Temperature-Differential Refrigerant Leak Detection for Indoor Units
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Solution Overview
Problem
Ceiling-mounted air conditioning indoor units with undersurface openings face challenges in installing gas sensors for refrigerant leakage detection, as they are costly and difficult to integrate, increasing product costs.
Innovation Solution
Incorporating first and second temperature sensors to measure air and refrigerant piping temperatures, allowing for refrigerant leakage determination based on temperature differences without the need for a gas sensor, using predetermined threshold values to ensure accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas sensor is installed inside the indoor unit for refrigerant leakage detection, then the reliability of refrigerant leakage detection is improved, but the product cost increases and the ease of manufacture deteriorates
Solution Approach 1:
The patent extracts the refrigerant leakage detection function from the indoor unit housing and relocates it to the refrigerant piping system. By installing the temperature sensor directly on the refrigerant piping, the detection function is separated from the costly gas sensor requirement while maintaining detection reliability through temperature-based leakage identification.
Solution Approach 2:
The patent replaces the chemical/direct detection method (gas sensor) with a thermal/indirect detection method (temperature sensor). Instead of directly detecting refrigerant gas concentration, the system uses temperature sensors to detect temperature changes in the refrigerant piping that indicate leakage, substituting a simpler, cheaper sensing mechanism.
2Reliability
If a gas sensor is installed inside the indoor unit for refrigerant leakage detection, then the reliability of refrigerant leakage detection is improved, but the product cost increases
Solution Approach 1:
The patent replaces the expensive gas sensor with a much cheaper temperature sensor. Temperature sensors are significantly less costly than gas sensors while still providing reliable refrigerant leakage detection through temperature differential measurement, thereby reducing product cost without sacrificing detection reliability.
Solution Approach 2:
The patent substitutes the complex gas sensing system with a simple temperature sensing system. The temperature-based detection method uses basic thermal principles and inexpensive sensors, replacing the sophisticated gas detection technology with a simpler, more cost-effective approach that maintains detection reliability.
3Ease of manufacture
If the refrigerant temperature is monitored to detect leakage, then the product cost is reduced and ease of manufacture is improved, but the measurement precision may be affected by environmental factors
Solution Approach 1:
The patent employs feedback by continuously monitoring the temperature difference between the refrigerant piping and the surrounding air. The system compares the measured temperature differential against expected values to identify leakage conditions, using this feedback loop to maintain measurement precision despite environmental variations.
Solution Approach 2:
The patent changes the measurement parameter from direct refrigerant gas concentration (gas sensor) to temperature differential (temperature sensor). By measuring temperature instead of gas concentration, the system achieves cost reduction while maintaining detection accuracy through the distinctive temperature signature that occurs during refrigerant leakage.
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 reliable refrigerant leakage detection in ceiling-mounted units without costly gas sensors, reducing product costs and improving detection precision by monitoring temperature differences and equilibration times.
Implementation Method 1
a first temperature sensor which measures the temperature of air in an air conditioning target space
Implementation Method 2
a second temperature sensor which measures the temperature of the refrigerant piping
Implementation Method 3
even if the refrigerant should leak out from the refrigerant piping while operation is stopped, the refrigerant temperature drops because of the drop in the pressure inside the refrigerant piping
Data Source
AI summary
An indoor fan, an indoor heat exchanger, and refrigerant piping are housed in a casing having an air inlet and air outlets. An air conditioning indoor unit includes a first temperature sensor that measures a temperature of air in an air conditioning target space, a second temperature sensor that measures a temperature of the refrigerant piping, and a determining component that determines if there is refrigerant leakage while operation is stopped. The determining component performs a refrigerant leakage determination that is a determination whether there is refrigerant leakage based on a difference between the temperatures detected by the first temperature sensor and the second temperature sensor.