Zeotropic Refrigerant Composition Correction in Refrigeration Cycles
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Solution Overview
Problem
Conventional refrigeration cycle devices face challenges in accurately detecting the circulation composition of zeotropic refrigerant mixtures, leading to increased costs due to the need for high-accuracy temperature and pressure sensors, and result in reduced heat exchange efficiency, compressor damage, and instability phenomena.
Innovation Solution
A refrigeration cycle device equipped with temperature detection means for the inlet and outlet sides of the compressor, pressure detection on the outlet side, a detection control unit to calculate the circulation composition, and a correction control unit to adjust sensor readings based on a reference composition, allowing for accurate detection without high-cost sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-accuracy temperature and pressure sensors are used to detect circulation composition, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a correction control unit that acts as an intermediary between the sensors and the composition calculation. This unit corrects sensor output values based on the relationship between detected temperatures, pressures, and actual circulation composition, thereby improving measurement accuracy without requiring inherently high-precision sensors. The correction unit mediates the relationship between raw sensor data and accurate composition values.
Solution Approach 2:
The patent changes the approach from relying on high-precision physical sensors to using computational parameter correction. By calculating circulation composition through multiple measurements at different times and correcting sensor outputs based on detected changes, the system achieves high measurement precision through parameter transformation rather than through sensor precision alone.
2Device complexity
If refrigerant composition changes are not detected, then device complexity is reduced, but heat exchange efficiency deteriorates and compressor damage risk increases
Solution Approach 1:
The patent performs preliminary detection of temperatures and pressures at multiple points in the refrigeration cycle before composition changes cause serious problems. By continuously monitoring and calculating circulation composition in advance, the system can detect leakage early and take corrective action before heat exchange efficiency deteriorates or compressor damage occurs.
Solution Approach 2:
The patent implements a feedback mechanism where the correction control unit continuously monitors sensor outputs, calculates circulation composition, and uses this information to correct subsequent measurements. This feedback loop ensures that composition changes are detected and accounted for, maintaining operational reliability while using a relatively simple detection system.
Data Source
AI summary
A refrigeration cycle device circulates a refrigerant, which is a zeotropic refrigerant mixture. In a refrigeration cycle, a compressor, a condenser, an expansion valve, and an evaporator are connected by a refrigerant pipe. The refrigeration cycle device calculates a circulation composition value of the refrigerant based on states before and after the refrigerant temperature and the refrigerant pressure change during the operation of the refrigeration cycle, calculates dT for calibrating a second temperature sensor and dP for calibrating a pressure sensor, based on a reference composition value and the circulation composition value of the refrigerant, corrects the value of the temperature of the refrigerant on an outlet side based on dT, corrects the value of the pressure of the refrigerant based on dP, and operates the refrigeration cycle.