raw · articles · ingested 2026-06-30
US 3,903,665 — Heat Energy Transmission Control Panel (Beadwall)
Source: Steve Baer / Zomeworks archive
Inventor: David Carl Harrison
Assignee: Individual (Harrison personally — not Zomeworks)
Filed: November 28, 1973
Granted: September 9, 1975
Status: Expired — Lifetime
Abstract
Adjustable window panel system controlling thermal energy transmission by pneumatically moving granular insulative material (expanded polystyrene beads) into and out of the chamber between two parallel transparent windows. Air blower propels beads into chamber (insulating) or returns them to storage bin (allowing solar gain). Check valves control flow.
Key claim
Two parallel transparent window members defining an internal chamber; a storage bin containing thermal insulative material; an air blower transporting material via ducts between bin and chamber to adjustably control heat transmission.
Significance
- Beadwall is the invention Baer credits as the finest in Sunspots: “Such elegant inventions as the beadwall indicate that the healthy response of architecture to increasing energy costs may be increased use of glass in building walls rather than a retreat to underground buildings.”
- Assigned to Harrison personally (not Zomeworks) — Harrison owned the invention; Zomeworks commercialized it
- Filed 1973, the same year Baer was serializing solar physics in the Tribal Messenger
- Applications include windows, solar collector protection, greenhouses, skylights