Expert Witness Services

District Heating and Cooling

Geothermal Heat Pumps

Heat Transfer in Soil Systems

Cold Regions Heat Transfer






Cleaning of the heat exchanger for the primary effluent sewage-source heat pump

Cleaning of the heat exchanger for the primary effluent sewage-source heat pump demonstration project at Ft. Greely, Alaska.

Thermal Properties Testing Device

GWA Research LLC’s thermal properties testing device. The data logging equipment is not shown; it plugs into the nylon terminal block to the left of the breaker panel for the heaters.  The blue cap covers the reservoir where the system is filled and air is purged to atmosphere.

Chart of thermal properties test results

Results from a thermal properties test using the GWA Research LLC test device. The blue line is the average of the supply and return temperatures from the test loop and the black line is the best fit line-source model used to determine the thermal conductivity.

Ground-Source (Geothermal) Heat Pumps


Gary Phetteplace’s experience with ground-source heat pumps (GSHP) dates back to demonstration installations of vertical and horizontal systems performed in the early 1980’s at the CRREL facilities in Hanover, NH.  He soon after was responsible for the demonstration of some open loop systems in family housing units at Ft. Dix, NJ.  His next major demonstration project was at Ft. Polk in the late 1980’s where several sets of vertical ground coupled systems (GCHP) were installed and closely monitored along with new air-to-air units for comparison purposes.  These demonstration projects led the way for the shared saving energy performance contract that retrofitted all 4003 family housing units on Ft. Polk to GCHPs. His role in these projects at Folk Polk won him Al Gore’s Vice-Presidential Hammer Award.  Gary Phetteplace also was responsible for projects that instrumented and monitored a hybrid vertical GCHP at Ft. Polk as well as a school for the Navy at Patuxent River Naval Air Station.  Gary Phetteplace organized and taught in whole or in part a number of courses in design of GCHP systems for both DoD and ASHRAE.  He currently is an instructor in HeatSpring Energy’s geothermal heat pump curriculum.  Gary Phetteplace has twice chaired ASHRAE’s Technical Committee TC6.8, Geothermal Energy and he remains active in the committee. 

Gary has provided GSHP design review and feasibility analysis services to various public and private entities.



© 2016 GWA Research, LLC         December 28, 2016