ABSTRACT
Harold R. Hay did as much to advance high-performance building envelopes as any person during the last half-century. Look up “passive cooling” strategies in any textbook on architecture and you will find Hay’s roofpond system right alongside the likes of courtyards and stack ventilation. Though decades of research have demonstrated outstanding performance in harsh climate regions, case studies are scarce and few design professionals have experience with the system.
This chapter will chronicle Hay’s development of the roofpond strategy – coined Skytherm – from his seminal discoveries during assignments in India and Central America through his prototyping and at-scale installations in the US Southwest. The chapter will then outline the unique history and advancement of Hay’s north adaptation of the roofpond. Following a number of roofpond installations in hot-arid locations, Hay conceived of an adaptation of the system for cold climate regions with considerable snow loads. Hay’s Skytherm North system was essentially a roofpond designed to be installed within a thermally enclosed attic with skylights. Only one Skytherm North demonstration was built until the Muncie Passive Solar Project in 2002, which featured the only fully monitored Skytherm North application on record. The chapter will outline how data from this research project was used to validate the performance characteristics of roofponds in cold climate regions, demonstrating once again the immense untapped potential of Hay’s system to make our housing stock more affordable to condition and more resilient in the face of severe climate conditions.
