Improved reagent for thermal machine
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Solution Overview
Problem
Current thermochemical cold production systems face challenges in optimizing both power and storage capacity, as existing reactive pairs and sorbent implementations often prioritize one over the other, leading to inefficiencies in heat transfer and sorption processes.
Innovation Solution
A reactive matrix comprising a mixture of manganese chloride sorbent and expanded graphite, compacted to specific density and grain size ranges, is used for efficient sorption and desorption of ammonia in a cold production device, enhancing both power and storage capacity by improving thermal conductivity and permeability while preventing agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high proportion of sorbent is used to increase refrigeration capacity, then storage capacity is improved, but thermal conductivity deteriorates leading to reduced power
Solution Approach 1:
The patent uses a composite material consisting of sorbent particles embedded in an expanded graphite matrix. The expanded graphite provides high thermal conductivity pathways while the sorbent particles provide refrigeration capacity. This composite structure allows simultaneous optimization of both thermal performance and storage capacity, resolving the contradiction between high sorbent proportion (needed for storage) and adequate thermal conductivity (needed for power).
Solution Approach 2:
The expanded graphite matrix forms a porous structure that accommodates sorbent particles while maintaining thermal conduction pathways. The porous structure allows for optimal distribution of sorbent throughout the matrix, ensuring both high refrigeration capacity through adequate sorbent quantity and maintained thermal conductivity through the graphite network.
2Productivity
If sorbent grain size is reduced to increase surface area for sorption, then sorption rate is improved, but agglomeration increases reducing permeability
Solution Approach 1:
The expanded graphite matrix provides a porous structure that physically separates fine sorbent particles, preventing them from agglomerating despite their small grain size. The porous network maintains permeability pathways while allowing high surface area sorbent particles to provide rapid sorption kinetics.
Solution Approach 2:
The expanded graphite acts as an intermediary matrix that holds the fine sorbent particles in place, preventing direct contact and agglomeration between particles. This intermediary structure enables the use of fine grains for high sorption rate while maintaining system permeability through the graphite network.
3Quantity of substance
If sorbent proportion is increased to maximize storage capacity, then energy density is improved, but heat transfer efficiency deteriorates
Solution Approach 1:
The composite structure of sorbent particles in an expanded graphite matrix allows high sorbent loading for maximum energy density while the graphite matrix provides continuous thermal conduction pathways. This resolves the contradiction by decoupling the thermal transport function (handled by graphite) from the storage function (handled by sorbent).
Solution Approach 2:
The system segments the functions of thermal storage and thermal transport into separate components: sorbent particles for storage and expanded graphite for heat transfer. This segmentation allows each component to be optimized for its specific function, enabling high energy density without sacrificing heat transfer 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
The matrix achieves balanced refrigeration capacity and thermal performance, maintaining optimal permeability and preventing clogging, thus ensuring efficient cold production and regeneration phases.
Implementation Method 1
to the chemical sorption of the vapours produced by the exothermic synthesis reaction occurring in the reactor
Implementation Method 2
enhancing both power and storage capacity by improving thermal conductivity
Implementation Method 3
the endothermic evaporation of the coolant in the evaporator at low pressure
Implementation Method 4
maintaining optimal permeability and preventing clogging
Data Source
AI summary
The disclosed subject matter relates to a reactive matrix for the sorption/desorption of a heat transfer fluid (FG) in a reactor of a cold production device, this matrix comprising a compacted mixture of sorbent, of the manganese chloride monohydrate type, and expanded natural graphite in a preferred proportion of 79/21. The disclosed subject matter also relates to a method for manufacturing a wafer from this matrix and a reactor comprising a stack of such wafers.