Section 312IAC13-8-1. Geothermal heat pump wells

   (a) This section establishes standards for drilling ground water heat pump systems that are in addition to the general requirements for drilling a well under 312 IAC 12.

  (b) If a return well is used with an open loop system, its design must provide water transmitting capacity that is at least one and one-half (1 1/2) times the required water supply of the heat pump unit.

  (c) With respect to a vertical closed loop system, boreholes must be pressure grouted from the bottom of the borehole to the ground surface with a neat cement or high solids bentonite grout that, to enhance thermal conductivity, may contain any of the following:

(1) Sand.

(2) Graphite.

(3) Another material approved by the division.

(Natural Resources Commission; 312 IAC 13-8-1; filed Nov 22, 1999, 3:34 p.m.: 23 IR 770; readopted filed Aug 4, 2005, 6:00 p.m.: 28 IR 3661; filed Jul 14, 2006, 1:23 p.m.: 20060809-IR-312050341FRA; readopted filed May 20, 2011, 3:28 p.m.: 20110615-IR-312110002RFA; filed Jan 23, 2015, 10:22 a.m.: 20150218-IR-312140204FRA)