Multi-Compressor Chiller Staging Using Parabolic Efficiency Models
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Solution Overview
Problem
Chiller systems face inefficiencies due to varying compressor load and lift conditions, leading to suboptimal operation and energy consumption, as existing methods fail to accurately model and adjust compressor efficiency in real-time to meet changing cooling demands.
Innovation Solution
The implementation of parabolic models for compressor efficiency, allowing for real-time calculation and composite efficiency determination of multi-chiller systems, enabling dynamic compressor selection and staging to optimize energy use based on observed efficiency data across various lift and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If real-time modeling of compressor efficiency is implemented to optimize compressor selection and staging, then chiller system efficiency is improved, but calculation complexity increases
Solution Approach 1:
The patent transforms the complex efficiency modeling problem by changing the mathematical representation from general efficiency curves to specific parabolic functions. This parameter transformation allows real-time calculation while maintaining accuracy, resolving the contradiction between optimization benefit and computational complexity.
Solution Approach 2:
The patent replaces complex iterative optimization algorithms with direct parabolic function calculations. By substituting the mechanical/computational approach with a mathematical closed-form solution, real-time efficiency optimization becomes computationally tractable without sacrificing accuracy.
2Measurement precision
If complex efficiency models are used to accurately represent compressor performance under varying lift and load conditions, then modeling accuracy is improved, but real-time calculation capability deteriorates
Solution Approach 1:
The patent changes the mathematical parameters from general efficiency curve representations to specific parabolic functions with defined coefficients. This parameter transformation maintains modeling accuracy while enabling closed-form real-time calculations, thus resolving the speed-accuracy tradeoff.
Solution Approach 2:
The patent extracts the essential characteristics of compressor efficiency behavior into simplified parabolic relationships, separating the critical efficiency patterns from unnecessary modeling complexity. This extraction enables real-time calculation while preserving the fundamental accuracy needed for optimization decisions.
3Power
If the number of compressors is increased to meet varying cooling demand, then cooling capacity is improved, but system efficiency deteriorates due to suboptimal compressor selection
Solution Approach 1:
The patent implements a feedback mechanism where real-time efficiency modeling continuously evaluates compressor performance under actual operating conditions. This feedback loop enables dynamic compressor selection and staging decisions that optimize both cooling capacity delivery and energy efficiency, resolving the contradiction between power output and energy loss.
Solution Approach 2:
The patent transforms static compressor selection into a dynamic optimization process. By continuously modeling efficiency based on real-time lift and load conditions, the system dynamically adjusts compressor operation to maintain optimal efficiency across varying cooling demands, preventing energy waste from suboptimal configurations.
Data Source
AI summary
Multi-compressor chiller systems can be efficiently operated by determining real time efficiency curves for the compressors currently in operation, along with any compressors that may be added to address demand, and using these efficiency curves to determine changes to compressor operation to improve efficiency in meeting chiller demand. The efficiency curves can be parabolic curves. The data used to determine the efficiency curves can be obtained through operation at a variety of lift points and a variety of load points within those lift points. The efficiency curves can be solved to find intersections where there may be staging points for adding or subtracting compressors from operation to efficiently meet demand. This operation can be automated through a controller of a control system for the multi-compressor chiller system.