My company is considering a geothermal system for an industrial facility. The proposed system is a well of approximately 150 meters deep, where water of appr 10 Deg C is pumped up and directly used for cooling of the building in summer time. However the same water will be used during wintertime for heating by using a heatpump.
This would meet the LEED requirement of “deep” however the use of a heat pump (vapor-compression system for heat transfer) would seem to disqualify this application for the on-site renewable credit? Doesn't seem right to me.
The LEED guidance document confused me:
Geothermal energy systems using deep earth water or steam sources (and not using vapor compression systems for heat transfer) may be eligible for this credit. These systems may either produce electric power or provide thermal energy for primary use at the building.
Geo-exchange Systems: (a.k.a. geothermal or ground-source heat pumps) Earth-coupled HVAC applications which do not obtain significant quantities of deep-earth heat, and use vapor-compression systems for heat transfer are not eligible as renewable energy systems. These systems are adequately addressed in EA Prerequisite 2, and may be considered under EA Credit 1.
Any ideas on whether this would qualify as on-site renewable?
Tristan Roberts
RepresentativeVermont House of Representatives
LEEDuser Expert
11477 thumbs up
September 3, 2011 - 10:43 pm
Jeff, this system would apparently be considered a "geo-exchange" system. You are basically using the water and its temperature as an efficiency measure, not as a source of energy. This is most clearly the case on the heating side, but I would say it also aopears that way on the cooling side: you are dumping heat into the Earth for cooling, which is an efficiency measure. One could even argue that the heat you are dumping in the summer is being extracted in the winter.