Perturbation analysis of the heat transfer in porous media with small thermal conductivity

h i g h l i g h t sThe paper presents a thermodynamic analysis of A-CAES using packed bed regenerators. The packed beds are used to store the compression heat. A numerical model is developed, validated and used to simulate system operation. The simulated efficiencies are between 70.5% and 71.1% for continuous operation. Heat build-up in the beds reduces continuous cycle efficiency slightly. a b s t r a c tThe majority of articles on Adiabatic Compressed Air Energy Storage (A-CAES) so far have focussed on the use of indirect-contact heat exchangers and a thermal fluid in which to store the compression heat. While packed beds have been suggested, a detailed analysis of A-CAES with packed beds is lacking in the available literature. This paper presents such an analysis. We develop a numerical model of an A-CAES system with packed beds and validate it against analytical solutions. Our results suggest that an efficiency in excess of 70% should be achievable, which is higher than many of the previous estimates for A-CAES systems using indirect-contact heat exchangers. We carry out an exergy analysis for a single charge-storage-discharge cycle to see where the main losses are likely to transpire and we find that the main losses occur in the compressors and expanders (accounting for nearly 20% of the work input) rather than in the packed beds. The system is then simulated for continuous cycling and it is found that the build-up of leftover heat from previous cycles in the packed beds results in higher steady state temperature profiles of the packed beds. This leads to a small reduction (<0.5%) in efficiency for continuous operation.

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“…More sophisticated analytical treatments of packed bed systems can be also be found, i.e. Villatoro et al [38].…”

Section: Heat Storage In Packed Bedsmentioning

confidence: 99%

Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage

et al. 2015

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“…The solution to Equations 7.1 and 7.2 yields the Schumann Curves for the temperature profile of the bed. A more sophisticated treatment of systems like this using perturbation methods can be found in Villatoro et al (2011).…”

Section: Heat Transfer In a Packed Bed Heat Exchangermentioning

confidence: 99%

Towards an objective method to compare energy storage technologies: development and validation of a model to determine the upper boundary of revenue available from electrical price arbitrage

Barbour

Wilson

Bryden

et al. 2012

Energy Environ. Sci.

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“…Perturbation methods are applied among others to obtain an approximate analytical solution involving the problems of one-dimensional thermal transmittance through porous materials. Such materials are characterized by a very low design thermal conductivity, which can play the role of a small parameter [28,35].…”

Section: Introductionmentioning

confidence: 99%

Estimation of thermal transmittance based on temperature measurements with the application of perturbation numbers

et al. 2017

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Fast estimation of thermal transmittance based on temperature measurements is uncertain, and the obtained results can be burdened with a large error. Nevertheless, such attempts should be undertaken merely due to the fact that a precise measurement by means of heat flux measurements is not always possible in field conditions (resentment of the residents during the measurements carried out inside their living quarters), and the calculation methods do not allow for the nonlinearity of thermal insulation, heat bridges or other fragments of building envelope of diversified thermal conductivity. The present paper offers the estimation of thermal transmittance and internal surface resistance with the use of temperature measurements (in particular with the use of thermovision). The proposed method has been verified through tests carried out on a laboratory test stand built in the open space, subjected to the influence of real meteorological conditions. The present elaboration involves the estimation of thermal transmittance by means of temperature measurements. Basing on the mentioned estimation, the authors present correction coefficients which have impact on the estimation accuracy. Furthermore, in the final part of the paper, various types of disturbance were allowed for using perturbation numbers, and the introduced by the authors Bcredibility area of thermal transmittance estimation^was determined.

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Perturbation analysis of the heat transfer in porous media with small thermal conductivity

Cited by 11 publications

References 19 publications

Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage

Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage

Towards an objective method to compare energy storage technologies: development and validation of a model to determine the upper boundary of revenue available from electrical price arbitrage

Estimation of thermal transmittance based on temperature measurements with the application of perturbation numbers

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