For this reason, they are nothing but a plastic or metal absorber plate.
insulation or glazing is used. (Figure 2-1 9)
Indoor pools used throughout the entire year typically use an indirect system. The
collectors are standard glazed flat-plate units with metal absorbers.
An Unglazed Pool
2.7.2 Pumps. The wetted components of pumps used for moving water are
normally constructed from bronze or stainless steel. These materials do not
deteriorate in water, do not contaminate the water and are compatible with the other
piping system materials normally used. No special seals or gaskets are required.
Pump components in contact with non-freezing solar fluids are normally made of
cast iron or steel. Special gaskets and seals are always required. See Appendix E
for a listing of fluids and materials compatibility. (Table 2-1)
For applications requiring a small (1/35 to 1/2 hp) circulating pump, the typical unit
is a "wet rotor" type. (Figure 2-20) The moving part of the pump motor, the rotor, is
surrounded by water. During operation, part of the water being pumped acts as a
lubricant and coolant for the motor. Wet rotor pumps require no other lubrication or
maintenance, other than periodic inspection.
Larger systems may use a number of small wet rotor pumps ganged together, but
the usual choice is one large pump of traditional design. (Figure 2-21) Because the
motor and pump are physically separated, periodic lubrication is usually required,
and inspection procedures include checking for shaft alignment and bearing wear.
2.7 COMPONENT OPERATION