Refrigerant Concentration Sensing via Saturation Pressure and Temperature
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Solution Overview
Problem
Existing methods for measuring the concentration of ammonia aqueous solutions in absorption type heat pump systems are inconvenient, dangerous, and prone to measurement errors due to the need for extraction, which can lead to evaporation or leakage, and the reliability of conductance-based prediction methods has not been verified.
Innovation Solution
An apparatus and method using a container with temperature and pressure sensors to measure the saturation pressure and temperature of a nonazeotrope refrigerant mixture, coupled with a controller that calculates concentration based on a database relating saturation vapor pressure, temperature, and quality, allowing for real-time measurement without extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extraction method (titration or density measurement) is used to measure ammonia aqueous solution concentration, then concentration can be measured, but real-time measurement is difficult and handling is inconvenient and dangerous
Solution Approach 1:
The patent replaces mechanical extraction and manual titration/density measurement methods with a sensor-based measurement system. Pressure and temperature sensors directly measure the refrigerant mixture properties in the container, and a controller calculates concentration from these measurements, eliminating the need for manual extraction and chemical analysis.
Solution Approach 2:
The measurement system uses the inherent properties of the refrigerant mixture itself (pressure and temperature in saturated state) to determine concentration. The system measures what is already present in the container without requiring external reagents or extraction processes, making the refrigerant mixture self-diagnostic.
2Measurement precision
If extraction method is used to measure ammonia aqueous solution concentration, then concentration can be measured, but evaporation or leakage occurs during extraction process causing measurement error
Solution Approach 1:
The patent replaces the extraction process with direct in-situ sensing. Pressure and temperature sensors measure the refrigerant mixture properties within the sealed container without opening it, eliminating evaporation and leakage that occur during extraction-based methods.
Solution Approach 2:
The patent introduces pressure and temperature sensors as intermediaries to indirectly measure concentration. Instead of directly extracting and analyzing the refrigerant mixture, the sensors detect physical parameters (pressure and temperature) that correlate with concentration, providing measurement without direct contact or extraction.
3Productivity
If conductance measurement method is used to predict ammonia aqueous solution concentration, then real-time measurement is possible, but reliability has not been verified
Solution Approach 1:
The patent changes the measurement parameters from electrical conductance to thermodynamic parameters (pressure and temperature of saturated refrigerant mixture). These parameters have well-established relationships with concentration through thermodynamic models and databases, providing both real-time measurement capability and verified reliability.
Solution Approach 2:
The patent replaces electrical conductance measurement with thermodynamic parameter measurement using pressure and temperature sensors. This substitution leverages fundamental thermodynamic relationships that are well-understood and verified, improving reliability while maintaining real-time measurement capability.
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
Enables accurate and safe real-time measurement of the concentration of liquid-state refrigerant mixtures, reducing errors and maintaining consistent conditions, while being easily integrated into existing systems without causing evaporation or leakage.
Implementation Method 1
a temperature sensor that measures a temperature of the liquid-state refrigerant mixture
Implementation Method 2
a pressure sensor that measures a pressure of the liquid-state refrigerant mixture in the saturated state or a pressure of the container
Implementation Method 3
a heater that heats the subcooled liquid-state refrigerant mixture to be in a saturated state
Implementation Method 4
when a nonazeotrope refrigerant mixture in which two kinds of refrigerants having different evaporation pressures are mixed, is in a saturated state
Data Source
AI summary
An apparatus and method for measuring concentration of a liquid-state refrigerant of a nonazeotrope refrigerant mixture. A container is disposed in such a way that a liquid-state refrigerant mixture of the nonazeotrope refrigerant mixture in a saturated state is temporarily stored with set quality. By measuring temperature and pressure of the liquid-state refrigerant mixture, concentration of the liquid-state refrigerant can be calculated from a database regarding a relationship between a saturation vapor pressure, temperature, quality, and concentration of the previously-stored nonazeotrope refrigerant mixture in the saturated state. Thus, a configuration for measuring the concentration of the liquid-state refrigerant-absorbent mixture includes a container, a temperature sensor and a pressure sensor and thus is very simple and the cost for the configuration can be reduced. In addition, the container can be easily mounted on existing equipment without disturbance of a flow.