Underground heating and cooling system

A method of heating or cooling a structure by utilizing the natural earth as a source of energy to heat and cool, due to the mean temperature lag phenomenon, comprising the steps of:

• circulating a generally closed system of air through said structure;
• directing the generally closed system of air from said structure into and through the ground to a depth of approximately five to ten feet;
• directing the generally closed system of air through elongated conduit means disposed underground and within the natural earth at a depth of generally between five and ten feet and wherein the elongated conduit means extend generally horizontal through the earth within said depth range of approximately five to ten feet deep over a substantial area of earth such that there is substantial surface area contact between said elongated conduit means and the natural earth;
• directing the air of said generally closed system through the elongated conduit means that extends generally horizontally through the natural earth within said depth range of approximately five to ten feet;
• effectuating a heat transfer between the air of said generally closed system of air and the natural earth lying adjacent said elongated conduit means such that the air is cooled when it is warmer than the adjacent earth and is heated when it is cooler than the adjacent earth;
• draining water and condensation from the elongated conduit means while said generally closed system of air is circulated through said elongated conduit means;
• directing the heated or cooled air of said generally closed system of air back to said structure for effectively heating or cooling said structure;
• and continuously circulating said generally closed system of air through said structure and through said elongated conduit means so as to continuously heat or cool said structure for a period of time.