This is episode 1 of a 3 part webinar series on Geothermal Systems. Here Guest educator John Siegenthaller P.E., describes the refrigeration cycle used in heat pumps, shows the main differences between geothermal heat pumps and other heat pump types, then uses the remainder of the presentation on geothermal heat pumps and their applications. Topics reviewed: heat sources and heat sinks for heat pumps, reversible vs. non-reversible heat pumps, performance indices, open vs. closed loop systems, earth loop options, manifolded earth loops, pipe fusion equipment and procedures.