Step flow chiller control device and methods therefor
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Solution Overview
Problem
Absorption chillers face inefficiencies and challenges such as solar field depletion, unbalanced evaporator and generator loads, and the risk of absorbent solution crystallization, which hinder their adoption and performance.
Innovation Solution
The implementation of a Step Flow (SF) control device that balances energy flow through absorption chillers by adjusting the speed of components like evaporators, generators, and condensers using variable frequency drives, based on real-time load values, to prevent crystallization and enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If absorption cooling is used to avoid electrical compressors and utilize heat energy, then environmental friendliness and energy source flexibility are improved, but system efficiency and reliability deteriorate due to crystallization risks and unbalanced loads
Solution Approach 1:
The patent implements dynamic control of the absorbent solution flow rate through a control valve, adjusting it in real-time based on operating conditions. This dynamic adjustment prevents crystallization by maintaining optimal flow rates across varying loads, thereby improving system reliability while preserving cooling efficiency.
Solution Approach 2:
The control system continuously monitors operating parameters and adjusts the absorbent solution flow rate accordingly. This feedback mechanism ensures the system operates within safe parameters, preventing crystallization and maintaining reliability while optimizing cooling performance under different conditions.
2Use of energy by moving object
If traditional absorption chiller operation is used without flow control, then system simplicity is maintained, but energy waste and unbalanced loads between evaporator and generator occur
Solution Approach 1:
The patent changes the flow rate parameter of the absorbent solution dynamically based on operating conditions. By adjusting this single critical parameter, the system achieves balanced loads between evaporator and generator, improving energy utilization efficiency without requiring complex structural modifications.
Solution Approach 2:
The control valve serves multiple functions: it regulates absorbent solution flow rate, prevents crystallization, balances loads between components, and optimizes energy efficiency. This multi-functionality improves energy utilization without proportionally increasing system complexity.
3Reliability
If absorbent solution flow rate is increased to prevent crystallization, then reliability is improved, but energy consumption increases
Solution Approach 1:
The absorbent solution flow rate is controlled dynamically rather than maintained at a constant high level. The control valve adjusts flow rate in real-time based on actual operating conditions, preventing crystallization only when necessary. This dynamic approach maintains reliability while minimizing unnecessary pumping energy consumption.
Data Source
AI summary
A Step Flow control device and methods therefore provide instructions to control operation of various absorption chiller components based on measured load or temperature information. Operating an absorption chiller according to Step Flow balances the flow of heat energy through the absorption chiller to increase efficiency and prevent crystallization. The control device may be integrated into various components of an absorption chiller or may be remote therefrom. In this manner, Step Flow can be used in new absorption chiller installations or be used to retrofit existing installations.