Multi-Pump Head Control During Smooth Pump Subset Switching
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Solution Overview
Problem
Existing multi-pump control systems for water supply networks face challenges in minimizing energy consumption due to incorrect identification of the most energy-efficient pump subset, as they rely on pre-known pump characteristics that may change over time and lack real-time flow measurements, leading to inefficient operation and increased power consumption.
Innovation Solution
A control system that uses pre-defined model curves to smoothly ramp up or down pumps, determining parameters through configuration cycles to maintain constant head and pressure, allowing for accurate approximation of pump characteristics and power consumption, even in the absence of real-time flow measurements, thereby optimizing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pre-known pump characteristics are used for control decisions, then control system complexity is reduced, but accuracy of identifying energy-efficient pump subset deteriorates due to manufacturing tolerances, wear, and fouling
Solution Approach 1:
The control system performs preliminary configuration cycles to determine actual pump characteristics before normal operation. During these cycles, pumps are operated at different speeds and the actual head-flow relationships are measured and stored. This preliminary characterization accounts for manufacturing tolerances, wear, and fouling specific to each pump, enabling accurate identification of energy-efficient pump subsets without requiring complex real-time measurements during operation.
2Measurement precision
If flow sensors are installed for real-time flow measurement, then pump operation accuracy is improved, but system cost and complexity increase due to expensive installation and maintenance
Solution Approach 1:
The system uses the pumps' own performance characteristics and operating parameters (speed, power consumption) to infer flow conditions without external flow sensors. By monitoring pump speed and power consumption alongside the pre-determined pump characteristics, the control system can calculate actual flow rates and identify optimal pump combinations based on each pump's efficiency at different operating points, eliminating the need for expensive flow measurement infrastructure.
3Speed
If pumps are cut in or out quickly to change operating configuration, then response time is improved, but energy consumption increases due to disturbances and transients in the fluid network
Solution Approach 1:
The control system dynamically adjusts pump speeds continuously rather than making abrupt on/off changes. When transitioning between different pump configurations, the system ramps pump speeds up or down following predetermined model curves that maintain constant head. This dynamic speed adjustment eliminates sudden flow and pressure transients in the network, reducing energy consumption during transitions while still achieving timely response to changing flow demands.
Data Source
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AI summary
The present disclosure provides a multi-pump control system (5) comprising a control module (7), a processing module (9),a communication interface (11), and a storage module (13), wherein the control module (7) is configured to a) ramp up the speed of k pumps in addition to a subset j of i pumps of a multi-pump system comprising N pumps and running at a speed ωj providing a total head Δp, wherein N ≥ 2, 1 ≤ k < N and 1 ≤ i < N, wherein the control module (7) is configured to ramp down the i pumps of the subset j from the speed ωj to a lower speed ωm, wherein the speed ωm is the speed required for a subset m of i+k pumps to provide the total head Δp, and/or b) ramp down the speed of k pumps of a subset j of i pumps of a multi-pump system comprising N pumps and running at a speed ωj providing a total head Δp, wherein N ≥ 2, 1 ≤ k < i and 1 < i ≤ N, wherein the control module (7) is configured to ramp up the i-k pumps of a residual subset r from the speed ωj to a higher speed ωr, wherein the speed ωr is the speed required for a residual subset r of i-k pumps to provide the total head Δp.