Doublewall

Doublewall refers to a design concept in which two walls are arranged in parallel with a gap or insulated cavity between them. This configuration is used to reduce heat transfer, improve thermal performance, and sometimes enhance structural rigidity or acoustic isolation. The term is applied across various industries, including consumer goods, architecture, and industrial storage.

Construction methods vary. The gap can be filled with air to rely on still-air insulation, or evacuated to form a vacuum that minimizes conductive and convective heat transfer. Some systems use insulating fills or gases within the cavity. Inner and outer walls are commonly made from metals, glass, concrete, or composites, and spacers or supports maintain the separation. In architecture, double-wall constructions are often referred to as double-skin façades, which can include operable layers for daylight control and ventilation.

Applications span several sectors. In consumer products, double-wall designs appear in vacuum bottles, insulated flasks, and other thermally insulated containers. In buildings, double-wall or double-skin façades aim to improve energy efficiency and occupant comfort. In industrial settings, double-wall containment is used in cryogenic dewars, LNG tanks, and other storage vessels to provide secondary containment and reduce heat ingress. Double-wall packaging, such as cardboard with two walls, also enhances strength and protection.

Advantages include reduced heat loss or gain, condensation control, improved acoustic isolation, and increased safety in some storage contexts. Limitations include higher manufacturing costs, added weight, potential degradation of vacuum over time or moisture ingress, and greater design and maintenance complexity.