Heat Source Unit Valve Segmentation for Flammable Refrigerant Trapping
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Solution Overview
Problem
Existing refrigeration systems face challenges in efficiently managing and recovering flammable refrigerants, particularly during power shutdowns and maintenance, which can lead to refrigerant leakage and increased risk of ignition.
Innovation Solution
The proposed heat source unit and refrigerant handling method incorporate strategically placed stop valves and shut-off valves in the refrigerant circuit, allowing for controlled refrigerant trapping and recovery, with service ports for efficient suction and reduced leakage risk, enabling safe and efficient refrigerant management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If all valves are opened to recover refrigerant, then refrigerant recovery is complete, but refrigerant leakage risk increases during power shutdown
Solution Approach 1:
The patent divides the refrigerant circuit into multiple segments controlled by different valves (first stop valve, second stop valve, first shut-off valve, second shut-off valve). This segmentation allows selective isolation of the outdoor unit from the refrigerant circuit while maintaining the ability to recover refrigerant when needed, thus reducing leakage risk without compromising recovery capability.
Solution Approach 2:
The patent implements preliminary action by automatically closing the first and second shut-off valves when power is supplied to the outdoor unit, and closing the stop valves when power is stopped. This preliminary closing action prevents refrigerant leakage before it can occur, while the service ports provide a controlled pathway for refrigerant recovery when needed.
2Object-affected harmful factors
If stop valves are added for refrigerant trapping, then leakage risk is reduced, but device complexity increases
Solution Approach 1:
The patent makes the stop valves and shut-off valves multi-functional. The shut-off valves serve both as normal operation valves and as automatic safety valves that close when power is supplied. The stop valves serve both as flow control valves and as isolation valves for refrigerant recovery. This multi-functionality reduces the need for additional dedicated safety valves, thereby limiting the increase in device complexity.
3Object-affected harmful factors
If service ports are positioned away from heat exchanger, then safety is improved, but refrigerant recovery time increases
Solution Approach 1:
The patent introduces service ports as intermediary access points to the refrigerant circuit. These service ports are positioned away from the heat exchanger to reduce ignition risk, but the first and second shut-off valves act as intermediaries that can quickly isolate the outdoor unit, enabling efficient refrigerant recovery through the service ports without requiring direct access to the heat exchanger area.
Data Source
AI summary
A first shut-off valve (46) and a second shut-off valve (47) are closed when power supply to a heat source unit (20) is stopped. At least one of the first shut-off valve (46) or the second shut-off valve (47) which corresponds to a stop valve (41, 42) having a first service port (44) is closer to a heat source heat exchanger (22) than the stop valve (41, 42) having the first service port (44) is.