Closed-Cycle Absorption System Pressure-Based Fluid Separation
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Solution Overview
Problem
Closed-cycle absorption systems face inefficiencies in separating working fluids from absorption fluids, leading to thermal energy loss and reduced purity of the working fluid, limiting the range of suitable heat sources and overall system efficiency.
Innovation Solution
The method involves separating a pressurized absorption mixture into a working effluent and an absorption effluent by subjecting it to a pressure at or above the condensation pressure of the pure working fluid or a temperature at or below its condensation temperature, allowing for a phase-specific separation based on physical properties, thereby reducing the need for heating and enhancing working fluid concentration in the evaporator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation-based evaporative separation is used to separate working fluid from absorption fluid, then separation can be achieved, but vast amounts of thermal energy are required and heat is not exploited efficiently
Solution Approach 1:
The patent changes the separation parameter from thermal (distillation) to mechanical (pressure). By pressurizing the absorption mixture to a pressure at or above the condensation pressure of the pure working fluid, the system achieves separation through phase change at lower temperatures, dramatically reducing thermal energy consumption while maintaining separation effectiveness.
Solution Approach 2:
The patent utilizes phase transition of the working fluid from liquid to gas through pressurization and subsequent expansion. The working fluid condenses under high pressure in the separator, then expands through the expansion machine, leveraging phase change for both separation and energy generation, thereby reducing the need for thermal energy input.
2Manufacturing precision
If the liquid mixture is heated up to increase working fluid vapor pressure for separation, then gaseous phase with high working fluid concentration can be obtained, but the mixture contains a lot of thermal energy that is lost to the cycle
Solution Approach 1:
The patent applies preliminary pressurization to the absorption mixture before separation. By pressurizing the mixture to conditions where the working fluid condenses, the system prepares the mixture for efficient separation without requiring subsequent heating. This preliminary action preserves thermal energy within the cycle.
Solution Approach 2:
The patent converts the typically harmful effect of high pressure (which requires energy input) into a beneficial phase change mechanism. The pressurization causes the working fluid to condense, and this condensed phase is then expanded through the expansion machine to generate useful work, turning the pressure input into a dual-purpose operation that both separates and generates energy.
3Manufacturing precision
If distillation-based separation is used, then a minimum temperature (boiling point) is required, but this limits the variety of suitable heat sources
Solution Approach 1:
The patent changes the controlling parameter for separation from temperature (boiling point) to pressure. By using pressure-based phase change, the system can achieve separation at various temperatures depending on the heat source available, rather than requiring a specific minimum temperature. This makes the system adaptable to diverse heat sources including low-temperature sources.
4Reliability
If the absorption fluid has lower partial vapor pressure than working fluid, then absorption fluid condenses first during expansion, but this has a highly negative impact on expansion efficiency
Solution Approach 1:
The patent applies excessive pressurization to ensure complete condensation of the working fluid while maintaining the absorption fluid in liquid phase. By pressurizing to conditions where only the working fluid condenses (based on its higher vapor pressure), the system achieves partial phase separation that prevents absorption fluid condensation during subsequent expansion, thereby protecting expansion efficiency.
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 approach reduces thermal energy loss, expands the range of suitable heat sources, and improves the purity of the gaseous working fluid, leading to more efficient energy conversion and broader applicability of the system.
Implementation Method 1
separating a pressurized absorption mixture into a working effluent and an absorption effluent by subjecting it to a pressure at or above the condensation pressure of the substantially pure working fluid
Implementation Method 2
subjecting it to a pressure at or above the condensation pressure of the substantially pure working fluid or a temperature at or below its condensation temperature, allowing for a phase-specific separation based on physical properties
Implementation Method 3
transferring thermal energy from a heat source to a liquid working mixture, within an evaporator, which working mixture at least comprises a working fluid, and whereby said working fluid is at least partly evaporated from said working mixture
Implementation Method 4
transferring thermal energy from a heat source to a liquid working mixture, within an evaporator
Implementation Method 5
expanding said evaporated working fluid, and absorbing said expanded working fluid into a liquid absorption mixture, within an absorber
Implementation Method 6
converting thermal energy into mechanical energy
Implementation Method 7
absorbing said expanded working fluid into a liquid absorption mixture, within an absorber
Data Source
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AI summary
The invention discloses a method for converting thermal energy into mechanical energy, and/or for cooling, comprising the steps of at least partly evaporating a working fluid, expanding said evaporated working fluid, absorbing said expanded working fluid into a liquid absorption mixture, at least partly extracting the absorption mixture from the absorber, pressurizing said extracted absorption mixture, separating said pressurized absorption mixture into a working effluent and an absorption effluent, and feeding said working and absorption effluent to the evaporator and absorber respectively. In particular, during said separation, the absorption mixture is subjected to a pressure at or above the condensation pressure of the substantially pure working fluid, and/or to a temperature at or below the condensation temperature of the substantially pure working fluid. The invention further discloses a closed-cycle absorption system, preferably suitable for performing the method.