Greenhouse construction - US4321775A

Expired US patent 4,321,775 (filed 1979) for a fully subterranean greenhouse with hinged roof, weather curtains, underslung artificial lights, ventilation and supplemental heating for photoperiodic and energy control. Patent US4321775A "Greenhouse construction," inventor Hiram J. Emerson, filed 1979-06-07, published 1982-03-30; status expired-lifetime. Abstract: subterranean structure adapted for greenhouse use with roof that can fully close enclosure or move to expose interior to natural light; curtain assemblies at free end/sides block wind/rain/snow; artificial lights under roof; ventilation and supplemental heating provided. Claims energy savings from subterranean installation and photoperiodic control by selective roof opening/closing.

Historical US patent—not a walipini standard and not Bolivian design IP.

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