|
Practical Off-Grid
Energy Systems
Living off-grid is not a compromise, it’s a
change in lifestyle. Here are a few
points to consider when becoming your own power company.
Living off-grid can be practical and affordable if you
make the best decisions regarding how to design both
your system and your lifestyle. System
Voltage By definition, an off-grid
system uses batteries. The number of batteries depends
on the
amount of storage capacity that you need. The voltage of
the battery bank is largely
determined by the system requirements. In general,
inverters today accept 12, 24, or 48
volts nominal. Nominal means that although the voltage
may drop below or rise above
this number, this is the base or the normal voltage for
this system. The system voltage you
choose will be decided by how you use the inverter power
and
the size of your off-grid system. Smaller cabin-sized
systems often use 12 or 24 volts
due to the close proximity of the system components and
the ability to use a smaller
battery bank. You also have the ability to run 12 volt
DC loads. Larger systems use 24 or
48 volt inverters due to the better efficiency at the
higher voltages and the higher output
capacity that the inverters can achieve. If you have a
choice always opt for the higher
voltage systems due to the greater efficiency of these
systems. Pure Sine Wave Inverters vs.
Modified Sine Wave Inverters This can
be a complicated subject, but let’s get down to the
important facts. A pure sine
wave inverter will produce electricity equal to or
better than your utility company.
Modified sine wave inverters produce a wave-form that’s
not as smooth and some
appliances will not work correctly. The
way in which you use the power coming from your inverter
determines which one to
use. If you use mostly lights, a television and a laptop
computer, appliances such as these
really don’t care about modified sine wave power. On the
other hand, if you use a
desktop computer, dishwasher, clothes washer, plug-in
power tools, hi-fi radio or
cordless phones, some of these appliances and others
like these don’t like modified sine
wave and will make noise or not work at all. My feeling
is go with the pure sine wave
and you won’t have to worry about what you plug in.
Lifestyle Changes That Help You Reduce the Size &
Cost of Your Off-Grid System The
first law of any off-grid system is if it’s electric and
produces heat it’s inefficient.
OK, so what do we mean by this? Think of a standard
incandescent light bulb. Most of
the energy it uses is released not as light, but as
heat. Electric heaters, electric stoves and
electric water heaters all use a greater energy factor
than their gas equivalents. So use
natural gas (NG) or liquid propane (LP) to heat as much
as possible. Keeping cool off-grid is
another issue that can be resolved with changes. First
insulate
your home to the maximum your floors, walls and attic
can accommodate. Use whole
house fans and room fans as your first choice for
cooling. As a last step you can use an
air-conditioning window unit to cool just the rooms you
will be in or a whole house AC
unit can be used but go for the most efficient unit
available and cool just the areas of the
home where cooling is needed. Geothermal heat
pumps are the most efficient all electric heating and
cooling systems available. Another option is an
evaporative cooler which can be used in drier
climates. Lighting is an easy place to
reduce power, but most people think that they just have
the
spiral compact fluorescent lights as a choice. Today we
have fluorescent bulbs to mimic any bulb that you may
have in your home. Also, the color choices of the light
can replicate any of
the older incandescent bulbs. The
second law of an off-grid lifestyle is that it’s not the
amount of power you use, it’s the
amount of time you plan on using it.
A perfect example of this is a 1500 watt microwave or a
clothes iron. Both of these use
large amounts electricity to heat but because they are
used for such short time periods, the
overall energy used is well within even a small off-grid
system’s capabilities. The standard refrigerator uses
just 50 watts of power per hour, but added up over 24
hours per
day, this number becomes a very large energy load.
Off-Grid Refrigerators: Propane vs. Electric
It used to be that the one compromise in an off-grid
system was using a propane
refrigerator instead of an electric one. Not so anymore.
Electric refrigerators have
increased the efficiency to the point where the extra
money spent on a propane
refrigerator is better spent on a few extra solar
panels. This saves the cost of paying for
propane gas for the life of the appliance and you
actually come out ahead since the solar
panels are a one-time cost and the propane gas is on
going. Monitor Your Energy Use
Another important idea is to include instrumentation in
your off-grid system design so that you can measure and
record your system's performance and your energy
consumption. You might decide to delay doing
laundry on a cloudy day or take advantage of a bright
sunny day to do energy intensive tasks. An
off-grid system will make you more aware of the weather.
Learn from the Experience of Others
There are several case studies here in our website about
off-grid system installations.
Please Contact Apex Solar
Whether it's solar modules, water pumps
or inverters, we'll help you through the confusion about
which components are right for you. We can package any
solar system components so you can be assured that
everything will work together and we'll get you up and
running.
We provide system
design and installation.
We can also help you do it
yourself.
Contact us for pricing on specific
solar components; we carry all the major brands.
Solar power is still new for a lot of people so let us
change that for you and answer those questions and myths
you may have heard about getting your power from the
sun.
Want more information or pricing?
Request a
quote.
|
