HVAC is a necessity in every building. Whether you're heating, cooling, or ventilating, you need to have systems in place that will do the job efficiently, effectively, and comfortably. But, there's not one system that will do the job for every facility. As technology develops, green becomes status quo, and people demand healthier, more comfortable places to live, work, and play, you may want to investigate other HVAC options.
If your HVAC systems haven't caused you big problems or complaints, why should you give them a second thought? The 2-20-200 rule is a good reason. Consider this: In a typical U.S. commercial building ...
Roughly $2 per square foot is spent each year on energy.
The cost of construction, amortized over 25 years, equals about $20 per square foot per year.
Overhead costs, salaries, etc. to keep occupants in the building total around $200 per square foot per year.
When you're able to increase occupant productivity by just 1 percent (the equivalent of about 5 minutes per day per person) via better indoor air quality or better temperature control, that increase pays for your building's energy use for an entire year. And, if you're able to increase occupant productivity by 10 percent, you could pay for your building.
If your HVAC system isn't cutting it anymore - or even if it is - check out some of these alternatives: chilled beam systems, geothermal, night-sky cooling, and thermal energy storage systems.
An example of night-sky cooling in use:
Located on Stanford University's campus in Stanford, CA, The Carnegie Institute for Global Ecology, built in 2004, makes use of a night-sky cooling system. Chilled water is supplied at between 55 and 60 degrees F. using only 0.04 kW/ton, and using approximately half as much water as a traditional water-cooled chiller.
An example of thermal energy storage in use:
The Ronald Reagan Washington National Airport in Arlington, VA, uses thermal energy storage; its system has been in operation since 1996. It utilizes a 2.2 million-gallon, above-ground chilled water storage tank that stores 40-degree F. chilled water to supply cooling to various airport locations. The stored water is also available for fire suppression.
An example of chilled beam systems in use:
In late 2009, the Constitution Center in Washington, D.C., will be the first large-scale building in the United States to use chilled beam technology. Chilled beams were chosen to overcome duct-distribution issues and offer comfort for tenants. The chilled beams serve the primary office area (floors 2 through 10). Conventional systems serve the entrance, lobbies, conference areas, etc.
An example of geothermal in use:
For the Killbear Provincial Park Visitor Centre, which opened in June 2006 and is located in Nobel, ON, the nearby Georgian Bay waters provide a cost-effective, energy-saving source for heating and cooling. A closed loop of condenser water using food-grade glycol sits 15-feet below the water's surface. The loop feeds 11 high-efficiency heat pumps inside the building and eliminates the need for a supplementary boiler or cooling tower.
Leah B. Garris ([email protected]) is senior associate editor at Buildings magazine