Multi-Unit Air Conditioner Subcooling Balance for Refrigerant Charging
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Solution Overview
Problem
Existing air-conditioning devices with multiple outdoor units face challenges in determining the proper refrigerant amount during charging due to the inability to accurately measure the degree of subcooling at the condenser outlet when the refrigerant is in a two-phase state, leading to imbalances in refrigerant distribution.
Innovation Solution
An air-conditioning device with a control section that uses temperature sensors to detect the subcooling circuit outlet temperature, sets a target subcooling value, and adjusts compressor rotation speeds to balance the subcooling difference among outdoor units by increasing the speed of units with higher subcooling and decreasing it for those with lower subcooling, ensuring proper refrigerant charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the degree of subcooling at the condenser outlet is used to determine refrigerant amount, then refrigerant charging can be performed, but accurate measurement becomes impossible when refrigerant is in two-phase state
Solution Approach 1:
The patent introduces a subcooling circuit as an intermediary component between the condenser outlet and the refrigerant charging determination point. By measuring the temperature at the outlet of this subcooling circuit rather than directly at the condenser outlet, the system obtains accurate temperature readings even when the refrigerant is in two-phase state at the condenser outlet. The subcooling circuit ensures the refrigerant is in a single-phase liquid state at the measurement point, resolving the measurement difficulty.
2Productivity
If refrigerant amount determination is performed in multiple outdoor units, then refrigerant distribution can be optimized, but imbalance in refrigerant amount occurs
Solution Approach 1:
The patent implements a feedback control mechanism where the control section continuously monitors the degree of subcooling at the subcooling circuit outlet for each outdoor unit and adjusts the compressor rotation speeds accordingly. The system compares the measured subcooling degree with a target value and modifies compressor operations to eliminate differences, ensuring balanced refrigerant distribution across multiple outdoor units while maintaining efficient charging operations.
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 approach allows for accurate determination and balancing of the refrigerant amount in the refrigerant circuit, ensuring efficient operation and maintaining a stable refrigerant balance among outdoor units.
Implementation Method 1
a temperature sensor configured to detect the temperature of refrigerant having passed through the subcooling circuit of each outdoor unit
Implementation Method 2
a compressor configured to compress a refrigerant gas to a high pressure and a high temperature
Implementation Method 3
a condenser configured to condense the refrigerant gas compressed by the compressor to a refrigerant liquid
Implementation Method 4
a condenser configured to condense the refrigerant gas compressed by the compressor to a refrigerant liquid
Data Source
AI summary
An air-conditioning device including multiple outdoor units and an indoor unit through a pipe includes a control section that obtains a degree of subcooling at an outlet of a subcooling circuit of each outdoor unit based on a temperature detected by a temperature sensor that detects the temperature of refrigerant having passed through the subcooling circuit of each outdoor unit, obtain a target value of the degree of subcooling based on the obtained multiple degrees of subcooling, and perform the control of increasing the rotation speed of a compressor of an outdoor unit having a higher degree of subcooling than the target value and decreasing the rotation speed of a compressor of an outdoor unit having a lower degree of subcooling than the target value such that a difference in the degree of subcooling at the outlet of the subcooling circuit of each outdoor unit is decreased.