Modular Air-Conditioning Control for Variable-Frequency Load Ratios
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Solution Overview
Problem
Conventional air conditioning systems with modular air-cooled/water-cooled chiller sets experience frequent start/stop of compressors and large fluid temperature fluctuations, leading to increased electrical energy usage and reduced energy efficiency due to the use of invariable frequency compressors.
Innovation Solution
A method and system for controlling a modular air conditioning system with variable frequency modular units, where a main controller adjusts the operating frequency of units based on energy adjustment amounts, allowing for load, unload, or hold operations within a target load ratio range to optimize energy efficiency and prevent frequent start/stop cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If invariable frequency compressors are used in modular air conditioning systems, then the system structure is simple, but frequent start/stop occurs and fluid temperature fluctuates greatly
Solution Approach 1:
The patent applies variable frequency control to compressors, transforming the static frequency system into a dynamic one that can adjust operating parameters in real-time. The main controller dynamically adjusts the frequency of each compressor based on load conditions and temperature differences, preventing frequent start/stop and reducing fluid temperature fluctuations while maintaining system reliability.
2Use of energy by moving object
If variable frequency compressors are used with conventional control methods, then energy adjustment is possible, but frequent start/stop occurs and electrical energy usage increases
Solution Approach 1:
The patent implements a feedback control mechanism where the main controller continuously monitors the difference between actual fluid temperature and target temperature, as well as the running time of each compressor. Based on this feedback, the controller adjusts compressor frequency to keep units within the target load ratio range, preventing frequent start/stop and reducing electrical energy consumption while maintaining energy efficiency.
Solution Approach 2:
The patent sets predetermined target load ratio ranges for compressors before operation begins. By establishing these target ranges in advance and using them as control boundaries, the system can proactively adjust compressor operation to prevent inefficient cycling, thereby reducing electrical energy loss while maintaining optimal energy efficiency.
3Adaptability or versatility
If variable frequency modular units operate outside target load ratio range, then operational flexibility is high, but energy efficiency decreases
Solution Approach 1:
The patent changes the operating parameters of variable frequency modular units by constraining them to operate within predetermined target load ratio ranges. The main controller adjusts the frequency parameters of compressors to maintain operation within these optimal ranges, ensuring high energy efficiency while still providing operational flexibility through variable frequency adjustment within the defined boundaries.
Data Source
AI summary
The present disclosure is directed to a method for controlling a system that includes a modular set having a plurality of variable frequency modular units. The method includes setting a load ratio range for the plurality of variable frequency modular units, inputting an energy adjustment amount, and setting different operations for the modular set based on the energy adjustment amount. During a first operation, a first frequency adjustment amount of a corresponding variable frequency modular unit is determined based on the energy adjustment amount and an operating position of the corresponding variable frequency modular unit. During a second operation, a second frequency adjustment amount of a corresponding variable frequency modular unit is determined based on the energy adjustment amount and the operating position of the variable frequency modular unit. The first operation or the second operation causes the variable frequency modular units to operate within the load ratio range.