System and method for identifying a refrigerant leak in multiple refrigeration circuits with one or more compressors
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Solution Overview
Problem
In HVAC systems with multiple compressor circuits, detecting a refrigerant leak is challenging because the leak detection sensor is shared among all circuits, leading to inefficient shutdown of the entire system and underutilization of non-leaking circuits.
Innovation Solution
The system leverages subcool, superheat, and saturated suction temperature values to identify which compressor circuit is associated with a refrigerant leak, isolates that circuit, and redistributes the air conditioning load to non-leaking circuits, ensuring seamless operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the HVAC system shuts down the entire system when a refrigerant leak is detected, then safety is ensured, but productivity and customer comfort deteriorate due to complete system stoppage
Solution Approach 1:
The system divides the HVAC system into multiple independent compressor circuits (first compressor circuit, second compressor circuit, etc.), each capable of independent operation. When a refrigerant leak is detected in one circuit, only that specific circuit is shut down while other circuits continue to provide cooling, thus maintaining productivity and customer comfort while ensuring safety.
2Object-generated harmful factors
If the HVAC system shuts down all compressor circuits when a refrigerant leak is detected, then harmful refrigerant release is prevented, but energy efficiency deteriorates due to underutilization of non-leaking circuits
Solution Approach 1:
The system segments the compressor circuits so that each can be independently controlled. When a leak is detected in one circuit, only that circuit is isolated while other circuits continue to operate efficiently, preventing energy waste from unnecessary shutdowns while still containing the refrigerant leak.
Solution Approach 2:
The system applies local isolation to the specific compressor circuit with the refrigerant leak, rather than globally shutting down the entire system. This localized response prevents harmful refrigerant release from the leaking circuit while maintaining energy efficiency by keeping non-leaking circuits operational.
3Difficulty of detecting and measuring
If the HVAC system cannot identify which specific compressor circuit has a refrigerant leak, then leak detection is simplified, but device complexity increases due to system-wide shutdown requirements
Solution Approach 1:
The system uses segmentation of compressor circuits combined with individual subcool value monitoring for each circuit to identify which specific circuit has a refrigerant leak. This approach maintains simple leak detection methodology while avoiding the need for system-wide shutdowns, as the controller can isolate only the affected circuit based on subcool value analysis.
Solution Approach 2:
The system implements feedback through continuous monitoring of subcool values from each compressor circuit and uses this information to identify which circuit has a refrigerant leak. This feedback mechanism enables precise identification of the leaking circuit without increasing overall system complexity, allowing selective isolation of only the affected circuit.
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 approach allows the HVAC system to continue providing air conditioning without interruption, balances the air conditioning load among non-leaking circuits, and identifies the location and component associated with the leak.
Implementation Method 1
a subcool sensor circuit configured to provide a subcool signal that indicates a subcool value associated with the condenser, wherein the subcool value corresponds to a temperature difference between a saturated refrigerant and a subcooled refrigerant associated with the condenser
Implementation Method 2
a superheat sensor circuit configured to provide a superheat signal that indicates a superheat value corresponding to a temperature difference between a superheated refrigerant and a saturated refrigerant state associated with the evaporator pressure
Implementation Method 3
a refrigerant detection sensor circuit that is common to all the refrigeration circuits and configured to detect a concentration of the refrigerant in a volume
Implementation Method 4
The condenser is configured to receive the first refrigerant and cool the first refrigerant flowing through
Data Source
AI summary
A refrigeration system to leverage subcool, superheat, and saturation suction temperature values to detect loss of charge due to refrigerant leak is disclosed. The system detects a refrigerant leak by detecting that a refrigerant concentration is more than a threshold concentration. In response, the system accesses subcool, superheat, and saturation suction temperature values associated with the compressor circuits. The system determines that the subcool value is less than a subcool threshold and whether the superheat value is more than a superheat threshold. In response, the system may determine that the compressor circuit associated with the subcool and superheat values is associated with the loss of charge. In response, the system isolates the compressor circuit from other components of the system and operates a blower. The system may continue cooling operation using non-leaking compressors.