Cascade Cooling Circuit for Wide-Range Environmental Testing Chambers
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Solution Overview
Problem
Current environmental testing apparatuses for hydrogen tanks are limited in their temperature control range, particularly failing to maintain low temperatures effectively in large chambers, which is necessary for comprehensive environmental testing considering various environments.
Innovation Solution
The apparatus employs a binary type cooling system with high and low temperature side circuits, a brine circulation apparatus, and a heating unit, allowing for temperature control within a broad range of −67.5° C. to 127.5° C., ensuring a wide space for testing multiple hydrogen tanks of varying sizes while maintaining uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the chamber space is enlarged to accommodate multiple hydrogen tanks or larger tanks, then the testing versatility and capacity are improved, but the ability to control low temperature becomes difficult
Solution Approach 1:
The cooling system is segmented into multiple independent cooling circuits (first cooling circuit, second cooling circuit, third cooling circuit) that can operate simultaneously or independently. Each circuit has its own compressor, condenser, expansion valve, and evaporator, allowing the large chamber to be cooled uniformly by distributing cooling capacity across multiple zones.
Solution Approach 2:
Multiple cooling circuits are merged into a single integrated system that shares common control logic and can coordinate their operation. The circuits are combined to provide sufficient total cooling capacity for the large chamber volume while maintaining individual circuit independence for flexible operation.
2Device complexity
If a single cooling circuit is used, then the device complexity is reduced, but the cooling capacity and temperature control range are insufficient
Solution Approach 1:
The cooling system is divided into three separate cooling circuits, each capable of providing a portion of the total cooling capacity. This segmentation allows the system to achieve high total cooling power without requiring a single overly complex circuit, as each individual circuit can be designed with standard components and moderate complexity.
Solution Approach 2:
Each cooling circuit is equipped with its own expansion valve and evaporator, allowing independent control of refrigerant flow and cooling output for each circuit. This local control capability enables precise temperature management across different regions of the large chamber while keeping each circuit's control mechanism relatively simple.
3Adaptability or versatility
If the temperature control range is extended to significantly low temperatures, then the environmental testing comprehensiveness is improved, but the control difficulty increases
Solution Approach 1:
The temperature control system is segmented into multiple independent circuits that can be controlled individually. This allows the system to achieve broad temperature control range (from -60°C to 120°C) by coordinating multiple simpler control units rather than using a single complex control system.
Solution Approach 2:
The cooling system incorporates dynamic control capabilities through electronic expansion valves and programmable controllers that can adjust refrigerant flow and system operation in real-time. This dynamic control allows the system to maintain stable temperatures across a wide range while keeping the control logic manageable through automated regulation.
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 setup enables efficient temperature control down to −60° C. and up to 120° C., allowing for thorough environmental testing of hydrogen tanks under diverse conditions, ensuring stability and reducing testing time within a relatively large chamber volume.
Implementation Method 1
a cascade condenser; with the low temperature side heating medium being configured to be cooled by the high temperature side heating medium in the cascade condenser
Implementation Method 2
the brine being configured to be cooled by the low temperature side heating medium in the evaporator
Implementation Method 3
a high temperature side compressor, a condenser, a high temperature side expansion valve and a cascade condenser are connected in this order by pipes so as to circulate a high temperature side heat medium
Data Source
AI summary
An environmental testing apparatus includes a chamber, a cooling unit including a cooling apparatus of a brine that cools the inside of the chamber, a heating unit and a control apparatus. The cooling apparatus includes: a high temperature side cooling circuit including a high temperature side compressor, condenser, high temperature side expansion valve and cascade condenser connected in this order to circulate a high temperature side heating medium; and a low temperature side cooling circuit including a low temperature side compressor, cascade condenser, low temperature side expansion valve and evaporator connected in this order to circulate a low temperature side heating medium. The low temperature side heating medium is cooled by the high temperature side heating medium in the cascade condenser, while the brine is cooled by the low temperature side heating medium in the evaporator. The control apparatus controls a temperature inside the chamber to between −67.5° C. and 127.5° C.