Indoor Unit Leak Detection With Adaptive Refrigerant Fan Control
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Solution Overview
Problem
Existing air-conditioning systems using flammable refrigerants face challenges in early detection of refrigerant leaks, leading to potential fires, and the continuous high-speed rotation of air-sending fans causes user discomfort and inefficiency.
Innovation Solution
An indoor unit with a temperature sensor in the pipe chamber to rapidly detect refrigerant leaks by measuring temperature changes, allowing for immediate control of the air-sending fan to rotate at high speed and then reduce or stop, ensuring safety and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a temperature sensor is arranged in the refrigerant circuit to detect refrigerant leakage, then the detection time is delayed, but if arranged in the pipe chamber, then early detection is achieved
Solution Approach 1:
The patent uses the pipe chamber as an intermediary space between the refrigerant circuit and the indoor space. The temperature sensor detects temperature changes in the pipe chamber, which serves as an early warning indicator of refrigerant leakage before the leaked refrigerant reaches the indoor space and causes fire hazards.
Solution Approach 2:
The temperature sensor is positioned in the pipe chamber to perform preliminary detection of refrigerant leakage. This allows the system to detect temperature changes caused by leaking refrigerant before the refrigerant actually enters the indoor space, enabling early warning and preventive action.
2Reliability
If the air-sending fan rotates at high speed continuously to diffuse refrigerant, then safety is improved, but user comfort deteriorates and energy consumption increases
Solution Approach 1:
The air-sending fan operates periodically rather than continuously. It rotates at high speed only when refrigerant leakage is detected to diffuse the refrigerant, and stops or reduces speed when no leakage is detected, thereby reducing energy consumption while maintaining safety.
Solution Approach 2:
The rotation speed of the air-sending fan is dynamically adjusted based on the detection results. The fan operates at high speed when refrigerant leakage is detected and at low speed or stops when no leakage is detected, optimizing both safety and energy efficiency.
3Ease of operation
If the air-sending fan operates continuously at high speed, then refrigerant diffusion is improved, but user comfort and system efficiency deteriorate
Solution Approach 1:
The air-sending fan operates periodically based on detection results. It rotates at high speed only when refrigerant leakage is detected to ensure proper diffusion, and stops or reduces speed during normal operation, thereby maintaining refrigerant diffusion capability while improving system efficiency.
4Measurement precision
If the temperature sensor is placed below the heat exchanger to detect refrigerant temperature, then detection capability is improved, but detection speed deteriorates
Solution Approach 1:
The pipe chamber serves as an intermediary detection zone. The temperature sensor detects temperature changes in the pipe chamber, which provides earlier warning of refrigerant leakage compared to detecting temperature changes in the refrigerant circuit components below the heat exchanger.
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
Enables early detection of refrigerant leaks, preventing fires and user discomfort by rapidly responding to temperature changes in the pipe chamber, ensuring efficient diffusion of refrigerant and reducing unnecessary fan operation.
Implementation Method 1
a temperature sensor arranged in the pipe chamber; a refrigerant leakage is detected based on a temperature T of the pipe chamber measured by the temperature sensor
Implementation Method 2
an air-sending fan arranged in the heat exchanger chamber; when a refrigerant leakage is detected, the controller executes a control to rotate the air-sending fan, thereby causing diffusion of the leaked refrigerant in an indoor space
Data Source
Figure 1
Figure 2
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AI summary
When a controller (10) determines that a leakage of refrigerant occurs, the controller (10) executes a control of rotating an air-sending fan (4) at high rotation speed. After the control, the controller (10) executes a control of stopping rotation of the air-sending fan (4) or reducing a rotation speed of the air-sending fan (4) in accordance with a result of detection by a first refrigerant sensor (28) provided in a lower portion of a heat exchanger chamber (1). Thus, the air-sending fan (4) is prevented from continuing the rotation at high rotation speed. Therefore, an indoor unit for an air-conditioning apparatus is excellent in safety and is capable of avoiding feeling of discomfort of a user due to the high-speed rotation of the air-sending fan.