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Solar Synergy at Vineyard
Symposium! EverythingWestport.com Tuesday,
January 6, 2009 Is 2009 the
year you’ll resolve to go solar?
A free 1
½ hour presentation on Solar Thermal and Solar Photovoltaics
(PV) for homeowners and business owners took place in the Long Acre House at
Westport Rivers Winery and Vineyard Tuesday evening to a crowd of about 40
interested attendees. Rob
Lamoureux is a representative of Alternative Energy and holds a bachelor of
science in electrical engineering from Worcester Polytechnic
Institution. As the energy conservation
project manager for Buzzards Bay Brewing and Westport Rivers Vineyard and
Winery, he has reduced annual electricity use at the two facilities by enough
power to run two typical homes. “Alternative
Energy promotes solar photovoltaics (electricity),
solar thermal (hot water), wind, hydro, and geothermal energy production,”
Lamoureux said. “Today we will explore the first two.” “Solar thermal
can heat our hot water and reduce our dependence on foreign oil. Solar photovoltaics
produce electricity with no harmful utility plant emissions. The technology is mature and the financial
incentives are numerous. You can
resolve to make 2009 the year you go solar,” said Lamoureux. There are
many “green” reasons to incorporate Solar Thermal and Solar Photovoltaics into you home’s energy plan, but the impact
on the pocketbook is probably the most compelling. Conserving
consumption is the most practical method of protecting our environment and
preserving fossil fuels. “The
least expensive electricity or fuel is one which is never used,” Lamoureux
said. “It is cheaper to invest in appliances that conserve energy, than to
invest in devices to replace utility energy. By modifying or improving the
efficiencies of electrical appliances, you can save the same amount of
dollars as that which can be obtained by installing solar panels.” This
honest assessment can give pause to even the most cost-conscious among us. “This
presentation will provide the homeowner or business owner valuable
information on the mature solar systems available and the latest government
grants and tax breaks that can make solar energy a reality for 2009,” said Lamoureux,
a Westport resident. How Solar Electric works.
A solar electric system, also known as a photovoltaic system or
(PV), provides power by converting the sun’s rays to DC electrical current
and then inverting it into AC current used in your home. The PV modules generate DC
electricity and send it to the inverter; the inverter transforms DC power
into AC electricity and regulates the charge of batteries or feedback to the
grid. The modules are silent and have no moving
parts. The solar electricity produced is fed to your meter and offsets the
electricity demand in your home. A solar system changes the dynamics of your relationship with
the utility. As an energy producer you will reap the benefits of net
metering. If the system produces more energy than you are using at that
time your meter will spin backwards crediting your account. When your energy
needs exceed your system’s output you pull power from the utility as you
always have and your meter spins forwards as normal. Your electric meter
measures the net difference and your utility company bills you for this
amount. A
valuable feature of grid-tie or grid-connected photovoltaic systems is the
ability to connect with the existing power grid and sell excessive
electricity back to the utility with a plan known as Net Metering. At
times when you are not using all of the electricity produced by your system,
your meter will spin backwards selling the electricity back to the grid at
retail rate. These systems do not include a battery. Power is obtained from
the utility grid when the system is not producing electricity, similar to a
wind turbine. Batteries may, however, be attached and used at night or during
blackouts (grid failure).
Diagram courtesy of Sun First! Solar
Energy Systems How Solar Hot Water works. “For
solar water heating in your home, there are basically two types of solar
collectors: conventional flat-plate collectors and evacuated tube collectors.
Evacuated tubes have a number of advantages: they work on overcast days, in
colder weather, and the tubes can be installed and replaced individually
without special tools. The evacuated tubes act like giant thermoses, allowing
93% of the sun's radiation in, but only 3 to 5% out,” Lamoureux said.
This type
of solar collector can achieve high temperatureso
in the range 170°F (77°C) to 350°F (177°C) and can, under the right set of
circumstances, work very efficiently. Evacuated-tube collectors are, however,
quite expensive, with unit area costs typically about twice that of
flat-plate collectors. They are well-suited to commercial and industrial
heating applications and also for cooling applications (by regenerating
refrigeration cycles). They can also be an effective alternative to
flat-plate collectors for domestic space heating, especially in regions where
it is often cloudy. For domestic hot water heating, flat-plate collectors
tend to offer a cheaper and more reliable option. Evacuated-tube
collectors fall into two main groups: Separated
inlet and outlet pipes (glass-metal). This is the traditional type of evacuated-tube collector.
The absorber may be flat or curved. As in the case of the concentric tube
design, the efficiency can be very high, especially at relatively low working
temperatures. The weakness again is the potential loss of vacuum after a few
years of operation. Two
glass tubes fused together at one end (glass-glass). The inner tube is coated with an
integrated cylindrical metal absorber. Glass-glass tubes are not generally as
efficient as glass-metal tubes but are cheaper and tend to be more reliable.
For very high temperature applications, glass-glass tubes can actually be
more efficient than their glass-metal counterparts
Left: Rob introduces his audience to the direct-flow evacuated-tube collector solar hot water system. Concentric
fluid inlet and outlet (glass-metal). These use a single glass tube. Inside this is a copper
heat pipe or water flow pipe with attached fin. This type of construction
means that each single pipe can be easily rotated to allow the absorber fin
to be at the desired tilt angle even if the collector is mounted
horizontally. The glass-metal design is efficient but can suffer reliability
problems. The different heat expansion rates of the glass and metal tubes can
cause the seal between them to weaken and fail, resulting in a loss of
vacuum. Without a vacuum, the efficiency of an evacuated-tube collector is no
better, and may be worse than, that of a flat-plate collector.
Pictures courtesy of the U.S. Department of
Energy. It’s not the pitch but the position. Lamoureux
spoke on roof requirements for the installation of solar. “A south facing
roof, either southeast or southwest is best,” he said. “The roof can be flat
or pitched, and should be free from shade. Solar can be ground mounted, but
this installation choice increases risk of accidental damage and vandalism.” Interestingly,
the pitch of a roof has little to do with the overall efficiency of solar
collection. “There is only a 10% gradual decrease in Kilowatt Hour output
from a roof with a 42.4 tilt degree to one with a 0 tilt degree,” Lamoureux
said. “It is also a good idea to install solar on a new or fairly new roof as
a solar system can easily outlive the roof. Flat solar panels can also add to
the longevity of an asphalt or wood roof (no slate please!) as the panels
protect them from the harsh elements of sun, wind and precipitation,” noted Lamoureux. “The size
of a system is determined by number of family members, usage pattern as
determined by your electric bill, hot water needs or winter heating needs,,
roof resources (see above), and of course your budget,” said Lamoureux. There may
be some concern about solar installations in historic districts, so be sure
to check with your local town Historic Commission before considering a system
for these districts,” Lamoureux said. It’s all about the rebates. Capital cost remains a barrier to widespread
adoption of solar systems in New England, according to NSTAR. Federal, state
and local utilities offer cash rebates for solar and energy efficient
technologies that make these systems more affordable to many homeowners, and
increase the incentives for the green-minded generation. “There is USDA money
for small farms and rural small businesses,” reported Lamoureux. “For
example, the Brewery qualified as a small business.” NSTAR has advertised that they will help you
harvest energy right from your roof if you select NSTAR Solar. They will set
up a home assessment and facilitate you in obtaining a rebate on the panel
installation through Massachusetts’s Commonwealth Solar program. www.nstar.com “There is
also assistance from state and federal tax credits,” Lamoureux said. “But be
aware that the state will not over invest, or invest in marginal
installations. They also limit their investment by kilowatt hour. Be sure to
investigate these limitations, and have a professional assist you in solar
selection. Lamoureux
presented an example of a typical solar thermal hot water system that would
generate 5.4 kW. Estimated cost is $8,565; and with a Keyspan
energy rebate of 15% ($1,284.75), a federal tax credit of $2,000, and a state
tax credit of $1,000, your total out of pocket expense would be $4280.25. How to get Started. “Ask a
supplier for a free home or business energy evaluation,” Lamoureux said. “Gather
up your electric bills for solar photovoltaic comparison, or energy bills for
solar hot water and heat analysis.” A reputable vendor will usually provide a
roof evaluation and a free production estimate and cost
proposal, Lamoureux added. Be sure
to ask about system replacement values, MBTF (mean time between failures) of
major components, and projected life expectancy of the system you are
considering. “Inverters, a component that can range in price from 2 -3
thousand dollars has a life expectancy of about 15 years,” Lamoureux said. “Overall,
a solar system should last 30 to 35 years and beyond with proper care and
maintenance,” he added. Another
element to check is whether your household insurance policy will cover damage
to your system, for example from an act of nature or vandalism. “Return
on investment (ROI) on a thermal hot water system can range from 3.15 to 7.16
years,” Lamoureux said. “Of course, that depends on what the cost of electric,
gas, oil, or propane is at the time.” With the wild swings we have seen lately
in gas prices at the pump, that number could be hard to project. “Do your
homework, and work with a reputable vendor,” Lamoureux said. For
additional information, call Rob at (781) 831-0379; or email him at: r.r.lamoureux@gmail.com - - - - - - End - - - - - - Community Events of Westport ©
2009 All rights reserved. |
