Effects of natural convection on latent heat storage performance of salt in a horizontal concentric tube
TL;DR: In this article, the effects of fin geometric parameters on the LHS performance were numerically investigated and the results showed that the local fins can improve the uniformity of the LIS process.
About: This article is published in Applied Energy.The article was published on 2015-04-01. It has received 154 citations till now. The article focuses on the topics: Annular fin & Natural convection.
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TL;DR: In this article, the authors focused on the classification of various paraffins and salt hydrates, and provided an understanding on how to maximize thermal utilization of PCM and how to improve the phase transition rate, thermal conductivity, latent heat storage capacity and thermo-physical stability.
484 citations
TL;DR: In this article, a comparative review of phase change material (PCM) based LHS performance enhancement methods is presented, which can be classified into three categories: using high thermal conductivity additives and porous media to enhance PCM thermal conductivities, using finned tubes and encapsulated PCMs to extend heat transfer surface, using multistage or cascaded LHS technique and thermodynamic optimization to improve the heat transfer uniformity.
Abstract: Latent heat storage (LHS) is considered as the most promising technique for thermal energy storage, due to its high energy storage density and nearly constant working temperature. However, the lower thermal conductivity of the phase change material (PCM) used in LHS system seriously weakens thermal energy charging and discharging rates. In order to improve the thermal performance of LHS system, a lot of research on performance enhancement have been carried out. This review paper will concern on the development of PCMs and performance enhancement methods for LHS system in the last decade. The available enhancement methods can be classified into three categories: using high thermal conductivity additives and porous media to enhance PCM thermal conductivity, using finned tubes and encapsulated PCMs to extend heat transfer surface, using multistage or cascaded LHS technique and thermodynamic optimization to improving the heat transfer uniformity. The comparative reviews on PCMs, corresponding performance enhancement methods and their characteristics are presented in present paper. That will help in selecting reliable PCMs and matching suitable performance enhancement method to achieve the best thermal performance for PCM based LHS system. In addition, the research gaps in performance enhancement techniques for LHS systems are also discussed and some recommendations for future research are proposed.
327 citations
TL;DR: In this article, a thermal system numerical solutions of the flow velocity field, temperature field, mass transfer and heat conduction had been produced out as functions of the viscoelastic number (E), Prandtl number (Pr) and buoyancy parameters (Gc, Gt), etc.
324 citations
TL;DR: In this article, the melting process in a shell-and-tube latent heat thermal energy storage (LHTES) unit with annular fins was investigated and commercial grade paraffin was employed as the p...
287 citations
TL;DR: In this paper, the melting performance of phase change materials (PCMs) in a horizontal concentric-tube thermal energy storage (TES) unit was numerically investigated with consideration of natural convection.
223 citations
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TL;DR: In this article, the state of the art in investigations and developments of high-temperature phase change materials perspective for storage thermal and a solar energy in the range of temperatures from 120 to 1000 °C.
Abstract: The development of energy saving technologies is very actual issue of present day. One of perspective directions in developing these technologies is the thermal energy storage in various industry branches. The review considers the modern state of art in investigations and developments of high-temperature phase change materials perspective for storage thermal and a solar energy in the range of temperatures from 120 to 1000 °C. The considerable quantity of mixes and compositions on the basis of fluorides, chlorides, hydroxides, nitrates, carbonates, vanadates, molybdates and other salts, and also metal alloys is given. Thermophysical properties of potential heat storage salt compositions and metal alloys are presented. Compatibility of heat storage materials (HSM) and constructional materials have found its reflection in the present work. Data on long-term characteristics of some HSMs in the course of repeated cycles of fusion and solidification are analyzed. Article considers also other problems which should be solved for creation of commercial high-temperature heat storage devices with use of phase change materials.
933 citations
TL;DR: In this article, the effects of metal foams on heat transfer enhancement in phase change materials (PCMs) are investigated based on the two-equation non-equilibrium heat transfer model, in which the coupled heat conduction and natural convection are considered at phase transition and liquid zones.
356 citations
TL;DR: In this article, an annular latent storage unit filled with paraffin RT35 is experimentally and numerically studied to analyze the influence of the heat transfer fluid (HTF) injection side on the system.
251 citations
TL;DR: In this article, a multidimensional phase change problem is tackled with an enthalpy-based method coupled to the convective heat transfer from the heat transfer fluid (HTF).
241 citations
TL;DR: In this article, the feasibility of using metal foams and expanded graphite to enhance the heat transfer capability of phase change materials in high temperature thermal energy storage systems is investigated, and the results show that heat transfer can be significantly enhanced by both metal foam and expandable graphite, thereby reducing the charging and discharging period.
232 citations