The document details tools and methodologies for designing photovoltaic (PV) systems, emphasizing the importance of site visits and data collection regarding shading, orientation, and access. It reviews various survey and software tools available for accurate measurements and system simulations, including the use of inclinometer apps and sophisticated shading analysis methods. Additionally, it discusses the role of different software in optimizing PV installation designs and assessing energy performance.

1. PV Systems Design
Tools of the Trade
Gavin D. J. Harper

2. Site Visit
• The Site Visit is an opportunity to collect key
information to inform a PV system design.
• Information to be collected on:
– Customer Wishes
– Usable Roof, Façade and Open Spaces
– Overshading
– Orientation / Angles of Slope
– Location for Balance of System Component
– Details of Electrical Installation
– Access considerations

3. Survey Tools
Inclinometer
• Used to determine angles of roof lines /
IMAGE: WWW.SUUNTO.COM SUUNTO TANDEM 360PC/360R DG
slopes
• Can be as accurate as digital when
used correctly.
 Requires no batteries
 Cheap and simple

4. Survey Tools
Inclinometer
• Very simple to use, held against soffit e.t.c.
• Requires physical access to the roofline.
• Health & Safety Considerations with Access
• May be cost considerations to safe access.
 Requires batteries
(Risk of them being flat!)
 More expensive
 Very Simple To Use
IMAGE: WWW.SUUNTO.COM SUUNTO MC-2/G/6400

5. Survey Tools
Inclinometer App
• Very simple to use, held against
soffit e.t.c.
• Requires physical access to the
roofline.
• Don’t drop your phone!!!
 Requires charge phone
(Risk of them being flat!)
 More expensive
 Very Simple To Use
 Ubiquitous Smartphones
 Free / Cheap (If you have phone!)
 One less tool to carry
HTTPS://PLAY.GOOGLE.COM/STORE/APPS/DETAILS?ID=COM.ANDROID.INCLINOMETERPRO

6. Survey Tools
Inclinometer App
• HOWEVER: Word of warning!
• Relies on the accuracy of phones
internal compasses and sensors.
• These may not be calibrated to
the same degree of precision as
dedicated devices.
• There may be some margin of
error.
• Check against another device to
ensure both agree.
HTTPS://PLAY.GOOGLE.COM/STORE/APPS/DETAILS?ID=COM.ANDROID.INCLINOMETERPRO

7. Shading Analysis
• Old SAP Calculation gave “Shading Factor”.
– Very subjective
– Open to interpretation
– Insufficient consideration given to near shading.
– 20% shade will still affect system; yet ignored in the SAP
method.
• Shonky installations resulted from the old method, but due to
subjectivity it was hard to argue in favour of customer due to
>20% factor.
– Hence… more sophisticated shading analysis required.

8. Shading Analysis
• In order to conduct a shading analysis, we
need to be able to capture the angular height
of obstacles and also their bearing.
• We can do this manually, or in a more
sophisticated way with expensive equipment.

9. Shading Analysis
• When selecting tools we need to consider:
– Quality of data
• Junk in, junk out: The better our model, the closer fit to
real world performance.
• “Good enough” data, ‘cheap’ equipment can yield
serviceable results.
– Speed of capture
• If we are doing lots of installations, then we want to be
able to use tools that allow us to work effectively.
– Workflow process
• Some automatic tools allow for automatic transfer of
data into modelling tools.

10. SURVEY TOOLS
There are a number of different tools which can be used to help in
the collection of on site survey data.

11. Survey Tools
Sighting Mirror Compass
• Used to determine bearing and
measure gradients and altitudes.
• These are vital considerations when
calculating azimuths, shading and
slopes.
 Requires no batteries
 Cheap and simple
IMAGE: WWW.SUUNTO.COM SUUNTO MC-2/G/6400

12. Survey Tools
Quick & Dirty Elevation Tool
• Laminated Sheet of Card
• String
• Small Weight
 Requires no batteries
 Cheap and simple
 You will feel like a wally
 You will envy the cool kids with shinier toys.
HTTP://WWW.MICROGENERATIONCERTIFICATION.ORG/IMAGES/MCS%20SHADING%202%20FINAL.PDF

13. Survey Tools
MCS installers have to record
information about shading and
obstructions even if it appears
that there are none.
Arms length site surveys are
banned in the 3rd Edition MCS
guidance.
Chris Laughton has a his *VERY* interesting blog post on this topic.
http://chrislaughton.files.wordpress.com/2013/10/image-3.jpg
Chris runs: http://www.solardesign.co.uk/

14. Survey Tools
Printable Sun Path Acetates
HTTP://WWW.SOLARDESIGN.CO.UK/MCS-DOWNLOAD.PHP

15. Survey Tools
Printable Sun Path Acetates
• Use with a “Solar Site Selector” tool.
• Tool holds acetate, and contains a Fisheye
Lens and a Compass
• Different acetates for different latitudes
available.
• Looking through lens, outlines of obstructions
are drawn onto the diagram using an OHP
Transparency erasable marker.
HTTP://WWW.SOLARDESIGN.CO.UK/MCS-DOWNLOAD.PHP

16. Survey Tools
Solar Site Selector Tool
• The following pictures show an acetate type solar site
selector tool as sold by Solar Design Company.
HTTP://WWW.SOLARDESIGN.CO.UK/MCS-DOWNLOAD.PHP

17. Survey Tools
Reflective Solar Dome Tool
HTTP://WWW.SOLARPATHFINDER.COM/PF

18. Survey Tools
Reflective Solar Dome Tool
• Highly polished transparent convex dome.
• Dome reflects surrounding landscape, but also
allows sun path diagram to be see transposed
against reflections.
• Different sun path diagrams for different
latitudes.
• Simple tool, no batteries to replace e.t.c.
• BUT- need a camera to record the data!
HTTP://WWW.SOLARPATHFINDER.COM/PF

19. Survey Tools
PanoramaMaster
PanoramaMaster assists in the capture of
aligned images that can be used in order to
calculate shading from a location.
The PanoramaMaster bracket mounts onto a
camera tripod.
The camera then mounts to the
PanoramaMaster Bracket.
IMAGE © CHRIS LAUGHTON of the Solar Design Company
HTTP://WWW.SOLARDESIGN.CO.UK/PANORAMAMASTER.PHP

20. Survey Tools
PanoramaMaster
• The images that are captured can then be processed and
‘stitched together’ using the software.
• This data can then be imported into software in order to
generate a skyline that can be used for simulating solar
shading in a simulation package.
• A sunpath and horizon can then be overlaid onto the image.
IMAGE © CHRIS LAUGHTON of the Solar Design Company
HTTP://WWW.SOLARDESIGN.CO.UK/PANORAMAMASTER.PHP

21. Survey Tools
Solmetric Suneye
Tool for making calibrated
measurements of solar shading.
Incorporates:
• Calibrated fisheye camera
• Electronic compass
• Tilt sensor
• Optional GPS
HTTP://WWW.SOLARDESIGN.CO.UK/MCS-DOWNLOAD.PHP

22. Survey Tools
Solmetric Suneye
HTTP://WWW.SOLARDESIGN.CO.UK/MCS-DOWNLOAD.PHP

23. Survey Tools
Solmetric Suneye
HTTP://WWW.SOLMETRIC.COM/BUY210.HTML

24. Survey Tools
Solmetric iSV App
• Augmented reality
• Combines camera with
sun path diagram
• Uses phone’s sensors
to add position
information
• $4.99 app vs 000’s for
specialised sun path
device.
HTTP://WWW.SOLMETRIC.COM/SOLMETRIC-ISV-IPHONE-APP.HTML

25. Survey Tools
http://www.microgenerationcertification.org/images/MCS%20Shading%202%20FINAL.pdf

26. SOFTWARE DESIGN TOOLS

27. Design Tools
• There are a great many different software design
tools for Photovoltaic Systems on the market.
• These range in complexity and cost from free to
very expensive.
• It is impossible to provide an exhaustive list, nor to
give a complete overview of their functionality within
the scope of this presentation.
• The following exposition is indicative of some of the
software available and the range of functionality
that can be achieved.

28. Design Tools
PVGIS
HTTP://RE.JRC.EC.EUROPA.EU/PVGIS/
• Online free solar
photovoltaic energy
calculator for stand alone
or grid connected PV
systems and plants, in
Europe and Africa.
• Solar electricity generator
simulation and solar
radiations maps
• Free Online Tool

29. Design Tools
PVGIS
HTTP://RE.JRC.EC.EUROPA.EU/PVGIS/
• Underestimates the
efficiency of modern solar
panels.
• Overestimates (default
settings) the power losses
that we would expect from
a well designed solar PV
array.
• Otherwise a very good tool
and free.

30. Design Tools
PV*SOL
• PV*SOL software is used for the design an
simulation of PV installations.
• There are two variations: PC*SOL & PV*SOL
Premium
• PV*SOL works in two dimensions, whereas PV*SOL
Premium has added functionality to allow work in
three dimensions.
HTTP://WWW.SOLMETRIC.COM/SOLMETRIC-ISV-IPHONE-APP.HTML

31. Design Tools
PV*SOL

32. Design Tools
PV*SOL

33. Design Tools
PV*SOL Premium
• PV*SOL software is used for the design an
simulation of PV installations.
• There are two variations: PC*SOL & PV*SOL
Premium
• PV*SOL works in two dimensions, whereas PV*SOL
Premium has added functionality to allow work in
three dimensions.
HTTP://WWW.SOLARDESIGN.CO.UK/PVSOL-PREMIUM.PHP

34. Design Tools
PV*SOL Photoplan
• PV*SOL Photoplan is used to to generate
photorealistic rendered diagrams of potential
solar installations.
• This can be used to help customers gauge
the aesthetic impact of a PV installation and
may be helpful in the process of planning
applications in certain situations.
• Listed Buildings
• Conservation Areas
• Areas of Outstanding Natural Beauty
HTTP://WWW.VALENTIN-SOFTWARE.COM/EN/PRODUCTS/PHOTOVOLTAICS/57/PVSOL-PREMIUM

35. Design Tools
Helios 3D
• Software specifically designed for planning utility
scale ground mounted PV arrays.
• Will take data into account about the terrain of the
installation from GIS data.
• The core functionality of HELIOS 3D is, to place
the racks without shadows casted on them on any
suitable terrain.
HTTP://WWW.HELIOS3D.COM/

36. LIDAR Data Collection
Source:
http://www.beg.utexas.edu/coastal/poster/
graphics/Terrain-mapping-plane.gif
http://www.phoenix-aerial.com/

37. Orientation
Analysis
Helios 3D analyses
terrain data for
orientation, noting
whether the slopes
face North, South,
East or West.
Orientation analysis is important for optimal site selection.

38. Design Tools
Helios 3D
HTTP://WWW.HELIOS3D.COM/

39. Design Tools
Helios 3D
HTTP://WWW.HELIOS3D.COM/
The longest
shadow cast in a
row is calculated.
The distance
between rows is
then set to this
measurement to
prevent
overshadowing.

40. Design Tools
Helios 3D
HTTP://WWW.HELIOS3D.COM/
• The software will also make
suggestions about how
earthworks and regarding of the
terrain may assist in optimisation
and improving the performance of
the system.
• The software considers the
optimal geometry for the rows of
PV devices in order to extract the
most energy from a given space.

41. Design Tools
Helios 3D
HTTP://WWW.HELIOS3D.COM/
• The software will take into account access
requirements for installation and maintenance.
• Access roads are optimally positioned
There are factors that are specific to the design of
ground mounted PV:
• Soil conditions
• Piling depth

42. Design Tools
Helios 3D
HTTP://WWW.HELIOS3D.COM/
• The software allows
modelling of obstructions
and objects which will cast
shadows on the installation.
Access road positioning
optimised to make use of
overshadowed space as a result
of tree providing overshadowing.

43. Other Tools
• Energy Savings Trust >4kW PV Estimator
http://www.energysavingtrust.org.uk/Generating-energy/Getting-money-back/Solar-Energy-Calculator

44. Other Tools
• Energy Savings Trust >4kW PV Estimator
– Limited to solar PV systems under 4kWp
– Limited design choices
– Overestimates system losses
– Doesn't factor RPI FIT payment increases
– Doesn’t factor predicted increases in electricity prices.
– BUT very easy to use and easy to understand
– Comprehensive solar PV Return on Investment (ROI) tool
http://www.energysavingtrust.org.uk/Generating-energy/Getting-money-back/Solar-Energy-Calculator

45. PV Software
• For a more exhaustive list of PV Software
tools, look at:
• http://photovoltaic-software.com/free.php
• http://photovoltaic-software.com/professional.php