Booster Pump Control Using Quadratic Curves for Efficient Flow
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Solution Overview
Problem
Existing booster pump systems in large buildings often operate inefficiently due to oversizing and the use of throttling valves, failing to meet ASHRAE 90.1 efficiency standards, and prior art solutions have not adequately addressed this issue.
Innovation Solution
A controller and server combination that implements software programs to derive quadratic models for pump and system curves, adjusting drive frequency and the number of active pumps to meet flow rate demands efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If throttling valves are employed to reduce flow when process flow requirements are less than the flow at the pumping system's natural operating point, then flow control is achieved, but pump efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from static flow control (throttling valves) to dynamic control through variable frequency drives that adjust pump speed in real-time. This allows the pump to operate at varying speeds to match actual flow demands, keeping the operating point near the efficiency curve peak rather than forcing operation at a fixed point with throttling.
Solution Approach 2:
The patent changes the operating parameters by using quadratic models to determine optimal pump speed and activation sequences. Instead of maintaining constant speed with variable flow demand (throttling), the system varies the rotational speed parameter to match demand, thereby changing the operating point along the pump curve to maintain high efficiency.
2Productivity
If pumps are oversized to meet peak demand, then flow rate requirements are satisfied, but energy efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by using variable frequency drives to adjust pump speed dynamically based on actual flow demand. This allows oversized pumps to operate at lower speeds during partial load conditions, keeping the operating point near the peak efficiency region of the pump curve rather than operating far to the right where oversized pumps typically run inefficiently.
Solution Approach 2:
The patent implements partial action by activating only the necessary number of pumps based on quadratic model calculations of current demand. Instead of running all oversized pumps continuously, the system activates partial capacity (one or two pumps) at optimized speeds to meet actual demand, avoiding the energy waste of running excessive capacity at low efficiency points.
3Loss of energy
If variable speed drives are used to adjust pump speed, then energy efficiency improves, but system complexity increases
Solution Approach 1:
The patent applies feedback by using flow meters and pressure sensors to continuously monitor system conditions, then using quadratic models to calculate optimal pump speeds and activation sequences. This closed-loop feedback system automatically adjusts VFD settings based on real-time measurements, eliminating the need for complex manual control while maintaining peak efficiency operation.
Solution Approach 2:
The patent uses quadratic models as simplified mathematical representations (copies) of the complex pump performance curves and system characteristics. These quadratic equations provide accurate enough predictions of optimal operating points without requiring complex computational fluid dynamics or extensive lookup tables, thereby reducing control system complexity while maintaining efficiency.
4Productivity
If multiple pumps are activated sequentially based on pressure thresholds, then flow demand is met, but energy efficiency deteriorates
Solution Approach 1:
The patent applies preliminary action by using quadratic models to predict the optimal number of pumps to activate and the optimal speed settings before actually meeting the flow demand. Instead of reactively turning pumps on/off based on pressure thresholds, the system calculates in advance the most efficient pump configuration and speed settings to meet the current flow requirement, preventing inefficient operation.
Solution Approach 2:
The patent applies dynamics by transitioning from static sequential pump activation (based on fixed pressure thresholds) to dynamic pump control where speed and activation are continuously optimized using quadratic models. This allows smooth transitions between pump configurations and speeds, keeping the system operating point near peak efficiency rather than making abrupt changes that move the operating point away from the efficiency curve.
Data Source
AI summary
The disclosure provides a controller and server combination, which implements a set of software programs to control a booster pump system. In a preferred embodiment, the software derives quadratic models for the pump performance curves, and the system curve. The system monitors the flow rate of the system, the pump performance curve model and the system curve model to adjust the drive frequency and the number of active pumps to meet flow rate demand efficiency.