Harry Indig, PMP
Prepared for Nicole and Ret Taylor
156 Northeast 59th Street Seattle, WA 98105
The customers home at 156 Ne 59th St in Seattle,
WA has been owned by the current owners since
2005. They were fortunate this house has had no
additions and minimally invasive remodels since its
construction in 1909. Being its century year, the
owners have sought to do an extensive remodel by
lifting its 990 square feet main floor off its original
foundation, raising it by 3 feet, upon setting it back
down. This will double it’s conditioned square
footage by allowing the current basement to
become livable space.
Conservation measures such as passive day
lighting, increased insulation, improved circulation,
the addition of a heating system, and replacement
of the existing hot water system, and with the
possibility of adding solar electric generation will
all be incorporated into the remodel.
As a class Project Photovoltaic at Shoreline Community College has agreed to review the analyze
of cost, efficiency, feasibility, and return of investment using a roof mounted solar photovoltaic
The customer’s objective is to look into the feasibility and long-term return on
investment of a roof-mounted solar photovoltaic array. The owners believe the retail expense
of power in the Seattle area is relatively inexpensive. However; both owners believe making
decisions for the good of our community for the future, needs to be evaluated. The prospect
of current energy prices increasing in the near future is also of concern. And with the
incentives being offered by our government on federal and state levels coupled with the
incentives being paid by the local power distribution companies for selling electricity to
them; generating their own solar power becomes an attractive venture.
Over all else, the owners would
like to know if they are getting a
good return on investment by
putting their capital towards solar
power versus investing in a
security such as a secured bond or
Is Solar Right for You?
Yes, if you...
Own the building where you
want to install solar;
Have a roof in good shape and
Are interested in making a
long-term investment to protect
yourself from rising energy
costs and want to reduce your
Benefits and Costs
Is a long-term investment that
increases in value as energy costs rise.
Reduces your "carbon footprint" -- the
amount of greenhouse gases produced
by your home or business, which in
turn lessens your overall impact on the
Costs (for a solar electric system) between $8,000 and $10,000 per kilowatt (average
residential systems are 1 to 3 kilowatts).
Is eligible for incentives offered by Washington State of $0.15 to $0.54 cents per kilowatt-
hour (kWh) generated (by a solar electric system) with a cap of $5,000 per year (HB6170).
Is eligible for a federal tax credit equal to 30% of the system cost.
To maximize the PV system
investment (by purchasing as little
electricity as possible) additional
conservation steps will be taken to
reduce electrical consumption.
Electrical conservation will be
achieved primarily through the
migration of thermal loads from
electrical to natural gas devices.
•27% less electricity will be consumed due to the combination of these upgrades at an initial cost of about $5,500.
•A federal tax credit of $1,640 for the 2009 – 2010 tax years will be earned due to the combination of these upgrades.
• Increase insulation in attic space
• Replace electric space heaters
• Replace electric hot water heater with
high volume tankless natural gas unit
ASSESSMENT HARDWARE SELECTION
What we do know about the Seattle
solar window can be explained and
analyzed with some basic tools of
our solar industry.
One is the SunEye™ by Solmetric.
The second device used was Solar
Pathfinder™ by Solar Pathfinder.
mathematical precision for accurate
shading assessment, solar system
sizing, collector placement, and
Sun Chart: Determination of Solar Exposure
Orientation. Azimuth Angles. Altitude Angles. Completing the Sun Chart
Reading the Sun Chart - Client Assistance Memo (CAM) 417 and 420
House’s East View
House’s West View
ANOTHER TRIP TO ROOF FOR SOLAR ANALYSIS
North Roof South Roof
East Roof 96.1% West Roof 89.8%
GROUP ANALYSIS OF PROPOSED PV SYSTEM
WorkBook on Solar Technical Details lll.xls
Solar Inverter Options
Financial Calculator = $
In the City of Seattle, the department of Planning Development
(DPD), there are two client assistance memo (CAM’s) for solar
systems covering both Photovoltaic and Thermal designs.
• CAM 417 Sun Chart: determination of Solar Exposure
• CAM 420 Solar Electric Systems
• Permit Requirements
• Electrical Permit
• Building Permit
• Land Use Requirements
• Nonconforming Residential Uses
• Lot Coverage Requirements
• Height Requirements
• Interconnection and Net Metering Requirements
• Net Metering Benefits
• Net Metering Required Forms
• Installation Considerations
• Solar Access, Sizing and Performance
• Mounting Solar Modules
• Structural Considerations
• Electrical Considerations
Typical utility interconnected solar electric system
(with optional backup battery storage)
HARDWARE SELECTION AND PRICING
(8) Silicon Energy 185 Watt Modules w/ racking $8,880
(1) Outback SmartRE 2500 Inverter $4,440
2 strings of 4 modules, 121.2 volts, 15.8 amps
SmartRE 2500 Battery Enclosure
(4) Group 27 106 Ah batteries
Balance of System Components $1480
(1) Combiner box
(1) Ground Fault Circuit Interruptor
(1) 600 Volt DC Fused Disconnect
(1) AC Fused Disconnect
(1) 240 Volt Production Meter
Miscellaneous conduit and fittings
Grand Total $16,280
($11 / watt installed)
WIRE SIZING and WIRING DIAGRAMS
1) Meter sockets must be located near each
other and outside or otherwise consistent
with location allowed by Seattle City Light
Requirements for Electric Service.
2) Standard utility socket with face cover (no
round sockets). Socket wired per sheet 2.
3) When production meter is removed,
bottom terminals will be energized and line
terminals will be de-energized (opposite
of billing meter).
4) Billing meter will run backwards and
subtract when energy flows to utility,
production meter only runs forward.
5) Delivered energy flows from utility.
6) Received energy flows to utility.
WIRE SIZING and WIRING DIAGRAMS
Production Meter Wiring and New components for Net Metering per Seattle City Light
OutBack Power Products
Up to 93% Inverter Efficiency
CURRENT ELECTRICAL SERVICE PANEL
Application of Solar Photovoltaic
We have seen photovoltaic cells and arrays, also known as solar modules, convert
sunlight into electrical energy. Now being used in a number of building
applications, including shingles and fenestration, photovoltaic's are becoming a
common onsite renewable energy source. Whether roof-mounted or built into the
design, solar cells are connected in series to achieve proper voltages. The energy
produced can either be stored in batteries or tied directly to the municipal grid. In
some cases, you may qualify for tax credits or rebates when purchasing and
installing photovoltaic modules. You also may be able to sell the extra energy you
produce back to your local utility.
The owner’s electric power consumption of 4845 kWh per year based on the past 2
years. This is 13.27 kWh/day. Several key parameters have been evaluated at this
home site, which has excellent solar access. Based on the shade analysis performed
we calculated 96.1% solar available sunlight. There is 228 square feet on the east
roof for solar array layout.
In 1980 the Solar Rating and Certification Corporation (SRCC) was incorporated
as a non-profit organization with the primary purpose being the development and
implementation of certification programs and national rating standards for solar
energy equipment. A simple installation of several PV solar arrays on this project
could use the equivalent sun hours per day based on SRCC certification data as
table 1 from the Average Daily Total Solar Radiation for City of Seattle with two
tilt angles. The infrastructure of the entire system on your roof needs to meet the
CAM requirements of the City of Seattle.
Table 1 Average Daily Total Solar Radiation for U.S. Cities
City MJ/m²·day MJ/m²·day Btu/ft²·day Btu/ft²·day
23 Tilt 45 Tilt 23 Tilt 45 Tilt
Seattle 11.65 11.63 1026 1024
Energy Payback Times for Photovoltaic Technologies
Energy payback time (EPBT) is the length of deployment required for a
photovoltaic system to generate an amount of energy equal to the total energy
that went into its production. Roof-mounted photovoltaic systems have
impressively low energy payback times, as documented by recent (year 2004)
engineering studies. The value of EPBT is dependent on three factors: (i) the
conversion efficiency of the photovoltaic system; (ii) the amount of
illumination (insolation) that the system receives (about 1700 kWh/m2/yr
average for southern Europe and about 1800 kWh/m2/yr average for the United
States); and (iii) the manufacturing technology that was used to make the
photovoltaic (solar) cells.
Flat-Plate PV Systems
The most common array design uses flat-plate PV modules or panels. These panels can
either be fixed in place or allowed to track the movement of the sun. They respond to
sunlight that is either direct or diffuse. Even in clear skies, the diffuse component of
sunlight accounts for between 10% and 20% of the total solar radiation on a horizontal
surface. On partly sunny days, up to 50% of that radiation is diffuse. And on cloudy
days, 100% of the radiation is diffuse. One typical flat-plate module design uses a
substrate of metal, glass, or plastic to provide structural support in the back;
encapsulates material to protect the cells; and a transparent cover of plastic or glass.
The simplest PV array consists of flat-plate PV panels in a
fixed position. The advantages of fixed arrays are that they
lack moving parts, there is virtually no need for extra
equipment, and they are relatively lightweight. These features
make them suitable for many locations, including most
residential roofs. Because the panels are fixed in place, their
orientation to the sun is usually at an angle that practically
speaking is less than optimal. Therefore, less energy per unit
area of array is collected compared with that from a tracking
array. However, this drawback must be balanced against the
higher cost of the tracking system .
I strive to obtain the best price and best technical product for our clients. Moreover,
this site could be a net producer of electrical power using any of several systems.
Every kilowatt-hour produced will earn at least 18 cents. If the solar modules and
inverters are manufactured within the state of Washington the incentive raises to 54
cents per kilowatt-hour. Silicon Energy LLC of Arlington produces such modules,
and has been self certified by National Laboratory met this requirement.
The new Silicon Energy design array is highly efficient and the solar cells are
encapsulated between two tempered glass plates. With 228 square feet of available
roof and modules being 16 square feet each, a total of 8 panels could be installed on
your roof with an output of 1.48 kW.
Panel size: Silicon Energy = 47 inches by 47 inches
Power output: Silicon Energy = 0.165 kW per panel
INDIVIDUAL PROJECT – DURING THE COURSE EACH
STUDENT WILL SELECT A PV INSTALLATION OF THEIR
CHOICE AND DEVELOP AN APPROPRIATE SYSTEM
DESIGN, THIS WILL INCLUDE A SITE ASSESSMENT,
SHADING ANALYSIS, LOAD CALCULATIONS,
ASSESSMENT HARDWARE SELECTION, WIRE SIZING,
WIRE SIZING and WIRING DIAGRAMS
Use parallel wiring to increase Use series wiring to increase voltage
This diagram shows a simple parallel The voltage of all 3 batteries add to give
circuit to increase current or power. us the effect of a battery 3 times the
Assume that we are using 12 volt voltage or in this case a very large 12 volt
batteries. The power of all 3 batteries battery. In this circuit the current is the
add to give us the effect of a battery 3 same as the current in just 1 of the
times as powerful but the voltage stays batteries. But since the 4 volt industrial
the same at 12 volts. Parallel wiring batteries are very large, we have in effect
increases current but the voltage does created a huge 12 volt battery.
not change. This is the wiring used
when jump starting a car for example.
This diagram shows a combination
Use series & parallel series and parallel circuit to
wiring in combination increase both the battery current
and voltage level at the same time.
The left to right series Assume this time we are using 12
connection add the two 12 volt batteries
volt batteries to make 24 volts.
And, since we did this 3 times
and then connected each
group of 2 (now 24 volts) in
parallel we end up with one
very large 24 volt battery. It
has twice the voltage of a
single 12 volt battery and 3
times the current or power
because all 3 groups are wired
WIRE SIZING and WIRING DIAGRAMS