Multi-Split Air Conditioning Leak Isolation With Branch Shutoff Valves
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Solution Overview
Problem
In multi-air-conditioning systems for buildings, the risk of refrigerant leakage poses safety hazards and environmental concerns due to the use of flammable or toxic refrigerants, especially in systems with long pipes and multiple indoor units, where existing solutions like refrigerant leakage sensors and pipe shutoff valves are inadequate in managing refrigerant leakage effectively.
Innovation Solution
An air-conditioning apparatus with a refrigerant concentration detecting device in a non-air-conditioned space that controls shutoff devices to minimize refrigerant leakage by determining the concentration of refrigerant and shutting off flows when it exceeds a predetermined limit, using branching devices to manage refrigerant circulation and convergence, and strategically placing shutoff devices to prevent refrigerant spread into air-conditioned spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If refrigerant quantity in the system is increased to meet cooling/heating demands in multi-air-conditioning systems, then cooling and heating performance is improved, but the risk of refrigerant leakage and its harmful effects on safety and environment increases
Solution Approach 1:
The refrigerant circulation system is segmented into multiple independent zones using shutoff valves installed at strategic locations (outdoor unit, indoor units, and intermediate positions). When a leak is detected by the refrigerant concentration detecting device, only the affected segment is isolated by closing specific shutoff valves, preventing refrigerant from spreading throughout the entire system while maintaining operation in unaffected areas.
Solution Approach 2:
A refrigerant concentration detecting device is introduced as an intermediary between the refrigerant circulation system and the environment. This device continuously monitors refrigerant concentration in the air and provides early warning of leaks, enabling timely activation of shutoff valves to prevent harmful effects before they escalate.
2Object-affected harmful factors
If refrigerant leakage detection and shutoff systems are installed to improve safety, then harmful effects of refrigerant leakage are reduced, but device complexity increases
Solution Approach 1:
The safety system is segmented into modular components: refrigerant concentration detecting devices positioned at strategic locations, multiple shutoff valves distributed throughout the system, and a control unit. This modular segmentation allows the safety function to be implemented incrementally and maintains manageable system complexity while providing comprehensive leak protection.
Solution Approach 2:
The system incorporates automatic control functionality where the control unit receives signals from the refrigerant concentration detecting device and automatically activates the appropriate shutoff valves without requiring manual intervention. This self-service capability reduces operational complexity while enhancing safety response effectiveness.
3Object-affected harmful factors
If shutoff valves are installed at multiple locations to prevent refrigerant spread, then safety is improved, but loss of refrigerant control and system complexity increase
Solution Approach 1:
The system is divided into controllable segments with shutoff valves positioned at key junctions (outdoor unit connection, indoor unit connections, and intermediate branch points). The refrigerant concentration detecting device identifies the specific leak location, and the control unit activates only the minimum necessary shutoff valves to isolate that segment, avoiding unnecessary closure of valves in unaffected areas and maintaining optimal system functionality.
Data Source
AI summary
An outdoor unit is configured to include a compressor and a heat source side heat exchanger. Indoor units are configured to include first expansion devices and use side heat exchangers, and air-condition an air-conditioned space. Branching devices, connected by pipes to the outdoor unit by a plurality of main pipes and connected by pipes to each indoor unit by a plurality of branch pipes, are configured to branch a refrigerant from a side of the main pipes and circulate the refrigerant to the branch pipes, and converge the refrigerant from a side of the branch pipes and circulate the refrigerant to the main pipes. A refrigerant concentration detecting device is installed in a non-air-conditioned space. A shutoff valve control device is configured, upon determining that the refrigerant has leaked, to control shutoff devices and to shut off the refrigerant flows.