There was a time in this country when a workers comfort was not much of a concern. In fact, not too long ago freshening or cooling the air in a commercial building wasn’t much more sophisticated than opening a window or turning on huge fans. Over the years air-handling equipment has certainly improved. And today, with numerous studies recognizing the impact the work environment can have on job performance, solving heating, cooling and air quality issues has become a priority. Today “The air conditioning system in modern office buildings or school buildings or industrial buildings has been designed to provide indoor air quality and a ventilation and a temperature and a humidity that’s satisfactory to human comfort. And all of those features work together as an assembly to provide the needs of the humans that occupy that space.” Says engineer and HVAC professional Larry Fagala.
However, airflow needs change as the work environment changes. Many factors such as, occupied or unoccupied conference rooms, use of office or kitchen equipment, even the position of the sun and clouds around the building, all vary heating and cooling requirements throughout the day. For this reason most building have some form of variable cooling system. But there can still be some problems with variable systems. For the most part they use induction motors to turn the fans within the units that control the flow of heated or cooled air. This type of motor has been designed for peak performance when turning at a steady pace, but often loses efficiency when forced to alter speeds. Sometimes these high voltage AC motors can actually wind up generating more heat while producing cool air. By leveraging a new type of motor, called an ECM, and combining it with micro processing technology, engineers have developed a state of the art Variable Air Volume system to address these concerns. ECM stands for Electronically Commutated Motor, commutated refers to internal switching it comes complete with an internal computer that gives it the ability to actually pre-program outputs and to optimize the internal switching. And the system incorporates a DC motor, which by its very nature uses less energy than an AC motor, found in the more traditional systems. In a side-by-side test of two identical AC units one powered by a traditional induction motor and one with an ECM motor the following results were observed. To turn the fan at 410 RPM’s the induction motor required a continuous 135 Watts of power the ECM only 19 -20 Watts to achieve the same RPM’s.
Developers are incorporating these units into the design of many new projects in metropolitan areas such as Chicago. “We as the developer win because we have a better indoor environment for these folks, better indoor air quality. The tenants themselves are more comfortable – we use less energy from the power plant, we use less coal, less pollutants are passed into the environment, and so it’s really a win/win for everyone concerned.”
“Green design” means being responsible to the environment and the people that live in it. An environmentally efficient building addresses issues not only of costs, but also of comfort and wellness. When it comes to concerns about working conditions in today’s commercial spaces, engineers and architects are joining forces so managers and employees can both breathe a little easier.