Refrigeration cycle apparatus
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Solution Overview
Problem
Conventional refrigeration cycle systems with multiple compressors face challenges in maintaining even oil distribution, leading to oil depletion and performance deterioration, which complicates installation and increases power consumption due to the need for oil equalizing pipes.
Innovation Solution
A refrigeration cycle apparatus with sensors to detect refrigeration oil levels in each compressor, allowing a controller to manage compressor operation modes to prevent oil depletion by adjusting the operation of outdoor units based on oil levels and time, eliminating the need for oil equalizing pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oil equalizing pipes are used to maintain even oil distribution among compressors, then oil distribution balance is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The patent removes the oil equalizing pipes from the system entirely. Instead of adding complex piping infrastructure, the invention extracts this component and replaces it with a control system that manages oil distribution through compressor operation scheduling based on operating hours accumulation, thereby simplifying the physical device structure while maintaining oil balance
Solution Approach 2:
The patent implements a feedback mechanism where the control device monitors the accumulated operating hours of each compressor and uses this information to determine switching timing. This feedback loop ensures that compressors are cycled in a manner that promotes even oil distribution without requiring physical equalizing pipes, resolving the contradiction between reliability and device complexity
2Reliability
If fixed-period oil equalizing operation is performed, then oil distribution is improved, but loss of time and operational flexibility worsen
Solution Approach 1:
The patent transitions from static fixed-period oil equalizing operations to dynamic operation scheduling based on accumulated operating hours. The control device dynamically determines when to switch compressors based on real-time operation time accumulation, allowing the system to adapt to varying operational conditions and reduce unnecessary downtime while maintaining effective oil distribution
Solution Approach 2:
The patent changes the control parameter from fixed time intervals to accumulated operating hours of individual compressors. This parameter change allows the oil equalizing operation to be triggered based on actual compressor usage patterns rather than arbitrary time schedules, improving both oil distribution effectiveness and operational efficiency
3Ease of operation
If uniform operation time control is applied to all compressors, then operational simplicity is improved, but oil equalization effectiveness deteriorates
Solution Approach 1:
The patent applies local quality by tracking accumulated operating hours for each compressor individually rather than using uniform control for all. The control device maintains separate operation time accumulation data for each compressor and uses this localized information to determine switching timing, ensuring that each compressor receives appropriate attention for oil equalization based on its specific usage pattern
Data Source
AI summary
A refrigeration cycle apparatus includes a plurality of outdoor units. Each of the plurality of outdoor units includes an outdoor heat exchanger, a compressor, and a sensor to detect the quantity of refrigeration oil in the outdoor unit. A controller has a first operation mode in which a part of the plurality of outdoor units is operated and another outdoor unit is stopped; and a second operation mode in which all of the plurality of outdoor units are operated. In the first operation mode, when the operating time of an operating outdoor unit exceeds a prescribed time and the quantity of refrigeration oil in the compressor of the operating outdoor unit is equal to or larger than a prescribed quantity, the controller stops the operating outdoor unit and makes a switch to bring a stopped outdoor unit of the plurality of outdoor units into operation.