effectiveness can be significantly increased above
0.5 for a small increase in heat exchanger cost.
Both shell-and-tube and multiplate or
plate-and-frame heat exchangers are allowable for
solar systems. Although the shell-and-tube
exchangers are more common, multiplate heat
exchangers are becoming readily available from a
variety of manufacturers. The multiplate heat
exchanger has the advantages over shell-and-tube of
being more compact, more efficient, easier to clean,
and it is commonly produced from superior materials.
They can also be easily expanded to larger sizes if
necessary, and many require little or no insulation.
The designer should consider use of these
exchangers whenever practical. Because of the wide
variety of configurations used by these heat
exchangers, they must often be sized by the
individual manufacturers. In accordance with TM
5-804-2, the flow rate on the storage side of the
heat exchanger should be 1.25 times that on the
collector side. Items to be shown on the drawings
must include:
a. Type of heat exchanger and heat exchanger
materials
b. Flow rates on both sides of heat exchanger
c. Plate or tube heat transfer area.
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[Flow rate in the collector loop shall be based on recommended collector
flow rate, and shall be as shown. Storage loop flow rate shall be 1.25
times the collector loop flow rate.] [System flow rate shall be based on
recommended collector flow rate, and shall be as indicated.] All flow
rates shall be below 1.5 meters/second 5 feet/second.
3.1.3.2
Pumps
[Pumps shall be installed on foundations, leveled, grouted, and realigned
before operation in accordance with manufacturers instructions.]
[Additional pipe supports shall be provided for close-coupled in-line
pumps.] [All base mounted pumps shall have a straight pipe between the
suction side of the pump and the first elbow. The length of this pipe
shall be a minimum of five times the diameter of the pipe on the suction
side of the pump, or a suction diffuser of the proper size shall be
attached to the suction side of the pump.] [All in-line pumps shall have
straight pipe between the suction side of the pump and the first elbow.
The length of this pipe shall be a minimum of five times the diameter of
the pipe size on the suction side of the pump.] Drain line sizes from the
pumps shall not be less than the drain trap or the pump dirt pocket, but in
no case shall the drain line be less than 15 mm 1/2 inch iron pipe size.
Drain lines shall terminate to spill over the nearest floor or open sight
drain.
3.1.3.3
Expansion Tank
Expansion tank shall be installed on suction side of pump as shown.
SECTION 13600A
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