Refrigeration Cycle Control Using Slope-Based Energy Optimization
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Solution Overview
Problem
Existing refrigeration cycle systems face challenges in minimizing input energy consumption, particularly due to high computational processing loads and the need for laborious calculations of heat exchanger capacity and energy input, which are not reflective of actual installation conditions, leading to slow stabilization of operational states.
Innovation Solution
A refrigeration cycle system incorporating a control unit that uses relational expressions to optimize energy input by adjusting compressor frequency, fan speeds, and heat exchanger capacities, reducing the need for pre-specified characteristic formulas and coefficients, and allowing for real-time adjustments based on actual installation conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If characteristic formulas and coefficients are specified in advance for each compressor frequency and fan rotating speed condition, then optimization control of input energy can be achieved, but the computational processing load increases significantly
Solution Approach 1:
The patent segments the control parameters by focusing on compressor frequency and fan rotating speed as primary variables. By dividing the control space into these key segments and using lookup tables pre-calculated for discrete frequency/speed combinations, the system avoids complex real-time calculations while maintaining optimization capability.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing characteristic formulas and coefficients in lookup tables for various compressor frequencies and fan rotating speeds before operation. This allows the control unit to quickly retrieve pre-computed optimization data without performing heavy computational processing during real-time operation, thus reducing the computational load while achieving energy optimization.
2Measurement precision
If characteristic formulas are specified for each system configuration, then accurate energy calculation is achieved, but the setup work becomes very laborious
Solution Approach 1:
The patent creates a universal control method that works across different system configurations (different numbers of compressors, heat exchangers, fan arrangements) by using a standardized approach with lookup tables. The same control algorithm and table structure can be applied universally regardless of specific system variations, eliminating the need to manually configure characteristic formulas for each unique setup while maintaining accurate energy calculation.
3Use of energy by moving object
If focus is placed on heat exchanger capacity and total input energy for optimization, then energy efficiency is improved, but the stabilization time of operational state increases
Solution Approach 1:
The patent implements feedback control by continuously monitoring the actual compressor frequency and fan rotating speed, comparing them with the optimal values retrieved from lookup tables, and adjusting the operating parameters accordingly. This feedback mechanism enables the system to rapidly converge to the optimal operational state and maintain stability by making real-time corrections based on actual system performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the computational processing load, minimizes energy input, and rapidly stabilizes the operational state by focusing on total energy input rather than individual components, effectively addressing the limitations of previous systems.
Implementation Method 1
a refrigeration cycle system for circulating a refrigerant in a refrigerant circuit configured by connecting a compressor, a heat-source-side heat exchanger, an expansion valve, and a usage-side heat exchanger
Data Source
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AI summary
Provided is a refrigeration cycle system capable of reducing an amount of information required to be specified in advance, reducing a computational processing load, reflecting differences in actual installation conditions, and speeding up stabilization of an operational state in which the total amount of required input energy is reduced. A refrigeration cycle system (300) is provided with a plurality of actuators, including outdoor fan motors (19m, 29m), compressors (15m, 25m), indoor fan motors (47m, 57m, 67m), and the like for causing a refrigerant circuit (310) to carry out a refrigeration cycle. A control unit (307) obtains the slope at the current evaporation temperature and/or the current condensing temperature on a graph of the function between the actuators and the evaporation temperature or the condensing temperature, and updates the value of the target evaporation temperature and/or the target condensing temperature so that the sum of the input energy to the actuators is less that the current level.