AHU Refrigerant Leak Relay Control for Ventilation Safety
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Solution Overview
Problem
Refrigerant leaks in climate control systems, such as HVAC systems, pose safety issues and disrupt heat transfer, as toxic and flammable refrigerants can lead to system inefficiency and safety hazards if not detected and managed promptly.
Innovation Solution
An interface control relay module and safety system for air handling units that includes a refrigerant sensor, airflow sensor, and a control unit to detect refrigerant leaks, activate or deactivate cooling and heating units, and trigger alerts or safety measures like smoke detectors, ensuring safe operation and efficient refrigerant management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If refrigerant is used for heat transfer in HVAC systems, then heat transfer efficiency is improved, but safety hazards increase due to toxic and flammable properties of refrigerant
Solution Approach 1:
The refrigerant sensor is installed in the air handling unit to detect refrigerant leaks before they accumulate to dangerous levels. The control unit receives signals from the sensor and activates safety measures (shutting down cooling unit, activating fans for ventilation) in advance, preventing the refrigerant concentration from reaching toxic or flammable thresholds.
Solution Approach 2:
The control unit acts as an intermediary between the refrigerant sensor and the safety execution components (cooling unit, fans, dampers). It processes sensor signals and coordinates the activation of multiple safety components, ensuring a systematic response to detected refrigerant leaks while maintaining normal operation when safe.
2Reliability
If refrigerant leak detection and safety control systems are added to air handling units, then safety is improved, but device complexity increases
Solution Approach 1:
The control unit performs multiple functions: it monitors refrigerant sensor signals, controls the cooling unit, activates fans for ventilation, and adjusts dampers. By consolidating these control functions into a single intelligent controller, the system achieves comprehensive safety without proportionally increasing complexity, as one component handles multiple safety-critical tasks.
3Object-affected harmful factors
If the cooling unit is deactivated upon refrigerant leak detection, then safety is improved, but heat transfer capability is reduced
Solution Approach 1:
The system dynamically adjusts its operation based on real-time refrigerant concentration levels. When no leak is detected, the cooling unit operates normally for efficient heat transfer. When a leak is detected, the control unit deactivates the cooling unit only until the refrigerant is vented and safe levels are restored, at which point normal operation can resume. This dynamic response minimizes disruption to heat transfer capability while maintaining safety.
Data Source
AI summary
The present disclosure provides an interface control relay module including a refrigerant sensor input connected to a refrigerant sensor of an air handling unit (AHU) that generates an input proportional to a concentration of a refrigerant leak in the AHU. The relay module further includes a control unit coupled to the refrigerant sensor input to receive the input from the refrigerant sensor; a first relay output and a second relay output, each connecting the control unit to a cooling unit of the AHU; a third relay output connecting the control unit to a fan of the AHU; and a fourth relay output connecting the control unit to a damper of the AHU. The control unit activates or deactivates at least one of the first relay output, the second relay output, the third relay output and the fourth relay output based on the input received from the refrigerant sensor.