Indoor Unit Sensor Layout for Accurate Refrigerant Leak Detection
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Solution Overview
Problem
The temperature of refrigerant in an indoor unit of an air-conditioning apparatus fluctuates significantly during different operating states, leading to false refrigerant leakage detection due to temperature differences between refrigerant and indoor air, particularly during defrosting operations.
Innovation Solution
The indoor unit is designed with the refrigerant detection sensor located below the heat exchanger and between the suction grille and fan, allowing for detection of refrigerant leakage in the air flowing through the unit before it reaches flammable concentrations, and ensuring detection even when the fan is stopped, with the sensor positioned to accumulate leaking refrigerant at the bottom of the casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature sensors are used to detect refrigerant leakage by measuring temperature difference between air and refrigerant, then refrigerant leakage detection is enabled, but false detection occurs during defrosting operation due to significant temperature changes
Solution Approach 1:
The patent replaces the temperature-based detection system with a gas sensor-based detection system. Instead of measuring temperature differences between air and refrigerant, the invention uses a gas sensor to directly detect the presence and concentration of refrigerant gas in the air, thereby eliminating false detections caused by temperature fluctuations during defrosting operations.
2Measurement precision
If the refrigerant detection sensor is positioned to detect refrigerant in the air stream during fan operation, then detection capability is improved, but detection accuracy decreases when the fan is stopped
Solution Approach 1:
The patent positions the gas sensor at the bottom of the casing below the heat exchanger, utilizing the gravitational dimension. Since refrigerant gas is heavier than air, it naturally accumulates at the bottom of the casing when the fan is stopped, allowing the sensor to detect leaked refrigerant effectively in this stationary state.
Solution Approach 2:
The patent creates different detection strategies for different operational states: during fan operation, the sensor detects refrigerant in the air stream near the suction grille; when the fan is stopped, the sensor detects accumulated refrigerant at the bottom of the casing. This localized adaptation to different conditions ensures reliable detection in both states.
3Speed
If the sensor is located to detect refrigerant during fan operation, then real-time detection is achieved, but detection is delayed when refrigerant accumulates at the bottom
Solution Approach 1:
The patent merges two detection locations/functions into a single sensor position at the bottom of the casing. The sensor is positioned to detect both refrigerant in the air stream during fan operation and refrigerant accumulated at the bottom when the fan is stopped, thereby eliminating detection delays for bottom-accumulated refrigerant.
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 improves refrigerant detection accuracy by diluting and detecting refrigerant in the air stream during operation and accumulating it at the bottom for detection when the fan is stopped, preventing false alarms and ensuring safety by preventing flammable concentrations.
Implementation Method 1
the refrigerant leaking from the casing is diluted, and even if refrigerant leakage cannot be instantly detected, the refrigerant detection sensor can detect the refrigerant contained in the air flowing out through the air outlet and flowing in through the air inlet
Implementation Method 2
the refrigerant detection sensor can detect the refrigerant contained in the air flowing out through the air outlet and flowing in through the air inlet
Implementation Method 3
during an operation of the fan, the refrigerant leaking from the casing is diluted, and even if refrigerant leakage cannot be instantly detected
Implementation Method 4
while the fan is kept stopped, the refrigerant remains on a bottom of the casing, and thus the refrigerant detection sensor can detect the refrigerant leakage
Data Source
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AI summary
An indoor unit of an air-conditioning apparatus includes a suction grille having an air inlet through which air flows in, a decorative panel to which the suction grille is mounted and having an air outlet through which the air flows out, a casing to which the decorative panel is mounted and defining an air passage between the air inlet and the air outlet, a fan located to face the suction grille in the casing and configured to cause the air to flow in through the air inlet and flow out through the air outlet, a heat exchanger located in the air passage between the fan and the air outlet in the casing and configured to exchange heat between refrigerant flowing in the heat exchanger and the air, and a refrigerant detection sensor configured to detect leakage of the refrigerant. The suction grille is located below the heat exchanger, and the refrigerant detection sensor is located below the heat exchanger and between the suction grille and the fan.