Heat conservation system for greenhouses

A greenhouse structure consisting of laterally extending spaced-apart arches supporting an air-inflated roof wall comprising spaced-apart layers of plastic, said arches connected together by inwardly spaced purlins under the inner plastic layer connected to said arches by stub connectors to prevent the inner plastic layer from contacting said purlins between said arches, and blower means selectively to introduce insulation particles into the space between said plastic layers and to evacuate air from between the plastic layers in order to collapse the outer plastic layer.

A greenhouse structure having a curved roof wall formed of two layers of plastic film with an air space between them, a fluid circulation system having conduit means for introducing insulation particles into said air space at one end of the top of said structure, and conduit means for evacuating said particles from the bottom sides of said air space at the other end of said structure, and valve means in said system to induce a longitudinal air channel through the particles in the top of the air space at the start of the evacuation of said particles so as to form downwardly extending particle-entraining air streams during evacuation.

The method of conserving heat within a greenhouse having a curved air-inflated roof wall formed by spaced-apart flexible plastic layers, comprising the steps of blowing insulation particles into the top of the wall at one end to completely fill the space between the layers during the nighttime, evacuating the particles progressively from one end to the other of said space into a storage enclosure during the daytime, inducing a longitudinal air channel through the particles in the top of the wall at the start of evacuation, and continuously withdrawing particles from the bottom sides of said curved wall to form particle-entraining air streams extending downwardly from said upper channel to said bottom sides, said downwardly extending air streams moving progressively longitudinally of said greenhouse and causing the outer plastic layer to collapse progressively behind said air streams as the particles are evacuated.