Method for operating a ventilation system and ventilation system
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Solution Overview
Problem
Existing ventilation systems struggle to accurately determine and maintain volume flow in fan arrangements when a fan fails, leading to incorrect pressure calculations and potential discomfort due to uncontrolled pressure changes in the room, as they rely on assumptions of identical fan contributions which are not valid during faults.
Innovation Solution
A method that calculates a reference ratio from differential pressure and absolute pressure measurements during normal operation, allowing for the estimation of volume flow in faulty conditions without using volume flow or temperature sensors, enabling continued operation and control of the ventilation system by storing this ratio for later use in case of fan failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If volume flow is calculated from differential pressure across fans assuming identical fan contributions, then the system can operate with simple minimalist measurement technology, but the volume flow calculation becomes incorrect when a fan fails
Solution Approach 1:
The system pre-calculates and stores reference ratios of differential pressure to volume flow during normal operation before any fan failure occurs. These reference values are stored in memory and later used to calculate accurate volume flow even when fans fail, eliminating the need for complex sensors while maintaining calculation accuracy during fault conditions
Solution Approach 2:
The patent introduces an intermediary calculation method using reference ratios as a mediator between differential pressure measurements and volume flow determination. Instead of directly calculating volume flow from differential pressure (which fails when fans are faulty), the system uses the stored reference ratio as an intermediary to derive accurate volume flow values even in fault conditions
2Reliability
If the fan arrangement is turned off when a fan fails, then pressure control in the room is maintained, but the ventilation system loses redundancy and operates with reduced availability
Solution Approach 1:
The system continuously monitors differential pressure across fans and uses feedback from this measurement, combined with stored reference ratios, to calculate actual volume flow in real-time. This feedback mechanism allows the control system to detect fan failures and adjust operation accordingly, maintaining pressure control while enabling continued operation with reduced fan capacity
Solution Approach 2:
When a fan failure is detected, the system changes operational parameters by switching from using real-time differential pressure to using stored reference ratios for volume flow calculation. This parameter change allows the system to adapt to the new fault condition and maintain reliable pressure control while continuing to ventilate with the remaining functional fans
3Productivity
If a fan fails in the fan arrangement, then the redundancy of multiple fans is compromised, but the system can continue operating with reduced performance if volume flow can be accurately determined
Solution Approach 1:
The system performs preliminary calculations during normal operation to determine and store reference ratios that represent the relationship between differential pressure and volume flow. These pre-calculated values are saved in memory and immediately available when fan failures occur, enabling continuous accurate volume flow determination without requiring complex sensors or recalibration
Solution Approach 2:
The patent creates a simplified copy or model of the normal operating conditions through stored reference ratios. This copy captures the essential relationship between pressure and flow without requiring the actual normal operating conditions to be present, allowing the system to accurately determine volume flow even when the physical system is in a faulty state with reduced fan capacity
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
Enables the ventilation system to maintain accurate volume flow control and prevent pressure imbalances even when a fan fails, utilizing the redundancy of multiple fans to ensure continuous operation and comfort by calculating a substitute volume flow based on stored reference ratios.
Implementation Method 1
a differential pressure sensor to measure the differential pressure across at least one of the fans of the corresponding fan arrangement
Implementation Method 2
a reference pressure being measured at a distance from the first fan arrangement
Data Source
Figure 1
Figure 1
AI summary
The invention relates to a method for operating a ventilation system for a room (1) with at least two air ducts (2, 3), in each of which a fan arrangement (4, 5) consisting of two or more identically controlled fans ([4a, 4b, 4c] , [5a, 5b, 5c]) is present, with a first of these fan arrangements (4) being determined via at least one of its fans (4a) and using this differential pressure (Δpzu) a pressure difference from the first fan arrangement ( 4) pumped volume flow (Qzu) is calculated. A reference pressure (p1) is measured at a distance from the first fan arrangement (4) and from this and the volume flow (Qzu) delivered by the first fan arrangement (4) a reference ratio (δnormal) is determined for use in faulty operation of the first fan arrangement (4) calculated and saved. The invention also relates to a ventilation system for carrying out the method.