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Bosch Geothermal Heat Pumps
Bosch Thermotechnology Corp.
Data subject to change
Applications Manual
9.11 Closed-Loop Header Design
A closed-loop header is simply a series of larger diameter
horizontal pipes that connects the geothermal ow center
to each of the smaller diameter circuits located within
each borehole. Parallel ground heat exchanger headers are
typically designed with consideration for pressure drop
and the ability to purge air from the ground loop. A typical
header for capacities up to 15 tons of cooling is shown
(Fig. 51).
Fig. 51 Header capacities up to 15 tons of cooling
The header shown next (Fig. 52) is designed for capacities
up to a nominal 5 tons of cooling. It uses 1-1/4 inch IPS
pipe for circuits 4 to 7, and ¾ inch IPS for circuits 1-3,
allowing minimum pressure drop while maintaining 2 Feet
per Second (FPS) velocity under normal ow conditions.
This means the header is actually self- ushing, as typical
ushing criteria outlined by IGSHPA requires a minimum of
2 FPS to purge a ground heat exchanger for eld use.
Fig. 52 Header capacities up to 5 tons of cooling
