Salmaan Craig is a lecturer in environmental technology at the Harvard Graduate School of Design. He is trying to “disinvent” the need for air conditioning by combining natural ventilation with specially designed materials, surfaces and building forms. He used to work for the architecture firm Foster + Partners, and before that, BuroHappold Consulting Engineers. He has an engineering doctorate in environmental technology and a bachelor’s degree in product design, both from Brunel University in London (his hometown).
Project: On Breathing Buildings and Termite Mounds (or How to Disinvent the Need for Air Conditioning)
I will develop entries for an interactive textbook. The primary audience is students of architecture at the Harvard Graduate School of Design. The applets and programming exercises will show how to design buildings to keep cool in a warming world. The idea is to use “smart” geometry and “dumb” materials to extract work from exterior temperature oscillations. I want to emphasize how the important thermodynamic relationships transcend architectural style—in other words, that designers may generate an infinite variety of forms that all conform to certain rules and thus all perform equally well.
Contents of the book include:
- Climate and Materials: Using the Wolfram database to answer where in the present and future world can we ventilate buildings naturally, and what materials should we use to build these “breathing” buildings?
- Emptying Filling Boxes: The principles of buoyancy ventilation, or how to ventilate naturally in the absence of wind. Includes a case study of a multistory building in Medellín, which will be the first office of its kind to have no air conditioning installed.
- Breathing Walls: On the design of porous building materials for decentralized heat recovery and ventilation. These “functionally upgraded” materials may be integrated into walls, floors or ceilings so that the interior space is tempered radiantly, while incoming fresh air is preheated or precooled.
- Termite Mounds: On the operation of termite mounds, which passively regulate interior temperature, humidity and fresh-air flow. The geometry and thermal mass together extract useful work from the exterior temperature oscillations.
- Morphed Mass: How to design the morphology of a surface to improve the heat-exchange between a massive building and its interior environment, using standard heat-exchanger design correlations.
- Thermal Resonance: When coupling a thermally massive building to an exterior temperature oscillation, it is possible to drive an oscillating cycle of buoyancy ventilation—up at night, down at day. In this regime, the building has a natural frequency. The airflow can be modulated by geometry to resonate at that same frequency, so the building extracts maximum work from the environment.