Dynamic study of a single effect absorption chiller using the pair LiBr/H 2 O

Ochoa, Álvaro; Dutra, José Carlos Charamba; Guerrero, Jorge Recarte Henriquez; Santos, Carlos Antônio Cabral

doi:10.1016/j.enconman.2015.11.009

Cited by 69 publications

(32 citation statements)

References 42 publications

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“…In the WGS reactor comprising high temperature-shifts (HTS) and low temperature-shifts (LTS) sub-reactors, only the exothermic WGS reaction, as in Equation 2, is assumed to occur. Thus, the mass balance equations for the WGS reactor are described in Equation (10).…”

Section: Methane Srmentioning

confidence: 99%

Performance and Efficiency Analysis of an HT-PEMFC System with an Absorption Chiller for Tri-Generation Applications

Gwak

Kim

et al. 2019

Energies

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An absorption chiller model for tri-generation (combined cooling, heating, and power) is developed and incorporated with the high temperature- (HT-) proton exchange membrane fuel cell (PEMFC) system model that was developed in our previous study. We employ a commercially available flow simulator, Aspen HYSYS, for solving the energy and mass balances of various system components, including an HT-PEMFC stack that is based on a phosphoric acid-doped PBI membrane, natural gas-fueled reformer, LiBr-H2O absorption chiller, balance of plant (BOP) components, and heat exchangers. Since the system’s operating strategy for tri-generation must be changed, depending on cooling or heating loads, a major focus of this study is to analyze system performance and efficiency under different requirements of electricity generation, cooling, and heating conditions. The system simulation results revealed that high-current fuel-cell operation is essential in raising the cooling capacity, but the overall system efficiency is slightly reduced as a result. Using a lower fuel-air ratio for the burner in the reforming module is one alternative that can minimize the reduction in the overall system efficiency under high-current fuel-cell operation and large cooling-capacity modes.

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Section: Methane Srmentioning

confidence: 99%

Performance and Efficiency Analysis of an HT-PEMFC System with an Absorption Chiller for Tri-Generation Applications

Gwak

Kim

et al. 2019

Energies

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“…The effects of the operating parameters of heat exchangers and maximum COP and ECOP have been analyzed in detail. Dynamic analysis of lithium bromide-water absorption chiller is given in [23]. Mathematical model has been developed with ability to simulate and predict the behavior of internal and external parameters such as temperature, concentrations, and pressures.…”

Section: Introductionmentioning

confidence: 99%

Energy analysis of heat exchanger in a heat exchanger network

Rauch

Galović

2018

THERM SCI

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Original scientific paper https://doi.org/10.2298/TSCI171231216R For many years now, heat exchanger optimization has been a field of research for a lot of scientists. Aims of optimization are different, having in mind heat exchanger networks with different temperatures of certain streams. In this paper mathematical model in dimensionless form is developed, describing operation of one heat exchanger in a heat exchanger network, with given overall area, based on the maximum heat-flow rate criterion. Under the presumption of heat exchanger being a part of the heat exchanger network, solution for the given task is resting in a possibility of connecting an additional fluid stream with certain temperature on a certain point of observed heat exchanger area. The connection point of additional fluid stream determines the exchanging areas of both heat exchangers and it needs to allow the maximum exchanged heat-flow rate. This needed heat-flow rate achieves higher value than the heat-flow rate acquired by either of streams. In other words, a criterion for the existence of the maximum heat-flow rate, as a local extremum, is obtained within this mathematical model. Results of the research are presented by the adequate diagrams and are interpreted, with emphasis on the cases which fulfill and those which do not fulfill the given condition for achieving the maximum heat-flow rate.

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“…Subsequently, the refrigerant is throttled by the valve and reaches the evaporator (point 4). And then, it evaporates to extract heat from outside (point 15,16), producing a cooling effect. Finally, the refrigerant vapor arrives in the absorber (point 5) to complete an absorption process.…”

Section: Principlementioning

confidence: 99%

“…However, the real-time operation of a commercial AC is governed by continuous transient processes, and the relaxation time required to achieve a new steady-state is rather long compared to the vapor compression chiller with a similar cooling capacity [15,16]. What's more, the dynamic process of AC is essential for the adjustment of AC and the control of the whole system, of which the stabilization can be affected by the transient process.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Performance Analysis for an Absorption Chiller under Different Working Conditions

Wang

Shang

et al. 2017

Applied Sciences

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Featured Application: The dynamic performance of the absorption chiller (AC) under different working conditions in this work is significant for the operation of the whole system, of which the stabilization can be affected by the AC transient process.Abstract: Due to the merits of energy saving and environmental protection, the absorption chiller (AC) has attracted a lot of attention, and previous studies only concentrated on the dynamic response of the AC under a single working condition. However, the working conditions are usually variable, and the dynamic performance under different working conditions is beneficial for the adjustment of AC and the control of the whole system, of which the stabilization can be affected by the AC transient process. Therefore, the steady and dynamic models of a single-effect H 2 O-LiBr absorption chiller are built up, the thermal inertia and fluid storage are also taken into consideration. And the dynamic performance analyses of the AC are completed under different external parameters. Furthermore, a whole system using AC in a process plant is analyzed. As a conclusion, the time required to reach a new steady-state (relaxation time) increases when the step change of the generator inlet temperature becomes large, the cooling water inlet temperature rises, or the evaporator inlet temperature decreases. In addition, the control strategy considering the AC dynamic performance is favorable to the operation of the whole system.

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Dynamic study of a single effect absorption chiller using the pair LiBr/H 2 O

Cited by 69 publications

References 42 publications

Performance and Efficiency Analysis of an HT-PEMFC System with an Absorption Chiller for Tri-Generation Applications

Performance and Efficiency Analysis of an HT-PEMFC System with an Absorption Chiller for Tri-Generation Applications

Energy analysis of heat exchanger in a heat exchanger network

Dynamic Performance Analysis for an Absorption Chiller under Different Working Conditions

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