Clean Room Air Conditioning with Switchable Pressure Mode Control
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Solution Overview
Problem
Existing air conditioning systems for clean rooms struggle to efficiently convert between negative and positive pressure settings, limiting their usability in different applications due to unadjusted rotation speeds of air discharge fans.
Innovation Solution
An air conditioning system with a controller that adjusts the rotation speeds of air supply and return fans based on pressure sensor readings, allowing for constant speed operation of one fan while varying the other to maintain predetermined room pressures, and enabling switching between positive and negative pressure modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If air supply fans are individually controlled to maintain pressure difference, then pressure control precision is improved, but the system cannot be easily converted between positive and negative pressure modes because air discharge fan speeds are not adjusted
Solution Approach 1:
The system dynamically switches the control mode between air supply fans and air discharge fans based on the desired pressure mode. When converting from negative to positive pressure mode, the controller transitions from controlling air supply fan speeds to controlling air discharge fan speeds, making the system adaptable to different operational requirements while maintaining precise pressure control
Solution Approach 2:
The system changes the controlled parameter from air supply fan rotation speeds to air discharge fan rotation speeds when converting between pressure modes. This parameter switching enables the same hardware system to achieve both positive and negative pressure conditions by adjusting which fan group's speeds are actively controlled based on pressure sensor feedback
2Device complexity
If both air supply and air discharge fans are controlled at constant speeds, then system complexity is reduced, but pressure control accuracy deteriorates
Solution Approach 1:
The control system is segmented into two distinct operational modes: one where air supply fans are controlled and air discharge fans run at constant speed, and another where air discharge fans are controlled and air supply fans run at constant speed. This segmentation allows the system to maintain simplicity in each mode while achieving accurate pressure control through active feedback from pressure sensors
Solution Approach 2:
Pressure sensors provide continuous feedback to the controller, which adjusts the rotation speeds of the actively controlled fan group to maintain the target pressure difference. This feedback mechanism ensures accurate pressure control while keeping the other fan group at constant speed, balancing control accuracy with system simplicity
Data Source
AI summary
Provided is a user-friendly air conditioning system. An air conditioning system comprises: a fan filter unit that has an air supply fan for supplying air to a clean room; and a fan filter unit that has an air return fan for returning or the like of air from the clean room. The air conditioning system further comprises: a pressure sensor that is installed in the clean room; and a control device that controls one of the air supply fan and the air return fan on the basis of the detection value of the pressure sensor, and controls the other fan at a constant speed. It is possible to switch between controlling one of the air supply fan and the air return fan on the basis of the detection value of the pressure sensor and the other fan at a constant speed.