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Bosch Geothermal Heat Pumps
Bosch Thermotechnology Corp.
Data subject to change
Applications Manual
Generally, header layouts are more cost effective with
short headers. This requires centrally locating the header
to all circuits and then bringing the circuits to the header.
Many installers simply direct all trenches into a common
pit area which allows the use of an “L” type header (Figure
56). This design helps achieve reverse return ow by
installing the headers in a mirror image con guration.
Fig. 56 L-type header
10.2 Piping Installation and Borehole
Alignment
Installation of the piping into the borehole is never perfect.
Under most conditions, the contractor/installer can follow
typical installation practices. Two typical examples are
shown below (Fig. 57, 58).
Alignment of a borehole is never perfect either, and under
most conditions, the installer can typically keep alignment
within practical limits by exercising good judgment and
care. Borehole alignment is more critical when utilizing
deeper boreholes. Misalignment of boreholes is typically
related to the type of the material penetrated while boring,
the trueness of the surface or bridge casing, the tension
of the cable tool drilling line, and the pull-down force on
the drill pipe when using rotary drilling. The borehole
should be aligned so that the closed-loop piping can be
placed into the entire borehole depth, while assuring that
borehole and piping do not intersect other boreholes and
piping.
For vertical earth loops, regulations which govern water
well installations also apply to vertical ground heat
exchanger installations. Vertical ground loop applications
typically require multiple boreholes. The boreholes
typically are a minimum of approximately 10 feet apart.
In more cooling dominated climates such as the southern
portion of the U.S., 15-20 feet is typical.
Available geothermal software programs like Bosch Geo
Solutions can provide detailed information concerning
loop lengths based on borehole spacing.
