Multi-Compressor Chiller Control for COP and Oil Balance
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Solution Overview
Problem
Conventional air conditioning devices face challenges in maintaining oil balance and achieving maximum Coefficient of Performance (COP) when using multiple compressors, particularly in chiller systems where efficient air conditioning control is critical.
Innovation Solution
An air conditioning device with a control unit that calculates and adjusts the drive frequencies of multiple compressors based on cooling-heating loads to determine the optimal number of compressors for maximum COP, while ensuring efficient oil distribution through bifurcation pipes and prioritizing oil supply to active compressors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple compressors are used to meet cooling-heating load requirements, then the air conditioning capacity is improved, but the oil balance among compressors deteriorates
Solution Approach 1:
The patent segments the oil supply system by providing separate oil supply paths from the oil separator to each compressor. This segmentation ensures that each compressor receives oil independently, preventing oil balance issues that would occur with a shared return path, while still allowing multiple compressors to operate simultaneously to meet cooling-heating load requirements.
2Adaptability or versatility
If the number of compressors is increased to handle varying loads, then the adaptability is improved, but the system complexity increases
Solution Approach 1:
The control unit continuously monitors the operating states of multiple compressors and the cooling-heating load requirements, then adjusts compressor operation accordingly. This feedback mechanism enables the system to adapt to varying loads efficiently while managing the complexity of controlling multiple compressors through centralized intelligent control.
3Use of energy by moving object
If compressors operate at varying loads, then the energy efficiency is improved, but the oil return to compressors deteriorates
Solution Approach 1:
The system establishes oil supply paths in advance from the oil separator to each compressor before operation begins. This preliminary arrangement ensures that regardless of how compressors are later operated at varying loads for energy efficiency, each compressor will have a guaranteed oil supply path, preventing oil loss and ensuring proper lubrication throughout different operating conditions.
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 allows for efficient air conditioning control with a high COP by optimizing compressor usage and maintaining oil balance, thereby enhancing the performance of chiller systems.
Implementation Method 1
a refrigerant-water heat exchanger configured to perform heat exchange between a refrigerant transferred from the outdoor unit and water
Data Source
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AI summary
An air conditioning device capable of performing efficient air conditioning at a high COP in accordance with a cooling-heating load when air conditioning as a chiller is performed is provided. The air conditioning device includes a control unit (60) configured to perform drive control of a plurality of compressors (11), and the control unit (60) calculates drive frequencies of n compressors among the plurality of compressors (11) in accordance with a cooling-heating load, calculates a COP for the calculated drive frequencies, determines the number of compressors (11) with which the COP is maximum, and performs drive control involving the determined number of compressors (11).