Air conditioning system and cooling method for drive motor thereof
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Solution Overview
Problem
Existing air conditioning systems with hermetic compressors face challenges in efficiently cooling the drive motor, which can lead to motor failure and affect system efficiency, particularly in multi-stage compression systems.
Innovation Solution
An air conditioning system with a cooling branch that includes multiple outlets and valves to control refrigerant flow based on motor temperature and suction pressure, allowing for optimized refrigerant mass flow and outlet selection to balance motor cooling and system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigerant is used to cool the drive motor, then motor temperature is reduced, but system efficiency deteriorates due to excessive refrigerant flow
Solution Approach 1:
The cooling branch is segmented into multiple outlets (first outlet connected to first-stage suction port, second outlet connected to intermediate-stage suction port) with independent valve control. This allows selective routing of refrigerant flow to different compressor stages based on motor temperature conditions, optimizing the balance between cooling effectiveness and system efficiency.
Solution Approach 2:
The system dynamically adjusts refrigerant flow distribution by controlling valve openings based on real-time motor temperature feedback. The control module monitors motor temperature and adjusts the opening degrees of valves in different branches to match cooling demand, preventing excessive refrigerant flow that would reduce system efficiency while ensuring adequate cooling when needed.
2Device complexity
If single outlet cooling branch is used, then device complexity is reduced, but adaptability to different operating conditions deteriorates
Solution Approach 1:
The cooling branch is divided into multiple outlets with independent valve control, allowing the system to adapt to different operating conditions by selectively activating appropriate branches. This segmentation provides versatility for handling various motor temperature scenarios while maintaining a relatively simple overall structure.
Solution Approach 2:
The cooling branch with multiple outlets serves multiple functions: it can cool the motor under light load conditions through the first outlet, provide intermediate cooling through the second outlet, and maintain system efficiency across different operating regimes. This multi-functional design enhances adaptability without proportionally increasing complexity.
3Temperature
If refrigerant flow is increased for better cooling, then motor cooling effectiveness is improved, but system efficiency deteriorates
Solution Approach 1:
The control module dynamically adjusts valve opening degrees based on motor temperature feedback, ensuring refrigerant flow is optimized for cooling effectiveness without excessive flow that would harm system efficiency. The system responds in real-time to motor temperature conditions, maintaining the optimal balance between cooling performance and overall system productivity.
Solution Approach 2:
The system changes refrigerant flow parameters (flow rate, pressure, temperature) by adjusting valve openings in different branches based on motor temperature conditions. This parameter optimization ensures adequate cooling while maintaining system efficiency by preventing excessive refrigerant consumption.
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
Effectively maintains or improves system efficiency while ensuring adequate motor cooling by regulating refrigerant flow through controlled outlets and valves, preventing liquid shock and optimizing pressure differences.
Implementation Method 1
the drive motor of the compressor will generate a lot of heat, so it needs to be cooled by such medium as refrigerant or coolant oil
Implementation Method 2
a main circuit having a multi-stage compressor, a condenser, a throttling element and an evaporator connected by pipelines
Implementation Method 3
a main circuit having a multi-stage compressor, a condenser, a throttling element and an evaporator connected by pipelines
Data Source
Figure 1
AI summary
An air conditioning system includes a main circuit having a multi-stage compressor, a condenser, a throttling element and an evaporator connected by pipelines; and a cooling branch, the inlet of which is connected to the main circuit between the condenser and the throttling element, and the outlet of which is connected to at least one of the first-stage suction port and the intermediate-stage suction port of the multi-stage compressor, wherein the cooling branch flows through the drive motor of the multi-stage compressor, and a regulating valve for controlling the opening of the cooling branch is provided on the cooling branch; and a control module that controls the opening of the regulating valve on the cooling branch based on the temperature of the outlet downstream of the drive motor on the cooling branch and the intermediate suction pressure of the intermediate-stage suction port of the multi-stage compressor.