Ask anybody you know if they would prefer to have an operable window in their office, and chances are you’ll find few people who would say “no.” So why are so many office buildings designed with sealed glass facades that don’t allow occupants to open a window and get a (real or imagined) “breath of fresh air”? Has our culture become addicted to air conditioning? How can we encourage engineers to be truly innovative, to move beyond conventional practice by designing or retrofitting buildings that provide the benefits of both natural ventilation and air conditioning?
Most contemporary office buildings are designed with sealed envelopes, are internal-load dominated, and are cooled by mechanical air conditioning systems. The hvac system is designed to maintain constant, uniform conditions throughout the interior, but at a significant cost in terms of capital, energy consumption, and associated environmental impact. Mechanical cooling and fan energy accounts for approximately 20% of commercial building electrical consumption in the United States.