Cooling Tower Fan Array Control for Fault-Induced Backflow
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Solution Overview
Problem
Heat rejection apparatuses, such as cooling towers, face operational challenges when one or more fans become non-operational, leading to reversed airflow and water loss, which can be exacerbated in subfreezing climates, and existing solutions like physical barriers are impractical for large arrays of fans.
Innovation Solution
A fan array fault response control system that automatically detects non-operational fans and adjusts the speed of operational fans to minimize reversed airflow and water loss, using a controller to set speed limits based on the proximity of operational fans to the non-operational ones and the operational state of the apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If operational fans continue to run at normal speed after a fan failure, then cooling capacity is maintained, but air and water escape through the non-operational fan opening causing harmful effects
Solution Approach 1:
The system dynamically adjusts fan speeds based on operational status. When a fan fails, the control system automatically reduces the speed of adjacent operational fans to prevent air and water escape through the non-operational fan opening, while maintaining adequate cooling capacity. This dynamic speed adjustment resolves the contradiction between maintaining productivity and preventing harmful effects.
Solution Approach 2:
The control system changes the operating parameters (speed) of operational fans in response to fan failure. By modifying the speed parameter of adjacent fans based on the location and status of non-operational fans, the system prevents water and air escape while maintaining sufficient cooling performance.
2Object-generated harmful factors
If physical barriers or louvers are installed between fans to prevent air recirculation, then air recirculation is reduced, but device complexity increases and maintenance access is impeded
Solution Approach 1:
The patent replaces mechanical physical barriers (louvers and barriers) with an electronic control system that adjusts fan speeds to prevent air recirculation. This substitution eliminates the need for complex mechanical structures between fans, reducing device complexity while maintaining the ability to prevent harmful air recirculation effects.
3Loss of substance
If fan speeds are reduced to prevent water egress, then water loss is minimized, but cooling performance decreases
Solution Approach 1:
The control system applies local quality by differentiating fan speed adjustments based on the specific location of non-operational fans. Adjacent fans to non-operational fans are slowed to prevent water escape, while fans farther away maintain higher speeds to preserve cooling performance. This localized approach minimizes water loss while maintaining overall cooling effectiveness.
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 system effectively reduces air and water leakage through non-operational fans by limiting fan speeds, preventing backflow and water egress, while allowing override during peak demand and automatically returning to normal operation upon rectification of faults.
Implementation Method 1
a pump operable to pump liquid from the sump to the liquid distribution system
Implementation Method 2
a plurality of fans configured to generate airflow relative to the heat exchanger
Implementation Method 3
a liquid distribution system configured to direct liquid toward the heat exchanger
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
In one aspect, a fan array fault response control system is provided for a cooling tower. The fan array fault response control system includes a fan interface configured to be in communication with a plurality of fans of the cooling tower and a processor operably coupled to the fan interface. The processor is configured to detect at least one non-operational fan of the plurality of fans. The processor configured to effect, in response to detecting the at least one non-operational fan, a reduced fan speed of at least one operational fan of the plurality of fans.