Visual monitoring of the melting front propagation in a paraffin-based PCM

Charvát, Pavel; Stetina, Josef; Mauder, Tomáš; Klimeš, Lubomír

doi:10.1051/epjconf/201714302042

Cited by 6 publications

(4 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, if the temperature differences in the thermal storage system are large, multiple temperature measurements aligned in a grid are required. The temperature grid technique has been applied in research for both lab-scale heat transfer experiments [55][56][57] as on full LTES heat exchangers [42,58].…”

Section: Introductionmentioning

confidence: 99%

Estimating the state of charge in a latent thermal energy storage heat exchanger based on inlet/outlet and surface measurements

Beyne

Couvreur

T’Jollyn

et al. 2022

Applied Thermal Engineering

View full text Add to dashboard Cite

The performance of latent thermal energy storage (LTES) heat exchangers is related to the stored energy (i.e. state of charge) during the (dis)charging of the energy storage system. Furthermore, methods to correlate performance indicators such as the averaged effectiveness and phase change time are based solely on the latent heat stored. Therefore, measuring the stored energy in the separate components is crucial to understand the behavior of LTES systems and expand the correlation methods for performance indicators. However, technical limitations often do not allow to measure the stored energy. This article presents a LTES heat exchanger where only measurements at the in-and outlet of the heat transfer fluid and on the outer surface of the heat exchanger were possible. Based on this sparse set of measurements, estimators for the stored energy are developed. To test these estimators, a finite volume model of the LTES heat exchanger is made and fitted to experiments. The estimators for the stored energy in the heat transfer fluid, metal and phase change material reach a maximum deviation of respectively 1.9 %, 10 % and 2.1 % with the stored energy predicted by the finite volume model. By analyzing the stored energy as a function of time, four charging phases can be distinguished. The present correlating methods for performance indicators focus on the third latent phase. By estimating stored energy, the other phases can also be understood and modeled which can expand correlating methods for LTES heat exchangers in future work.

show abstract

Section: Introductionmentioning

confidence: 99%

Estimating the state of charge in a latent thermal energy storage heat exchanger based on inlet/outlet and surface measurements

Beyne

Couvreur

T’Jollyn

et al. 2022

Applied Thermal Engineering

View full text Add to dashboard Cite

show abstract

“…The challenges in the modeling of latent storage are mainly linked to the fact that the phase change process is non-linear and, therefore, an exact analytical solution is only possible for extremely simple cases [16]. Moreover, according to the specific layout of the storage, natural convection may occur, which further increases the complexity of the simulation, due to the need for solving a Navier-Stokes equation for the PCM [17]. Finally, PCM properties are temperaturedependent, thus increasing the required number of equations and the computational time to model them.…”

Section: Introductionmentioning

confidence: 99%

A Fast-Reduced Model for an Innovative Latent Thermal Energy Storage for Direct Integration in Heat Pumps

Palomba

Frazzica

2021

Applied Sciences

View full text Add to dashboard Cite

In the present paper, the numerical modeling of an innovative latent thermal energy storage unit, suitable for direct integration into the condenser or evaporator of a heat pump is presented. The Modelica language, in the Dymola environment, and TIL libraries were used for the development of a modular model, which is easily re-usable and adaptable to different configurations. Validation of the model was carried out using experimental data under different operating modes and it was subsequently used for the optimization of a design for charging and discharge. In particular, since the storage unit is made up of parallel channels for the heat transfer fluid, refrigerant, and phase change material, their number and distribution were changed to evaluate the effect on heat transfer performance.

show abstract

“…Based on the known relation between temperature and phase fraction, phase fraction fields and mean phase fractions (SoC) in the PCM were calculated. Among many other studies applying temperature sensors within the PCM to monitor the phase change, one can mention Beaupere et al [17], Charvat et al [18], Zhou et al [19], and Wang et al [20]. Wang et al [20] used a relatively high number of temperature sensors to accurately measure the temperature distributions in the solid and the fluid domain in a small rectangular test cell.…”

Section: Introductionmentioning

confidence: 99%

“…Image sensor or camera was also used for academic research to monitor phase front propagation in small test cells for studying specific phenomena and to derive from this the solid/liquid fraction of the PCM and the SoC. Charvat et al [18] monitored the melting front propagation in a rectangular cavity filled with a paraffin-based PCM by means of a digital camera, although their study was not intended to monitor the SoC of the storage. An in-house image processing code was used for conversion of the photos into black and white images to monitor the propagation of the melting front and to assess the melt fraction.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the State of Charge of a Solid/Liquid Phase Change Material in a Thermal Energy Storage Tank

et al. 2020

View full text Add to dashboard Cite

Monitoring of the state of charge of the thermal energy storage component in solar thermal systems for space heating and/or cooling in residential buildings is a key element from the overall system control strategy point of view. According to the literature, there is not a unique method for determining the state of charge of a thermal energy storage system that could generally be applied in any system. This contribution firstly provides a classification of the state-of-the-art of available techniques for the determination of the state of charge, and secondly, it presents an experimental analysis of different methods based on established sensor technologies, namely temperature, mass flow rates, and pressure measurements, tested using a lab-scale heat exchanger filled with a commercial phase change material for cooling applications. The results indicate that, depending on the expected accuracy and available instrumentation, each of the methods studied here can be used in the present application, the deviations between the methods generally being below 20%. This study concludes that a proper combination of two or more of these methods would be the ideal strategy to obtain a more reliable and accurate estimation of the state of charge of the latent heat thermal energy storage.

show abstract

Visual monitoring of the melting front propagation in a paraffin-based PCM

Cited by 6 publications

References 7 publications

Estimating the state of charge in a latent thermal energy storage heat exchanger based on inlet/outlet and surface measurements

Estimating the state of charge in a latent thermal energy storage heat exchanger based on inlet/outlet and surface measurements

A Fast-Reduced Model for an Innovative Latent Thermal Energy Storage for Direct Integration in Heat Pumps

Evaluation of the State of Charge of a Solid/Liquid Phase Change Material in a Thermal Energy Storage Tank

Contact Info

Product

Resources

About