Supercooling Valve Control for Multi-Unit Air Conditioner Flash Prevention
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Solution Overview
Problem
Air conditioners experience refrigerant flow sound due to flash occurrences in refrigerant pipes, leading to inadequate cooling performance and maldistribution of refrigerant flow among indoor units with different temperature settings.
Innovation Solution
The implementation of a supercooling circuit with a supercooling heat exchanger, supercooling pipe, and adjustable supercooling control valve, where the supercooling control valve is adjusted based on the air conditioning load of connected heat exchangers to prevent refrigerant flashes and ensure sufficient supercooling, thereby minimizing refrigerant flow sound and ensuring required cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional supercooling circuit with capillary tube is used, then the structure is simple, but the refrigerant cannot be sufficiently reduced in pressure when operating capacity is small, causing insufficient supercooling and refrigerant flash
Solution Approach 1:
The patent replaces the fixed capillary tube with an electronically controlled expansion valve that can dynamically adjust the degree of pressure reduction based on operating conditions. This parameter change allows the system to adapt to varying refrigerant flow rates and maintain effective supercooling across different operating capacities, resolving the contradiction between structural simplicity and supercooling reliability.
Solution Approach 2:
The invention introduces a dynamic control mechanism where the expansion valve opening is automatically adjusted based on detected refrigerant temperature and pressure conditions. This dynamic adaptation ensures that sufficient pressure reduction is always achieved regardless of operating capacity variations, eliminating the insufficient supercooling problem that occurs with fixed capillary tubes at low operating capacities.
2Productivity
If liquid refrigerant flows through the liquid connection pipe during heating operation, then the system operates efficiently, but the refrigerant may flash and turn into gas-liquid two-phase state, causing refrigerant flow sound
Solution Approach 1:
The patent applies preliminary supercooling to the liquid refrigerant before it enters the liquid connection pipe by diverting some refrigerant through the supercooling heat exchanger. This preliminary action ensures the refrigerant remains in liquid phase throughout the heating operation, preventing flash occurrence and the associated refrigerant flow sound while maintaining heating efficiency.
Solution Approach 2:
The supercooling heat exchanger acts as an intermediary device that facilitates heat exchange between the liquid refrigerant in the liquid connection pipe and the refrigerant passing through the supercooling circuit. This intermediary mechanism enables controlled supercooling to prevent refrigerant flash and eliminate harmful flow sounds without disrupting the main heating operation.
3Adaptability or versatility
If multiple indoor units with different temperature settings are connected, then system versatility is improved, but refrigerant maldistribution occurs where larger amount flows to units requiring higher cooling capacity
Solution Approach 1:
The patent implements a feedback control system where temperature sensors detect refrigerant temperature at various points, and the controller adjusts the expansion valve opening accordingly. This feedback mechanism ensures that each indoor unit receives the appropriate refrigerant flow based on its specific cooling load requirements, preventing maldistribution while maintaining system versatility.
Solution Approach 2:
The invention applies different refrigerant flow conditions to different locations in the system by controlling the expansion valve to provide localized pressure reduction. This allows each indoor unit to receive refrigerant at optimal conditions tailored to its specific requirements, ensuring proper flow distribution across multiple units with different temperature settings.
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 effectively suppresses refrigerant flow sound and ensures consistent cooling performance across indoor units by adjusting the supercooling control valve according to the air conditioning load, preventing refrigerant flashes and ensuring sufficient refrigerant flow for each unit.
Implementation Method 1
liquid refrigerant flowing through the liquid connection pipe is supercooled
Implementation Method 2
a capillary tube for reducing the pressure of refrigerant flowing through the supercooling pipe
Implementation Method 3
refrigerant diverted from the liquid connection pipe is reduced in pressure by the capillary tube and evaporates in the supercooling heat exchanger
Implementation Method 4
a supercooling heat exchanger, a supercooling pipe branching from the liquid connection pipe passing through the supercooling heat exchanger
Data Source
AI summary
Out of switching mechanisms (30A, 30B), the switching mechanism (30A) connected to an indoor heat exchanger (41) performing a heating operation is configured so that the opening of a supercooling control valve (53) is adjusted according to the air conditioning load of another indoor heat exchanger (41) performing a cooling operation downstream of a liquid connection pipe (13) connected to the former indoor heat exchanger (41).