Performance optimization of a photovoltaic/thermal collector using microencapsulated phase change slurry

2019 ◽  
Vol 44 (3) ◽  
pp. 1812-1827 ◽  
Author(s):  
Yuting Jia ◽  
Chuqiao Zhu ◽  
Guiyin Fang
Keyword(s):  
Phase Change ◽  
Performance Optimization

Thermal Performance Optimization of Shape Stabilized Phase Change Material Used in Building Envelopes

2017 ◽  
Vol 744 ◽  
pp. 201-206
Author(s):  
Yin Zhang ◽  
Ming Shan Zhang
Keyword(s):  
Thermal Comfort ◽  
Phase Change ◽  
Performance Optimization ◽  
Optimization Design ◽  
Phase Change Materials ◽  
Transfer Model ◽  
Building Envelopes ◽  
Practical Applications ◽  
Indoor Thermal Comfort ◽  
Heating Loads

Integrating phase change materials (PCM) with building envelopes is an effective way to reduce the cooling or heating loads, improve indoor thermal comfort and save building energy consumptions. In this paper, the heat transfer model of building envelopes with shape stabilized PCM is established and the optimal phase change temperature and enthalpy of PCM for internal walls are determined. Moreover, different PCM locations in external walls are compared based on the evaluation index of integrated uncomfortable degree. The results shows that to improve indoor thermal comfort, it is preferable to put the PCM in the middle of external wall. It also indicates that the overall integrated uncomfortable degree in a whole year decreases with increasing thickness of the inserted shape stabilized PCM plate. This work is of great significance in guiding the optimization design of building envelopes with PCM for practical applications.

Performance Optimization of Thermal Energy Storage Based Solar Collector

2021 ◽  
Author(s):  
Vivek R. Pawar ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Energy Storage ◽  
Phase I ◽  
Phase Change ◽  
Heat Pipe ◽  
Phase Ii ◽  
Performance Optimization ◽  
Solar Collector ◽  
Phase Change Materials ◽  
Normal Operation ◽  
On Demand

Abstract The application of solar collectors in water heating systems has attracted attention in recent years, however, due to the inconsistency of solar radiation, performance of such systems will fluctuate over time. In this study, performance optimization of a heat pipe evacuated tube solar collector integrated with phase change materials (PCMs), is investigated under normal and on-demand operations. In phase-I, the effect of heat pipe position and in phase-II, the effect of various PCMs are investigated. The results from phase-I show phase change process of PCM was expedited by 48 minutes under on-demand operation compared with conventional system. Additionally, in normal operation, thermal storage enhancement is achieved by 24% increase in PCM’s melting fraction. In Phase-II, the selected PCMs are tritriacontane paraffin, xylitol, and erythritol. In normal mode, the paraffin tube exhibited highest total energy storage of 295.39 kJ/kg, however, the fin temperature of xylitol tube was around 10° C higher compared with the other tubes throughout the day. In on-demand operation, erythritol tube shows energy storage of 413.15 kJ/kg, however, the paraffin tube shows fin temperature difference of 14°C compared with other tubes. Consequently, utilization of paraffin/xylitol in normal and paraffin/erythritol in on-demand operation is recommended to enhance system’s thermal performance.

Thermal Conductivity Measurements and Modeling of Phase-Change GST Materials

2007 ◽  
Author(s):  
Yizhang Yang ◽  
Taehee Jeong ◽  
Hendrik F. Hamann ◽  
Jimmy Zhu ◽  
Mehdi Asheghi
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Data Storage ◽  
Flash Memory ◽  
Performance Optimization ◽  
Phase Change Materials ◽  
Memory Cell ◽  
Data Access ◽  
Optical Recording ◽  
Access Time

Phase-change technology has been widely used in rewritable disks for optical recording applications. Recently, it has also received attention as a candidate for future high storage density non-volatile random access memory, due to its much longer cycle life (∼1013) and fast data access time (∼100ns) compared with the existing Flash memory technology. In this paper, we present thermal conductivity data and models for phase-change GeSbTe material that would be helpful in performance optimization and improvement in the reliability (i.e., enhancement of data rate, cyclability, control of mark-edge jitter) of phase-change-based data storage devices and systems. We perform the thermal characterization of Ge4Sb1Te5 and Ge2Sb2Te5 phase-change materials for the application of optical recording and phase-change memory cell using the techniques of thermoreflectance and electrical resistance thermometry. The limits of lattice and electronic thermal conductivities are investigated to determine their relative contributions as a function of tellurium concentration at different crystalline structures.

The effect of an aluminum heat-sink layer on the laser-induced amorphization of SiOx/TeGeSn/SiOx phase-change recording films

1989 ◽  
Vol 47 ◽  
pp. 574-575
Author(s):  
Matthew R. Libera ◽  
Martin Chen
Keyword(s):  
Thin Film ◽  
Phase Change ◽  
Heat Sink ◽  
Multilayer Film ◽  
Glassy Phase ◽  
Film Structure ◽  
Glass Forming ◽  
Active Storage ◽  
Dielectric Layers ◽  
Amorphous States

Phase-change erasable optical storage is based on the ability to switch a micron-sized region of a thin film between the crystalline and amorphous states using a diffraction-limited laser as a heat source. A bit of information can be represented as an amorphous spot on a crystalline background, and the two states can be optically identified by their different reflectivities. In a typical multilayer thin-film structure the active (storage) layer is sandwiched between one or more dielectric layers. The dielectric layers provide physical containment and act as a heat sink. A viable phase-change medium must be able to quench to the glassy phase after melting, and this requires proper tailoring of the thermal properties of the multilayer film. The present research studies one particular multilayer structure and shows the effect of an additional aluminum layer on the glass-forming ability.

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