This presentation covers the basic methods of ground coupling as well as other terrestrial sources/sinks for heat. Considerations in evaluating sources will be delineated including design requirements (quantities available, temperature, distance from use point, etc.), material properties (fouling propensity, corrosion potential, toxicity), as well as societal issues (extraction and disposal permitting, codes for use/protection of workforce/community, etc.). List of topics to be covered: – Ground Coupling (vertical horizontal including slinkies, angled bores) – Ground Water (open w/surface disposal, open w/reinjection, standing column well) – Surface Water (open and closed loop coupled, lake/river/sea water) – Waste Water Heat Exchange – Considerations for novel sources (fouling, corrosion, toxicity, permitting, disposal, etc.)