Relay Unit Layout for Fewer Refrigerant Shutoff Valves
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Solution Overview
Problem
Existing air-conditioning apparatuses face challenges in completely shutting off refrigerant flow due to the inability of flow control valves to be fully closed and solenoid valves not operating correctly under reversed pressure conditions, leading to refrigerant leakage and increased costs with multiple shutoff valves and complex control systems.
Innovation Solution
The air-conditioning apparatus is designed with a reduced number of refrigerant shutoff valves connected to indoor units, utilizing a relay unit with bi-directional flow control valves and check valves to manage refrigerant flow, allowing for efficient refrigerant recovery and leakage prevention with simplified control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple refrigerant shutoff valves are installed in liquid pipes connected to each indoor unit, then refrigerant leakage can be prevented, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple shutoff functions into a single refrigerant shutoff valve installed in the liquid pipe of the branch unit. This single valve can shut off refrigerant flow to multiple indoor units simultaneously, replacing what would traditionally require multiple individual valves for each indoor unit connection, thereby reducing device complexity while maintaining leakage prevention capability
Solution Approach 2:
The refrigerant shutoff valve in the branch unit serves multiple functions: it prevents refrigerant leakage to multiple indoor units, controls refrigerant distribution across different branches, and can isolate specific sections of the system for maintenance. This multi-functional design reduces the overall number of components needed in the system
2Extent of automation
If solenoid valves are used to control refrigerant flow, then automated control is achieved, but the valves cannot be fully closed under reversed pressure conditions
Solution Approach 1:
The patent introduces a check valve as an intermediary component that works in conjunction with the solenoid valve. The check valve ensures unidirectional flow and complements the solenoid valve's shutoff action, guaranteeing complete closure even when pressure reverses direction. This intermediary mechanism compensates for the solenoid valve's limitation without compromising automated control
3Productivity
If flow control valves are used to control refrigerant flow rate, then cooling/heating performance is optimized, but the valves cannot be fully closed
Solution Approach 1:
The patent segments the flow control function from the shutoff function. The flow control valve handles refrigerant flow rate modulation for performance optimization, while a dedicated refrigerant shutoff valve (or solenoid valve with check valve) handles complete closure. This functional segmentation allows each component to excel at its specific task without compromise
4Reliability
If refrigerant leakage is detected and shutoff valves are closed, then leakage is reduced, but refrigerant already in indoor units cannot be recovered
Solution Approach 1:
The patent implements preliminary action by enabling refrigerant recovery operations before system shutdown. When leakage is detected or before maintenance, the system can actively recover refrigerant from indoor units back to the outdoor unit or designated storage, ensuring minimal loss before the shutoff valves are closed to prevent further leakage
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 design reduces refrigerant leakage, lowers costs, and simplifies control systems by using fewer shutoff valves, effectively managing refrigerant flow and recovery within the air-conditioning system.
Implementation Method 1
air in a space to be air-conditioned is heated or cooled by using heat rejection from or heat removal by the refrigerant
Implementation Method 2
a refrigerant circuit including an outdoor unit being a heat source unit
Data Source
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AI summary
Provided is an air-conditioning apparatus, comprising an outdoor unit including a compressor and an outdoor heat exchanger, a plurality of indoor units each including an indoor heat exchanger, and a relay unit configured to distribute refrigerant supplied from the outdoor unit to the plurality of indoor units, the relay unit including a first branch unit in which liquid-side pipes connected to the plurality of indoor units join together, and a refrigerant shutoff valve, which is configured to control bidirectional flow of the refrigerant, and is provided to the first branch unit, the number of the refrigerant shut off valve being smaller than a number of the plurality of indoor units.