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Phase change materials (PCM) are used in many industrial and residential applications for their advantageous characteristic of high capacity of latent thermal storage by means of an isothermal process. In this context, it is very useful to have predictive mathematical models for the analysis of the thermal performance and for the thermal design of these layers. In this work, an experimental validation of an analytical model that resolves the steady periodic heat transfer problem in a finite layer of PCM is presented. The experimental investigation was conducted employing a PCM with thermophysical and thermochemical behavior very close to those hypothesized in the formulation of the analytical model. For the evaluation of the thermophysical properties of the PCM sample used, an experimental procedure created by the authors was employed. In all tests realized in a sinusoidal and non-sinusoidal periodic regime, the comparison between the measured and calculated trends of the temperature at different sample heights and of the surface heat fluxes show an excellent agreement. Moreover, also having verified the analytical total stored energy, the analytical model constitutes a valid instrument for the evaluation of the latent and sensible contribution and the trend in time of the position of the bi-phase interface. Peer Reviewed

Phase change materials (PCM) are used in many industrial and residential applications for their advantageous characteristic of high capacity of latent thermal storage by means of an isothermal process. In this context, it is very useful to have predictive mathematical models for the analysis of the thermal performance and for the thermal design of these layers. In this work, an experimental validation of an analytical model that resolves the steady periodic heat transfer problem in a finite layer of PCM is presented. The experimental investigation was conducted employing a PCM with thermophysical and thermochemical behavior very close to those hypothesized in the formulation of the analytical model. For the evaluation of the thermophysical properties of the PCM sample used, an experimental procedure created by the authors was employed. In all tests realized in a sinusoidal and non-sinusoidal periodic regime, the comparison between the measured and calculated trends of the temperature at different sample heights and of the surface heat fluxes show an excellent agreement. Moreover, also having verified the analytical total stored energy, the analytical model constitutes a valid instrument for the evaluation of the latent and sensible contribution and the trend in time of the position of the bi-phase interface. Peer Reviewed

This paper presents a comprehensive review of all correlations and experimental studies available in the literature to determine the heat transfer coefficient of supercritical CO2 flowing in heat exchangers. The different applications in which it is used are also reviewed and discussed. The correlations obtained from extensive experimental measurements are presented for different geometries (horizontal, vertical and inclined tubes, closed-loop circular pipes, and mini-channels) and dimensions. The review shows that there is a lack of a unique universal correlation for each geometry, suggesting the need for more work in this area. The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement N°PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES), and the funds received by the Royal Society of New Zealand. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

This paper presents a comprehensive review of all correlations and experimental studies available in the literature to determine the heat transfer coefficient of supercritical CO2 flowing in heat exchangers. The different applications in which it is used are also reviewed and discussed. The correlations obtained from extensive experimental measurements are presented for different geometries (horizontal, vertical and inclined tubes, closed-loop circular pipes, and mini-channels) and dimensions. The review shows that there is a lack of a unique universal correlation for each geometry, suggesting the need for more work in this area. The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER) and ENE2015-64117-C5-3-R (MINECO/FEDER)). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement N°PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES), and the funds received by the Royal Society of New Zealand. Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940.

©2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This paper presents a network clustering (NC) method for active distribution networks (ADNs). Following the outage of a section of an ADN, the method identifies and forms an optimum cluster of microgrids within the section. The optimum cluster is determined from a set of candidate microgrid clusters by estimating the following metrics: total power loss, voltage deviations, and minimum load shedding. To compute these metrics, equivalent circuits of the clusters are estimated using measured data provided by phasor measurement units (PMUs). Hence, the proposed NC method determines the optimum microgrid cluster without requiring information about the network’s topology and its components. The proposed method is tested by simulating a study network in a real-time simulator coupled to physical PMUs and a prototype algorithm implementation, also executing in real time. Peer Reviewed