Method for controlling balanced frosting of outdoor units in multi-split air-conditioning system
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Solution Overview
Problem
In multi-connection air conditioning systems, uneven frosting of outdoor units leads to inefficient heating capacity utilization, resulting in waste of resources, as all units must defrost when one is frosty, even if others are not, due to unbalanced output capacities and refrigerant distribution.
Innovation Solution
A method to control outdoor unit frosting by calculating individual unit frosting degrees, judging imbalance conditions, and adjusting output capacities to ensure balanced operation, where units with higher frosting are turned off and those with lower frosting are turned on, maintaining total output capacity requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all outdoor units are directly connected through pipelines, then the system structure is simple, but when one outdoor unit needs defrosting, all outdoor units must enter defrosting state, resulting in low heating capacity utilization
Solution Approach 1:
The system divides the outdoor units into different groups based on their frosting degrees. Units with high frosting degrees form a defrosting group, while units with low frosting degrees continue normal operation. This segmentation allows independent control of defrosting operations for different units, preventing unnecessary shutdown of non-frosted units and maintaining higher heating capacity utilization.
2Adaptability or versatility
If outdoor units with different output capacities operate simultaneously, then the system can meet diverse heating demands, but the frosting degrees of individual units become uneven, causing some units to frost heavily while others frost lightly
Solution Approach 1:
The system applies different control strategies to different outdoor units based on their individual characteristics. Units with larger output capacities that frost more heavily are assigned to defrosting operations first, while units with smaller capacities that frost lightly continue normal heating operations. This localized quality approach ensures each unit operates optimally according to its specific frosting condition.
3Object-affected harmful factors
If outdoor units are turned off to reduce frosting, then frosting degree decreases, but the total heating capacity is reduced, affecting system heating performance
Solution Approach 1:
The system dynamically adjusts the operational state of outdoor units based on real-time frosting degree monitoring. Instead of statically turning off units, the controller continuously evaluates frosting conditions and selectively initiates defrosting operations only for units that require it. This dynamic approach maintains heating capacity by keeping non-frosted units operational while removing frost from units that need it.
Data Source
AI summary
A method for controlling the balanced frosting of outdoor units in a multi-split air-conditioning system solving the problem in existing multi-split air-conditioning systems of resource waste caused by a low utilization efficiency of the heating capability of outdoor units as a result of some of the outdoor units entering a defrosting state when the heating capability is not fully utilized. According to the control method, by determining whether an outdoor unit set satisfies a frosting unbalance condition, the actual output capability of outdoor units of the outdoor unit set is selectively controlled on the basis of the frosting degrees of all the outdoor units. Thus, the difference between the frosting degrees of different outdoor units in the outdoor unit set at the same time can be reduced, such that the heating capability of all the outdoor units can be fully utilized when the outdoor unit set enters a defrosting state.