Root zone warming system and method for natural turf athletic field

A system for warming an athletic field of natural grass wherein the natural grass has downwardly directed roots that define a root zone, wherein the roots of the natural grass extend downwardly into an air permeable particulate subsurface, thereby defining the root zone, with a piping network residing in the particulate subsurface, the piping network including pipes with openings therein that permit water to flow into the piping network by gravity to drain the athletic field, the piping network also including an outlet for draining the athletic field, comprising:

• a vault located adjacent the athletic field, the outlet of the piping network terminating at the vault, so as to operatively connect the piping network and the vault in fluid communication;
• a positive displacement blower operatively connected to the vault via a conduit extending therebetween, the positive displacement blower adapted to push air from an output end thereof into the vault via the conduit, for flow thereafter into the piping network;
• a variably controllable valve residing along the conduit between the positive displacement blower and the vault and operable to vary a flow resistance to air flow therethrough, whereby an increase in the flow resistance causes a corresponding increase in temperature of the positive displacement blower and hence an increase in temperature of the air pushed therefrom;
• and
• a controller operatively connected to the positive displacement blower and the variably controllable valve, the controller adapted to operate the positive displacement blower to cause the air to be pushed from the output end thereof through the conduit, including the variably controllable valve, and thereafter into the vault, the piping network, the subsurface particulate material and the root zone, and upwardly from the athletic field, the controller also adapted to operate the variably controllable valve so as to selectively set the flow resistance in the conduit adjacent the output end of the positive displacement blower, thereby to correspondingly change the temperature of the air pushed by the positive displacement blower, whereby the temperature-changed air moves into the vault, the piping network, the subsurface particulate material and the root zone, and eventually upwardly from the athletic field.