CO2 Refrigeration Cycle with Expander-Driven High-Pressure Control
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Solution Overview
Problem
Existing vapor refrigeration processes using carbon dioxide as a refrigerant face complexity in frequency controlling and regulating high pressure, which complicates the control and efficiency of the process.
Innovation Solution
The apparatus includes a motor-operated main compressor, high pressure heat exchanger, expander, sub-cooler, and high pressure compressor, allowing for simplified control and regulation of the vapor refrigeration process by using the energy of the expansion process for subcooling and compressing a separate mass flow, with a direct mechanical connection between the expander and high pressure compressor, and optional multi-stage expansion and slide valve control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If frequency controlling process is used to regulate high pressure, then high pressure regulation is achieved, but device complexity increases
Solution Approach 1:
The patent replaces the electrical frequency controlling system with a purely mechanical pressure regulation system. The hydraulic pressure intensifier uses a piston and cylinder mechanism to mechanically amplify and regulate pressure, eliminating the need for complex frequency controllers and electrical control systems while achieving the same high pressure regulation objective.
Solution Approach 2:
The patent introduces a hydraulic pressure intensifier as an intermediary device between the compressor and the refrigeration system. This intensifier acts as a mechanical mediator that receives lower pressure from the compressor and transforms it into the required high pressure through hydraulic amplification, simplifying the overall control architecture.
2Productivity
If work-performing expansion process is used, then refrigeration performance is improved, but device complexity increases
Solution Approach 1:
The patent combines the expansion process with the existing refrigeration cycle components, integrating the work-performing expansion into the flow path between the high pressure heat exchanger and the evaporator. This merging allows the expansion to contribute positively to refrigeration performance while maintaining a compact and relatively simple system architecture.
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 regulation of high pressure levels, increases performance by 15% compared to simple vapor refrigeration processes, reduces energy losses, and allows for a space-saving design without the need for frequency control systems, while maintaining comparable high pressure values.
Implementation Method 1
a high pressure heat exchanger in order to cool the mass flow of the fluid that is at the high pressure level, to increase the density thereof and to reduce a temperature of the fluid due to the cooling process
Implementation Method 2
The mass flow of the fluid coming from the high pressure heat exchanger is expanded in an expander in work-performing manner to the evaporating pressure level
Implementation Method 3
The evaporator is equipped to absorb heat so that the density of the fluid when going through the evaporator decreases and the temperature of the mass flow at evaporating pressure level that is coming from the expander and being fed through the evaporator increases
Implementation Method 4
the fluid which is then at intermediate pressure level absorbs heat in a counter-flow arrangement in the sub-cooler and thereby subcools the mass flow which is at the high pressure level in the sub-cooler
Implementation Method 5
A high pressure compressor which is mechanically connected directly to the expander and is equipped such as to compress from intermediate pressure level to high pressure level exclusively the mass flow which was branched off between the sub-cooler and before the expander
Data Source
AI summary
The present invention relates to an apparatus and to a method for carrying out a vapour refrigeration process. The apparatus has a motor-operated main compressor which is equipped to suck-in a mass flow of a fluid serving as a refrigerant which is at evaporating pressure level and to compress this mass flow to a high pressure level, and also a high-pressure heat exchanger which is equipped to cool the mass flow of the fluid at a high pressure level, to increase a density and to reduce a temperature of the fluid. Also provided is an expander which is equipped to expand the mass flow of the fluid coming from the high pressure heat exchanger to evaporating pressure level in work-performing manner, and an evaporator which is equipped to absorb heat such that the density of the fluid decreases as it passes through the evaporator and the temperature of the mass flow coming from the expander at evaporating pressure and the temperature of the fluid being fed through the evaporator increase. Finally, there is a sub-cooler which is connected downstream of the high-pressure heat exchanger and upstream of the expander, wherein, downstream of the sub-cooler and upstream of the expander, part of the fluid is divertible from the mass flow and expandable by means of a high-pressure regulating valve to an intermediate pressure level so that the fluid which is then at the intermediate pressure level absorbs heat in a counter-flow arrangement in the sub-cooler and thereby additionally sub-cools the mass flow at high pressure level, and also a high-pressure compressor which is mechanically directly connected to the expander and is equipped to compress, to the high-pressure level, only that part of the fluid that is diverted upstream of the expander and is being fed in counter-flow in the sub-cooler, and to mix this fluid, upstream of the high-pressure heat exchanger, with the mass flow coming from the motor-operated main compressor.