Temperature-dependent thermal properties of solid/liquid phase change even-numbered n-alkanes: n-Hexadecane, n-octadecane and n-eicosane

Vélez, Catalina; Khayet, M.; Zárate, José M. Ortiz de

doi:10.1016/j.apenergy.2015.01.054

Cited by 242 publications

(155 citation statements)

References 53 publications

(129 reference statements)

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“…Moreover the process of phase change is almost isothermal for pure substances, and occurs over a finite range of temperature for composite materials, which is often an advantage compared to SHS systems. Solid-liquid transition proved to be the most economically attractive solution for LHS [12,13,15], due to the capability to store a relatively large amount of thermal energy within a narrow temperature range, without a large volume change [14]. However, the research and development conducted in the past showed also disadvantages concerning the low thermal conductivities typical of many PCMs, resulting in low rates of the charging and discharging processes [16].…”

Section: Introductionmentioning

confidence: 99%

Modelling and simulation of phase change material latent heat storages applied to a solar-powered Organic Rankine Cycle

2016

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Solar energy is one of the most promising renewable energy sources, but is intermittent by its nature. The study of efficient thermal heat storage technologies is of fundamental importance for the development of solar power systems. This work focuses on a robust mathematical model of a Latent Heat Storage (LHS) system constituted by a storage tank containing Phase Change Material spheres. The model, developed in EES environment, provides the time-dependent temperature profiles for the PCM and the heat transfer fluid flowing in the storage tank, and the energy and exergy stored as well. A case study on the application of the LHS technology is also presented. The operation of a solar power plant associated with a latent heat thermal storage and an ORC unit is simulated under dynamic (time-varying) solar radiation conditions with the software TRNSYS. The performance of the proposed plant is simulated over a one week period, and the results show that the system is able to provide power in 78.5% of the time, with weekly averaged efficiencies of 13.4% for the ORC unit, and of 3.9% for the whole plant (from solar radiation to net power delivered by the ORC expander).

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Section: Introductionmentioning

confidence: 99%

Modelling and simulation of phase change material latent heat storages applied to a solar-powered Organic Rankine Cycle

2016

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“…In this study, it is desired to determine the viability of using paint containing n-octadecane microencapsulated in resorcinol-modified urea-melamine-formaldehyde (UMF) shells as an LHS (cooling) system for buildings. The paraffin n-octadecane (C 18 H 38 ), with a melting point of 27C [5], is used since it is the most suitable organic PCM to be used for indoor room temperature conditions in the Philippine setting (the average year-round temperature in the Philippines is approximately 26.6º C [6]), while UMF is used since it has been reported that the polymer can enhance the chemical and physical stability properties of the C 18 H 38 [7].…”

Section: Introductionmentioning

confidence: 99%

Characterization of MEPCM-Incorporated Paint as Latent Heat Storage System

Tumolva¹,

Sabarillo²

2017

IJCEA

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Abstract-This study aimed to determine the effect of the mixing speed and pre-polymer dropping rate during synthesis of microencapsulated phase change materials (MEPCMs), and to assess the performance of MEPCM-incorporated paint as a latent heat storage (LHS) system. N-octadecane as phase change material was encapsulated with resorcinol-modified ureamelamine-formaldehyde at two different mixing speeds and four different pre-polymer dropping rates, and Fourier transform infrared (FTIR) spectroscopy was done to confirm success of microencapsulation. Scanning electron microscopy (SEM) revealed that increasing the homogenization speed and decreasing the pre-polymer dropping rate decreases the microcapsule size. Differential scanning calorimetry results showed that latent heat and encapsulation ratio increases with increasing mixing speed and decreasing pre-polymer dropping rate. The synthesized MEPCMs were incorporated into white paint at three different concentrations, and temperature profiling revealed that the paint's temperature buffering capacity generally increases with increasing mixing speed, decreasing pre-polymer dropping rate and increasing MEPCM concentration.Index Terms-Heat storage, MEPCM, phase change material, microencapsulation.

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“…[16][17][18] By constantly storing and retracting latent heat, 19 the MPCMs are expected to maintain the dynamic equilibrium of output temperatures when the surrounding temperature is around the PTR. More attractively, since the liquid PCMs above PTR store a higher accumulative energy (latent heat + sensible heat) but exhibit a much lower specific heat capacity than the PCMs within PTR, 20,21 the temperatures of PCMs and heat-generating structures would increase synchronously. [22][23][24][25][26][27][28] Consequently, a higher energy storage capacity will be achieved; 17 meanwhile, more heat will be emitted from the MPCMs above PTR to eliminate the convective heat dissipation in the heat-generating systems, 29 resulting in an increased the overall output temperature.…”

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confidence: 99%

Microencapsulated Phase Change Materials in Solar-Thermal Conversion Systems: Understanding Geometry-Dependent Heating Efficiency and System Reliability

et al. 2016

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The performance of solar-thermal conversion systems can be improved by incorporation of nanocarbon-stabilized microencapsulated phase change materials (MPCMs). The geometry of MPCMs in the microcapsules plays an important role for improving their heating efficiency andreliability. Yet few efforts have been made to critically examine the formation mechanism of different geometries and their effect on MPCMs-shell interaction. Herein, through changing the cooling rate of original emulsions, we acquire MPCMs within the nanocarbon microcapsules with a hollow structure of MPCMs (h-MPCMs) or solid PCM core particles (s-MPCMs). X-ray photoelectron spectroscopy and atomic force microscopy reveals that the capsule shell of the hMPCMs are enriched with nanocarbons and have a greater MPCMs-shell interaction compared to s-MPCMs. This results in the h-MPCMs being more stable and having greater heat diffusivity within and above the phase transition range than the s-MPCMs do. The geometry-dependent heating efficiency and system stability may have important and general implications for the fundamental understanding of microencapsulation and wider breadth of heating generating systems.3 Solar-thermal conversion, where solar irradiation is harvested and converted to heat for beneficial usage, has gained renewed interest in the past decade and made it a special asset in energy conversions due to its operational simplicity and high energy conversion efficiency. [1][2][3][4] Microencapsulated phase change materials (MPCMs, 1-100 µm diameter), often considered unique micrometer-scaled composites with a superior performance of latent heat thermal storage as compared with bulk PCMs, are currently emerging as positive additives/dopants to the solarthermal conversion systems. Nanocarbon-stabilized MPCMs are of particular interest as they combine the advantages of nanocarbons for their outstanding energy conversion/transfer performance, [5][6][7] MPCMs with an accelerated heat storage/release due to a relatively high surfacearea-to-volume ratio [8][9][10][11][12][13] and the PCM-nanocarbon interactions which often fosters an enhanced enthalpy and better crystallinity. 14,15 A new avenue is therefore opening to enhance the heatgenerating efficiency at a output temperature within and even higher than the solid-liquid phasetransition range (PTR). [16][17][18] By constantly storing and retracting latent heat, 19 the MPCMs are expected to maintain the dynamic equilibrium of output temperatures when the surrounding temperature is around the PTR. More attractively, since the liquid PCMs above PTR store a higher accumulative energy (latent heat + sensible heat) but exhibit a much lower specific heat capacity than the PCMs within PTR, 20,21 the temperatures of PCMs and heat-generating structures would increase synchronously. [22][23][24][25][26][27][28] Consequently, a higher energy storage capacity will be achieved; 17 meanwhile, more heat will be emitted from the MPCMs above PTR to eliminate the convective heat dissipation in the heat-gen...

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Temperature-dependent thermal properties of solid/liquid phase change even-numbered n-alkanes: n-Hexadecane, n-octadecane and n-eicosane

Cited by 242 publications

References 53 publications

Modelling and simulation of phase change material latent heat storages applied to a solar-powered Organic Rankine Cycle

Modelling and simulation of phase change material latent heat storages applied to a solar-powered Organic Rankine Cycle

Characterization of MEPCM-Incorporated Paint as Latent Heat Storage System

Microencapsulated Phase Change Materials in Solar-Thermal Conversion Systems: Understanding Geometry-Dependent Heating Efficiency and System Reliability

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