Heat pump device using a non-azeotropic mixture refrigerant
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Solution Overview
Problem
Heat pump devices using non-azeotropic mixture refrigerants face challenges in accurately detecting and controlling the composition ratio, which can lead to increased flammability and disproportionation reactions due to changes in refrigerant composition during operation.
Innovation Solution
A heat pump device with a refrigerant circuit including a compressor, four-way switching valve, condenser, expansion mechanisms, and a container equipped with temperature and pressure measurement units, allowing the control unit to estimate the physical properties of the non-azeotropic mixture refrigerant based on temperature and pressure measurements, thereby controlling the composition ratio and preventing adverse reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a non-azeotropic mixture refrigerant is used in a heat pump device, then the refrigeration efficiency is improved, but the composition ratio of the refrigerant changes during operation leading to increased flammability and disproportionation reactions
Solution Approach 1:
The system continuously monitors the temperature and pressure of the refrigerant in the accumulator, uses these measurements to estimate the composition ratio through a refrigerant property calculation unit, and feeds this information back to the control unit which adjusts the expansion valve opening degree to maintain safe operating conditions
Solution Approach 2:
The patent replaces direct chemical analysis methods with a physical measurement-based estimation system, using temperature and pressure sensors combined with refrigerant property calculations to determine composition ratio, avoiding the need for complex chemical detection equipment
2Reliability
If the composition ratio of the non-azeotropic mixture refrigerant is not controlled, then flammability increases and disproportionation reactions occur, but implementing composition detection and control increases device complexity
Solution Approach 1:
The system introduces a refrigerant property calculation unit as an intermediary that computes the composition ratio from readily available temperature and pressure measurements, serving as a bridge between simple physical measurements and the required composition information without requiring direct chemical sensing
Solution Approach 2:
The system creates a virtual model of the refrigerant composition by calculating it from temperature and pressure data, rather than directly measuring the actual composition, using the relationship between physical properties and composition to generate an accurate representation of the refrigerant state
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
The solution enables precise estimation and control of the refrigerant composition, reducing flammability risks and preventing disproportionation reactions, ensuring safe and efficient operation of the heat pump device.
Implementation Method 1
The temperature measurement unit measures a temperature of the non-azeotropic mixture refrigerant in the container
Implementation Method 2
The pressure measurement unit measures a pressure of the non-azeotropic mixture refrigerant in the container
Implementation Method 3
the control unit estimates a composition ratio of the non-azeotropic mixture refrigerant circulating in the refrigerant circuit based on the temperature and the pressure of the non-azeotropic mixture refrigerant accumulated in the container
Data Source
AI summary
In an air conditioner, during an operation, a gas-liquid two-phase non-azeotropic mixture refrigerant enters a receiver and accumulates in the receiver in a state where a gas phase and a liquid phase are separated. For example, when the non-azeotropic mixture refrigerant includes two components, i.e., a high-boiling refrigerant and a low-boiling refrigerant, the controller may estimate the ratio (composition ratio) between the low-boiling refrigerant and the high-boiling refrigerant in each of the gas phase and the liquid phase based on the temperature and the pressure of the non-azeotropic mixture refrigerant in the receiver. Thus, the controller may estimate the composition ratio of the liquid-phase non-azeotropic mixture refrigerant flowing out of the receiver as the composition ratio of the non-azeotropic mixture refrigerant circulating in the refrigerant circuit.