Transport refrigeration unit with compressor with capacity modulation
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Solution Overview
Problem
Scroll compressors in refrigeration systems often operate under low-load conditions with high compression ratios, limiting efficiency, and variable speed systems face challenges in refrigeration and temperature control due to varying gas density, especially at higher setpoint conditions.
Innovation Solution
A high-pressure side scroll compressor with a primary and intermediate suction port, and a control valve that directs fluid flow between these ports based on system demand, allowing for variable capacity operation through different modes of operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a scroll compressor is selected based on the most extreme operation conditions to ensure sufficient capacity, then the compressor capacity is adequate for extreme conditions, but the compressor operates under low-load conditions during normal operation, limiting efficiency
Solution Approach 1:
The patent implements a variable capacity compressor system with multiple suction ports (first and second suction ports) that can dynamically switch between different operating modes. The control system activates different suction ports based on system demands, enabling the compressor to adapt its capacity from high to low load conditions while maintaining optimal efficiency across varying operating conditions.
2Adaptability or versatility
If variable speeds are incorporated into the transport refrigeration system to improve adaptability, then the system can respond to varying conditions, but the variation in gas density imposes challenges in refrigeration and temperature control
Solution Approach 1:
The system incorporates variable speed operation with dynamic capacity adjustment through multiple suction ports. The control system modulates compressor capacity based on system demands and gas density conditions, maintaining precise temperature control across varying operating conditions by adapting both speed and capacity.
Solution Approach 2:
The patent changes operating parameters including suction port selection, compressor speed, and capacity settings based on system conditions. By adjusting these parameters dynamically, the system maintains optimal temperature control precision while adapting to varying gas density and refrigeration demands.
3Device complexity
If a single suction port configuration is used to simplify the compressor design, then the device complexity is reduced, but the compressor cannot efficiently operate across varying capacity requirements
Solution Approach 1:
The compressor is segmented into multiple suction ports (first suction port and second suction port) with distinct capacities. This segmentation allows the system to select appropriate suction ports based on operating conditions, providing capacity adjustment capability while maintaining a relatively simple overall compressor structure.
Solution Approach 2:
The compressor design incorporates multiple suction ports that serve different capacity requirements within a single device. This multi-functional configuration enables the compressor to handle both high and low capacity demands without requiring separate compressor units, balancing complexity and versatility.
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 configuration enables efficient operation across normal and extreme conditions by adjusting compressor capacity, improving temperature control and reducing energy consumption while maintaining lubrication efficiency.
Implementation Method 1
a control valve operable to direct a flow of fluid moving along the primary compressor inlet flow path to at least one of the primary suction port to the intermediate suction port in response to a mode of operation of the refrigeration system
Implementation Method 2
high-pressure side scroll compressor having a primary suction port and an intermediate suction port
Implementation Method 3
an evaporator having an inlet and an outlet
Data Source
Figure 1
Figure 2
AI summary
A refrigeration system includes a high-pressure side scroll compressor (20, 120) having a primary suction port (48; 142) and an intermediate suction port (47; 146), an evaporator (136) having an inlet and an outlet, a primary compressor inlet flow path fluidly coupling the outlet of the evaporator (136) with both the primary suction port (48; 142) and the intermediate suction port (47; 146), and a control valve operable to direct a flow of fluid moving along the primary compressor inlet flow path to at least one of the primary suction port (48; 142) to the intermediate suction port (47; 146) in response to a mode of operation of the refrigeration system. A capacity of the compressor (20; 120) associated with the primary suction port (48; 142) is greater than a capacity of the compressor (20; 120) associated with the intermediate suction port (47; 146).