In this episode, Wolfgang Kessling — a physicist by training — talks of the challenge of indoor comfort, and its impact on global energy demand.
In most projects, consultants will prescribe mechanical solutions for heating and cooling, operating within a narrow bandwidth of conditions. Wolfgang argues that this is a failure of imagination and almost always leads to high energy use.
To counter this approach, he traces the scientific roots of thermal comfort and looks to the theory of adaptive comfort which rejects the idea of static, uniform conditions, and posits that human perception depends on context and climate.
In Luma Arles, an art gallery in France, the entry foyer is a thermal transition zone, mediating between outdoor and indoor climate-controlled spaces with a mixed-mode condition that combines passive and active systems.
© Wolfgang Kessling, Transsolar
Designing for adaptive comfort begins with an understanding of where people are, how they behave, and the conditions they find comfortable. In this interview, Wolfgang explains how this principle was operationalised in several projects including the Brac University campus, in Bangladesh.
The Brac University campus has multiple thermal zones. A substantial part of the building relies on passive strategies such as natural ventilation.
© Obilia
In yet another hot-humid setting, Singapore, Wolfgang designed a novel hybrid cooling system for SDE4, a net zero energy building at the National University of Singapore.
The SDE4 relies on passive strategies of favourable solar orientation, porous form and envelope shading to reduce the demand for cooling.
© Rory Gardiner | Courtesy of NUS College of Design and Engineering and Serie Architects
SDE4 combines ceiling fans with moderately cooled ducted air which, together, feel like air-conditioning, and consume substantially less energy than a conventional air conditioning system.
The hybrid system of SDE4 delivers comfort to occupants where they sit. Ceiling fans, relying on sensors, switch on only when an occupant is nearby.
© Rory Gardiner | Courtesy of NUS College of Design and Engineering and Serie Architects
Wolfgang has worked in many climatic zones from hot-humid to desert. In each, the principle of low energy, low tech is the same, however, the outcome is different since this depends on human behaviour and expectations of comfort.
The Brac University campus is situated in the dense urban context of Dhaka in a hot-humid climate. Many who live in this city are acclimatised to passive modes such as natural ventilation, aided by ceiling fans.
© Patrick Bingham-Hall
Wolfgang’s journey has taken him from aspiring nuclear physicist to one of the world’s leading energy-comfort experts. He reminisces how the Chernobyl disaster in 1986 compelled him to ask what kind of world he wants to help build. He switched his focus to solar energy and never looked back.