Macroporous Desiccant Honeycomb Matrix for High Humidity Adsorption

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Solution Overview

Problem

Existing desiccant honeycomb matrices used in HVAC systems have limited moisture adsorption capacity at high relative humidities, typically less than 40% between 50% and 100% RH, and rely on microporous desiccants that are ineffective in saturated conditions, requiring thermal activation and using binders that reduce performance and lead to desiccant washout.

Innovation Solution

A macroporous honeycomb matrix is synthesized in-situ with a pore diameter of 40 to 200 Å and pore volume of 0.40 to 0.80 gm/cc, using a fiberglass substrate impregnated with water glass and metal salts, allowing for high adsorption capacity and stability at high humidities without thermal activation, and used as a chemical filter with enhanced chemisorption capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If microporous desiccant is used in honeycomb matrix, then surface area is increased, but moisture adsorption capacity at high relative humidity is limited

Engineering Contradiction:

Improvesurface areaVSAvoidmoisture adsorption capacity

Core Design Contradiction:

Area of stationary objectVSQuantity of substance

Solution Approach 1:

The patent changes the pore size parameter from microporous (conventional) to macroporous structure with pore diameters of 40-200 Å, fundamentally altering the adsorption characteristics to enable high moisture capacity at high relative humidities while maintaining adequate surface area

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure combining fiberglass substrate with macroporous desiccant material synthesized in-situ, achieving synergistic effects where the substrate provides structural support and the macroporous desiccant provides enhanced adsorption capacity

Inventive Principle:

Principle #40Composite materials

2Reliability

If thermal activation is used for desiccant regeneration, then dehumidification performance is improved, but energy consumption increases

Engineering Contradiction:

Improvedehumidification performanceVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The macroporous desiccant material inherently maintains high moisture adsorption capacity at high relative humidities without requiring external thermal activation, enabling the system to regenerate and maintain performance through natural vapor pressure gradients alone

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If binders are used in desiccant matrix, then structural stability is improved, but desiccant washout and performance reduction occur

Engineering Contradiction:

Improvestructural stabilityVSAvoiddesiccant washout resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent removes binders from the desiccant matrix formulation, relying instead on the mechanical interlocking of macroporous desiccant particles and their direct adhesion to the substrate, thereby eliminating the washout problem associated with binder degradation

Inventive Principle:

Principle #2Taking out (Extraction)

4Volume of stationary object

If macroporous structure is used, then pore volume is increased, but surface area decreases

Engineering Contradiction:

Improvepore volumeVSAvoidsurface area

Core Design Contradiction:

Volume of stationary objectVSArea of stationary object

Solution Approach 1:

The patent optimizes the pore diameter parameter to 40-200 Å range, creating a macroporous structure that achieves the dual benefit of increased pore volume for moisture storage and sufficient surface area for vapor adsorption, unlike conventional microporous structures

Inventive Principle:

Principle #35Parameter changes

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 macroporous desiccant matrix achieves a differential adsorption capacity of over 50% at 50% and 100% RH, providing higher water holding capacity and energy savings by maintaining performance at saturated conditions, while being odorless, non-toxic, and cost-effective, with improved chemisorption and reduced pressure drop.

Implementation Method 1

Desiccant materials have a high affinity for water vapor. An example of a commonly used desiccant material is silica gel. Typically their moisture content (moisture holding capacity) is a function of the relative humidity of the surrounding air.

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

Large capillaries provide a high capacity for condensed water, which gives the adsorbent a higher capacity at high relative humidities.

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Data Source

PatentUS11612857B2Honeycomb matrix comprising macroporous desiccant, process and use thereof

Publication Date: 2023.03.28 DESICCANT ROTORS INT PVT

AI summary

Macroporous desiccant based honeycomb matrix containing the macroporous desiccant synthesized “in-situ”, the desiccant having a differential water adsorption. Process for the “in-situ” preparation of the macroporous desiccant based honeycomb matrix including the steps of soaking honeycomb substrate impregnated with water glass, in aqueous metal salt(s) solution or acid solution, or combination thereof, until such time that the hydrogel honeycomb matrix is obtained and thermally activating the hydrogel honeycomb matrix to produce macroporous desiccant based honeycomb matrix.