possible on the designer's drawings. Of particular
interest are the length and width of the collector
(for spacing and roof layout reasons), the
recommended flow rate of the collector, and the
rated pressure drop at that flow rate. The designer
should verify that the values of the following
parameters are indicated in schedules on the
drawings:
a. Number of collectors
b. Gross area and net aperture area
c. Collector height and width
d. Collector fluid volume
e. Collector filled weight
f. Collector manufacturer's warranty period
g. Recommended collector flow rate
h. Pressure drop across the collector at
recommended flow rate.
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Collectors shall be of the flat plate, liquid, internally manifolded type.
Each collector shall be provided with cover glazing, an absorber plate,
heat transfer liquid flow tubes, internal headers, weep holes, insulation,
and a casing. Collectors shall be of weather-tight construction. Solar
collectors shall withstand a stagnation temperature of 177 degrees C 350
degrees F and a working pressure of 862 kPa 125 psig without degrading,
out-gassing, or warping. Collector net aperture area shall be as shown and
shall be a minimum of 2.6 square meters 28 square feet. Collector length,
width, and volume shall be as shown.
2.4.2
Absorber Plate and Flow Tubes
Absorber sheet or plate shall be copper. Top of absorber plate shall be
coated with selective surface of black chrome and shall have an emissivity
less than 0.2 and absorptivity greater than 0.9. Flow tubes shall be Type
L or Type M copper, and shall be soldered, brazed, or mechanically bonded
to the absorber plate. Tubes shall be installed on the absorber plate so
that they drain by gravity.
2.4.3
Cover Glazing
Each collector shall have a single layer of cover glazing made of clear
float, water white or low iron type tempered glass. Glass shall meet ASTM
C 1048. Cover glazing shall be completely replaceable from the front of
the collector without disturbing the piping or adjacent collectors. Cover
glazing shall be separated from the collector by a continuous gasket made
of EPDM rubber.
2.4.4
Insulation
Back and sides of the absorber plate shall be insulated. Insulation shall
fill space between absorber plate and casing and shall have an R value of 4
minimum. Insulation shall conform to EPA requirements in accordance with
Section 01670 RECYCLED / RECOVERED MATERIALS and shall be fibrous glass,
polyisocyanurate, urethane foam, or other material suitable for the
intended purpose, and shall withstand the moisture, sun exposure, and
stagnation temperature limitations of the solar collector.
Polyisocyanurate insulation shall not come in contact with the absorber
plate.
SECTION 13600A
Page 14
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