Cryogenic refrigeration system and cryogenic pump
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Solution Overview
Problem
Existing cryogenic refrigeration systems are limited by the compressor's capabilities in terms of pressure difference and mass flow rate, which are constrained by power consumption and thermal limitations, leading to inefficient cooling performance, particularly at low temperatures.
Innovation Solution
A cryogenic refrigeration system with a variable speed compressor controlled by circuitry to maintain power consumption below a threshold, initially operating at reduced frequency during cooldown and increasing frequency as refrigerant pressure falls, allowing for higher operation without overheating, and optionally using additional refrigerant through increased filling pressure or a buffer volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor speed is increased to increase mass flow rate and pressure difference, then the cooling performance is improved, but the power consumption increases and the compressor may overheat
Solution Approach 1:
The patent applies dynamics by making the compressor speed variable rather than fixed. The control circuitry dynamically adjusts the compressor frequency based on real-time temperature and pressure conditions, allowing the system to optimize between cooling performance and power consumption across different operating states (cooldown vs steady-state).
Solution Approach 2:
The patent changes the operating parameters (frequency, power consumption) of the compressor based on system state. During cooldown, the compressor operates at reduced frequency to limit power consumption, while during steady-state operation, the frequency can be increased to maximize cooling performance, thus adapting parameters to operational requirements.
2Productivity
If the initial filling pressure is increased to improve cooling power, then the mass flow rate increases, but the power consumption during cooldown exceeds the threshold and causes thermal overload
Solution Approach 1:
The patent applies preliminary action by pre-charging the system with additional refrigerant at higher filling pressure, but compensating for the resulting high power consumption during cooldown by limiting compressor frequency. This preliminary refrigerant loading prepares the system for better steady-state performance while the frequency limitation prevents thermal overload during the initial cooldown phase.
Solution Approach 2:
The control circuitry acts as an intermediary that mediates between the conflicting requirements of high filling pressure (for better cooling power) and compressor frequency limitation (to prevent thermal overload). It coordinates the compressor operation to allow high filling pressure while managing power consumption through frequency control.
3Stress or pressure
If the compressor operates at high frequency during cooldown, then the pressure difference is maintained, but the power consumption exceeds the threshold and causes thermal overload
Solution Approach 1:
The patent applies partial action by providing only sufficient pressure difference during cooldown rather than maximum pressure difference. The compressor frequency is limited to a level that maintains adequate pressure for refrigerant circulation while avoiding excessive power consumption that would cause thermal overload. The full pressure difference capability is reserved for steady-state operation.
4Reliability
If the compressor frequency is limited during cooldown to prevent thermal overload, then power consumption is controlled, but the cooling performance is reduced
Solution Approach 1:
The patent applies periodic action by using different compressor frequency settings for different operational periods. During the cooldown period, frequency is limited to prevent thermal overload. During the steady-state period, frequency is increased to maximize cooling performance. The system transitions between these periodic operational modes based on temperature and pressure 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
Enhances cooling power and efficiency by optimizing compressor speed and refrigerant pressure, maintaining effective operation within predefined limits, thereby improving steady-state performance and preventing thermal overload.
Implementation Method 1
a variable speed compressor configured to compress refrigerant
Implementation Method 2
a refrigerator unit comprising an expansion unit; a variable speed compressor configured to compress refrigerant
Data Source
AI summary
A cryogenic refrigeration system and method are disclosed. The cryogenic refrigeration system comprises: a refrigerator unit comprising an expansion unit and a variable speed compressor configured to compress refrigerant. The variable speed compressor is configured to receive refrigerant from the refrigerator unit via a lower pressure line and to supply compressed refrigerant to the refrigerator unit via a higher pressure line. There is also control circuitry configured to control the variable speed compressor to maintain a power consumption of the variable speed compressor below a predetermined threshold value, by during cooldown controlling the compressor to initially operate at a reduced frequency and later increasing a frequency of operation of the variable speed compressor such that the variable speed compressor operates at a higher frequency.