Refrigerant Circuit Layout for Low-Charge Air Conditioner Heating
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Solution Overview
Problem
Air conditioners face challenges in reducing refrigerant usage while maintaining the performance of auxiliary heat exchangers, especially with the increasing regulations on HFC refrigerants and the resulting rise in refrigerant costs, as existing technologies lower the heat exchange rate during heating operations when refrigerant is in a mixed gas-liquid state.
Innovation Solution
Incorporating a rectifier with check valves and bypass passages in the refrigerant circuit to control the flow of refrigerant through auxiliary and outdoor expansion valves, ensuring refrigerant remains in a mixed state, and using a supercooling expansion valve to maintain efficient heat exchange in both cooling and heating operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the refrigerant in a mixed gas-liquid state is depressurized by the outdoor expansion valve upstream of the auxiliary heat exchanger in heating operation, then the refrigerant circulation is maintained, but the heat exchange rate of the refrigerant in the auxiliary heat exchanger is lowered
Solution Approach 1:
The patent inverts the conventional flow sequence by using a rectifier to make the refrigerant flow through the auxiliary heat exchanger first, then through the outdoor expansion valve. This reversal ensures that liquid refrigerant enters the auxiliary heat exchanger for efficient heat exchange before being depressurized, resolving the contradiction between maintaining circulation and preserving heat exchange performance.
Solution Approach 2:
The rectifier acts as an intermediary device that controls and directs the refrigerant flow sequence. It mediates between the outdoor expansion valve and the auxiliary heat exchanger, ensuring that refrigerant flows in the optimal sequence (auxiliary heat exchanger first, then expansion valve) during heating operation, thereby maintaining both circulation reliability and heat exchange efficiency.
2Quantity of substance
If an outdoor expansion valve is provided between an auxiliary heat exchanger and the indoor heat exchanger to reduce refrigerant amount, then refrigerant usage is reduced, but the performance of the auxiliary heat exchanger is lowered in heating operation
Solution Approach 1:
The patent applies flow sequence inversion by positioning the outdoor expansion valve downstream of the auxiliary heat exchanger in the refrigerant circuit and using a rectifier to control the flow direction. This ensures that during heating operation, refrigerant flows through the auxiliary heat exchanger in liquid state first for optimal heat exchange performance, then gets depressurized by the expansion valve, thus maintaining both reduced refrigerant quantity and high auxiliary heat exchanger performance.
3Device complexity
If refrigerant flows through the auxiliary heat exchanger in mixed gas-liquid state, then the refrigerant circuit operation is simplified, but the heat exchange efficiency is reduced
Solution Approach 1:
The rectifier serves as an intermediary flow control device that manages the refrigerant state and flow sequence. During heating operation, it ensures liquid refrigerant is directed to the auxiliary heat exchanger first for efficient heat exchange, then controls the flow through the outdoor expansion valve. This mediation maintains heat exchange efficiency while keeping the overall circuit operation relatively simple through automatic flow direction control.
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 configuration reduces refrigerant usage, prevents performance degradation of auxiliary heat exchangers, and maintains efficient operation by ensuring refrigerant flows optimally through the system in both cooling and heating modes.
Implementation Method 1
a rectifier configured to allow a refrigerant flowing from the outdoor heat exchanger toward the indoor expansion valve in a cooling operation or a refrigerant flowing from the indoor expansion valve toward the outdoor heat exchanger in a heating operation to sequentially flow through the auxiliary heat exchanger and the outdoor expansion valve
Implementation Method 2
the refrigerant passes through the auxiliary heat exchanger and is then depressurized in the outdoor expansion valve, thereby being in a state where gas and liquid are mixed
Implementation Method 3
an outdoor heat exchanger, an outdoor expansion valve, an indoor expansion valve, and an indoor heat exchanger
Data Source
AI summary
An air conditioner including a refrigerant circuit including a compressor, an outdoor heat exchanger, an outdoor expansion valve, an indoor expansion valve, and an indoor heat exchanger. The refrigerant circuit including an auxiliary heat exchanger provided on a refrigerant pipe between the outdoor heat exchanger and the indoor expansion valve and connected in series with the outdoor expansion valve, and a rectifier configured to allow a refrigerant flowing from the outdoor heat exchanger toward the indoor expansion valve in a cooling operation or a refrigerant flowing from the indoor expansion valve toward the outdoor heat exchanger in a heating operation to sequentially flow through the auxiliary heat exchanger and the outdoor expansion valve.