Supercooling of phase change: A new modeling formulation using apparent specific heat capacity

2020 ◽  
Vol 147 ◽  
pp. 106121 ◽  
Author(s):  
Tanguy Davin ◽  
Benoît Lefez ◽  
Alain Guillet
Keyword(s):  
Heat Capacity ◽  
Phase Change ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Apparent Specific Heat

Thermal Analysis of Phase Change Material Based Heat Transfer Fluid in Solar Thermal Collector

2020 ◽  
Author(s):  
Tyler J. E. O’Neil ◽  
Celine S. L. Lim ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Heat Capacity ◽  
Phase Change ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Phase Change Materials ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Liquid Form ◽  
High Specific Heat ◽  
Multi Walled Carbon Nanotubes

Abstract Phase change materials (PCMs) are commonly used as energy storage mediums in solar thermal systems. This paper investigates the mixture of PCM doped with nanoparticles to be used as HTFs directly integrated in a U-pipe ETC to be applied in solar thermal collectors. The selected type of PCM-HTF in this study is erythritol (C4H10O4), with high specific heat capacity in liquid form, as well as its unique sub-cooling behavior. In order to overcome the low thermal conductivity of erythritol and further enhance specific heat capacity, a weight concentration of 1% multi-walled carbon nanotubes (MWCNT) is added. Additionally, to insure even distribution of MWCNT and consistent properties of the HTF, triethanolamine (TEA) is proposed to be incorporated as a dispersant. The samples were each tested in a Thermogravimetric Analyzer (TGA) and Differential Scanning Calorimeter (DSC) to analyze their thermal properties. The results from the DSC tests show 12.4% enhancement of specific heat capacity of the proposed HTF mixture as well as nearly 5° C depression of freezing onset temperature. This study allows for the optimization of the operating temperature range of the collector when integrated with these materials, where direct heat gain can be obtained in the collector.

scholarly journals Determination of effective specific heat capacity of interior plaster containing phase change materials

2019 ◽  
Vol 282 ◽  
pp. 02052
Author(s):  
Václav Kočí ◽  
Jiří Maděra ◽  
Robert Černý
Keyword(s):  
Heat Capacity ◽  
Phase Change ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Building Materials ◽  
Phase Change Materials ◽  
Calorimetric Data ◽  
Thermal Oscillation ◽  
Effective Specific Heat

A precise technique for determination of effective specific heat capacity of building materials is presented within this paper. The applicability of the technique is demonstrated on a PCM-enhanced plaster, being characterized by a phase change between 15 and 30 °C. The effective specific heat capacity is determined by means of inverse analysis of calorimetric data using computational model of the device. The identified effective specific heat capacity values reached up to 1890 J·kg-1·K-1 when cooled and 1580 J·kg-1·K-1 when heated. Using this quantity in simulation of thermal performance, the PCM-enhanced plaster showed to have a promising potential to be used in buildings’ interiors as a thermal regulator to stabilize inner environment as it contributed to a thermal oscillation decrease by up to 2.5 °C

scholarly journals Methodology to determine the apparent specific heat capacity of metal hydroxides for thermochemical energy storage

2017 ◽  
Vol 133 (1) ◽  
pp. 207-215 ◽  
Author(s):  
Daniel Lager ◽  
Wolfgang Hohenauer ◽  
Christian Knoll ◽  
Peter Weinberger ◽  
Andreas Werner
Keyword(s):  
Heat Capacity ◽  
Energy Storage ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Metal Hydroxides ◽  
Apparent Specific Heat

scholarly journals Microencapsulated Phase Change Material Suspension for Cold Start of PEMFC

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1514
Author(s):  
Sitong Chen ◽  
Shubo Wang ◽  
Xueke Wang ◽  
Weiwei Li ◽  
Baorui Liang ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Phase Change ◽  
Specific Heat ◽  
Latent Heat ◽  
Specific Heat Capacity ◽  
Proton Exchange Membrane ◽  
Phase Change Materials ◽  
Chemical Properties ◽  
Cold Start ◽  
Proton Exchange

We added microencapsulated phase change materials (MPCMs) into the homemade antifreeze fluid to take advantage of the latent heat of phase change materials, and explored the possibility of solving the cold start problem of proton exchange membrane fuel cells (PEMFC) with variable specific heat capacity antifreeze. The physical and chemical properties of the MPCMs and their suspensions were tested, and a PEMFC platform for cold start with a thermal management system was established to compare the exothermic performance of MPCS and commercial antifreeze fluid. According to the output voltage, temperature and polarization curves before and after cold start, the MPCMs has a stronger heat transfer capacity than the commercial antifreeze fluid, and the addition of MPCMs can transform the latent heat generated during the phase transition into apparent specific heat capacity, leading to a better solution to the problem of PEMFC cold start.

scholarly journals A Novel Method for the Synthesis of Binary Molten Salt Nanofluids Adding SiO2 Nanoparticles

2020 ◽  
Author(s):  
Joohyun Seo
Keyword(s):  
Heat Capacity ◽  
Sample Preparation ◽  
Phase Change ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Sio2 Nanoparticles ◽  
Bottom Surface ◽  
Unexpected Result ◽  
Novel Method

Abstract In this study, the new method has been suggested for the synthesis of a binary molten salt eutectic adding nanoparticles (i.e. molten salt nanofluids). Solar salt (i.e. NaNO 3 -KNO 3 , 60:40 by weight) adding 10nm of SiO 2 nanoparticles was prepared to measure the specific heat capacity of molten salt nanofluids by a modulated differential scanning calorimeter (MDSC). In previous studies the sample preparation of a molten salt eutectic follows the same procedure. Each chemical of a molten salt eutectic and nanoparticles is dissolved in an aqueous solution. These homogeneous salts are completely mixed by a sonication. Nano-mixtures are scrapped off the bottom surface of a vial after drying. However, there are complex steps in the process of getting fresh molten salt eutectic nanofluids before MDSC measurements. An unexpected result is able to occur due to phase change (i.e. solid-liquid-solid) at each step and then it has an affect on the specific heat capacity of molten salt nanofluids. A suggested novel method (i.e. Liquid-to-Liquid) can not only prevent unexpected errors (e.g. the possibility of contamination) by phase change in the sample preparation, but also enhance the specific heat capacity of molten salt nanofluids.

Effect of heating rate and sample geometry on the apparent specific heat capacity: DSC applications

2011 ◽  
Vol 519 (1-2) ◽  
pp. 59-64 ◽  
Author(s):  
T. Kousksou ◽  
A. Jamil ◽  
K. El Omari ◽  
Y. Zeraouli ◽  
Y. Le Guer
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Heating Rate ◽  
Specific Heat Capacity ◽  
Sample Geometry ◽  
Apparent Specific Heat
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