Control method and system in a refrigeration system and compressor of a refrigeration system
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Solution Overview
Problem
Variable speed compressors in refrigeration systems require electronic thermostats, increasing costs and inefficiencies due to lack of adaptation to installed capacity and disturbance response, especially in commercial applications where ON/OFF technology migration has rendered previous solutions obsolete.
Innovation Solution
A control method and system using general and specific logic to measure torques and cycle times, allowing ON/OFF thermostats to control compressor speed, monitor disturbances, and adjust angular speed for optimal efficiency, without additional hardware costs, by leveraging existing mechanical thermostats and inverter technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable speed compressors are used with electronic thermostats, then refrigeration capacity adjustment is improved, but system cost increases
Solution Approach 1:
The control system is designed to work with both electronic thermostats and mechanical ON/OFF thermostats, making it universal. The system can detect the type of thermostat connected and adapt its operation accordingly, allowing variable speed compressor control without requiring expensive electronic thermostat upgrades throughout the system.
Solution Approach 2:
The control system acts as an intermediary between the thermostat (electronic or mechanical) and the variable speed compressor. It translates simple on/off signals from mechanical thermostats into appropriate compressor speed commands, enabling variable speed operation without requiring direct electronic thermostat control.
2Device complexity
If variable speed compressors operate without disturbance monitoring, then device complexity is reduced, but efficiency is worsened
Solution Approach 1:
The control system continuously monitors system parameters such as compressor current, runtime, and cycle patterns to detect disturbances like door openings, load changes, or system anomalies. This feedback mechanism allows the compressor to adjust its speed in response to actual system conditions, optimizing efficiency without requiring complex additional sensors.
Solution Approach 2:
The control system uses the existing electrical parameters already present in the variable speed compressor operation (current, voltage, runtime data) to monitor system status and detect disturbances. This self-service approach allows efficient disturbance response without adding external monitoring hardware or increasing system complexity.
3Ease of operation
If ON/OFF thermostat control is used with variable speed compressors, then ease of operation is improved, but productivity is worsened
Solution Approach 1:
The system replaces the traditional mechanical on/off control approach with electronic inverter-based variable speed control, while maintaining compatibility with simple mechanical or electronic thermostat switches. This substitution allows the compressor to modulate its speed continuously rather than cycling on/off, improving efficiency while keeping the thermostat interface simple.
Solution Approach 2:
The control system dynamically adjusts the compressor speed based on the thermostat signal and monitored system conditions. Instead of fixed on/off operation, the compressor can operate at any speed within its range, dynamically responding to thermal load changes and optimizing refrigeration efficiency while maintaining simple thermostat control.
Data Source
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AI summary
A control method and a control system for a compressor in a refrigeration system, by means of the implementation of at least one control logic based on the monitoring of parameters of the refrigeration system, where these parameters may include, for example, a previous load (Cant), a current load (Catu), a reference load (Cref), a measured cycle time (tciclo) and a target time (talvo).