A Numerical Analysis on a Solar Chimney With an Integrated Thermal Energy Storage With Phase Change Material

2021 ◽  
Author(s):  
Bernardo Buonomo ◽  
Lucia Capasso ◽  
Angelo Fatigati ◽  
Oronzio Manca ◽  
Sergio Nardini
2020 ◽  
Vol 197 ◽  
pp. 08001
Author(s):  
Bernardo Buonomo ◽  
Lucia Capasso ◽  
Oronzio Manca ◽  
Ferdinando Menale ◽  
Sergio Nardini

In this paper, a two-dimensional numerical investigation on a prototypal solar chimney system integrated with an absorbing capacity wall in a south facade of a building is presented. The capacity wall is composed of a high absorbing plate and an assigned thickness of phase change material in metal foam. The chimney consists of a converging channel with one vertical absorbing wall and the glass plate inclined of 2°. The channel height inside the chimney is equal to 4.0 m, whereas the channel gap is at the inlet equal to 0.34 m and at the outlet it is 0.20 m. The thermal energy storage system is 4.0 m high. The numerical analysis was intended to evaluate the thermal and fluid dynamic behaviors of the solar chimney integrated with a latent thermal energy storage system. The investigation has shown that in all cases PCM has not fully melted during the day and the presence of aluminum foam inside the box attenuates the variation of temperatures during the day. The results show that the three different thickness of the thermal storage system present very similar fluid dynamic and thermal behaviors. For the analyzed configurations, the phase change material does not reach a total melting during the considered day.


2017 ◽  
Vol 39 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Nima Bonyadi ◽  
Süleyman Kazım Sömek ◽  
Cemil Cihan Özalevli ◽  
Derek Baker ◽  
İlker Tarı

Author(s):  
Bernardo Buonomo ◽  
Lucia Capasso ◽  
Angelo Fatigati ◽  
Oronzio Manca ◽  
Sergio Nardini

Abstract In this paper, a two-dimensional numerical investigation on a prototypal solar chimney system integrated with an absorbing capacity wall in a south facade of a building is presented. The capacity wall is composed of a high absorbing plate and an assigned thickness of phase change material. The chimney consists of a converging channel with one vertical absorbing wall and the glass plate inclined of 2°. The chimney is 5.0 m high, with the channel height equal to 4.0 m, whereas the channel gap is at the inlet equal to 0.34 m and at the outlet it is 0.20 m. The thermal energy storage system is 4.0 m high with a paraffin wax. The transient analysis on a two-dimensional model in airflow is carried out and the governing equations for natural convection in turbulent flow with Boussinesq assumption and thermophysical properties temperature independent are given in terms of k-ε turbulence model. The problem is solved by means of the commercial code Ansys-Fluent using the finite volume method. The numerical analysis was intended to evaluate the thermal and fluid dynamic behavior of the solar chimney integrated with a latent thermal energy storage system for different values of the PCM thickness. The analysis is accomplished at the 21 June by the sunrise to sunset with the chimney oriented towards south. The simulations are performed considering the solar chimney located in Aversa, Italy. Results are given in terms of wall temperature distributions, air velocity and temperature fields and transversal profiles in the channel whereas in terms of liquid fractions, temperature and stream function fields for the phase change material. Thermal and fluid dynamics behaviors are evaluated in order to have some indications to improve the energy conversion system.


Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum

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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