Fan Plenum Separators and Inlet Impedance Against Failed-Fan Recirculation
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Solution Overview
Problem
Recirculation of air through a failed fan in information processing devices reduces cooling capacity, leading to potential component damage and performance issues, and existing solutions like fan replacement or active airflow blocking are costly, complex, or impractical.
Innovation Solution
Implementing a recirculation inhibition mechanism with separators and a plenum impedance element to separate airflow paths and impose positive impedance, reducing recirculation by forcing air to pass through the impedance element twice, thereby maintaining cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a common fan plenum is used to flow air through the device, then cooling capacity is improved, but recirculation occurs upon fan failure which reduces cooling effectiveness
Solution Approach 1:
The patent divides the common fan plenum into multiple separate compartments using partitions. Each fan is assigned to a specific compartment, preventing air recirculation between fans when one fails. This segmentation maintains cooling effectiveness by isolating failed fans from the airflow paths of operational fans.
Solution Approach 2:
The patent introduces an impedance element as an intermediary component in the airflow path between the plenum inlet and the fans. This element creates positive impedance that forces air to pass through it twice, effectively blocking recirculation paths and maintaining proper airflow direction even when a fan fails.
2Reliability
If active airflow blocking mechanisms are implemented to prevent recirculation, then cooling effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses simple partition walls to segment the plenum into separate compartments for each fan. This passive segmentation approach prevents recirculation without requiring complex active mechanisms, sensors, or control systems, thereby maintaining low device complexity while improving reliability.
Solution Approach 2:
The impedance element and partition structure automatically prevent recirculation based on the physical configuration alone, without requiring external control systems, sensors, or power sources. The system self-regulates airflow paths passively, reducing complexity while maintaining cooling effectiveness.
3Reliability
If fan replacement is performed immediately upon failure, then cooling capacity is maintained, but cost and operational downtime increase
Solution Approach 1:
The patent designs the plenum with built-in recirculation prevention features (partitions and impedance elements) that cushion against the harmful effects of fan failure. This allows the system to continue operating with reduced cooling capacity for extended periods without immediate fan replacement, reducing operational downtime and replacement costs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mechanism effectively inhibits recirculation, allowing the device to operate within thermal limits despite a failed fan, reducing the need for immediate replacement and minimizing thermal issues.
Implementation Method 1
the plenum impedance element is disposed on or in the plenum such that all the air entering the plenum from an inlet side thereof passes through the plenum impedance element prior to reaching the fans
Data Source
AI summary
An information processing device comprises heat generating components, a plenum, and fans arranged to flow air through the plenum and to cool the heat generating components. The device also comprises a recirculation inhibition mechanism to reduce the amount of air recirculation in the event a fan fails. The recirculation inhibition mechanism comprises a plenum impedance element extending across the plenum such that the air passing through the plenum passes through the plenum impedance element prior to reaching the fans, and dividers disposed in the plenum and defining sub-compartments in the plenum. Each of the sub-compartments corresponds to one of the fans and is configured to supply air to or receive air from the corresponding fan. In the event of one of the fans failing, air recirculating through the failed fan passes though the plenum impedance element twice before reaching an adjacent fan.