Demand-controlled Filtration

One of the major energy uses in cleanrooms is in the management of particles in the space. The acceptable level of particles depends on the use of the space, as indicated by the cleanroom specification. Recirculation of air is a means to the end, but the question of whether higher air change rates necessarily yield higher levels of cleanliness has not been adequately addressed. LBNL began its research on this topic in the mid-1990s, which focused on analyzing the potential for dynamically managing air change rates in response to real-time particle-count measurements. By doing so, desired environmental conditions can be maintained without excessive energy use. The results of a lab study were very positive, indicating an economic payback time of 1 to 4 years, depending on whether or not the facility's recirculation system is already equipped with variable speed drives. Industry receptiveness to this thinking is evident in a site benchmarked by the LBNL cleanrooms project, where substantial nighttime air change setbacks in a Class-100 cleanroom were found not to compromise the process. In another study, energy savings were evident while maintaining required cleanliness levels.

Demand Controlled Filtration in an Industrial Cleanroom

Faulkner, D., D. DiBartolomeo, and D. Wang. LBNL-63420. September 2007