In-situ reactive absorption for equilibrium-shifting of non-condensable gases

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Solution Overview

Problem

Thermochemical energy devices based on hygroscopic salts suffer from low degrees of conversion/desorption due to gas leakage, decomposition, and side reactions producing non-condensable gases, which reduce storage capacity and device performance.

Innovation Solution

A salt composition comprising a base and a hygroscopic salt that can produce a gas by reacting with an acid, presented in a porous configuration to shift the reaction equilibrium and suppress gas formation, thereby enhancing energy storage capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If hygroscopic salts are used for water absorption/release in thermochemical energy storage, then energy storage capacity is improved, but gas production from side reactions reduces system performance and storage efficiency

Engineering Contradiction:

Improveenergy storage capacityVSAvoidgas production

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

A base substance is introduced as an intermediary component that reacts with non-condensable gases to form condensable species. This mediator converts harmful non-condensable gases into beneficial condensable vapors that can be removed through the condenser, thereby eliminating gas accumulation while maintaining energy storage capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful effect of non-condensable gas production into a beneficial process by using the base to transform these gases into condensable species. The previously harmful gas evolution reaction is redirected to produce condensable vapors that facilitate water transport and can be efficiently removed, turning a system degradation mechanism into a functional advantage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If the system operates under vacuum to prevent gas leakage, then system reliability is improved, but non-condensable gases still accumulate and reduce heat transfer efficiency

Engineering Contradiction:

Improvesystem vacuum maintenanceVSAvoidheat transfer efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention exploits phase transition by converting non-condensable gases into condensable vapors through chemical reaction with the base. These condensable species then undergo phase change from vapor to liquid in the condenser, enabling efficient removal from the system and preventing heat transfer degradation while maintaining vacuum integrity.

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The base acts as a chemical intermediary that modifies the physical properties of reaction gases, transforming them from non-condensable to condensable state. This intermediary substance enables the system to handle gas byproducts in a manner consistent with vacuum operation requirements while preserving thermal efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If the degree of desorption is increased to maximize charging capacity, then energy storage density is improved, but gas production from side reactions increases and reduces overall efficiency

Engineering Contradiction:

Improvecharging capacityVSAvoidgas production

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

By introducing the base, the invention converts the harmful gas production that increases with higher desorption rates into a beneficial condensable vapor generation. This allows the system to operate at high charging capacities where gas evolution is more pronounced, while the base continuously transforms these gases into removable condensable species, maintaining efficiency even at high productivity levels.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 presence of a base in the salt composition significantly improves the energy storage capacity of thermochemical energy devices by reducing gas production and maintaining high accessibility of the condenser, leading to enhanced performance and reduced gas accumulation.

Implementation Method 1

In-situ reactive absorption for equilibrium-shifting of non-condensable gases

Methodology Applied

Scientific EffectReactive absorption: Absorption (physical)

Implementation Method 2

During the charging of the device (i.e. the storing of heat) an endothermic reaction or desorption occurs by consuming heat

Methodology Applied

Scientific EffectDesorption: Desorption

Implementation Method 3

The released water is removed from the dried hygroscopic salt, generally by condensation, and stored separately

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 4

During the discharging of the device (i.e. release of heat), the reverse process, an exothermic reaction or sorption occurs and heat is released

Methodology Applied

Scientific EffectSorption: Sorption

Data Source

PatentEP3510119B1In-situ reactive absorption for equilibrium-shifting of non-condensable gases

Publication Date: 2023.01.04 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO

Figure 1~2

AI summary

The invention is directed to a salt composition for use in a thermochemical energy storage device, said salt composition comprising a base and a hygroscopic salt that can produce a gas by reacting with an acid. In further aspects the invention is directed to ab energy storage compartment and a thermochemical energy storage device comprising the salt composition.