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Step-by-Step Guide to Solar Electric Systems
The design and installation of a solar electric
system requires planning and assessment of the customer’s needs
to ensure the correct type of system is installed on their home. A
solar electric system encompasses many parts, from the solar panels
attached to the roof, wire runs to the electrical panel, inverters,
batteries, and related electrical equipment. All of these components
must be installed to electrical code standards, and inspected by
an electrical inspector. In order to help consumers understand the
process, we have put together a step-by step guide that shows you what
to consider when looking at a solar electrical system.
1.
Decide if you want or need an Autonomous,
Hybrid or Grid-tied System.
Almost any house on any site in southern Canada can be retrofitted
to benefit from solar power. But if you're starting from scratch and
do not own a piece of land or haven't yet designed your house, the
decisions you make early in the process can pay off later.
An ideal site for a solar house has a southern
exposure which is not shaded by hills, trees or other buildings
between the hours of 9am and 3pm in either winter or summer. Ten
per cent shading of a Solar Module can reduce power output by 100
per cent. The best house design will take advantage of passive
solar heating. Orientation, layout, placement of windows, and construction
materials are all factors to consider. The most efficient solar
houses are custom designed but, "off-the-shelf" house
designs can be oriented and adapted to take advantage of the
sun.
In most cases, the ideal location for a solar array is on the roof
of the house. This alleviates most shading concerns, and its large,
flat surface makes mounting relatively easy. It also can reduce snow
buildup in front of the modules. So the orientation and angle of the
roof is an important consideration when determining the type of solar
system you install. Solar modules should face true south and be angled
perpendicular to the sun.
If the siting of your house or the orientation and angle of its roof
are less than ideal you may still be able to take advantage of solar
electricity by mounting a solar array on a pole separated from the
house. Pole-mounted arrays can even automatically track the sun throughout
the day and throughout the year so they are always perpendicular to
the sun's rays.
It is always cheaper to conserve electricity than to generate
it. Build or retrofit your house to the highest standards of
energy efficiency. Before you spend thousands on solar power,
invest a few dollars in insulation and weather-stripping. An
average Canadian home consumes 25 kWhrs of electricity per day.
Off-grid homes typically consume much less— 5 to 9 kWhrs.
Once we've determined that solar electricity is feasible
on your site, the next step is to estimate your energy
needs. This is a critical step for off-grid houses or
cottages, as you'll will be relying on the solar system
to provide all or most of the electricity. This step
is less important for grid-tied systems as solar is being
used to replace or supplement an existing source — the
sizing in this case is often based on how large a system
you can afford.
To estimate your power needs, first list all the electrical appliances
and tools you want to power, obtain their rated wattage, and estimate
the number of hours per day they will be used. If available, use the
rating indicated on the label of the appliance or use the typical values
provided on the Natural Resources Canada website. They also provide
a worksheet to help with your calculations.
http://www.canren.gc.ca/prod_serv/index.asp?CaId=101&PgId=551 http://www.canren.gc.ca/prod_serv/index.asp?CaId=101&PgId=550#step1
Basically this is dividing the total daily load (Wh/d) by the number
of hours of sunshine. But the effeciency of the hardware components
such as battery chargers etc. will affect the calculations. It's at
this phase that we recommend you make an appointment with an experienced
technician at Ottawa Solar Power.
If your planning an autonomous or hybrid solar electric house
you need a battery bank to store the power you generate. How
many days do you need to store power when the sun is not shining?
How efficient are the batteries? What's the battery's normal
operating temperature? OSP can help you answer these questions
and calculate the size and type of batteries you'll need. Improper
sizing of your battery bank will decrease your system performance.
Consult our online catalogue.
Read over the manufacturers' specifications fact sheets.
Make up your shopping list. Make a preliminary budget
based on your parts list and a ballpark estimate of
installation costs. For rough calculation purposes
labour may equal or exceeed the materials cost. At
this point you should pause and answer the question; Can
I afford the solar system I think I need? If
the answer is "NO", go back and revise your plan — see
if you can save dollars by conserving energy.
Consider designing an expandable system which allows
you to add PV panels (and batteries) as you can afford
them.
Draw lot plan and house elevations showing siting of pole-mounted PV
panels and position of roof panels. Draw detailed electrical or wiring
diagrams including vented battery storage housing and connections to
existing electrical service panel. These design drawings will need
to presented to and approved by your local municipal building authority
before you go any further with your project.
Add up the cost of the hardware
components, the labour estimate based on the selected bid, the
taxes, and a contingency of 10-20%.
Arrange financing including Incentives. Order hardware. Confirm
electrician availabity. Schedule installation including inspections.
We've
been designing and installing systems form more than 10 years.
From experience we know what works and how to get the job done.
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