3 - Site Evaluation
To achieve good performance and a good return on investment, the Appliance must be sized correctly
and it must be oriented properly. Site evaluation is necessary to determine whether a site is appropriate
and to evaluate the complexity of the installation. It is also necessary to determine the hot water loads,
number of individuals in a home, number of collectors and size of solar storage tank.
A site survey (see Appendix – Residential Site Survey) has been developed to assist installers in
evaluating potential installation locations. This can be removed from the Appendices and copied as
needed. Solar simulation software may assist in determining the best location and orientation for the
solar collectors.
For roof-mounting, installer should ensure that roof cladding or sheathing is in good repair. Also
ensure that rafters and trusses are adequate to support weight of solar collector(s) and mounting
assembly.
Building and plumbing permits and/or inspections may be necessary to proceed with installation.
Follow all code requirements and regulations.
Collector(s) should face as close to south as possible for
optimal performance. Within 45° of south is acceptable
as there is less than 10% loss (Fig. 3.1.1).
The roof angle from horizontal for optimal year-round
performance is equivalent to latitude of location plus or
minus 15°. A steeper angle provides better winter
performance as the sun is lower in the sky. Collectors will
also shed snow more effectively. A shallow angle
maximizes energy capture in summer when sun is high.
Be cautious of placement on low angle roofs due to
snow shedding and potential for ice-damming. A
minimum collector angle of 14° (3:12 pitch) is necessary
for stagnation-control device to function.
Shading of collectors greatly reduces performance.
When selecting installation location, consider potential
shading by trees and other buildings, especially
between peak solar hours of 10:00 and 15:00. A Solar
Pathfinder or similar device may be used to determine
potential shading throughout the year.
3.1 Collector Location, Orientation and Shading
Fig. 3.1.1 – Collector Orientation.
7
Module 4
Solar Collector
Installation Manual
Summary of Contents for EWRA1
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