Variable Speed Pump Control for Water Supply Energy Reduction
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Solution Overview
Problem
Existing water supply apparatuses lack a flexible solution to meet energy-saving demands, as they operate at higher rotational speeds and consume more electric power when controlling pumps based on standard control head curves with a margin, which is not optimized for reduced energy usage.
Innovation Solution
A water supply apparatus with a controller that stores multiple control head curves, allowing users to select and switch between them using a selector button, enabling operation at lower rotational speeds while maintaining constant flow rates, thereby reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is controlled based on a standard control head curve with a margin, then the water supply reliability is improved, but the energy consumption increases
Solution Approach 1:
The system dynamically switches between multiple control head curves (standard curve with margin and energy-saving curve without margin) based on real-time water demand conditions. The controller selects the appropriate curve to maintain reliability when needed while reducing energy consumption when possible, making the system adaptable rather than static.
Solution Approach 2:
The system changes the control parameter (control head curve) based on operating conditions. By switching between different head curves with different margin levels, the system can adjust its operational characteristics to balance reliability and energy efficiency according to actual water supply needs.
2Productivity
If the pump operates at higher rotational speed to meet peak demand, then the flow rate is improved, but the electric power consumption increases
Solution Approach 1:
The system dynamically adjusts the pump's rotational speed based on real-time water demand by selecting between different control head curves. During peak demand periods, the standard curve ensures sufficient flow rate; during low-demand periods, the energy-saving curve reduces speed and power consumption, optimizing the balance between productivity and energy use.
Solution Approach 2:
The system periodically evaluates water demand conditions and switches between operational modes (standard vs. energy-saving curves). This periodic adjustment allows the pump to operate at high speeds only when necessary for peak demand while reducing speed during normal or low-demand periods, thereby reducing overall energy consumption.
3Ease of operation
If a single standard control head curve is used, then the system is simple to operate, but it lacks flexibility for energy-saving optimization
Solution Approach 1:
The control system is designed with multi-functionality by incorporating multiple control head curves (standard curve with margin and energy-saving curve without margin) within a single apparatus. This allows the system to perform both reliable water supply and energy-saving operations using the same hardware, providing versatility without complicating the overall system structure.
Solution Approach 2:
The system dynamically selects between different operational modes based on water demand conditions. The controller automatically chooses the appropriate control head curve, maintaining ease of operation while providing the flexibility needed for energy-saving optimization when conditions permit.
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 apparatus achieves energy savings by operating the pump at lower rotational speeds, reducing electric power consumption and CO2 emissions, with the option to select control head curves based on energy-saving levels.
Implementation Method 1
a pump (1) for pressurizing and delivering water
Implementation Method 2
a frequency converter (2) for supplying electric power to the pump (1)
Implementation Method 3
a discharge-side pressure sensor (4) for detecting a pressure at a discharge side of the pump (1)
Data Source
Figure 1
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AI summary
A water supply apparatus is configured to meet energy-saving demands by controlling a pump so that the rotational speed of the pump is lowered while keeping a constant flow rate. The water supply apparatus includes a pump for pressurizing and delivering water, a frequency converter for supplying electric power to the pump to operate the pump at a variable rotational speed, a discharge-side pressure sensor for detecting a pressure at a discharge side of the pump, and a controller (15) for controlling the rotational speed of the pump. The controller (15) stores a plurality of control head curves (B, C1, C2, C3) representing different relationships between flow rates (Q) and heads (H), and controls the rotational speed of the pump based on an alternatively selected one of the control head curves (B, C1, C2, C3).