Steve Baer and the double-play thermosiphon

This 2025 academic paper by Cem S. Kayatekin, published in ICON: Journal of the International Committee for the History of Technology (vol. 30, no. 2, pp. 120–153), traces the development of Baer’s water-based thermosiphon passive heating and cooling system — what Baer called a “double-play structure.”

Key claims

Claim	Detail
Overlooked innovation	The double-play thermosiphon is broadly overlooked in the existing discourse on Baer.
Long development arc	Seeded in the late 1960s, refined through the 1980s–2010s, still evolving at Baer’s death in May 2024.
New Communalist roots	Baer’s work grew out of the counterculture’s trust in design over politics, tracing through Buckminster Fuller.
Southwest landscape	The American Southwest was a critical experimentative landscape for alternative building.

Historical framing

The paper places Baer within the New Communalist thread of the American counterculture — the strand that sought to reshape society through material and built-world interventions rather than political struggle. Kayatekin traces this back to Fuller’s ambition to redistribute goods and technologies extracted from the military-industrial complex.

Baer’s path: Amherst College → UCLA → US Army in Germany → ETH Zurich (engineering + metal welding) → return to Albuquerque with wife Holly → disenchantment with conventional life → founding Zomeworks.

What a double-play structure is

A double-play structure is a water-based thermosiphon system that serves both heating and cooling from the same hardware — what Baer meant by “double play” was a system achieving both functions of an interior space, ideally in a simple, passive manner. Water circulates passively (no pump needed) between a roof-level radiator/absorber and indoor storage: at night in summer, hotter water rises to the roof, radiates to the sky, and sinks back cooled (night-flush cooling); by day the cycle self-stops because the radiator is warmer than the interior. Winter heating proved the harder half of the play — solved variously with louvers, south-facing absorbers, or a water Trombe wall.

Development arc (per Kayatekin)

Stage	Date	What happened
Stock pond melter	1967–68	Closed loop of aluminium and rubber piping filled with methyl alcohol keeps a hole open in a frozen stock pond; patented (US 3,618,569, Nov 9, 1971) but never sold — “I have come to suspect that the cowboys enjoy their winter ice-breaking expeditions.” The seed of the double-play loop.
Harold Hay contact	1968	Baer met Hay (Skytherm roof ponds, movable insulation) at the International Solar Energy Conference in Palo Alto.
Cool Cell	late 1980s	Closed-loop idea reborn at industrial scale to cool remote telecom battery arrays: interior water array (heat sink) + smaller rooftop radiator array in one bubble-free loop. Became about 70% of Zomeworks sales for several years.
Andy Shack	1988	10 ft × 10 ft test cabin on Zomeworks grounds: sub-ceiling array of 8-in water-filled PVC pipes, rooftop black pig-mat radiator, aluminium louvers below — effectively a hybrid of Hay’s Skytherm and the stock pond melter thermosiphon.
Bruce Davis Studio	2003–04	Baer and [[concepts/bruce-w-davis
Vertical vs. horizontal	2000s	Baer preferred horizontal sub-ceiling arrays and reverted to them at Zomeworks; Davis’s vertical wall array (adopted to avoid leaks over his drawings) opened a simpler path, developed further with [[concepts/karen-terry
Double Play 2.0	unbuilt	Davis’s sketch: internal array vertical against south glazing so it doubles as a water Trombe wall for winter heating; drainable roof radiator to avoid freezing; exterior roller shades. The current bleeding edge of the concept.

The productized Double Play (Zomeworks R&D)

Zomeworks’ own R&D page (fetched 2026-07-13) describes the productized “Double Play” building system: one or more absorber panels on the south side, water storage in the ceiling as thermal mass, radiator/absorber cooling coils on the roof, aluminum louvers to control radiant heat flow, and an optional fan. Summer: “Warm air rises to the mass of water in the ceiling and cool air returns,” with the roof coils dumping stored heat to the night sky. Winter: “heat radiates to the space below only when the louvers are open.”

Status per Zomeworks: two test outbuildings at Zomeworks headquarters (one for sale, one used for meetings and tours), plus a 20′ × 8′ cargo container retrofitted with roof water bladders as a lower-cost variant to be tested in Albuquerque — see Zomeworks shipping container prototype. “Double Play systems work best in dramatic climates such as the West and Southwest of the United States, where nights are cool, days are hot and winters are sunny.” The remaining hurdle is cost reduction.

Attribution disagreement: the Zomeworks page credits the concept to Norman Saunders, as explained in Bill Shurcliff’s Super Solar Houses, while Kayatekin traces the lineage to Baer’s own stock pond melter thermosiphon of 1967–68. The sources disagree on origin; both are primary in different senses (vendor page vs. history-of-technology paper).

Pitch context (2026)

A July 2026 research digest assembles external evidence for pitching a Double Play demonstration building at the Larry P. Abraham Agri-Nature Center (Village of Los Ranchos de Albuquerque, NM) — regional solar heritage, comparable demonstration buildings at education sites, radiant-cooling economics (17–42% savings vs. VAV HVAC, largest in hot-arid climates), and USDA funding routes. Its sourcing caveats: the term “Double Play” is documented only in Zomeworks’ own materials and the Kayatekin paper (cite those for the system itself), and the built demo of record is the 2004 Bruce Davis Studio.

Why it matters

historical depth + overlooked innovation + counterculture context = richer archive understanding

This is the only academic paper in the archive that examines Baer’s work from a history-of-technology perspective. It fills in biographical and intellectual context that the technical documents do not provide, and it confirms that the double-play concept was central to Baer’s career — not a side project.