san diego, CA
jamal
Basics of Solar Power Generators
Real-World Applications:
With PV solar power becoming popular in many different applications, more engineers are needed who understand how to maximize a PV panel’s power output so they can design PV arrays that create as much clean energy as possible from this technology. This energy can replace energy from non-renewable sources that pollute the environment. The optimal design of a PV array depends on the location and position of the panels, so engineers must understand the basics of solar angles to design the most-efficient systems.
Introduction:
From our perspective on Earth, the sun is always changing its position in the sky. It is pretty obvious that every day the sun moves from the east to the west between sunrise and sunset, but did you know that it also moves from north to south throughout the course of the year? If you were to measure the position of the sun every day at solar noon it would be at a different angle every day. The exact location of the sun in the sky depends on where you live, the day of the year, and, of course, the time of day. This effects the design decisions engineers make when they are installing photovoltaic (PV) panels. It is important for engineers to know where the sun will be throughout the year so they can install PV panels at the ideal angle to absorb the maximum amount of sunlight during the course of a year. To improve PV panel efficiency, engineers also design creative ways so more sunlight hits the surface of the panel.
The angle between a photovoltaic (PV) panel and the sun affects the efficiency of the panel. That is why many solar angles are used in PV power calculations, and solar tracking systems improve the efficiency of PV panels by following the sun through the sky.
(Figures 1)
(Figures 2)
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There are 3 basic solar arrays configurations utilized in the industry:
A) Solar Arrays mounted at a fixed tilt configuration.
B) Solar Arrays mounted on a single-axis trackers.
C) Solar Arrays mounted on a dual-axis Tracker.
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A) Solar Arrays mounted at a fixed tilt configuration
Fixed tilt Configuration such that on roof tops of houses, buildings or on open landscape, the solar Collectors (Array) is placed on such a position to produce a good average throughout the year (Figures 1 & 2). Examples of finished installations are shown in Figures 3, 4 & 5.
(Figure 3)
(Figure 4)
(Figure 5)
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B) Solar Arrays mounted on a single-axis trackers
Usually, the axis of rotation for a single-axis tracker is optimized at a fixed horizontal 0° or tilted somewhere in between 20° to 30°. Tilted single-axis trackers have some of the advantages of horizontal designs, such as the ability to be densely packed per land unit. These trackers allows for a 6–7% increase in performance over horizontal-axis trackers.
(Source of images http://solarprofessional.com/ )
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C) Solar Arrays mounted on a dual-axis Tracker
Tracking both the sun’s east-to-west azimuth and elevation off of the horizon maintains a more constant and accurate angle of incidence between the collector surface plane and the sun. This results in a higher capacity factor and specific yield compared to fixed-tilt or single-axis tracker mounting, which may be desirable in certain flat-plate PV applications. In other applications,dual-axis tracking is a design requirement. This is the case when the PV technology in question relies exclusively on direct normal irradiance as the fuel source. While low concentration PV technologies, like those being developed by Solaria, are designed to work with single-axis tracking, concentrated PV designs, like the technology pioneered by Amonix, require a tracking accuracy of within 1° to maintain consistent power output, which only dual axis tracking can provide.
Dual-axis PV tracking started simply enough, with passive tracker designs like those from Zomeworks. Modern designs, like the products from Mecasolar (see cover photo), can support more than 13 kW of flat-plate PV per tracker. The mammoth proprietary dual-axis tracker from Amonix supports a concentrated PV array rated at 53 kWac. Arrays are constructed with galvanized steel and usually mounted on a single central pole supported by a concrete foundation. Dual-axis arrays tend to be taller with increased wind and structural loading. These trackers also need to be spread out to alleviate shading, which decreases the relative power density per acre compared to horizontal single-axis trackers or fixed-tilt mounting.
In the above Figure, The power curve for any PV array mounted on a tracker is broader than that for a fixed array (Houses, Commercial buildings, field installed), and thus is deemed to add a better shoulder to the curve. This figure shows the relative power curves for Flat-Plate PV mounted. Shown below, an example of a higher tracking solar farm utilizing dual-axis PV setup.
Tracking the sun maximizes solar power generation, providing between 30-50% more power compared to untracked panels.
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san diego, CA
jamal