Systems and methods for modeling of chiller efficiency and determination of efficiency-based staging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing chiller systems struggle to optimize compressor efficiency in multi-chiller systems due to varying cooling demands, compressor loads, and lift conditions, leading to suboptimal energy usage.
Innovation Solution
The system performs real-time modeling of compressor efficiency using parabolic models based on lift and load conditions, allowing for composite efficiency determination and optimal compressor selection and staging to improve overall system efficiency.
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 composite efficiency of the chiller system is improved, but device complexity and calculation complexity increase
Solution Approach 1:
The patent transforms complex compressor efficiency characteristics into simplified parabolic models with adjustable parameters. By representing efficiency curves as quadratic functions with configurable parameters (peak efficiency, optimal load point, curvature), the system maintains modeling accuracy while enabling real-time calculations. This parameter-based approach allows the control system to work with simplified mathematical representations rather than complex thermodynamic models.
Solution Approach 2:
The patent creates simplified mathematical copies (parabolic approximations) of the actual compressor efficiency curves. Instead of using detailed thermodynamic models or extensive lookup tables, the system employs quadratic function approximations that capture the essential behavior of compressor efficiency across different operating conditions. These simplified copies enable rapid real-time optimization while preserving the key characteristics of the original complex systems.
2Productivity
If parabolic models are used for compressor efficiency calculation, then calculation speed is improved for real-time operation, but modeling precision may be reduced compared to complex thermodynamic models
Solution Approach 1:
The patent employs parameter-based parabolic models that can be calibrated to match actual compressor performance. By adjusting the parameters (peak efficiency value, optimal load point, curve curvature) based on manufacturer data or field measurements, the simplified models achieve sufficient accuracy for real-time control decisions while maintaining computational efficiency.
Solution Approach 2:
The patent applies partial modeling by focusing on capturing the essential characteristics of compressor efficiency behavior rather than modeling every physical detail. The parabolic approximation provides sufficient accuracy for staging and load optimization decisions without requiring complete thermodynamic fidelity, achieving the right balance between simplicity and accuracy for the intended application.
3Loss of energy
If compressor staging is optimized based on real-time efficiency curves, then energy consumption is reduced, but control system complexity increases
Solution Approach 1:
The control system utilizes parameter-based parabolic efficiency models that enable straightforward comparison of different compressor configurations. By representing each compressor's efficiency as a simple quadratic function with defined parameters, the control algorithm can rapidly evaluate various staging scenarios and load distributions without requiring complex simulations, thus reducing control system complexity while maintaining optimization capability.
Solution Approach 2:
The system implements feedback-based optimization where real-time measurements of actual versus predicted efficiency are used to refine the parabolic model parameters. This feedback mechanism allows the control system to adapt to changing operating conditions and maintain accurate efficiency predictions, enabling continuous optimization of compressor staging and load allocation while keeping the control logic relatively simple.
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.