Quality Engineered Structures Control Systems Image 1

Cleanroom Control Systems
Pressurization, Temperature, Relative Humidity, and Energy Usage Control

Quality Engineered Structures Control Systems Image 2 Critical environmental control systems provide a precise and stable environment for cleanroom spaces. Cleanroom manufacturing facilities have very exacting requirements when it comes to maintaining a sterile stable environment. Downtime in a production facility of this type is extremely costly; therefore a highly reliable control system that does not require on-going maintenance is a must. A host computer should issue the commands to each controlled device and control and monitor the status of the devices within the cleanroom environment.

Energy use of cleanroom environmental systems varies with the system design, cleanroom functions, and critical parameter control including temperatures and relative humidity. In particular, cleanroom cleanliness requirements specified by “cleanliness class” often cast large impact on energy use. A review of studies on cleanroom operation costs indicated that energy costs could amount to 65-75% of the total annual cost associated with cleanroom operation.

Cleanroom Control Systems Parameters:
  • Temperature control for cleanroom environments requires operating and controlling air handling systems, either chilled water or direct expansion, with recirculating coils, pumps, variable speed fan motors, and condensing unit components. Each of these components must be independently controlled in an integrated system to correctly manage temperature and the tight tolerances required by cleanroom environments. Controlling these units based on ambient conditions at time of day, and geographical location, will determine cleanroom energy usage and cleanroom operating cost required to maintaining cleanroom temperature.

  • Relative Humidity is regulated by either heat exchangers, reheat, or desiccant type systems. Either of these systems and their associated pumps, coils, steam generators, and fans require independent control in an integrated method, based on time of day and geographical location, to control cleanroom energy usage and cleanroom operating cost. The conventional method of controlling indoor humidity involves the use of a reheat system. The reheat process entails overcooling the air, then reheating it to achieve the desired temperature. This process, though effective, is fraught with excessive capital and operating costs. A cost-efficient alternative to the reheat system involves the use of a heat exchanger. This process saves on energy because the heat pipe precools the warm air and produces reheat from the warm return air. The use of heat pipe heat exchangers reduces humidity levels from 50% to 100%.

  • Cascading Pressurization ,in either positive or negative cleanroom zones is controlled by variable speed fan motor controls and dynamic dampeners installed in the cleanroom air distribution system. Cleanroom exhaust systems comprised of the same dampeners and motor controls must be integrated into the cleanroom controls system to effectively manage cleanroom pressurization and control to meet required pressure differentials for governing regulatory agents.

  • Cleanroom Cleanliness Classification ,dependent on the type, number, and fan speed. Filtration modules can be adjusted and controlled for maximum efficiency during operating and off peak schedules. Air speed can also be increased during shift changes to maintain particulate control and cleanroom recovery.

  • Process Equipment support can be controlled to reduce or turn off equipment fans and motors not required at time of day.

  • Cleanroom Lighting Systems support can be controlled to reduce illumination at time of day or motion in area.

Florida Modular Office & Partition Systems designs and engineers cleanroom control systems to provide the following features and benefits:

  • Minimal Energy Consumption
  • Increased Service Intervals
  • Extended Filter Life
  • Reduced Downtime
  • Assist in EN 16001 Compliancy

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