The next time you step into a brand-new building, take a look at the wall. The "thermostat" you see may have another box with a CO2 sensor inside. That CO2 sensor is the end result of years of research into balancing indoor air quality (IAQ) and energy efficiency in building design.
Every home, classroom and office building requires a constant flow of fresh, conditioned air to make it comfortable for the people who work and live inside. In the past, finding fresh air was not a problem because most buildings were porous, i.e. outdoor air “leaked” into the building around windows and under doors. Everyone has experienced a cold draft in an old house or building.
While “leaky” buildings insure fresh air, they are also expensive to heat and cool. As energy prices have risen dramatically over the last few decades architects started designing new buildings that minimized energy loss. For example, throughout the 1970’s many school and office buildings were designed with permanently sealed windows. While this saved energy, it had the unexpected consequence of sealing in mold, bacteria, and potentially harmful gases like radon, VOCs (volatile organic compounds), and carbon dioxide (co2).
Studies showed that high concentrations of the gas and contaminants created health problems for occupants, and the term “sick building syndrome” was created to describe these new, sealed, air trapping structures.
To combat “sick building syndrome” HVAC (heating, ventilation, and air conditioning) designers and installers have developed systems that regulate a constant flow of fresh, outdoor air into buildings. The idea was that wasting energy to condition outdoor air was the price you had to pay to provide fresh air indoors. In some cases, these HVAC systems either provided non-stop fresh air, or in other cases they were set on timers that would open fresh air dampers when the building was occupied.
In other words, the solution to providing fresh air was to open a window!
In countries where energy is more expensive, an alternative method of providing fresh air was used. Instead of constantly providing fresh air, buildings used carbon dioxide sensors to “sense” when the buildings were occupied. When enough people enter a room, the CO2 level rises because of the CO2 from their exhaled breath, and the HVAC system begins to bring in fresh air. When the people leave, the CO2 level drops because they are no longer breathing in the room, and the fresh air dampers close.
In addition to emitting less carbon dioxide and using less water, sustainable designed buildings cost less to operate. According to a recent report by the US Department of Energy's Pacific Northwest National Laboratory government facilities with sustainable HVAC practices cost 19 percent less to maintain. The results are included in a white paper released by the Government Services Administration, or GSA.
One other example in regards to CO2 monitoring and energy efficiency, is the Empire State Building. The Empire State Building had an energy-savings retrofit in 2011 including VAV systems controlled by CO2 transmitters. In 2014, the building management reported that they had surpassed the energy savings originally guaranteed for the third consecutive year. The property beat its energy-efficiency guarantee by 15.9 percent, saving $2.8 million. Over the past few years, the program has generated a total of approximately $7.5 million in savings.
This system of using CO2 monitoring devices to trigger/control HVAC systems is starting to catch on in the U.S. Many new commercial buildings are now designed to meet LEED (Leadership in Energy and Environmental Design) specifications. LEED was designed and is administrated by the USGBC (United States Green Building Council) and the testing and certification of the program is conducted by the Green Business Certification Inc. (GBCI). The LEED program provides a rating system for energy efficient building design. Included in LEED is are specifications for utilizing CO2 sensors to control fresh air circulation.
Do note, that outdoor CO2 measurement is not required for LEED credit, and may only be useful under certain scenarios. Companies seeking LEED certification for new buildings should consult a LEED-certified engineer for the most recent rules.
Also note, that the American Society of Heating and Refrigeration Engineers (ASHRAE) recommendation for not exceeding 1,000ppm of CO2 in office buildings still applies, as well as current ASHRAE workplace safety limits.
One of the sensor technologies that makes buildings like the examples above possible, is the next generation of low power CO2 sensors like the LP8. These low-power sensors are already being designed into OEM Devices with long-life batteries and WiFi so they can easily be installed in every room. They can report back to the HVAC system to modify the environment or confined space in real time.
At CO2Meter.com, we provide an array of wall mount Indoor Air Quality Fixed and Portable Safety Devices, used worldwide to control HVAC systems. So the next time you see a wall thermostat, look for a box beside it.
It might just say CO2Meter.com on the label.
For more information on selecting the proper IAQ sensor or device for CO2 monitoring for your application - speak to one of our experts today. Sales@CO2Meter.com