Clean Room Air Pressure Control for Energy-Saving Operation
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Solution Overview
Problem
Existing clean room air handling systems consume excessive energy when the clean room is not in use, despite the need to maintain cleanliness standards, and lack efficient methods to transition between energy-saving and full-capacity operations.
Innovation Solution
A method and system that utilize speed-adjustable fans and position-controllable return air dampers to manage air pressure and volume across compartments within the clean room, allowing for energy-efficient operation by adjusting air flow based on particulate count requirements, and rapidly returning to full capacity upon demand or unexpected events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air handling system operates at full capacity continuously, then the cleanliness of the clean room is maintained at or below predetermined ISO levels, but energy consumption is excessive
Solution Approach 1:
The air handling system transitions from static full-capacity operation to dynamic variable-speed operation. The controller adjusts fan speeds and damper positions based on real-time particle count measurements, allowing the system to operate at reduced capacity when contamination levels are acceptable and at full capacity when contamination thresholds are approached. This dynamic adaptation resolves the contradiction by matching energy consumption to actual cleanliness requirements.
Solution Approach 2:
The system changes operational parameters (fan speed, damper position) based on measured particle counts. When particle counts are below thresholds, the system reduces air flow parameters to save energy; when particle counts approach thresholds, the system increases parameters to maintain cleanliness. This parameter adjustment strategy resolves the contradiction between energy consumption and cleanliness maintenance.
2Use of energy by moving object
If the air handling system reduces operation to save energy, then energy consumption decreases, but the ability to maintain cleanliness standards may be compromised
Solution Approach 1:
The system implements closed-loop feedback control where particle counters continuously monitor contamination levels and feed this information back to the controller. The controller then adjusts fan speeds and damper positions accordingly. This feedback mechanism ensures that energy reduction does not compromise cleanliness standards, as the system automatically increases energy consumption only when particle counts indicate a threat to cleanliness.
Solution Approach 2:
The system takes preliminary action by reducing energy consumption proactively when particle counts are well below thresholds, rather than waiting for contamination problems to develop. This preliminary energy-saving action is safe because the feedback system will detect any approaching contamination thresholds and trigger full-capacity operation before cleanliness standards are compromised.
3Speed
If the air handling system transitions rapidly from energy-saving to full capacity operation, then response to unexpected events is improved, but system stability may be affected
Solution Approach 1:
The system uses periodic monitoring of particle counts to determine when transitions are needed. Rather than continuous full-capacity operation, the system periodically checks contamination levels and adjusts capacity accordingly. This periodic action allows rapid response to contamination events while maintaining stability during normal operation, resolving the contradiction between response speed and system stability.
Data Source
AI summary
In a system and method of controlling particulate count in a clean room having a number of compartments/zones in series, in response to a first level of energy consumption by speed adjustable fans supplying a first volume of air per unit of time to the clean room, differential air pressures are established in the clean room compartment/zone-by-compartment/zone in series from a first compartment/zone which has a requirement for the highest air pressure to a last compartment/zone which has a requirement for the lowest air pressure. In response to a second level of energy consumption by the speed adjustable fans supplying a second volume of air per unit of time to the clean room, the same differential air pressures are substantially maintained in the clean room.