Rectifier for a generator of refrigerant vapour for absorption thermal machines, and generator comprising such rectifier

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Solution Overview

Problem

Existing absorption thermal machines face challenges in managing power variations, solution flow and level variations, and maintaining efficiency while preventing leaks and reducing footprint and costs.

Innovation Solution

A rectifier for a generator of refrigerant vapour that incorporates a modular configuration with open-cell ceramic foam bodies for efficient heat exchange and vapour purification, allowing for compact design and cost-effective production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a plate column with filler (metal raschig rings or ceramic saddles) is used for fractionated distillation, then refrigerant purity is improved, but the height and cost of the generator increase

Engineering Contradiction:
Improverefrigerant purityVSAvoidgenerator height
Core Design Contradiction:
Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent uses a porous ceramic body as the rectifying element in the generator. This porous material provides a large surface area for mass exchange between the vapor and liquid phases, enabling effective fractionated distillation of refrigerant vapor without requiring a tall column structure. The porous structure allows vapor to percolate through while liquid flows down the external surface, creating efficient counter-current heat and mass transfer in a compact horizontal configuration.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention transitions from a vertical plate column configuration to a horizontal arrangement with porous elements. This dimensional change allows the rectifying process to occur in a compact horizontal space rather than requiring vertical height, thus reducing the overall generator height while maintaining distillation effectiveness through the porous structure's internal surface area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If structured materials with liquid distributors are used for continuous distillation, then refrigerant purity is improved, but the cost of the stripper increases

Engineering Contradiction:
Improverefrigerant purityVSAvoidstripper cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The porous ceramic body performs multiple functions simultaneously: it acts as the rectifying medium for fractionated distillation, provides structural support, and eliminates the need for separate liquid distributor components. This multi-functionality simplifies the overall structure, reduces the number of parts, and lowers manufacturing costs while achieving continuous distillation and high refrigerant purity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The porous ceramic body serves as both the rectifying medium and the structural element that distributes liquid. The porous structure naturally facilitates liquid distribution through capillary action and gravity flow along its external surface, eliminating the need for additional liquid distributor components and reducing overall system cost.

Inventive Principle:
Principle #31Porous materials

3Loss of energy

If triple coil or complex plate column circuits are used for internal heat recovery, then heat exchange efficiency is improved, but the complexity and costs of the stripping column increase

Engineering Contradiction:
Improveinternal heat recoveryVSAvoidstripping column complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention merges the heat exchange function and the rectifying function into a single integrated porous ceramic body structure. The external surface of the porous element serves as the heat exchange surface where liquid flows down, while the internal porous structure provides the rectifying pathway for vapor. This integration eliminates the need for separate heat exchange coils and complex circuit arrangements, reducing structural complexity while maintaining effective internal heat recovery.

Inventive Principle:
Principle #5Merging (Combining)

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 rectifier achieves efficient vapour purification with high refrigerant purity, reduces the footprint and construction costs of the generator, and allows for optimal control of refrigerant purity and operating pressure.

Implementation Method 1

which can be crossed by flows of liquid solution to be boiled and by vapour flows generated by boiling, so as to come into contact with one another

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

at least one first body (105) consisting of an open-cell ceramic foam

Methodology Applied
Scientific EffectPorous material heat transfer: Porosity

Implementation Method 3

serves to reduce the concentration of absorber in the vapour flow produced by the boiler by mass exchange with the solution rich of refrigerant entering the generator

Methodology Applied
Scientific EffectMass exchange: Diffusion

Implementation Method 4

in which the refrigerant vapour is stripped from the refrigerant-rich solution by means of direct contact with the hot vapour flows produced by the boiler

Methodology Applied
Scientific EffectDistillation: Distillation

Implementation Method 5

as well as a dephlegmator or partial condenser that allows for a further increase in the purity of the refrigerant contained in the vapour flows produced

Methodology Applied
Scientific EffectPartial condensation: Condensation

Data Source

PatentEP4370845B1Rectifier for a generator of refrigerant vapour for absorption thermal machines, and generator comprising such rectifier
Publication Date: 2025.02.12 POLITECNICO DI MILANO
  • EP4370845B1 patent drawingFigure 1
  • EP4370845B1 patent drawingFigure 2
  • EP4370845B1 patent drawingFigure 3

AI summary

Rectifier (100) for a generator (200) of refrigerant vapour, said rectifier being adapted to modify the percentage of a refrigerant substance present in vapour flows (V) generated by boiling a liquid solution (L) comprising at least one absorbent substance and a refrigerant substance absorbed and characterized in that it comprises at least: • - a casing (101) which extends along a substantially vertical reference axis (X) and includes at least a first transversal duct (102) suitable for allowing the introduction of flows of said liquid solution (L) to be boiled; • - at least a first body (105) consisting of an open cell ceramic foam which is housed in said casing (101) below said first duct (102) so as to be crossed by flows of the liquid solution (L) to be boiled which, going downwards, wet its surfaces, and by vapour flows (V) generated by boiling which, going upwards, exchange heat with the solution itself which wets the surfaces of the first body (105), causing at the same time evaporation of refrigerant from the liquid solution (L) and the condensation of at least a part of the absorbent substance contained in said vapour streams (V) going upwards.