“The conditioned mind will learn by comparison. The enlightened mind will learn by analysis.” – Frank Lloyd Wright
How many software programs does it take to choose a light bulb? The answer is 36, according to Software Solutions technical roundtable gurus Michael Marvin (Buro Happold) and Jessica Zofchak (Atelier Ten).
Designers have used computers to model building energy use for almost 50 years, and the recent combination of available processing power and a need to meet energy codes has made modeling central to building design. The classic problem is that as the design process proceeds, the information necessary to make good decisions often comes after the window to make changes is past. Thus, buildings get “locked in” to designs that aren’t as good as they could be.
Used together, those 36 programs allow many different scenarios to be modeled virtually so that designers can compare radically different approaches and then tweak the final scheme to within an inch of its life. Through integrated design, in which different models interact with each other, substantial energy savings can be achieved. For example, if the façade R-value is improved, it lowers mechanical cooling and heating needs. That might mean smaller equipment and distribution, which means less space needed above the ceiling, which means lower floor-to-floor heights. While the usable floor area doesn’t change, the total building height is thus lowered, which means less money spent on the façade! In the end, what might at first seem like an added expense for better glass could actually translate into a net savings, since less glass and smaller equipment and ductwork are needed, even before any energy savings are taken into account.
In an age where seemingly every new building tries to maximize glass area (while still meeting code), this kind of modeling is essential. While codes begin by mandating values for heat gain and insulation, designers can turn this process on its head by using models to choose the best overall solution involving various factors (including cost) and then finding manufacturers making products that meet the determined criteria. These models are turning up some interesting results. “Owners are driven by daylighting and views,” Marvin said, “but we’ve shown these can be maximized with 55% vision glass area or even less.”
It’s fun to watch the building models spin onscreen, but of course, the map is not the territory. What gets built is never exactly what was designed, and moreover, the design documents say little or nothing about how the building will be operated once occupied. Marvin gave the example of building owners who complained about condensation from chilled beams in the lobby ceiling, telling the designers “You designed it wrong!”. Upon investigation, it was discovered that cheap door closers were breaking, prompting staff to prop open the front doors and allowing warm, moist air to constantly enter the lobby. In this case, the fix was as easy as better door closers. And when computer modelers find a way to include the human factor, expect an Urban Green technical roundtable on the topic.