14 June 2002
possible building orientations and roof area availability. Within the possible orientation
constraints, the designer should develop an acceptable preliminary array layout (or a
variety of layouts) which satisfy the following criteria:
(a) Array is facing within 20 degrees of true south.
(b) All banks contain same number of collectors.
(c) Minimum row spacing criteria satisfied or collector rows are to be
(d) Layout(s) satisfy geometrical symmetry.
(e) No interference from other rooftop apparatus (chillers, vents, etc.).
Final array layout determined and accepted by architect or project
(7) Total collector area (Area). Determine the final system size (total
collector area) by multiplying the number of collectors in the final array layout by the
collector unit area. This value will be used in the detailed design of the system.
d. System Planning - Equipment Room Size. The equipment room should be
designed to include the equipment for both the solar system and the backup water
heating system, if possible. The following information should be taken into
(1) Storage tank size can be as large as 2 gals per square feet (81.5 L per
square meter) of collector area. This will be the largest piece of equipment in the room.
The storage tank can be located outside only if an inside location is not practical.
(2) Heat exchanger size will be small in comparison with other equipment,
but will require a small amount of floor area. Indicate access area allowance for heat
exchanger tube pull-out or plate-stack disassembly.
(3) Expansion tank volume will be roughly between 1.5 and 2 gals (5.7 and
7.6 L) per collector unit.
(4) Pumps, connecting piping, control panel. Indicate access area
allowance for the propylene glycol drum(s) (55 gal) for the fill and drainage of the
Access to all equipment by maintenance personnel.
a. Collector Subsystem. The designer must choose a particular collector unit
around which to design the system. The components of the solar system are sized