Performance of Latent Heat Solar Thermal Energy Storage System Using Various Heat Transfer Fluids

2015 ◽  
Vol 787 ◽  
pp. 27-31
Author(s):  
M. Gajendiran ◽  
P.M. Sivaram ◽  
N. Nallusamy

In the present work the thermal performance of Phase Change Material (PCM) based solar thermal energy storage system under the influence of different heat transfer fluids (HTF) have been investigated. Water, Ethylene Glycol–water and Copper nanofluid are selected as HTF. Paraffin is used as PCM and encapsulated in cylindrical capsules. The thermal energy storage (TES) tank acts as a storage unit consisting PCM capsules packed in three beds surrounded by water, which acts as sensible heat storage (SHS) material. HTF circulated by a pump transfers heat from solar flat plate collector (FPC) to the TES tank. 25% ethylene glycol -75% water HTF is prepared by mixing ethylene glycol (EG) with water. Copper-distilled water nanofluids (0.3% by weight) are prepared using prolonged sonication with sodium dodecyl benzene sulphonate (SDBS) as the surfactant. Various performance parameters such as charging time, instantaneous heat stored, cumulative heat stored and system efficiency are studied for various HTFs. It is found that the charging time is reduced by 33.3% for copper nanofluid and 22.2% for ethylene glycol- water mixture HTFs. It is also observed that there is an increase in system efficiency and cumulative heat stored with reference to charging time for these HTFs when compared with conventional HTF 1 i.e. water.

Author(s):  
Saeed Tiari ◽  
Addison Hockins ◽  
Samantha Moretti

Abstract In the current study, the thermal characteristics of a latent heat thermal energy storage system enhanced with annular and radial fins are investigated experimentally. Rubitherm RT-55 is used as the phase change material (PCM) and is enclosed within a vertical cylindrical container. Water is used as the heat transfer fluid (HTF) which is circulated in a copper pipe that passes through the center of the container. The hot HTF is circulated through the system until the entire mass of solid PCM inside the container is melted. Twelve k-type thermocouples are inserted into the container at different levels to monitor the PCM temperature during the charging processes. A thermal imaging camera is used to take thermal images of the latent heat thermal energy system as it operates. The effects of different number of annular and radial fins attached to the central pipe on the thermal performance of the latent heat thermal energy storage system during the charging processes have been studied. It was found that the inclusion of 10 and 20 annular fins decreased the charging time by 79.5% and 82.8%, respectively. The two radial fin designs of 4 fins and 8 fins were assessed and found to decrease charging time by 81.9% and 86.6%, respectively.


2019 ◽  
Vol 7 (25) ◽  
pp. 15042-15047 ◽  
Author(s):  
Zhihang Wang ◽  
Raul Losantos ◽  
Diego Sampedro ◽  
Masa-aki Morikawa ◽  
Karl Börjesson ◽  
...  

Molecules capable of reversible storage of solar energy have recently attracted increasing interest. Here, a liquid azobenzene molecule has been studied for solar thermal energy storage applications and integrated into flow-chemistry devices.


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