INVESTIGATING THE USE OF PHASE-CHANGE MATERIALS FOR TEMPERATURE CONTROL DURING FAST FILLING OF HYDROGEN CYLINDERS

Author(s):  
Vishagen Ramasamy ◽  
Edward S. Richardson ◽  
Philippa Reed ◽  
Warren Hepples ◽  
Andrew Wheeler
Fluids ◽  
2021 ◽  
Vol 6 (8) ◽  
pp. 275
Author(s):  
Ahmed J. Hamad

One essential utilization of phase change materials as energy storage materials is energy saving and temperature control in air conditioning and indirect solar air drying systems. This study presents an experimental investigation evaluating the characteristics and energy savings of multiple phase change materials subjected to internal flow in an air heating system during charging and discharging cycles. The experimental tests were conducted using a test rig consisting of two main parts, an air supply duct and a room model equipped with phase change materials (PCMs) placed in rectangular aluminum panels. Analysis of the results was based on three test cases: PCM1 (Paraffin wax) placed in the air duct was used alone in the first case; PCM2 (RT–42) placed in the room model was used alone in the second case; and in the third case, the two PCMs (PCM1 and PCM2) were used at the same time. The results revealed a significant improvement in the energy savings and room model temperature control for the air heating system incorporated with multiple PCMs compared with that of a single PCM. Complete melting during the charging cycle occurred at temperatures in the range of 57–60 °C for PCM1 and 38–43 °C for PCM2, respectively, thereby validating the reported PCMs’ melting–solidification results. Multiple PCMs maintained the room air temperature at the desired range of 35–45.2 °C in the air heating applications by minimizing the air temperature fluctuations. The augmentation in discharging time and improvement in the room model temperature using multiple PCMs were about 28.4% higher than those without the use of PCMs. The total energy saving using two PCMs was higher by about 29.5% and 46.7% compared with the use of PCM1 and PCM2, respectively. It can be concluded that multiple PCMs have revealed higher energy savings and thermal stability for the air heating system considered in the current study.


Author(s):  
Roberto Bubbico ◽  
Francesco D'Annibale ◽  
Barbara Mazzarotta ◽  
Carla Menale

Abstract Temperature control is one of the most significant factors to improve the performance and extend the cycle life of a battery. It is, therefore, important to design and implement an effective battery thermal management system (TMS). Phase change materials (PCMs) can be used as a cooling means for batteries. In the present paper, a preliminary analysis of the thermal behavior of PCMs used to cool down a heated metal surface was carried out. Tests have shown that pure PCMs are able to limit the temperature increase, but only for relatively low-heat fluxes. At higher values of the heat produced, the thermal conductivity of the PCM was increased by using solid foams characterized by higher thermal conductivity; it was, thus, possible to keep the surface temperature within safe limits for longer times. A computational fluid dynamics (CFD) model of the composite material (PCM + solid foam) was also developed, which allowed to predict the temperature trend within the system under different boundary conditions. However, the average thermal conductivity of the composite system that best fitted the experimental results was found to be much lower than that theoretically predicted by using common semiempirical correlations.


2021 ◽  
Vol 13 ◽  
Author(s):  
Seyed Mostapha Musavi ◽  
Ghodratollah Roudini ◽  
Farahnaz Barahuie ◽  
Siti Ujila Binti Masuri

Background: The utilization of high-performance phase change materials (PCMs) that can reversibly store thermal energy is of immense interest and strategy for effective energy conservation and management. Methods: In this work, a new PCM nanocomposite, consisting of a eutectic mixture of stearic acid and n-nonadecane as core and SiO2 as shell, was prepared by direct impregnation method. Additionally, a laboratory scaled test room was designed to investigate the intelligent temperature control function of the nanocomposite in building materials. Results: The optimized nanocomposite was characterized using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM) techniques. The DSC data demonstrated that the PCMs eutectic mixture content in the stearic acid- n-nonadecane–SiO2 nanocomposite was 52.8 wt.% and the melting temperatures and latent heats of stearic acid - n-nonadecane eutectic mixture and optimized nanocomposite were 45.1 and 44.0 °C, and 163.7 and 86.5 J/g, respectively. Furthermore, the accelerated thermal cycling test confirmed the excellent thermal cycling stability of the nanocomposite after 500 heating-cooling cycles. Moreover, the laboratory scaled test room results showed that the incorporation of the resulting nanocomposite in the gypsum could reduce indoor temperature fluctuation, and the performance was improved with the increase in the mass percentage of the nanocomposite in the gypsum composite. Conclusion: The obtained nanocomposite had good thermal reliability and temperature control performance and thus can be a promising candidate for hi-tech applications in intelligent temperature control and precise thermal management.


2013 ◽  
Vol 746 ◽  
pp. 161-166
Author(s):  
Tao Hu ◽  
Yan Li ◽  
Duo Su ◽  
Hai Xia Lv

Three thermal modeling methods for phase change materials (PCMs): enthalpy-based method, effective heat capacity method and apparent heat capacity method, are presented in details. Their characteristics and application limitations are compared and discussed. We found that enthalpy-based method and effective heat capacity method are both approximation treatments, and can be well used in steady state problems, while apparent heat capacity method tracks the moving phase change boundary in PCMs, and it is the most accurate and applicable method of the three for dealing with transient processes. This work might provide useful information for the study of using PCMs in temperature control field, especially in aircraft environmental temperature control and thermal management.


Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1623 ◽  
Author(s):  
Caixia Ren ◽  
Fangfang Liu ◽  
Malik Muhammad Umair ◽  
Xin Jin ◽  
Shufen Zhang ◽  
...  

Light-driven phase change materials (PCMs) have received significant attention due to their capacity to convert visible light into thermal energy, storing it as latent heat. However, continuous photo-thermal conversion can cause the PCMs to reach high thermal equilibrium temperatures after phase transition. In our study, a novel light-driven phase change material system with temperature-control properties was constructed using a thermochromic compound. Thermochromic phase change materials (TC-PCMs) were prepared by introducing 2-anilino-6-dibutylamino-3-methylfluoran (ODB-2) and bisphenol A (BPA) into 1-hexadecanol (1-HD) in various proportions. Photo-thermal conversion performance was investigated with solar radiation (low power of 0.09 W/cm2) and a xenon lamp (at a high power of 0.14 W/cm2). The TC-PCMs showed a low equilibrium temperature due to variations in absorbance. Specifically, the temperature of TC-PCM180 (ODB-2, bisphenol A and 1-HD ratio 1:2:180) could stabilize at 54 °C approximately. TC-PCMs exhibited reversibility and repeatability after 20 irradiation and cooling cycles.


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