hints for the keyboard keys. You can hide them with the key "K".

 

Then you see a small table titled "Yearly sum, kWh/m2". It shows yearly sums for the displayed curves. The order and colors are same as in the list of curves.

 

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

 

Page 2: Daily shading

 

The page shows the daily shading of the collector system. The shading is expressed in the dimensionless units in range from 0 to 1. It means the part of the energy that is lost. We distinguish self-shading (only by elements of the system) and full shading (a result of self-shading and the shading by other objects) -- the case is controlled by the "S" key.

 

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

 

 

The first line of the legend says us whose curves are displayed -- of the entire PV-system or a chosen PV-string.

 

Curves:

 

 

Average values are shown without brackets.

 

The table titled "Yearly ..." shows yearly average values of cos(i) and RFT, and then shading losses (in percents) of yearly productivity for the cases of "blocked" PV-strings, "blocked" PV-modules, and MPP-tracking. Colors help to distinguish the sense of values.

 

The table titled "Annual energy yeld ..." shows  the very important and useful characteristic of your system, the annual energy yield in kWh/kWp -- the annual productivity of each one installed kW of the peak power. Values are shown for four cases: without shading (Free), with "blocked" PV-strings (BS), with "blocked" PV-modules (BM), and with the MPP-tracking (MP).

 

Page 3: Daily productivity

 

The page shows the daily productivity of your collector system (the daily generated energy in kWh) for four cases: without shading (Free), with "blocked" PV-strings (BStr), with "blocked" PV-modules (BMod), and with the MPP-tracking.

 

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

 

 

The first line of the legend says whose power curves are displayed -- of the entire PV-system or a chosen PV-string.

 

Curves:

 

 

The table titled "Yearly productivity ..." shows the yearly productivity in kWh and percents (in compare with the "Free" case). Colors help to identify curves and their daily values.