Indoor Fan Shutdown Cycles for Refrigerant Leak Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Refrigerant leakage detection in air-conditioning devices using mildly flammable refrigerants is challenging due to diffusion by indoor unit fans, making it difficult to detect leaks promptly, especially in ceiling-mounted units where air currents interfere with detection.
Innovation Solution
The air-conditioning device implements a refrigerant leakage detection system that temporarily stops the fan operation at predetermined intervals to allow refrigerant sensors to check for leaks, preventing refrigerant diffusion and enabling early detection before concentrations reach hazardous levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan operates continuously to provide air conditioning, then cooling/heating performance is maintained, but refrigerant leakage detection is delayed due to diffusion
Solution Approach 1:
The fan operates periodically with alternating on/off cycles. During off-periods, refrigerant leakage detection is performed without fan-induced diffusion. During on-periods, air conditioning function is restored. This periodic operation resolves the contradiction by temporarily suspending air flow to enable accurate detection, then resuming it to maintain productivity.
Solution Approach 2:
Refrigerant leakage detection is performed preliminarily during fan off-periods before the fan starts operating again. This ensures that any leakage is detected before the fan diffusion effect begins, allowing early warning and prevention of hazardous conditions while maintaining overall system productivity through continuous monitoring cycles.
2Productivity
If the fan operates at high speed to improve air circulation, then air conditioning efficiency increases, but refrigerant diffusion prevents timely leakage detection
Solution Approach 1:
The system alternates between high-speed fan operation for efficient air conditioning and zero-speed operation for leakage detection. During detection phases, the fan is completely stopped to eliminate any diffusion effect, ensuring accurate refrigerant concentration measurement by the sensor.
Solution Approach 2:
The fan operation is preemptively stopped before leakage detection to prevent the harmful diffusion effect. This preliminary anti-action eliminates the interference that would otherwise make measurement difficult, allowing accurate detection to occur without subsequent fan-induced mixing.
3Measurement precision
If the fan is stopped for leakage detection, then detection accuracy improves, but air conditioning function is interrupted
Solution Approach 1:
The system implements periodic leakage detection by stopping the fan at predetermined intervals rather than continuously. This allows brief interruption of air conditioning function only when necessary for detection, minimizing time loss while maintaining measurement precision. The system alternates between service mode and detection mode efficiently.
Solution Approach 2:
Instead of stopping the fan completely and continuously for detection, the system uses partial stopping only during scheduled detection intervals. This excessive action (stopping more than minimally needed) ensures complete elimination of diffusion effects and maximizes detection accuracy, while the limited duration of stops minimizes overall service interruption.
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 timely detection and prevention of refrigerant leaks, ensuring safety by stopping refrigerant circulation before concentrations reach explosive levels, even in configurations with low leakage rates or high air flow rates, thereby reducing the risk of accidents.
Implementation Method 1
a refrigerant sensor that detects, when the operation of the indoor unit is stopped, the refrigerant leakage from the indoor unit
Implementation Method 2
an indoor fan which generates an air flow passing through the heat exchanger
Implementation Method 3
a heat exchanger implementing heat exchange between refrigerant flowing in the pipes and air
Data Source
Figure 1~2
Figure 3
Figure 4~4(c)
AI summary
The present invention provides an air-conditioning device capable of detecting any refrigerant leaking at an early stage. The air-conditioning device includes an indoor unit that includes a heat exchanger through which refrigerant flows, a refrigerant sensor configured to detect any refrigerant leaking from the heat exchanger into air, a fan configured to send air to the heat exchanger, and a controller configured to control operation of the refrigerant sensor and the fan, wherein the controller stops operation of the fan and makes the refrigerant sensor detect any refrigerant.