The ‘Air-Wall’: Re-Evaluating a Mid-Twentieth Century Four-Sided Double-Skin Façade

In the 1950s, architect William Hajjar built a four-story research building with a two-story double-skin facade (DSF) on all four building sides with the intention to explore solar heat control strategies: in winter, the movement of warm air from sun-exposed DSFs toward the cold sides to reduce heating loads, and in summer, the removal of the DSF’s warm air to reduce cooling loads. The article presents archival studies, computational fluid dynamics simulations, and smoke experiments, all undertaken to explore the performance of four-sided DSFs with regard to heat distribution and airflow patterns in winter. The studies confirm the potentials to create a temperature equilibrium around the facade and reduce heating loads. However, excessive heat build-up in the DSFs on clear days remains challenging.