Test chamber and method for controlling
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Solution Overview
Problem
Existing cooling systems in temperature-controlled test chambers face inefficiencies due to frequent compressor switching and high energy consumption when compensating for small temperature differences, leading to reduced compressor lifespan.
Innovation Solution
A method and system utilizing a carbon dioxide refrigerant with a bypass and storage mechanism, allowing the low-pressure compressor to be switched off during low cooling demand, and using a high-pressure compressor with a medium-pressure bypass to maintain operational readiness, reducing energy consumption and extending compressor life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the low-pressure compressor is frequently switched on and off to match cooling demand, then energy consumption is reduced, but compressor service life is reduced
Solution Approach 1:
The system pre-charges the storage device with gaseous refrigerant during periods of high cooling demand. This preliminary action ensures that when cooling demand decreases, the high-pressure compressor can continue operating by drawing refrigerant from the storage device, avoiding frequent shutdowns and extensions the compressor service life while maintaining energy efficiency.
Solution Approach 2:
The storage device acts as an intermediary between the compressors and the cooling load. It buffers refrigerant supply, allowing the high-pressure compressor to operate continuously at a steady state while the low-pressure compressor can be cycled off during low-demand periods, thus resolving the conflict between energy efficiency and compressor reliability.
2Measurement precision
If the low-pressure compressor remains on to maintain temperature precision, then temperature control precision is improved, but energy consumption increases
Solution Approach 1:
The system uses partial action by employing only the high-pressure compressor during low cooling demand periods. The high-pressure compressor operates alone to provide sufficient cooling capacity for small temperature adjustments, avoiding the excessive energy consumption that would result from running both compressors at full capacity.
Solution Approach 2:
The cooling system is segmented into two independent compressor units (low-pressure and high-pressure) that can operate independently or together. This segmentation allows the system to select the appropriate compressor configuration based on cooling demand, enabling energy-efficient operation during low-demand periods while maintaining temperature control precision.
3Power
If both compressors operate at full capacity, then cooling capacity is maximized, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts compressor operation based on real-time cooling demand. The control unit monitors cooling requirements and automatically switches between operating modes: both compressors for high demand, high-pressure compressor alone for low demand, or storage device discharge when no cooling is needed. This dynamic adaptation maximizes cooling capacity when required while minimizing energy consumption during low-demand periods.
Solution Approach 2:
The system changes operational parameters by switching between different compressor configurations and refrigerant flow paths based on cooling demand. This includes changing the operating state of compressors (on/off, full capacity/partial capacity) and the phase/state of refrigerant in the storage device, allowing the system to optimize the balance between cooling capacity and energy consumption.
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
The system achieves efficient temperature control with reduced energy usage and extended compressor lifespan by adjusting compressor performance based on cooling requirements, optimizing operation across various temperature ranges.
Implementation Method 1
a low-pressure compressor and a high-pressure compressor following the low-pressure compressor in a flow direction
Implementation Method 2
a high-pressure compressor following the low-pressure compressor in a flow direction
Implementation Method 3
a gas cooler, a storage device for refrigerant and an expansion valve
Implementation Method 4
an expansion valve
Implementation Method 5
a heat exchanger in the test chamber
Implementation Method 6
a cooling circuit with a refrigerant, a heat exchanger in the test chamber, a low-pressure compressor and a high-pressure compressor following the low-pressure compressor in a flow direction, a gas cooler, a storage device for refrigerant and an expansion valve
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a test chamber and a method for conditioning air in a temperature-insulated test chamber that can be sealed off from the environment and is used to hold test specimens, wherein a temperature control device of the test chamber, comprising a cooling circuit (11) with carbon dioxide (CO2) as a refrigerant, a heat exchanger (12) in the test chamber, a low-pressure compressor (13) and a high-pressure compressor (14) following the low-pressure compressor in a flow direction, a gas cooler (15), a storage device (16) for refrigerant and an expansion valve (17), is used to establish a temperature within a range of -20 °C to +180 °C within the test chamber, wherein the temperature in the test chamber is controlled and/or regulated by means of a control device of the test chamber.wherein gaseous and/or liquid refrigerant is metered into the storage device by means of a high-pressure valve (22) of the cooling circuit arranged downstream of the gas cooler in the flow direction, wherein the storage device is connected via a medium-pressure bypass (25) of the cooling circuit to a medium-pressure side (20) of the cooling circuit upstream of the high-pressure compressor and downstream of the low-pressure compressor in the flow direction, wherein gaseous refrigerant is metered from the storage device into the medium-pressure side by means of a medium-pressure valve (26) when the low-pressure compressor is switched off.