ENERGY AND FEASIBILITY ANALYSIS OF APPLYING BIO-BASED PHASE CHANGE MATERIALS TO BUILDINGS IN EAST ASIA

2020 ◽  
Vol 15 (2) ◽  
pp. 157-181
Author(s):  
Abdo Abdullah Ahmed Gassar ◽  
Geun Young Yun ◽  
Sumin Kim ◽  
Choong-Hee Han
Keyword(s):  
Phase Change ◽  
East Asia ◽  
Melting Temperature ◽  
Phase Change Materials ◽  
Computer Modelling ◽  
High Heat ◽  
Economic Feasibility ◽  
Key Factor ◽  
High Heat Capacity ◽  
Phase Temperature

ABSTRACT The application of phase change materials (PCMs) in building envelopes can help promote energy efficiency due to its high heat capacity. Our study aimed to provide energy and economic insights for deploying PCM to buildings in eight different regions of East Asia through a series of energy and economic analysis using computer modelling and simulations. The static payback period (SPP) and dynamic payback (DPP) methods were used to evaluate the economic feasibility of applying a PCM at different melting phase temperatures (20°C, 23°C, 25°C, 27°C and 29°C). Results show that the proper choice of a PCM melting temperature is a key factor to improve the performance of the PCM applied to buildings. A melting phase temperature of 29°C achieved the highest economic feasibility in Seoul, Tokyo; Pyongyang; Beijing; and Ulaanbaatar and a melting temperature of 23°C in Hong Kong had the highest economic feasibility. Overall, the combined economic and energy analysis presented in this study can play an important role in improving the energy and economic feasibility of PCM in buildings.

scholarly journals Breakdown of the Stokes-Einstein relation above the melting temperature in a liquid phase-change material

2018 ◽  
Vol 4 (11) ◽  
pp. eaat8632 ◽  
Author(s):  
Shuai Wei ◽  
Zach Evenson ◽  
Moritz Stolpe ◽  
Pierre Lucas ◽  
C. Austen Angell
Keyword(s):  
Liquid Phase ◽  
Phase Change ◽  
Melting Temperature ◽  
Phase Change Materials ◽  
Dynamic Properties ◽  
Switching Behavior ◽  
Einstein Relation ◽  
Elastic Neutron ◽  
Phase Switching ◽  
Memory Applications

The dynamic properties of liquid phase-change materials (PCMs), such as viscosity η and the atomic self-diffusion coefficientD, play an essential role in the ultrafast phase switching behavior of novel nonvolatile phase-change memory applications. To connect η toD, the Stokes-Einstein relation (SER) is commonly assumed to be valid at high temperatures near or above the melting temperatureTmand is often used for assessing liquid fragility (or crystal growth velocity) of technologically important PCMs. However, using quasi-elastic neutron scattering, we provide experimental evidence for a breakdown of the SER even at temperatures aboveTmin the high–atomic mobility state of a PCM, Ge1Sb2Te4. This implies that although viscosity may have strongly increased during cooling, diffusivity can remain high owing to early decoupling, being a favorable feature for the fast phase switching behavior of the high-fluidity PCM. We discuss the origin of the observation and propose the possible connection to a metal-semiconductor and fragile-strong transition hidden belowTm.

scholarly journals Computational Study of Heat Transfer inside Different PCMs Enhanced by Al2O3 Nanoparticles in a Copper Heat Sink at High Heat Loads

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 284 ◽  
Author(s):  
Nadezhda S. Bondareva ◽  
Nikita S. Gibanov ◽  
Mikhail A. Sheremet
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Computational Study ◽  
Conjugate Problem ◽  
High Heat ◽  
Solid Particles ◽  
Heat Sinks ◽  
Al2o3 Nanoparticles ◽  
Electronic Elements ◽  
The Impact

The cooling of electronic elements is one of the most important problems in the development of architecture in electronic technology. One promising developing cooling method is heat sinks based on the phase change materials (PCMs) enhanced by nano-sized solid particles. In this paper, the influence of the PCM’s physical properties and the concentration of nanoparticles on heat and mass transfer inside a closed radiator with fins, in the presence of a source of constant volumetric heat generation, is analyzed. The conjugate problem of nano-enhanced phase change materials (NePCMs) melting is considered, taking into account natural convection in the melt under the impact of the external convective cooling. A two-dimensional problem is formulated in the non-primitive variables, such as stream function and vorticity. A single-phase nano-liquid model is employed to describe the transport within NePCMs.

scholarly journals Temperature Control in (Translucent) Phase Change Materials Applied in Facades: A Numerical Study

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3286 ◽  
Author(s):  
Tenpierik ◽  
Wattez ◽  
Turrin ◽  
Cosmatu ◽  
Tsafou
Keyword(s):  
Temperature Gradient ◽  
Phase Change ◽  
Specific Heat ◽  
Melting Temperature ◽  
Phase Change Materials ◽  
Numerical Study ◽  
Melting Process ◽  
Large Temperature ◽  
Energy Efficient Buildings ◽  
High Solar Radiation

Phase change materials (PCMs) are materials that can store large amounts of heat during their phase transition from solid to liquid without a significant increase in temperature. While going from liquid to solid this heat is again released. As such, these materials can play an important role in future energy-efficient buildings. If applied in facades as part of a thermal buffer strategy, e.g., capturing and temporarily storing solar energy in so-called Trombe walls, the PCMs are exposed to high solar radiation intensities, which may easily lead to issues of overheating. This paper therefore investigates the melting process of PCM and arrives at potential solutions for countering this overheating phenomenon. This study uses the simulation program Comsol to investigate the heat transfer through, melting of and fluid flow inside a block of PCM (3 × 20 cm2) with a melting temperature of around 25 °C. The density, specific heat and dynamic viscosity of the PCM are modeled as a temperature dependent variable. The latent heat of the PCM is modeled as part of the specific heat. One side of the block of PCM is exposed to a heat flux of 300 W/m2. The simulations show that once part of the PCM has melted convection arises transporting heat from the bottom of the block to its top. As a result, the top heats up faster than the bottom speeding up the melting process there. Furthermore, in high columns of PCM a large temperature gradient may arise due to this phenomenon. Segmenting a large volume of PCM into smaller volumes in height limits this convection thereby reducing the temperature gradient along the height of the block. Moreover, using PCMs with different melting temperature along the height of a block of PCM allows for controlling the speed with which a certain part of the PCM block starts melting. Segmenting the block of PCM using PCMs with different melting temperature along its height was found to give the most promising results for minimizing this overheating effect. Selecting the optimal phase change temperatures however is critical in that case.

scholarly journals A Meta Study of the Relationship Between Phase Change Material Parameters and Temperature Reduction in Fire Fighter Protective Clothing

2019 ◽  
Vol 6 ◽  
pp. 28-37
Author(s):  
Josef Richmond ◽  
Lesley Spencer ◽  
Tommy Tran ◽  
Evan Williams
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Protective Clothing ◽  
Phase Change Materials ◽  
High Heat ◽  
Heat Fluxes ◽  
Fire Fighter ◽  
High Flux ◽  
Temperature Reduction ◽  
Change Material

Firefighters are exposed to high risk scenarios in which the prevention of extreme heat injuries is largely dependent on the effectiveness of their protective clothing. The following meta-study examines contemporary literature to determine the usefulness of phase change materials (PCM’s) in improving the effectiveness of the current firefighter protective clothing (FFPC) model in order to better protect firefighters. The time- temperature for multiple PCM’s in environments with low, medium and high heat fluxes (taken as 2.5-5 kW/m2 for 700 seconds, 10-15 kW/m2 for 300 seconds and 20-40 kW/m2for 30 seconds respectively) were compared in terms of the rate of temperature increase and final temperature. The study found that PCM I produced the best temperature reduction in a low flux, PCM K did so in a medium flux, and PCM B did so in a high flux. The study also found that overall the PCMs were most effective in a low flux, therefore further study should be directed towards creating PCMs that are more effective in high-flux environments. Keywords: Phase Change Material; Fire Fighter Protective Clothing; Heat Flux

Review on Microencapsulated Phase Change Materials (MPCM) Slurries: Materials, Rheological Behavior and Applications

2014 ◽  
Vol 953-954 ◽  
pp. 1109-1112 ◽  
Author(s):  
Pan Zhang ◽  
Zhong Zhu Qiu ◽  
Mei He
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Rheological Behavior ◽  
Phase Change Materials ◽  
High Heat ◽  
Building Energy Efficiency ◽  
High Heat Transfer ◽  
Microencapsulated Phase Change Materials ◽  
Reduction Effect ◽  
Flow Drag

Microencapsulated phase change materials (MPCM) slurries with high heat transfer and great latent heat can serve as both the heat transfer fluids and energy storage medias. Studies showed that the effective specific heat and heat transfer rate increased by 28.1% and 23.6% respectively as using MPCM slurries. The rheological behavior of slurries do not change as adding MPCM with low concentration, can be characterized by Newtonian fluid feature with mass fraction <0.25. MPCM particles have flow drag reduction effect under turbulent situation, which was applied to building energy efficiency and refrigeration, obtained remarkable energy conservation effect.

scholarly journals PEMODELAN PHASE CHANGE MATERIALS PADA DISTRIBUSI TERMAL SELUBUNG BANGUNAN HOTEL

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Solli Dwi Murtyas ◽  
Siti Nur Cholida ◽  
Muhammad Kholid Ridwan
Keyword(s):  
Phase Change ◽  
Melting Temperature ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Comsol Multiphysics

Phase change materials (PCM) merupakan salah satu rekayasa selubung bangunan berupa bahan atau substan tambahan yang diaplikasikan pada selubung bangunan. Tujuan penggunaan PCM yaitu menyerap termal dari lingkungan atau melepaskan termal ke lingkungan sebelum didistribusikan kedalam bangunan. PCM sebagai penyimpanan energi termal bangunan akan menyerap dan melepaskan energi termal pada suhu yang telah ditentukan dan dijaga. Dua pemodelan ruangan dengan dan tanpa PCM dilakukan menggunakan COMSOL Multiphysics 5.0. Hasil persebaran panas ruangan dengan dan tanpa PCM akan dibandingkan. Ruangan yang disimulasikan merupakan ruangan hotel Cakra Kusuma berukuran 5 x 3,95 x 3 m. PCM dengan ketebalan 1 cm ditempatkan pada eksterior selubung bangunan yang mendapatkan sinar matahari langsung. Jenis PCM yang digunakan adalah paraffin murni dengan melting temperature sebesar 28℃ dan latent heat sebesar 244 kJ/kg. Hasilnya menunjukkan bahwa pemakaian paraffin dengan melting temperature 28℃, cocok diaplikasikan pada ruangan. Hal ini dikarenakan suhu tersebut termasuk dalam rentang suhu di Provinsi Yogyakarta. Pengaplikasian PCM dapat mengurangi suhu rata - rata ruangan sebesar 0,81℃. Suhu maksimum ruangan yang menggunakan PCM terletak di sekitar pintu, di mana tidak terdapat aktifitas penghuni. Sedangkan suhu minimum ruangan berPCM terletak di permukaan ruangan yang bersentuhan dengan PCM dan ditengah ruangan

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