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District Heating and Cooling

Geothermal Heat Pumps

Heat Transfer in Soil Systems

Cold Regions Heat Transfer





Gary E. Phetteplace


BS in Mechanical Engineering, Northeastern University, 1975.

MS in Engineering, Thayer School of Engineering, Dartmouth College, 1981.

Ph.D. in Mechanical Engineering, Stanford University, 1994.  Dissertation Title: "Optimal Design of Piping Systems for District Heating".

My major areas of study, both undergraduate and graduate, were: thermodynamics, fluid systems, energy conversion, heat transfer, numerical methods, optimization, and applied mathematics.


Much of my experience was obtained as a Research Mechanical Engineer in the employ of the US Army Cold Regions Research and Engineering Laboratory (CRREL), Hanover, NH, from 1975 until my retirement in July 2007. My research at CRREL was concentrated in the areas of: theory and practice of district heating and cooling (DHC), heat pump systems, numerical and analytical methods for approximating heat transfer in soil systems including freezing and thawing, and energy conversion.

Since 2007 as President of GWA Research LLC I have acted as a private consultant/expert for various interests in the fields of DHC, Ground-Source Heat Pumps (GSHP), heat transfer, and other areas. I have extensive experience both analytical and experimental in heat transfer from buried piping systems and the calculation and impacts of surrounding soil temperatures.

I recently led an international team of experts in authoring the ASHRAE District Cooling Guide (published in June 2013) and a ASHRAE District Heating Guide (published in September 2013). This was a five year effort for the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).

I have served on, or chaired, a number of panels and committees on both the national and international level. I am a frequent reviewer of papers, reports, and journal articles for various national and international organizations. I am a frequent and major contributor to guidance documents for the engineering community, such as the ASHRAE Handbooks. Until recently I was the long-standing editor and Handbook Committee Chairman for ASHRAE TC6.2, District Heating and Cooling. In that capacity I contributed all the thermal and hydraulic analysis sections as well as other portions for many past editions and the current 2012 edition of the ASHRAE Handbook, HVAC Systems and Equipment Volume, Chapter 12. Until the present, this has been the most authoritative design guidance for district heating and cooling systems in the US; it has now been eclipsed by the ASHRAE guides my team prepared as discussed above.

My field experience is extensive and includes projects in all regions of the continental United States as well as Alaska, Greenland, and Antarctica. I have participated in approximately 200 exploratory excavations of steam, hot water, and chilled water distribution systems and many more inspections of adjacent manholes for such systems.

Major Awards:

November 1987 - October 1988, Department of Defense Research and Engineering Fellowship, two months spent at Technical University of Denmark and ten months spent at Stanford University.

1997, Vice Presidential “Hammer” Award, for role in Ground-Coupled Heat Pump Project at Ft. Polk.

1998, Guest Professorship (two months) at Technical University of Denmark, Lyngby, Denmark to work on heat transfer from buried piping systems.

2005, Army R&D Achievement Award and ERDC R&D Achievement Award for role in Microencapsulated Phase Change Material project.

2011, Antarctic Service Medal, National Science Foundation, for contributions to the U. S. Antarctic Program.

2011, George B. Hightower Technical Achievement Award, American Society of Heating, Refrigerating, and Air Conditioning Engineers, (ASHRAE) in recognition of excellence in volunteer service in the area technical leadership and contributions.


Registered Professional Engineer: Alaska, California, Massachusetts, Maryland, New Hampshire, and Vermont.

Member, American Society of Mechanical Engineers (ASME).

Member, American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). Member and Past Chairman (two non-concurrent terms) of Technical Committee (TC) 6.8 - Geothermal Energy Utilization. Member and Past Chairman of TC 6.2 - District Heating and Cooling. Past Chairman of Research Subcommittee of TC6.2. Past Chairman of Handbook Subcommittee TC6.2.

Member, ASTM International, member of Task Group developing standard for low temperature district heating piping.


Over 140 publications. A list is available upon request.

Contact Information:

Gary Phetteplace, PhD, PE

GWA Research, LLC

7 Masa Morey Lane

Lyme, NH 03768