First cycle simulations of the Honigmann process with LiBr/H<sub>2</sub>O and NaOH/H<sub>2</sub>O as working fluid pairs as a thermochemical energy storage

Jahnke, Anna; Strenge, Lia; Fleßner, Christian; Wolf, Nikola; Jungnickel, Tim; Ziegler, Felix

doi:10.1093/ijlct/ctt022

Cited by 12 publications

(9 citation statements)

References 4 publications

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“…It should be noted that the heat capacities of the working fluids c p,E , c p,A , enthalpy of dilution l A and heat losses in the HXs are dependent on the absolute temperature, which might change during the charging or discharging process. However, for the working-fluid pair in question, the change in absolute temperature is small during discharging (e.g., compare simulations in [44]); therefore, its influence on the working-fluid properties and heat losses is negligible.…”

Section: Analysis For a Constant Vapor Mass Flowmentioning

confidence: 99%

“…Thus, for the prediction of an arbitrary power output, this interdependency between the thermal and the mechanical systems has to be taken into account. While this was performed (for mechanical discharging only) in dynamic simulations in [44], for a specific expansion device delivering a specific mass flow rate (in this case, a turbine delivering a mass flow rate depending on the pressure ratio between evaporator and absorber), the present study focuses on the thermal interdependency for an arbitrary mass flow rate (and thus for arbitrary power out-and input).…”

Section: Introductionmentioning

confidence: 99%

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Thermal Operation Maps for Lamm–Honigmann Thermo-Chemical Energy Storage—A Quasi-Stationary Model for Process Analysis

Thiele

Ziegler

2022

Processes

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The Lamm–Honigmann energy storage is a sorption-based storage that can be arbitrarily charged and discharged with both heat and electrical power. The mechanical charging and discharging processes of this storage are characterized by an internal heat transfer between the main components, absorber/desorber and evaporator/condenser, that is driven by the working-fluid mass transferred between those components with the help of an expansion or compression device, respectively. In this paper, thermal operation maps for the mechanical charging and discharging processes are developed from energy balances in order to predict power output and storage efficiency depending on the system state, which, in particular, is defined by the mass flow rate of vapor and the salt mass fraction of the absorbent. The conducted method is applied for the working-fluid pair LiBr/H2O. In a first step, a thermal efficiency is defined to account for second-order losses due to the internal heat transfer; e.g., for discharging from a salt mass fraction of 0.7 to one of 0.5 (kg LiBr)/(kg sol.) at a temperature of 130 ∘C, it is found that the reversible shaft work output is reduced by 1.1–2.9%/(K driving temperature difference). For lower operating temperatures, the reduction is larger; e.g., at 80∘C, the efficiency loss due to heat transfer rises to 3.5%/K for a salt mass fraction of 0.5 (kg LiBr)/(kg sol.). In a second step, a quasi-stationary assumption leads to the thermal operation map from which the discharging characteristics can be found; e.g., at an operating temperature of 130 ∘C for a constant power output of 0.4 kW/m2 heat exchanger area at volumetric and inner machine efficiencies of ηi=ηvol=0.8 and for an overall heat-transfer coefficient of 1500 W/(K m2), the mass flow rate has to rise continuously from 1.5 to 4.2 g/(s m2), while the thermal efficiency is reduced from 97% to 83% due to this rise and due to the dilution of the sorbent. For this discharging scenario, the corresponding discharge time is 4.4 (min·m2)/(kg salt). This results in an exergetic storage density of around 29 Wh/(kg salt mass). For a charge-to-discharge ratio of 2 (charging times equals two times discharging time) and with the same heat-transfer characteristic and machine efficiencies for constant power charging with adiabatic compression, the system is charged at around 0.75 kW/m2, resulting in a round-trip efficiency of around 27%. Besides those predictions for arbitrary charging and discharging scenarios, the derived thermal maps are especially useful for the dimensioning of the storage system and for the development of control strategies. It has to be noted that the operation maps do not illustrate the transient behavior of the system but its quasi-stationary state. However, it is shown, mathematically, that the system tends to return to this state when disturbed.

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Section: Analysis For a Constant Vapor Mass Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal Operation Maps for Lamm–Honigmann Thermo-Chemical Energy Storage—A Quasi-Stationary Model for Process Analysis

Thiele

Ziegler

2022

Processes

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“…Recharging can be accomplished with the input of heat to desorb the water out of the aqueous solution. The water vapour will be condensed at a lower temperature, to recover the water and maintain a closed cycle, [53].…”

Section: Lamm-honigmann-processmentioning

confidence: 99%

“…One advantage of the technology is the absence of self-discharge (except for minor heat losses). An in-depth analysis of the process is missing thus far, although recent studies show the growing interest in the technology [53].…”

Section: Lamm-honigmann-processmentioning

confidence: 99%

Carnot battery technology: A state-of-the-art review

Dumont

Frate

Pillai

et al. 2020

Journal of Energy Storage

192

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“…The notable advantages of thermochemical processes can make these processes economically The coupling of absorption or desorption processes with mechanical vapor expansion or compression was patented by Moritz Honigmann in 1883 [21]. Recently, the so-called 'Honigmann process' was re-evaluated by Jahnke et al [22] as thermochemical storage producing power during desorption phase, and later simulated for the LiBr/H2O and NaOH/H2O working pairs [23]. Bao et al developed the idea of combining thermochemical processes with vapor compression [24] and with vapor expansion [25].…”

Section: Introductionmentioning

confidence: 99%

Hybrid system combining mechanical compression and thermochemical storage of ammonia vapor for cold production

Fitó

Coronas

Mauran

et al. 2019

Energy Conversion and Management

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This paper studies a hybrid system for cold production consisting of a compression cycle combined with a thermochemical process by sharing the same condenser, evaporator and refrigerant fluid. The aim of this hybridization is to solve mismatch issues between the demand of cold and the source of energy (availability and/or price) with a system as compact as possible. One important side benefit is that the interaction between the compressor and the thermochemical reactor reduces the activation temperature for ammonia desorption in the thermochemical reactor. To study this interaction a quasi-steady simulation model for both storage and de-storage phases has been developed and experimentally validated by means of a small scale (approx. 300 Wh of cold storage) experimental bench with ammonia as refrigerant and barium chloride (BaCl2) as reactant salt. Experiments proved a 35 K reduction in the activation temperature of the desorption reaction with respect to desorption without compressor. Model validation by adjusting permeability and thermal conductivity of the reactive composite showed an acceptable agreement between predicted and experimental reaction advancement-time curves. The validated model was used for simulation of the system in a preliminary case study, representative in power (40 kW) and temperature (-25°C) of an industrial cold demand. It is shown that during ammonia de-storage, the hybrid achieves a higher COP than a conventional mechanical vapor compression system. It increases exponentially with the relative share of thermochemical storage in the cold production.

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First cycle simulations of the Honigmann process with LiBr/H₂O and NaOH/H₂O as working fluid pairs as a thermochemical energy storage

Cited by 12 publications

References 4 publications

Thermal Operation Maps for Lamm–Honigmann Thermo-Chemical Energy Storage—A Quasi-Stationary Model for Process Analysis

Thermal Operation Maps for Lamm–Honigmann Thermo-Chemical Energy Storage—A Quasi-Stationary Model for Process Analysis

Carnot battery technology: A state-of-the-art review

Hybrid system combining mechanical compression and thermochemical storage of ammonia vapor for cold production

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First cycle simulations of the Honigmann process with LiBr/H2O and NaOH/H2O as working fluid pairs as a thermochemical energy storage

Cited by 12 publications

References 4 publications

Thermal Operation Maps for Lamm–Honigmann Thermo-Chemical Energy Storage—A Quasi-Stationary Model for Process Analysis

Thermal Operation Maps for Lamm–Honigmann Thermo-Chemical Energy Storage—A Quasi-Stationary Model for Process Analysis

Carnot battery technology: A state-of-the-art review

Hybrid system combining mechanical compression and thermochemical storage of ammonia vapor for cold production

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Product

Resources

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First cycle simulations of the Honigmann process with LiBr/H₂O and NaOH/H₂O as working fluid pairs as a thermochemical energy storage