Green Collar Careers - Solar Site Survey
The purpose of a Site Survey is to determine:
- Solar exposure period and obstacles
- Location and mounting of the solar collectors and/or Solar PV
- Define system requirements and specifications
- Location of support equipment; thermal storage tanks, inverters
- Routing of plumbing and wiring
- Access and hazards for installers
- Ingress/egress to installed equipment
The following items will be needed for the Solar Site Survey:
- Compass - with flat edge to line up with a wall, and with
degree readouts - a good hiking compass will do
- Solar Surveying Tool -
Fabricating a Solar Site
- 100 foot tape measure
- 25 foot tape measure
- Something that can measure a pipe diameter
- Clip Board
- Sharp pencils with erasers
- Print out of Sun Path Chart
- Print out of Site Survey Data
- Note pad - graph paper preferred
- Digital Camera
You will also need to create these documents for the Solar Site
- Solar Site Diagram -
- Sun Path Chart - Section
- Site Survey Worksheet -
Note the time of day and the compass orientation of the property.
Walk around the perimeter of the property to identify the property
lines and note any obstacles that will potentially shadow the solar
facing equipment. For example trees that are on the home owners
property may or may not be acceptable for trimming.
Use the best practical solution to identifying the location of the
solar facing equipment. Most solar facing equipment tends to be
roof mounted as it takes up the least space and reduces attic heating.
Roof top mounting is not always the best option depending on the roof
geometry and devices to be installed. If roof top installation
doesn't fit the best solution find a different location that offers
the best solution for the homeowner.
Sun Path Analysis
- Once you've identified the ideal and alternative locations for
the solar facing equipment, set up the transit locating true north.
- Using the Sun Path Chart
that was created for your location, you'll identify the angles of
obstacles in relation to the time of day by elevation and azimuth.
- Aim the transit at the azimuth angles for the first hour of
sunlight hour shown on the scale and line up with the lowest
elevation angle that's unobstructed to the horizon. At that
elevation angle, mark the Sun Path
Chart with a dot - and repeat this for every hour.
See example 1.
- After filling in the dots, connect them -
See example 2.
- 80% of the solar energy through the year is provided in the
green shaded region. You could compute this down to an exact
number, but using the 80% Sun Path image as a guide you should be
able to determine if the shadows are excessive for the first
location you've selected.
If excessive shadowing is a problem for the first location selected
you have three options:
- Remove the object creating the shadow
- Relocate the solar facing equipment
- Reduce the efficiency of the solar facing device
Support Equipment Placement
After you've determined where the solar facing equipment will be
located comes the support equipment. For the solar heating
system this is usually the storage tank, controller and pump, and for
the solar electric system this is the inverter.
There will be cabling and plumbing routes to consider.
Rooftop mounting of the solar facing equipment generally requires an
attic routing although that may not always be the best path.
That's what you'll need to determine.
If you choose a site that has isn't attached to the structure its
almost certain that your routing path will need to be underground.
Most local codes require conduit or some durable cable specification
with junction boxes etc. at exit points. Buried cables/pipes
need to take into consideration of any other buried pipes or wiring
including automatic sprinkler systems.
Note property lines and distances from the house to the
property. There may be obstacles that don't belong to the
homeowner or in the event of a ground installation of the solar
collector it needs to be on their property and within any
boundaries established by local codes. If you see these
types of concerns, document them, otherwise its not that
- Layout a preliminary sketch and identify locations of solar
facing equipment and support equipment.
- Using the transit site the roof angles of interest and note
them on the sketch.
- Measure the length and width of the roof section from the
ground and try to remain within 6" and add those dimensions to
the sketch. (You may need to use the second copy for this.)
Identify a corner of the house as a reference point for these
dimensions as you'll be using that reference for other things to
determine pipe lengths & routes and wiring lengths & routes.
- For solar heating systems, locate the existing water heater and measure the relative
location to the reference point you identified.
Note the floor the water heater is on.
- Investigate the best path to route the Closed Loop piping
from the Solar Collector to the existing Hot Water Heater.
Do not offer to relocate the Storage Tank/Heater, it will only
- Sketch the room where the hot water heater is located to
indicate clearances from walls, access doors, and any objects.
Take plenty of pictures of this room/closet to make sure you
have it documented.
- Inspect the attic area under the proposed solar collector
position and determine the most viable routing of the Closed
Loop piping. Keep in mind that the piping must be
insulated so blind access or wall drops of pipes is not a
preferred solution. In some cases a wall drop may be the
only solution and in that event consider the potential of
cutting out a section of wallboard to install the insulation -
that will probably add $200 or more to the cost.
- Take plenty of pictures inside the attic underneath the
proposed proposed solar collector position and note the size of
the rafters. Most solar collectors are under 10 lbs per
square foot load and usually pose no issues, but be sure in case
you're asked for permitting purposes.
- Draw a sketch of the plumbing path. Take pictures of
everywhere you expect to run piping. While its not
preferred for aesthetic reasons in some homes there is no
alternative but to run piping externally. Always keep that
in mind as an alternative route and you will want pictures of
all possible routes. Measure out the plumbing routes, both
vertical and horizontal.
- Identify the water piping used. In most cases it will
be 3/4" copper but don't guess - know what is currently
connected to the existing water heater.
- Note the brand, model, age, size, and capacity of the
existing hot water heater.
- Consider any alternative ground locations for the solar
collector. It may surprise you how many times a ground
mount is the best solution, particularly if the hot water system
is just on the other side of the wall. There are even some
systems that have been built over a doorway or elevated along a
wall as an awning!
- If this is a roof mount, note the type of roof construction
- shingles, metal, tile etc.
- Interview the homeowner to complete the Site Survey Data and
review the proposed location.
- For solar heating systems, approximate the total length of
tubing (both ways) and the number of elbows and joints required.
- Identify any requirements for buried cable or plumbing.
After the Site Survey
As your preliminary sketch will have lots of scribbles (unless
you're extraordinarily neat) you'll probably want to create a clean
set of sketches.
- Mounting Diagram - shows where the solar collector will be
located relative to a reference point.
- Storage/Hot Water tank with relative dimensions to the
walls, doors and reference point - include some printed key
- Closed Loop Routing Diagram - include any lengths and
elbows etc. required.
- Closed Loop Pump - Location, type (Solar or AC)
- Review the sketches and drawings with the installer at
your earliest convenience to get an estimate for the job.
- Complete the Bill of Materials, Installer estimate and
system cost and contact the customer to discuss the