Control device and air conditioning device
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Solution Overview
Problem
Existing air-conditioning systems face challenges in accurately determining the refrigerant amount during charging due to the two-phase state of refrigerant at the condenser outlet, which prevents proper determination of the degree of supercooling and subsequent refrigerant balance among outdoor units.
Innovation Solution
The system employs a control device with a supercooling bypass pipe and temperature sensors to monitor and adjust compressor and fan rotation speeds, ensuring balanced refrigerant distribution by maintaining equal supercooling degrees among outdoor units through dynamic control of compressor and fan speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the degree of supercooling at the condenser outlet is used to determine refrigerant amount, then refrigerant charging operation can be performed, but when refrigerant is in a two-phase state, no temperature change is shown and the degree of supercooling cannot be properly obtained
Solution Approach 1:
The patent introduces a subcooling circuit as an intermediary component between the condenser outlet and the refrigerant charging determination point. This subcooling circuit ensures that the refrigerant is fully liquidified before measurement, eliminating the two-phase state measurement problem. The subcooling circuit acts as a mediator that transforms the refrigerant state to enable accurate supercooling degree measurement.
Solution Approach 2:
The patent changes the measurement location from the condenser outlet to the subcooling circuit outlet, where the refrigerant has already undergone parameter transformation (complete liquidification). By measuring at this new location with different refrigerant state parameters (fully liquid instead of two-phase), the system achieves reliable supercooling degree determination.
2Quantity of substance
If compressor rotation speed is decreased on the lower supercooling degree side to balance refrigerant amount, then refrigerant distribution can be improved, but the system complexity increases due to multiple sensors and control mechanisms
Solution Approach 1:
The patent implements a feedback control mechanism where supercooling degree sensors continuously monitor the refrigerant state at each outdoor unit, and the control device adjusts compressor rotation speeds based on this feedback. The system compares supercooling degrees among multiple outdoor units and dynamically adjusts compressor speeds to balance refrigerant distribution, creating a closed-loop control system.
Solution Approach 2:
The patent employs dynamic adjustment of compressor rotation speeds based on real-time supercooling degree measurements. Instead of fixed speed settings, the system continuously adapts compressor operating parameters to maintain balanced refrigerant distribution across multiple outdoor units, making the system flexible and responsive to changing conditions.
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 precise determination and balancing of refrigerant amounts, ensuring proper refrigerant charging and efficient operation of air-conditioning systems by maintaining consistent supercooling levels across multiple outdoor units.
Implementation Method 1
a temperature sensor that detects a temperature of refrigerant at an outlet of the supercooling circuit
Implementation Method 2
a supercooling circuit that cools refrigerant
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A control device of an air-conditioning device including multiple outdoor units and an indoor unit connected to the multiple outdoor units through a pipe includes a control section configured to obtain, before refrigerant charging to a refrigerant circuit including the multiple outdoor units and the indoor unit is completed, the degree of supercooling at an outlet of a supercooling circuit of each outdoor unit based on a temperature detected by a temperature sensor configured to detect the temperature of refrigerant having passed through the supercooling circuit of each outdoor unit, obtain a target value of the degree of supercooling based on the obtained multiple degrees of supercooling, and perform the control of increasing the rotation speed of a compressor of an outdoor unit having a higher degree of supercooling than the target value and decreasing the rotation speed of a compressor of an outdoor unit having a lower degree of supercooling than the target value such that a difference in the degree of supercooling at the outlet of the supercooling circuit of each outdoor unit is decreased.