Indoor AC Unit Refrigerant Leak Detection Without Gas Sensors
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Solution Overview
Problem
Ceiling-mounted air conditioning indoor units with undersurface openings face challenges in detecting refrigerant leakage without using costly gas sensors, which increases product costs.
Innovation Solution
The air conditioning indoor unit employs temperature sensors to detect refrigerant leakage by measuring the difference in air and refrigerant temperatures, eliminating the need for gas sensors by using predetermined threshold values and correction factors to ensure accurate leakage determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas sensor is installed to detect refrigerant leakage, then detection reliability is improved, but product cost increases
Solution Approach 1:
The patent replaces the gas sensor (chemical detection system) with a temperature sensor-based detection system that monitors temperature differences between the refrigerant piping and ambient air. This substitution eliminates the need for expensive gas sensors while maintaining reliable refrigerant leakage detection through thermal measurement principles.
Solution Approach 2:
The patent introduces temperature difference as an intermediary parameter to indirectly detect refrigerant leakage. Instead of directly detecting refrigerant concentration with a gas sensor, the system uses temperature sensors to measure the temperature difference between the refrigerant piping and ambient air, which serves as an indirect indicator of leakage conditions.
2Reliability
If a gas sensor is installed inside the unit, then refrigerant leakage can be detected, but device complexity increases
Solution Approach 1:
The patent replaces the complex gas sensor installation with a simpler temperature sensor-based system. The temperature sensors can be positioned on the refrigerant piping without requiring installation inside the unit cavity, thereby reducing device complexity while maintaining detection capability.
Solution Approach 2:
The patent uses temperature sensors that measure thermal characteristics as a copy or proxy for direct refrigerant concentration detection. By measuring the temperature difference of the refrigerant piping, the system obtains indirect information about leakage conditions without requiring direct exposure to refrigerant gases.
3Ease of manufacture
If temperature sensors are used to detect refrigerant leakage, then product cost is reduced, but measurement precision requirements increase
Solution Approach 1:
The patent changes the detection parameter from refrigerant concentration (requiring gas sensors) to temperature difference (measurable with standard temperature sensors). This parameter change allows the use of less expensive temperature sensors while the precision requirement is managed through differential measurement and threshold comparison techniques.
Solution Approach 2:
The patent substitutes the high-precision gas sensor measurement system with a temperature-based measurement system. While temperature sensors are generally less expensive, the system compensates for precision requirements through differential measurement (comparing refrigerant piping temperature with ambient air temperature) and established threshold values for leakage detection.
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 solution allows for reliable refrigerant leakage detection without gas sensors, reducing product costs and improving precision by equilibrating refrigerant piping pressure with ambient temperature, enabling effective refrigerant management.
Implementation Method 1
a first temperature sensor configured to measure the temperature of air in an air conditioning target space
Implementation Method 2
a second temperature sensor configured to measure the temperature of the refrigerant piping
Implementation Method 3
the determining component is configured to perform a refrigerant leakage determination that is a determination as to if there is refrigerant leakage based on the difference between the temperatures detected by the first temperature sensor and the second temperature sensor
Data Source
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AI summary
It is a problem of the present invention to provide an air conditioning indoor unit that can detect refrigerant leakage without using a gas sensor. In an indoor unit (20) of an air conditioning system (10), even if refrigerant should leak from refrigerant piping while operation is stopped, the pressure inside the refrigerant piping drops because of the refrigerant leakage and the refrigerant temperature (Tf) concomitantly drops, so the difference between the air temperature (Ta) and the refrigerant temperature (Tf) increases. Consequently, by presetting as a first threshold value (K1) a value corresponding to the difference that appears when the refrigerant has leaked, a determining component (83) can determine if there is refrigerant leakage by comparing the difference (Ta - Tf) and the first threshold value (K1).