Multi-Split Air Conditioner Subcooling Bypass for Stable Refrigerant State
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Solution Overview
Problem
Multi-type air conditioners face challenges in preventing refrigerant overheating into a pure gas state during heat exchange, while maintaining a suitable subcooling degree for each indoor unit, which affects operational efficiency and performance.
Innovation Solution
The system incorporates a subcooling refrigerant pipe that passes through multiple subcooling units, allowing refrigerant to absorb heat from operational units and prevent overheating, with temperature sensors to adjust the subcooling expansion valve, ensuring the refrigerant remains in a suitable liquid-gas state for efficient circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigerant passes through subcooling units to maintain subcooling degree, then subcooling performance is improved, but refrigerant may overheat into pure gas state after heat exchange
Solution Approach 1:
A third refrigerant pipe is introduced as an intermediary pathway that allows refrigerant to flow between the outdoor heat exchanger and indoor heat exchangers without passing through the subcooling units. This mediator pathway enables the refrigerant to maintain its temperature and phase state while still achieving the cooling effect, thus preventing overcooling into pure liquid state while avoiding overheating into pure gas state.
Solution Approach 2:
The refrigerant circulation system is segmented into multiple independent pathways: a first refrigerant pipe for heating mode, a second refrigerant pipe for cooling mode with subcooling units, and a third refrigerant pipe that bypasses subcooling units. This segmentation allows selective routing of refrigerant based on operational requirements, enabling precise control over refrigerant temperature and phase state in different operating conditions.
2Productivity
If refrigerant is delivered to indoor heat exchanger for cooling operation, then cooling effect is achieved, but refrigerant may fail to be overheated into pure gas state
Solution Approach 1:
The system dynamically adjusts refrigerant flow pathways based on operational mode and load conditions. During cooling operation, the control unit can selectively open or close valves to route refrigerant through the third refrigerant pipe bypassing subcooling units when the indoor unit is the only operating unit, or through subcooling units when multiple indoor units operate simultaneously. This dynamic adaptation ensures optimal refrigerant temperature and phase state for different operating scenarios.
3Adaptability or versatility
If multiple subcooling units are used for each indoor unit, then subcooling control is improved, but system complexity increases
Solution Approach 1:
The third refrigerant pipe serves multiple functions: it acts as a bypass pathway for refrigerant during cooling operations, enables direct connection between outdoor and indoor heat exchangers, and provides an alternative route when subcooling units are not required. This multi-functional design achieves versatile subcooling control without proportionally increasing system complexity, as a single third refrigerant pipe can serve multiple operational needs.
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 configuration effectively prevents refrigerant overheating and maintains a suitable subcooling degree, enhancing the efficiency and performance of the air conditioner by ensuring the refrigerant is in a suitable state for both heating and cooling operations.
Implementation Method 1
The subcooling unit is configured to allow a refrigerant, which passes through the first branch refrigerant pipe, to exchange heat with a refrigerant, which passes through the subcooling refrigerant pipe
Implementation Method 2
an outdoor expansion valve to expand the refrigerant under decompression before the refrigerant is introduced into the outdoor heat exchanger during a heating operation
Implementation Method 3
The outdoor unit may include a compressor to compress a refrigerant
Data Source
Figure 1
Figure 2
AI summary
A multi-type air conditioner includes an outdoor unit disposed at an exterior space, a plurality of indoor units disposed at interior spaces, and a mode conversion unit connected to the outdoor unit and the plurality of indoor units through refrigerant pipes to circulate a refrigerant between the outdoor unit and the plurality of indoor units. The mode conversion unit includes a plurality of supercooling units which are configured to supercool a refrigerant before the refrigerant is introduced to the plurality of indoor units, using a supercooling refrigerant pipe which sequentially passes through at least one of the plurality of supercooling units, so that a refrigerant after having passed through the supercooling unit, is in a state of pure gas while ensuring a desired supercooling degree that is suitable for each indoor unit.