scholarly journals The trend of using solar energy of a green intelligent building and thermal energy storage to reduce the energy intensity of the building

2021 ◽  
Vol 1209 (1) ◽  
pp. 012069
Author(s):  
M Gorás ◽  
Z Vranayová ◽  
F Vranay
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Intensity ◽  
Storage System ◽  
Storage Period ◽  
Storage Process ◽  
Intelligent Building ◽  
Operation Costs ◽  
System Power

Abstract The trend is to reduce the energy intensity of buildings. Thermal energy storage (TES) is the biggest challenge for buildings. It is a technology that supplies thermal energy by heating or cooling a tank, which then serves for the system in the building. Comparison of hitherto known systems ATES, BTES, PTES and research TTES. The most important factors for the accumulation of thermal energy are capacity (the energy stored in the system - depends on the storage process, the medium, and the size of the system), power (how fast the energy stored in the system can be discharged and charged), efficiency (the ratio of the energy provided to the user to the energy needed to charge the storage system. It accounts for the energy loss during the storage period and the charging/discharging cycle), storage (how long the energy is stored and lasts hours to months), charging and discharging (how much time is needed to charge or discharge the system), and cost (refers to capacity (€/kWh) or power (€/kW) of the TES system and depends on the capital and operation costs of the storage equipment and its lifetime).

Thermal Energy Storage Through Melting of a Commercial Phase Change Material in an Annulus with Radially Divergent Longitudinal Fins

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Operating Conditions ◽  
Melting Time ◽  
Bottom Part ◽  
Change Material

This study reports on the unsteady two-dimensional numerical investigations of melting of a paraffin wax (phase change material, PCM) which melts over a temperature range of 8.7oC. The PCM is placed inside a circular concentric horizontal-finned annulus for the storage of thermal energy. The inner tube is fitted with three radially diverging longitudinal fins strategically placed near the bottom part of the annulus to accelerate the melting process there. The developed CFD code used in Tabassum et al., 2018 is extended to incorporate the presence of fins. The numerical results show that the average Nusselt number over the inner tube surface, the total melt fraction, the total stored energy all increased at every time instant in the finned annulus compared to the annulus without fins. This is due to the fact that in the finned annulus, the fins at the lower part of the annulus promotes buoyancy-driven convection as opposed to the slow conduction melting that prevails at the bottom part of the plain annulus. Fins with two different heights have been considered. It is found that by extending the height of the fin to 50% of the annular gap about 33.05% more energy could be stored compared to the bare annulus at the melting time of 82.37 min for the identical operating conditions. The effects of fins with different heights on the temperature and streamfunction distributions are found to be different. The present study can provide some useful guidelines for achieving a better thermal energy storage system.

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