| Abstract |
Geothermal heating and cooling systems integrate a groundcoupled heat exchanger, heat pumps and ancillary equipment, indoor distribution systems (either forced air or radiant piping) and controls into a single operating facility. Equipment sizing, operating efficiencies and run-fractions of components are matched for compatibility; over-sizing of any item impairs system efficiency. Installation of elements occurs at different stages of building construction, so a Design-Build geothermal contractor makes repeated entries onto a project. Quality control and assurance at each stage of installation are essential. Project Management is more complex than standard mechanical subcontracting and job costs reflect multiple mobilizations and payment rates for different trades. The latter include excavation, plumbing, electrical, refrigeration, and mechanical work. Geothermal design and construction are “custom work” rather than mass production so skilled labor may be limited and competitive bidding or procurement practices may be ineffective: “Low Bid and No Experience” is not acceptable for geothermal work. |