Pillow Dome

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The Pillow Dome, built by Jay Baldwin in the early 1980s, pioneered the concept of using inflated pillows made of Tefzel in three layers. Argon was used as the inflating agent, leading to even better thermal insulation. The Ark housed a growing environment consisting of intensive organic gardens, irrigated by the "exhaust" from large, transparent tanks containing fish. The high, open interior space included tall fish pond (see aquaponics), a large fig tree, and vegetable beds. The tanks also served as an effective heat sink, allowing an indoor climate warm enough to grow bananas in February, in New England, with no fossil fuel heat source. The Pillow Dome pioneered the technology that was later used in the Eden Project in Cornwall.
Inside the tropical Biome at Eden Project: The covered biomes are constructed from a tubular steel (hex-tri-hex) with mostly hexagonal external cladding panels made from the thermoplastic ETFE. Glass was avoided due to its weight and potential dangers. The cladding panels themselves are created from several layers of thin UV-transparent ETFE film, which are sealed around their perimeter and inflated to create a large cushion. The resulting cushion acts as a thermal blanket to the structure.

(This page was in part excerpted from Fluoropolymers.)


The Pillow Dome was a project by Jay Baldwin that was built in the early 1980s at The New Alchemy Institute on Cape Cod. The New Alchemy team was advised by John Todd (one of the Institute's founders), captained by John Wolfe, who also did solar calculations, with horticulture by Liz Fial. Daryl Bergquist developed the instrumentation and aided construction.

Technical Detail About The Pillows

The pillows were made up in three layers, heat-scaled together with a seam 3 inches inboard from the edge of the material. A gas-loading valve was installed near one corner. Pillows are installed on the tubular frame by means of long, semi-cylindrical clamping strips fashioned from slit PVC water pipe. The 3 inch flaps on each pillow are overlapped "downhill" under the clamping strips before being secured to the frame with 3/16 inch poprivets spaced every 6 inches. This produces a reliable, mechanical, waterproof seal well able to withstand heavy weather conditions and expansion contraction that has engendered so many leaks in other domes. The pillows are cut from roll stock with no waste.

Inflation is with Argon gas at a pressure of 1/2 lb/ft2. Argon is inert, nontoxic, and about a 30 percent better insulator than air. The pillows end up about 4 inches thick at the center, giving an effective, triple-glazed, transparent, insulated panel of about the same transmissivity as one layer of low-iron solar glass. The pillows also offer a certain amount of fire protection - if one should be punctured by a flame, the inert gas would quickly snuff it out. Another attribute is the very good acoustics. The bulged pillows completely kill the obnoxious echo usually found in domes.

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