Solar energy systems come in various configurations. The three main types of solar power systems are:
·
Off-grid
- also known as a stand-alone power system (SAPS)
The common components
of the three types:
Solar
panels: Solar panels or solar modules are installed
together in what is known as a solar array. Modern solar panels are made up of
many solar cells or photo-voltaic (PV) cells which generate direct current (DC)
electricity from sunlight or energy from the sun.
Solar inverter: Solar panels generate DC electricity which needs to
be converted to alternating current (AC) electricity for use in our homes and
businesses. This is the role of the solar inverter.
Switchboard:
AC electricity is sent to the switchboard where it is directed to the various
circuits and appliances in your house that are using electricity at the time.
Any excess electricity is sent to either a battery storage system if you have an
off-grid or hybrid system or to the electricity grid if you have an on-grid
system.
Off
Grid Solar System
An off-grid system is
not connected to the electricity grid and therefore requires battery storage. It
allows storing solar power in batteries. An off-grid solar system must be
designed appropriately so that it will generate enough power throughout the year
and have enough battery capacity to meet the home’s requirements, even in the
depths of winter when there is less sunlight.
Equipment for Off-Grid Solar Systems
Typical off-grid solar
systems require the following extra components:
• Solar Charge Controller
• Battery Bank
• DC Disconnect (additional)
• Off-Grid Inverter
• Backup Generator (optional)
Solar
Charge Controller
Solar chargecontrollers are also known as charge regulators or just battery regulators.
Solar battery chargers limit the rate of current being delivered to the battery
bank and protect the batteries from overcharging.
Battery
Bank
Without a battery bank
(or a generator) it’ll be lights out by sunset. A battery bank is essentially a
group of batteries wired together. In an off-grid system there is no public
electricity grid. Once solar power is used by the appliances in your property,
any excess power will be sent to your battery bank. Once the battery bank is
full it will stop receiving power from the solar system. When your solar system
is not working (night time or cloudy days), your appliances will draw power
from the batteries.
DC
Disconnect Switch
AC and DC safety
disconnects are required for all solar systems. For off-grid solar systems, one
additional DC disconnect is installed between the battery bank and the off-grid
inverter. It is used to switch off the current flowing between these
components. This is important for maintenance, troubleshooting and protection
against electrical fires.
Off-Grid
Inverter
There`s no need for an
inverter if you`re only setting up solar panels for your boat, your RV, or
something else that runs on DC current. You will need an inverter to convert DC
to AC for all other electrical appliances. Electrical current flows from the
solar panels through the solar charge controller and the bank battery bank
before it is finally converted into AC by the off-grid-inverter.
Backup
Generator
Installing a backup
generator that runs on diesel is a better choice than investing in an oversized
battery bank that seldom gets to operate at its full potential. Generators can
run on propane, petroleum, gasoline and many other fuel types. . The size of
the gen-set (measured in kVA) should to be adequate to supply your house and
charge the batteries at the same time. Backup generators typically output AC,
which can be sent through the inverter for direct use, or it can be converted
into DC for battery storage.
On-Grid
Solar Systems
On-Grid Solar powerSystems can only generate power when the utility electricity grid is
available. They must connect to the grid
to function. They can send excess power
generated back to the grid when you are overproducing so you credit it on the
bill. On-grid or grid-tie solar systems are by far the most common and widely
used by homes and businesses.
Equipment
for Grid-Tied Solar Systems
Standard grid-tied
solar systems rely on the following components:
• Grid-Tie Inverter (GTI) or
Micro-Inverters
• Power Meter
Grid-Tie
Inverter (GTI)
Grid-tie inverters,
also known as grid-interactive or synchronous inverters, synchronize the phase
and frequency of the current to fit the utility grid (nominally 60Hz). The
output voltage is also adjusted slightly higher than the grid voltage in order
for excess electricity to flow outwards to the grid.
Micro-Inverters
Micro-inverters go on
the back of each solar panel, as opposed to one central inverter that typically
takes on the entire solar array.
Power
Meter
This device, often
called a net meter or a two-way meter, is capable of measuring power going in
both directions, from the grid to your house and vice versa.
Batteries are able to
be added to an on-grid solar system at a later stage if required..
In an on-grid system,
this is what happens after electricity reaches the switchboard:
Excess solar energy
runs through the meter, which
calculates how much power you are either exporting or importing (purchasing).
Electricity that is
sent to the grid from your solar system can then be used by other consumers on
the grid (your neighbours). When your solar system is not operating, or you are
using more electricity than your system is producing, you will start importing
or consuming electricity from the grid.
Hybrid
System
Due to the decreasing
cost of battery storage, systems that are already connected to the electricity
grid can start taking advantage of battery storage as well. This means being
able to store solar energy that is generated during the day and using it at
night. When the stored energy is depleted, the grid is there as a backup,
allowing consumers to have the best of both worlds. Hybrid systems are also
able to charge the batteries using cheap off-peak electricity.
The battery bank in
hybrid system once solar power is used by the appliances in your property, any
excess power will be sent to your battery bank. Once the battery bank is full,
it will stop receiving power from the solar system.
Depending on how your
hybrid system is set up and whether you’re utility allows it, once your
batteries are fully charged excess solar power not required by your appliances can
be exported to the grid via your meter. When your solar system is not in use,
and if you have drained the usable power in your batteries your appliances will
then start drawing power from the grid. Hybrid
solar systems combine the best from grid-tied and off-grid solar systems. These
systems can either be described as off-grid solar with utility backup power, or
grid-tied solar with extra battery storage. Hybrid solar systems with battery
storage are able to automatically isolate from the grid (known as islanding)
and continue to operate during a blackout.
Comments
Post a Comment