Air-conditioning apparatus
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Solution Overview
Problem
Existing air-conditioning systems face challenges in efficiently managing refrigerant composition, particularly in mixed refrigerant systems, which can lead to energy inefficiencies and safety concerns due to varying boiling points and leakage risks.
Innovation Solution
An air-conditioning apparatus that includes a refrigeration cycle with a zeotropic refrigerant mixture of tetrafluoropropene and R32, equipped with a composition detection circuit using pressure and temperature sensors to accurately determine the refrigerant composition, allowing for precise control of the refrigerant expansion and heat exchange processes, thereby optimizing energy efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a zeotropic refrigerant mixture containing tetrafluoropropene and R32 is used, then energy efficiency is improved through optimized heat exchange, but the refrigerant composition varies during circulation due to different boiling points, making precise control difficult
Solution Approach 1:
The patent employs pressure sensors and temperature sensors to detect the actual refrigerant state during circulation, feeding this information back to a controller that adjusts the expansion valve opening degree accordingly. This closed-loop feedback system compensates for composition variations in the zeotropic mixture, maintaining stable and efficient operation despite the inherent compositional drift of mixed refrigerants with different boiling points.
2Measurement precision
If pressure and temperature detection devices are added to detect refrigerant composition, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent uses pressure and temperature as intermediary parameters to indirectly detect refrigerant composition. Rather than directly analyzing refrigerant composition, the system measures easily obtainable pressure and temperature values at specific locations (suction side and discharge side of the compressor) and uses these as proxies to infer composition, simplifying the detection system while maintaining measurement precision.
Solution Approach 2:
The patent replaces complex mechanical or chemical composition analysis devices with simple electronic pressure and temperature sensors coupled with computational algorithms. The controller calculates composition based on thermodynamic relationships between pressure, temperature, and refrigerant properties, substituting mechanical/chemical complexity with electronic sensing and software processing.
3Adaptability or versatility
If the outdoor unit and heat medium relay unit are disposed separately, then adaptability is improved for different installation environments, but the refrigerant circulation path becomes longer, potentially affecting efficiency
Solution Approach 1:
The patent employs dynamic flow control through electronically controlled expansion valves and flow switching devices that can adapt refrigerant flow paths and rates in real-time. This dynamic adjustment compensates for the increased path length caused by separate unit disposition, optimizing flow characteristics to minimize efficiency losses while maintaining installation flexibility.
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 system achieves high energy efficiency, reduces energy consumption, and minimizes refrigerant leakage into conditioned spaces, ensuring a safe and environmentally friendly operation by accurately detecting and managing the refrigerant composition in real-time.
Implementation Method 1
a compressor that sends out a zeotropic refrigerant mixture containing tetrafluoropropene and R32
Implementation Method 2
a heat source side heat exchanger for exchanging heat of the refrigerant
Implementation Method 3
a refrigerant expansion device for controlling pressure of the refrigerant
Implementation Method 4
a heat exchanger related to heat medium that is capable of exchanging heat between the refrigerant and a heat medium different from the refrigerant
Implementation Method 5
a low-pressure side pressure detection device for detecting low-pressure side pressure corresponding to pressure of the refrigerant suctioned by the compressor
Implementation Method 6
a high-pressure side temperature detection device for detecting high-pressure side temperature corresponding to temperature of the refrigerant flowing into the bypass expansion device
Implementation Method 7
a low-pressure side temperature detection device for detecting low-pressure side temperature corresponding to temperature of the refrigerant discharged from the bypass expansion device
Implementation Method 8
a heat medium sending device for circulating the heat medium for the heat exchange performed by the heat exchanger related to heat medium
Data Source
AI summary
An air-conditioning apparatus includes a high-pressure side pressure detection device detecting high-pressure side pressure, a low-pressure side pressure detection device detecting low-pressure side pressure, a high-low pressure bypass pipe connecting a pipe on a discharge side of a compressor and a pipe on a suction side of the compressor, a bypass expansion device disposed in the high-low pressure bypass pipe, a high-pressure side temperature detection device detecting high-pressure side temperature, and a low-pressure side temperature detection device detecting low-pressure side temperature; an outdoor unit side controller that detects circulation composition of refrigerant on the basis of the high-pressure side pressure, the low-pressure side pressure, the high-pressure side temperature, and the low-pressure side temperature; and a relay unit side controller performing at least one of a calculation of evaporating temperature and degree of superheat, and a calculation of condensing temperature and degree of subcooling on the basis of the circulation composition.