A vapour-compression circuit
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Solution Overview
Problem
Existing vapor-compression circuits in transport refrigeration units and vehicles face challenges in ensuring adequate lubrication of multiple compressors operating under different conditions, leading to potential compressor damage and reduced efficiency.
Innovation Solution
A vapor-compression circuit design featuring two compressors in parallel branches with an oil separator and distribution network, where an oil separator removes oil from the discharge line and re-supplies it to dedicated oil supply locations for each compressor, controlled by a valve arrangement and controller to optimize lubrication based on operational modes and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple compressors are operated in parallel branches, then the system can operate under different operational conditions, but it becomes difficult to ensure adequate lubrication for each compressor
Solution Approach 1:
The oil distribution network is segmented into multiple independent oil supply lines, with each line dedicated to a specific compressor. This segmentation allows independent oil supply control to each compressor, ensuring that each compressor receives adequate lubrication regardless of which compressors are operating. The oil distribution manifold divides the oil flow into separate channels that can be independently controlled via solenoid valves.
Solution Approach 2:
The control system uses feedback from compressor operation status to dynamically control oil distribution. The controller receives signals about which compressors are running and automatically activates the corresponding oil supply solenoid valves, ensuring oil is supplied only to operating compressors. This feedback mechanism prevents oil starvation of active compressors while avoiding unnecessary oil supply to inactive ones.
2Reliability
If oil is continuously circulated through the system, then compressors receive lubrication, but oil may accumulate in some compressors and be depleted in others
Solution Approach 1:
The oil distribution system is divided into separate, dedicated supply lines for each compressor through an oil distribution manifold. This physical segmentation ensures that oil flows independently to each compressor based on its specific needs, preventing the imbalance where some compressors accumulate oil while others experience depletion. Each compressor has its own controlled oil pathway.
Solution Approach 2:
The oil distribution system is made dynamic through electronically controlled solenoid valves that can rapidly switch oil flow to different compressors based on real-time operational requirements. This dynamic control allows the system to adapt oil distribution instantly when compressors are started or stopped, maintaining optimal oil levels in each compressor's sump without manual intervention.
3Device complexity
If a single oil supply system is used for multiple compressors, then the system is simpler, but oil supply to individual compressors cannot be optimized
Solution Approach 1:
While maintaining a single integrated oil separator and control unit, the system segments the oil distribution into multiple independent lines through a manifold structure. This segmentation enables individual optimization of oil supply to each compressor via dedicated solenoid valves, allowing the system to adapt to different operational configurations without requiring completely separate oil supply systems for each compressor.
Solution Approach 2:
The oil distribution manifold serves multiple functions: it distributes oil to different compressors, controls flow direction based on operational mode, and enables selective supply to specific compressors. This multi-functional component allows a single oil supply system to provide optimized, individualized lubrication to multiple compressors operating under different 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
Ensures effective lubrication of compressors during start-up and operation, reducing wear and improving performance by preventing oil sump dryness and excessive accumulation, while maintaining energy efficiency and allowing the use of lower global warming potential refrigerants.
Implementation Method 1
an oil separator and an oil distribution network, wherein the oil separator is located along the discharge line and is configured to remove oil from working fluid in the discharge line
Data Source
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AI summary
The present disclosure relates to a vapour-compression circuit 400, 400' for circulating a working fluid. The vapour-compression circuit 400, 400' comprises: a first compressor 402A, a second compressor 402B, a suction line 418, a discharge line 412, an oil separator 510 and an oil distribution network 520. The first compressor 402A and the second compressor 402B are provided in respective first 411A and second 411B parallel branches between the suction line 418 and the discharge line 412. The oil separator 510 is located along the discharge line 412 and is configured to remove oil from working fluid in the discharge line 418. The oil distribution network 520 is configured to re-supply oil removed from the working fluid by the oil separator 510 to a first oil supply location 522A, 522A' at or upstream of the first compressor 402A along the first branch 411A, and also to a second oil supply location 522B, 522B' at or upstream of the second compressor 402B along the second branch 411B.