Refrigerant Cooler Valve Layout for Low-Charge Air Conditioners
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Solution Overview
Problem
In air conditioners with a refrigerant circuit configured by connecting an outdoor unit and indoor units via liquid and gas refrigerant communication pipes, the existing configurations face challenges in reducing the amount of refrigerant while maintaining refrigeration capacity and operating efficiency, particularly due to pressure drops that affect the refrigerant's flow through the refrigerant cooler, leading to inadequate cooling and efficiency.
Innovation Solution
The integration of a refrigerant returning pipe and a refrigerant cooler, along with a liquid pressure adjusting expansion valve located between the liquid refrigerant communication pipe and the refrigerant cooler, allows the refrigerant to flow in a gas-liquid two-phase state, ensuring it exits the cooler in a liquid state, thereby maintaining high pressure and flow quality, and a control system adjusts the expansion valves to achieve target subcooling and pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an outdoor expansion valve or capillary tube is used to reduce refrigerant pressure before the liquid refrigerant communication pipe, then the amount of refrigerant to be filled into the refrigerant circuit is reduced, but the pressure of the refrigerant falling makes it impossible to flow the refrigerant with a high level of wetness through the refrigerant cooler and secures a difference in pressure between the refrigerant flowing through the outdoor liquid refrigerant pipe and the refrigerant flowing through the refrigerant returning pipe
Solution Approach 1:
The patent divides the pressure reduction function into two separate components: the outdoor expansion valve performs the primary pressure reduction, and the liquid pressure adjusting expansion valve performs fine-tuned pressure adjustment. This segmentation allows each component to operate optimally - the outdoor expansion valve reduces pressure to enable refrigerant cooler function, while the liquid pressure adjusting expansion valve maintains the necessary pressure difference for proper refrigerant flow distribution.
Solution Approach 2:
The liquid pressure adjusting expansion valve acts as an intermediary component between the outdoor expansion valve and the liquid refrigerant communication pipe. It mediates the pressure levels, ensuring that the refrigerant maintains appropriate pressure and wetness for the refrigerant cooler while also maintaining the pressure difference needed between the liquid refrigerant pipe and refrigerant returning pipe.
2Productivity
If the liquid pressure adjusting expansion valve is located in the outdoor liquid refrigerant pipe at a part between the liquid refrigerant communication pipe and the refrigerant cooler, then the refrigerant flows through the liquid refrigerant communication pipe in a gas-liquid two-phase state and flows through an outlet of the refrigerant cooler in a liquid state, but the device complexity increases
Solution Approach 1:
The liquid pressure adjusting expansion valve serves multiple functions simultaneously: it controls refrigerant pressure to maintain gas-liquid two-phase flow in the communication pipe, ensures liquid state flow at the refrigerant cooler outlet, and helps maintain the pressure difference between pipes. This multi-functionality justifies the additional component by consolidating several control objectives into a single device.
3Use of energy by moving object
If the refrigerant cooler is used to cool the refrigerant flowing through the outdoor liquid refrigerant pipe using the refrigerant flowing through the refrigerant returning pipe, then the operating efficiency is improved, but the pressure difference between the refrigerant flowing through the outdoor liquid refrigerant pipe and the refrigerant flowing through the refrigerant returning pipe becomes insufficient
Solution Approach 1:
The liquid pressure adjusting expansion valve provides feedback control for refrigerant pressure. By continuously adjusting the valve opening based on pressure conditions, the system maintains the necessary pressure difference between the liquid refrigerant pipe and refrigerant returning pipe, ensuring that the refrigerant cooler operates efficiently without compromising the pressure gradient needed for proper refrigerant circulation.
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 the refrigerant amount in the circuit while enhancing refrigeration capacity and operating efficiency by maintaining high wetness flow through the refrigerant cooler and securing pressure differences, leading to improved cooling performance and reduced pressure losses.
Implementation Method 1
the refrigerant cooler is configured to cool the refrigerant flowing through the outdoor liquid refrigerant pipe using the refrigerant flowing through the refrigerant returning pipe
Implementation Method 2
the outdoor expansion valve or the liquid pressure adjusting expansion valve is used to reduce the pressure of the refrigerant... so that the refrigerant flowing through the liquid refrigerant communication pipe enters in a gas-liquid two-phase state
Implementation Method 3
the outdoor expansion valve or the liquid pressure adjusting expansion valve is used to reduce the pressure of the refrigerant before the refrigerant is sent to the liquid refrigerant communication pipe
Implementation Method 4
the refrigerant flowing through the liquid refrigerant communication pipe enters in a gas-liquid two-phase state
Data Source
AI summary
An air conditioner includes a liquid pressure adjusting expansion valve that is located in an outdoor liquid refrigerant pipe at a part thereof closer to a liquid refrigerant communication pipe than to a refrigerant cooler and configured to reduce a pressure of a refrigerant so that a refrigerant flows through the liquid refrigerant communication pipe in a gas-liquid two-phase state and so that the refrigerant flows through an outlet of a refrigerant cooler in a liquid state.