Binary Refrigerant Leak Detection for Low-GWP Air Conditioning Systems
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Solution Overview
Problem
Air conditioning systems using moderate-to-low global warming potential (GWP) refrigerants pose a fire risk due to their mild flammability, and existing refrigerant leak detectors, such as NDIR sensors, are overly expensive and complex for leak detection applications, which is not necessary for detecting the presence of refrigerant leaks.
Innovation Solution
A controllable refrigerant leak detection system with a refrigerant detection sensor that produces binary signals indicative of leak or non-leak conditions, using a band pass filter and IR radiation to detect refrigerant presence, and a controller that activates or deactivates ventilation based on these signals to mitigate potential hazards, eliminating the need for accurate concentration determination and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If commercial NDIR sensors are used for refrigerant leak detection, then detection accuracy is improved, but device cost increases significantly
Solution Approach 1:
The patent extracts only the essential function of NDIR sensors (detecting refrigerant presence) while removing unnecessary components (optical benches, temperature compensation circuits, concentration calculation algorithms). The simplified sensor uses a basic infrared LED, photodetector, and bandpass filter arrangement that eliminates complex optical paths and electronic compensation mechanisms, achieving leak detection without accurate concentration measurement.
Solution Approach 2:
The patent replaces expensive, complex commercial NDIR sensors with inexpensive, simplified infrared detection components that can be easily manufactured and replaced. The design uses basic infrared LEDs, simple photodetectors, and minimal filtering components that cost a fraction of commercial sensors, accepting that these simpler components may have shorter operational lifetimes but are economically viable for leak detection applications.
2Reliability
If commercial NDIR sensors are used for refrigerant leak detection, then detection capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the refrigerant detection function from the ventilation control function into separate binary outputs. The sensor provides simple leak/not-leak detection without attempting to measure concentration, and the controller independently handles ventilation control based on this binary signal. This segmentation allows each component to be manufactured simply without the complexity of integrated concentration measurement and control systems.
Solution Approach 2:
The patent uses a simplified optical path that copies the basic principle of NDIR detection (infrared absorption by refrigerant) without replicating the complex commercial sensor architecture. The design replicates only the essential infrared absorption measurement capability using inexpensive components, eliminating the need to copy complex optical benches, multiple filters, and temperature compensation mechanisms.
3Reliability
If the system continuously monitors refrigerant concentration, then detection reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic sampling of refrigerant presence rather than continuous monitoring. The simplified sensor takes periodic binary readings (leak/not-leak) and triggers ventilation only when leakage is detected, rather than continuously operating at full capacity. This periodic action maintains detection reliability by regularly checking for leaks while significantly reducing energy consumption compared to continuous high-power operation.
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
The system effectively detects refrigerant leaks and mitigates hazards by activating ventilation to dilute or vent the refrigerant, reducing the risk of fire without the need for expensive and complex sensors, and allows for self-calibration and diagnostics to maintain reliability.
Implementation Method 1
a refrigerant detection sensor that produces binary signals indicative of leak or non-leak conditions, using a band pass filter and IR radiation to detect refrigerant presence
Data Source
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AI summary
An air conditioning system is provided and includes a unit receptive of refrigerant having a moderate-to-low global warming potential (GWP) value for thermal interaction with a fluid, an enclosure, a fan disposed and configured for urging a flow of the fluid through the unit, a refrigerant detection sensor and a controller. The refrigerant detection sensor is disposed in the enclosure to be operable in a first mode in which a baseline response is established and a second mode in which refrigerant leak detection is executed based on the baseline response. The refrigerant detection sensor is further configured to generate a binary output of leak and non-leak signals in accordance with a result of the refrigerant leak detection. The controller is configured to control operations of the fan and the vent based on the binary output.