This paper describes the Architectural Design Studies undertaken by Mario Cucinella Architects as part of a three year JOULE research project into the application of Passive Downdraught Evaporative Cooling (PDEC) in non-domestic buildings. The objective of the research was to develop a viable passive alternative to air-conditioning through architectural design, experimentation and performance assessment. MCA’s architectural research investigations involved 1) designing and constructing a full-scale experimental building to explore passive ways of capturing and conducting air through a tower into test cells and 2) designing a new office building in Catania Italy to develop the application of PDEC and undertake building performance assessment. Experimental work included wind tunnel tests, computer simulations and daylighting tests. The result of the design work is a new energy efficient building typology that is both a successful application of the evaporative cooling system and a direct architectural response to scientific problem.