Optimizing Laboratory Ventilation: Use Of Sophisticated Modeling Tools
A large component of the operating costs for a laboratory facility can be attributed to the HVAC systems. With rising fuel prices and resultant increases in energy costs, designing more efficient HVAC systems is becoming more important than ever for sustainable building design, because of the reduced energy usage, and ultimately the survival of the research industry. The presentation will focus on the specific issue of laboratory ventilation, both internally and externally, and will illustrate how considering both early in the design process can provide an optimized design that is "right-sized" for the intended use of the laboratory space.
Many laboratory designers are aware that ventilation systems tend to be over-designed. There is often a reluctance to reduce the ventilation rates due to the risk involved. Part of the risk is associated with the potential to compromise the indoor air quality and comfort within the laboratory space. This aspect of risk can be addressed at the design stage through the use of detailed modeling and optimization of the ventilation system. Internally, this would involve the use of computational fluid dynamics (CFD) modeling to determine the minimum number of air changes per hour (ACH) and optimal air distribution configuration that would lead to appropriate indoor air quality and comfort. This modeling has the ability to consider several internal variables as desired by the designer/owner; such as diffuser locations, heat from windows and equipment and chemical spills outside of fume hoods. Externally, dispersion modeling of the exhaust (using numerical or physical wind tunnel techniques) would be used to optimize the ventilation rate. Through evaluation of parameters such as exhaust and intake location, stack height and stack exit velocity, the minimum exhaust ventilation rates required to maintain acceptable air quality levels at the air intakes can be determined. Thus, any air entering the laboratory space would not compromise the indoor quality of air supplied by the internal ventilation system.
Specific examples will be used to demonstrate how these sophisticated modeling tools can be used to reduce the risk involved with "right-sizing" the laboratory ventilation system.
Labs21 Connection
Aspects of the application that are unique/noteworthy and apply the Labs21 Approach include:
Minimize overall environmental impacts
- Providing methodology/approach to achieve sustainable goals with respect to energy use while reducing the liability concerns.
- Will contribute to reduction in energy use and consumption of fossil fuels, which would in turn reduce the emissions believed to be responsible for global warming.
Optimize whole building efficiency on a life-cycle basis
- An optimized ventilation system can save owners a considerable amount in operating costs.
- Combined approach that considers the "whole building" concept (e.g., how external and internal ventilation issues affect one another).
Establish goals, track performance, and share results for continuous improvement
- Use of sophisticated modeling tools allows detailed evaluation of the building operations during the design stage (i.e., predictive).
The above discussion and points highlight that this presentation will focus on an approach that will achieve many, if not all of the Labs21 objectives. The main focus of the presentation is centered on increasing the efficiency of the laboratory's energy use, and providing designers with a method that will allow them to provide a more efficient design without concern for potential liability. Optimizing the system will result in less energy use and less fuel consumption, which will reduce the overall environmental impact. The consideration of both internal and external ventilation will protect occupant safety, and considers a whole building approach.
The full presentation has been converted to PDF (2.7MB) with a linked animation (7.8MB). (You must be connected to the Internet to view the animation.)
If you have Adobe Reader 6 or higher, this PDF (8MB) has the animation embedded.
