Forum 2016 - Infrastructure Space - Detroit (Ruby Press)
107 106 oning technology. 4 The story is docu- mented in thermal-comfort standards written by air-conditioning engineers (who were invariably white, male, and conservatively clothed). 5 For the major part of the twentieth century, engineers’ attention was focused on reliably changing the state of the air-vapor mix. 6 This was com- plex enough; the subtlety of human physiology and psychology was se- condary and intractable. They worked on refining a definition for a universal range of thermal conditions. The more people, activities, climates, and buil- dings this applied to, the better. The implicit goal was to nullify thermal sensation. The simplest way to con- trol complexity, after all, is to avoid it entirely. The designation of thermal “com- fort” implies some recognition or anticipation of contrast. It’s that mild endorphin reward released on a favorable change, or at the prospect of a favorable change. Marketeers in America’s golden age of cinema knew this well; when air-conditioning was rare in homes, offices, and cars, and the thought of escaping to a cold mo- vie theater was genuinely enticing. 7 Today it is quite possible to move from home to car to office to mall without having to experience the outdoors. In the absence of contrast, thermal “comfort” begins to lose its meaning. Thermal “monotony,” “neut- rality,” or “indifference” is more apt. 8 Or perhaps thermal “non-sense.” In the history of technology, the sleepwalk into luxury traps is a well-trodden path. 9 Luxuries tend to The inefficient infrastructure that and heats and cools our buildings to offset the effects of changing clima- tes is increasingly contributing to that change. To overcome this fact, not only must we learn how to unplug from HVAC (heating, ventilation and air-conditioning) infrastructure, we must also challenge the division (and the divide) between infrastructure and architecture, argues Salmaan Craig. Blunted Sensorium At the dawn of twentieth century, du- ring the era of electrification, demand for artificial light far outstripped any energy savings from improved light- bulbs. 1 The same is happening today with artificial cold. Globally, energy for cooling is set to exceed energy for heating by 2060. 2 The “cold crunch” is on the horizon, and more efficient versions of the same buildings won’t buck the trend. 3 Before thinking of alternative designs, we must question our ex- pectations for thermal comfort. Our Paleolithic tolerances have narrowed alongside the evolution of air-conditi- Mass and Material Architecture: How to Unplug from HVAC Infrastructure Salmaan Craig become necessities and to spawn new obligations. Once people get used to a certain luxury, they take it for granted. Then they begin to count on it. Finally, they reach a point where they can’t live without it. How does the dulling of thermal sensibility affect us? It’s hardly a hot topic of research. One old military study shows that while each of us have broadly the same number of sweat glands, the total that grow to be fully operational depends on how much heat stress we experience in youth. 10 This effect is the same as a person that has strong bones today because while growing up she spent more time running and jumping than sitting and watching television. Breathing Buildings New thermal-comfort standards ack- nowledge important subtleties in ther- mal sensation, such as our automatic adaptation to seasonal changes. 11 This hard-fought revision has loose- ned the shackles significantly. A wider target comfort range, and a closer overlap with exterior temperatures, means that air-conditioning can stay switched off for longer. Design teams can now seriously consider natural ventilation. It is hard to overstate the importan- ce of this revision. The target comfort range is the starting point or closing door to all conversations on passive design. Not efficiency add-ons and afterthoughts, such as hi-tech glazing or new insulation materials, but bold, effective architectural designs, cen- tered on natural ventilation. An overly conservative comfort range can give design teams the false impression that natural ventilation is possible for only a small proportion of hours in the year. Little wonder that connections to the exterior—atria, chimneys, buffer zones, and plenums—often appear frivolous. One of the major challenges of natural ventilation is the unpredictab- le frequency, direction, and strength of wind. In the last decade, however, significant progress has been made in understanding a more reliable driving force. Buoyancy ventilation is natural ventilation too, but it does not rely on the wind—it is powered by the waste heat from occupants, computers, and other internal heat gains. The greater the internal gains, and the taller the room, chimney, or atrium, the greater the driving pressure difference. Out flows warm stale air from the top; in flows fresh cool air from below. Unlike wind-driven ventilation, the fresh air is pulled in, not pushed. Much of the theoretical work has come from a lineage of researchers with connections to a group at Cam- bridge University. 12 The findings have been summarized into simple mathe- matical models so that engineers can size openings and stacks relative to the internal heat loads, and thereby deliver a reliable stream of fresh air and sustain a comfortable interior temperature. 13 With wind-driven ventilation, there is often a mismatch between oc- cupancy and the availability of the breeze. Not so with buoyancy venti- Even as climates become more extreme, i terior temperatures r main constant through the use f HVAC (heating, ventilation, and air conditioning) systems that exacerbate the very conditions they are meant to control. Focusing on cooling, Salmaan Craig argues for a dual approach: broadening th definition of thermal comfort and designing architectural solutions suitable for bulk use.