Multi-Split AC Oil Return Control to Prevent Indoor Unit Dripping
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Solution Overview
Problem
In multi-split air conditioning systems, frequent oil return by the compressor can lead to dewing and dripping at indoor units in an off state due to inadequate oil return control methods, affecting user comfort and system performance.
Innovation Solution
The control method determines whether an indoor unit is at risk of dewing and adjusts fan operation accordingly during oil return, either keeping the fan off or operating it at a low speed, and opens the throttling device to manage refrigerant flow, thereby preventing dewing and dripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the fan of the indoor unit is kept off during oil return to save energy, then energy consumption is reduced, but dewing and dripping occur affecting user comfort
Solution Approach 1:
The patent changes the operational parameter of the fan from completely off to low-speed operation during oil return. This parameter change allows the fan to produce sufficient airflow to prevent dewing and dripping while consuming minimal energy, thus resolving the contradiction between energy saving and preventing harmful effects.
Solution Approach 2:
The patent introduces dynamic control of the fan based on the dewing risk assessment. The system dynamically adjusts the fan speed according to real-time conditions (humidity, temperature, oil return status), transitioning from a static off state to a dynamic low-speed state when needed, thereby preventing dewing while maintaining energy efficiency.
2Object-affected harmful factors
If the fan of the indoor unit is turned on during oil return to prevent dewing, then user comfort is improved, but energy consumption increases
Solution Approach 1:
The patent optimizes the fan operational parameter by setting it to low-speed mode rather than full-speed operation. This parameter optimization provides just enough airflow to prevent dewing and dripping while minimizing energy consumption, thus resolving the contradiction between preventing harmful effects and energy saving.
Solution Approach 2:
The patent applies partial action by operating the fan at low speed rather than full speed. This partial operation is sufficient to achieve the desired effect of preventing dewing during oil return, avoiding the excessive energy consumption that would result from full-speed operation while still effectively addressing the harmful effect.
3Productivity
If the throttling device is opened during oil return to enable refrigerant flow, then oil return efficiency is improved, but refrigerant loss increases
Solution Approach 1:
The patent optimizes the throttling device opening parameter to a moderate range (30%-60%) rather than fully opening it. This parameter optimization maintains sufficient refrigerant flow for effective oil return while minimizing refrigerant loss through the throttling device, thus resolving the contradiction between productivity and substance loss.
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 effectively reduces dewing and dripping issues by promoting evaporation of refrigerant in the indoor heat exchanger during oil return, enhancing user comfort and system reliability.
Implementation Method 1
promoting evaporation of refrigerant in the indoor heat exchanger during oil return
Data Source
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AI summary
A control method for a multi-split air conditioning system, the multi-split air conditioning system comprising a compressor and a plurality of indoor units (2) respectively arranged on a plurality of parallel branches, the indoor unit (2) comprising a fan (22), and the control method comprising : in a cooling mode of the multi-split air conditioning system, when the multi-split air conditioning system requires oil return, determining whether an indoor unit (2) in an off state has reached a condensing condition, opening the branch on which the indoor unit (2) is located, and implementing different control of the fan (22) of said indoor unit (2) on the basis of the determining results. Also provided is a multi-split air-conditioning system. The present multi-split air conditioning system control method and multi-split air conditioning system can effectively solve the problem of condensation dripping at an indoor unit triggered by the frequent oil return of a compressor, improving user comfort.