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1. Solar Energy
Electrical and Mechanical Components of a Solar Panel System Lecture 4
Dr. Basman M. Hasan Alhafidh
Department of Computer Engineering
College of Engineering
Mosul University

2. Agenda
Solar energy basics
 Overview of the major sources of energy
 How solar Panel convert light into electricity
 Calculating Energy Efficiency
 Electrical and Mechanical components of a solar panel system
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3. Electrical and Mechanical components of a solar panel system
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 By the end, you should be able to
- Identify the major photovoltaic components including the photovoltaic panel, the inverter,
the battery, and the charge controller.
- Identify the balance of system components, mounting, wiring, and electrical protections,
and identify the electrical code requirements.

4. Electrical and Mechanical components of a solar panel system
 We're going to start with the photovoltaic module on the rooftop, then go to the
inverter, and then eventually to the connections in the home.
 As a reminder, it's comprised of several photovoltaic cells which are wired together
in series to produce the photovoltaic module. Multiple modules are wired together,
typically in series, to produce a photovoltaic array.
 What do we do with that full array?
- The electricity produced from the photovoltaic array is DC or direct current.
Whereas most homes, buildings and resonances run on alternating current or AC.
- An inverter is needed to convert the electricity produced by the photovoltaic array
so it can be used in the buildings. (The inverter is really the heart of the
connection between the photovoltaic module and the building).
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5. Electrical and Mechanical components of a solar panel system
 What do we do with that full array?
- The electricity produced from the photovoltaic
array is DC or direct current. Whereas most
homes, buildings and resonances run on
alternating current or AC.
- An inverter is needed to convert the electricity
produced by the photovoltaic array so it can be
used in the buildings. (The inverter is really the
heart of the connection between the
photovoltaic module and the building).
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6. Electrical and Mechanical components of a solar panel system
1- Inverter There're several types of inverters that are available.
1 - Larger inverters can accept and convert photovoltaic
electricity from about 10 to 80 modules.
2 - You can also have multiple smaller inverters in one large
installation serving only five to 10 modules per inverter.
3 - There's also a newer option on the market called a
microinverters:
* In all cases, you need some sort of monitoring system to both
quantify the amount of electricity being produced and monitor
the electrical grid connection.
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7. Electrical and Mechanical components of a solar panel system
1- Inverter
 Microinverters:
- are designed to have a single panel connection and
out of that microinverter
comes alternating current or AC.
- That means, a single photovoltaic module's DC output
is converted to alternating current and wired directly
into the home.
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8. Electrical and Mechanical components of a solar panel system
1- Inverter
 Microinverters:
- Microinverters also comply with something called
rapid shutdown because each panel is connected
to one micro inverter, which can then respond to
changes in the grid such as calls for shut down
when needed.
- compatible with small and uniquely designed
systems.
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9. Electrical and Mechanical components of a solar panel system
2- Batteries
- Batteries may be required as a backup in the case of electrical failure, in the case of
being off-grid. (Batteries are not a requirement if one is wired or connected to the
grid)
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10. Electrical and Mechanical components of a solar panel system
2- Batteries
- Battery banks are made of either sealed or flood type cells of lead
acid batteries, the lithium ion batteries are just starting to come
onto the market.
- One code requirement for battery banks is that they have to be
within 20 feet or about three meters of the inverter.
- Batteries are generally installed inside a basement space or storage
utility area where there's enough support for the weight of the
battery as well as a close connection to the inverter.
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11. Electrical and Mechanical components of a solar panel system
3 - Charge controller:
- Ensures the batteries are not undercharged or overcharged to prevent the risk of failure and or fire.
- Is an important piece and its brings of the operation between when the battery gets charged or
discharged.
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12. Electrical and Mechanical components of a solar panel system
4 - Electrical panel and the wiring infrastructure
-Photovoltaics integrate with existing distribution systems =>a photovoltaic electrical input is
wired directly into the electrical main panel along with a great connection or in this case of off-
grid wired alongside a generator.
- The breaker controlling the photovoltaic system is generally within the main electrical panel,
=> No need to rewire the electrical system.
- There are several electrical code requirements detailing how photovoltaic systems are
electrically integrated safely into buildings.
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13. Electrical and Mechanical components of a solar panel system
4 - Electrical panel and the wiring infrastructure
Finally, the last piece for electrical consideration is the national electric code (Article 690 of
the National Electric Code):
- The U.S. National Electric Code, or NEC, dictates the type and size of wiring that is required
and allow for allowable distances and conduit.
- Some municipalities use a separate electrical code from the NEC, and countries outside the
United States will also have their own code requirements as well.
- According to the NEC, one requirement is that there are disconnects placed between the DC
side of the photovoltaic system and the inverter as well as a disconnect on the AC side of the
system. That shut off is typically part of the inverter itself.
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14. Electrical and Mechanical components of a solar panel system
4 - Electrical panel and the wiring infrastructure
- There are strict grounding requirements stating that electrical systems are grounded as well as
the metal components of the photovoltaic system, and the mounting system.
- All of these rules are defined in article 690 of the National Electric Code, which specifically
addresses solar installation considerations.
- Once all the electrical components are considered, a system diagram can be designed by a solar
designer or an electrician.
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15. Electrical and Mechanical components of a solar panel system
4 - Electrical panel and the wiring infrastructure
- This is a three-line diagram that shows where photovoltaic modules are wired to a disconnect,
the disconnect to an inverter, and the inverter wired into another AC disconnect, and then wired
to the main breaker which then connects to the rest of the building components as well as the
utility.
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16. Electrical and Mechanical components of a solar panel system
Any question?
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17. Electrical and Mechanical components of a solar panel system
Now that we've looked at the electrical considerations, let's consider the
Mechanical components
- connect the photovoltaic array to the building.
- are metal racks that connect the photovoltaic panels using specialized clips, and
those metal racks are then attached to mounting points.
- Those mounting points are then connected to a rooftop using lag bolts or clamps.
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18. Electrical and Mechanical components of a solar panel system
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19. Electrical and Mechanical components of a solar panel system
Mechanical components:
- So, first, we connect the photovoltaic panel to the racks and then the racks to the roof. All of
the weight considerations need to be addressed by an engineer and/or architect before
proceeding with installation.
- Waterproofing systems protect the roof and building from water penetration using rubber
gaskets and sealed boots. The mount points are then lag bolted into rafters, thus, connecting the
system from rafter to module.
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20. Electrical and Mechanical components of a solar panel system
Mechanical components:
 In case of
- a standing seam roof => a metal seem clamp attached to the rack and then to the roof
prevents roof penetration.
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21. Electrical and Mechanical components of a solar panel system
Mechanical components:
 In case of
- For flat roofs => one of the ways to be able to attach the panels is to use a ballasting. Ballasting
provides a weighted system so roof penetration is not needed, and there's enough weight
provided in the ballast system that prevents a wind shear and the photovoltaic panels from lifting
off of the roof.
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22. Electrical and Mechanical components of a solar panel system
Mechanical components:
 In case of
- Ground mounted systems are somewhat simpler to
design and install because they're located on the ground
and the weight loading is typically not an issue. The
mounting systems remain the same but the racks are
connected either to a single post that's connected to a
single concrete footer or a rack is constructed that's
attached to concrete pads.
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23. Electrical and Mechanical components of a solar panel system
Mechanical components:
 In case of
- Pole-mounted systems have the added
advantage of being able to be tilted and
turned including compatibility with tracking
systems.
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24. Electrical and Mechanical components of a solar panel system
 In summary, you should be able to:
- Identify the major photovoltaic system components including the module, the inverter, the
battery, and the charge controller.
- Identify the balance of system components like the mounting system, the wiring, and the
electrical protections.
- Reference Article 690 in the NEC that addresses solar photovoltaic code in United States.
 Interesting Links:
- https://www.youtube.com/watch?v=IyOPxAzbzTY&feature=youtu.be
- https://www.youtube.com/watch?v=o9CgbUSUnjg&feature=youtu.be
- https://www.youtube.com/watch?v=Q93RRjdoPyo&feature=youtu.be
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25. Electrical and Mechanical components of a solar panel system
Any question?
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