According to a survey conducted by lab professionals in 2010, approximately 43% of fume hoods among 247 labs across United States are conventional CAV (Constant Air Volume) fume hoods. An average CAV fume hood can consume as much as about 3.5 times the amount of energy consumed by an average American family.
Despite the fact that a variety of products were invented in the past decades to save energy for fume hoods, such as sash monitors and sash alarms, it still hasn’t raised much awareness for users who don’t close the sash and use the fume hoods properly to save energy. On the other hand, VAV (Variable Air Volume) fume hoods vary the volume of room air exhausted while maintaining the face velocity at a set level. The system is also electronically connected to the building HVAC system so the supply and exhaust can be adjusted and balanced with ease.
Consequently, it will bring a higher initial investment, but in the long term, a considerable amount of energy savings can be expected due to the reduction in total volume of conditioned air exhausted from the laboratory. However, unfortunately, only 30 out of 247 surveyed labs were installed with VAV fume hoods in 2010 in the United States. Although VAV fume hoods have a much more complex ductwork structure than conventional fume hoods, the energy savings could be enormous, and the initial cost would undoubtedly eventually pay off.
For example, if the laboratory's ventilation system uses 100% once-through outside air and the value of conditioned air is assumed to be $7 per CFM per year (this value would increase with very hot, cold or humid climates), a 6-foot VAV fume hood at full open for experiment set up 10% of the time (2.4 hours per day), at 18 inch working opening 25% of the time (6 hours per day), and completely closed 65% of the time (15.6 hours per day) would save approximately $6,000 every year compared to a hood that is fully open 100% of the time; according to U.S. Department of Energy back in 2012.
Nevertheless, this saving is highly dependent on users’ behaviour. If the personnel closes the sash when needed, the savings could be significant. Therefore, different universities and labs are applying their own campaigns to convey the idea that closing fume hood sashes significantly matters in terms of impacting the energy bill for the whole building.
Also, VAV fume hoods provide superior flow control with extremely fast and stable response times that secures users’ safety. It also eliminates the need for re-balancing, regardless of system changes or filter loading. Furthermore, it produces negligible noise which is greatly appreciated by users in the lab and surrounding university environment.
Air Master Systems is a well-known fume hood and accessory producer in North America. Its unique energy saving design and outstanding quality has earned lots of reputation in the industry. Its signature product, the Green Solution Hood, is designed to have 96% less energy consumption than a standard fume hood, as well as 70% lower in operation cost. With its special chemical filtration system named Erlab®, it effectively absorbs acids, solvents, liquids and even powders with HEPA accessories. Belnor Engineering is proud to be a distributor of this clean fume hood technology, and we have received abundant praise and appreciation for this innovative product line. Please contact Belnor Engineering for more detail.
In conclusion, with the rising need and demand of sustainability, VAV fume hoods are setting a global trend of protecting our nature and environment by saving energy. Also, the awareness of closing fume hood sashes when unattended needs to be raised by different research communities and educational institutions in order to communally reap more energy savings.