Session: K6-04: HEAT TRANSFER IN ENERGY SYSTEMS - ENERGY STORAGE II

Paper Number: 131313

131313 - Numerical Analysis Comparing the Thermal Performance of Two Solar Chimneys Combined With Thermal Energy Storage Made of Phase Change Materials Embedded in a Metal Foam 

Abstract: 

A solar chimney is a solar system that finds application in various areas such as providing ventilation for thermal comfort, passive solar heating and cooling of buildings, solar energy drying, and electric power generation. It utilizes solar radiation to elevate the air temperature and takes advantage of the buoyancy of warm air to enhance the airflow within the system. Evaluating the thermal and fluid dynamic characteristics is crucial for designing an effective solar chimney, especially when incorporating a thermal energy storage system. Key parameters for the design include the dimensions of the cavity (height, width, and depth), the type of glazing, absorber specifications, and the presence of insulation or thermal mass. Additionally, external factors such as location, climate, and orientation can influence its performance.
This study presents a two-dimensional numerical investigation of a solar chimney integrated with a wall featuring a phase change material on the south facade of a building. The absorbing capacity wall is constructed using a phase change material and metal foam, and the chimney comprises a converging channel with a vertical absorbing wall and an inclined glass plate at a 2° angle. The chimney channel is 4.0 m with an inlet channel of 0.34 m, and an outlet section of 0.20 m. Four different positions of the absorbing capacity wall made as latent thermal energy storage are analysed to determine the optimal configuration for thermal performance. The thermal energy storage system is 2.0 m high in the first three configurations and is 4.0 m high in the last configuration. The numerical analysis involves a transient examination of a two-dimensional airflow model, employing the governing equations for natural convection in turbulent flow with the Boussinesq assumption and temperature-independent thermophysical properties expressed in terms of the k-ε turbulence model. The analysis is conducted using the finite volume method with the commercial code Ansys-Fluent. The investigation aims to assess the thermal and fluid dynamic behaviour of the solar chimney integrated with a latent thermal energy storage system, considering various thickness values for the phase change material. Simulations are carried out for the dates of June 21 and December 21, from sunrise to sunset, with two different composite phase change materials, namely paraffin wax with melting points of 31°C and 42°C embedded in aluminium foam. The location for the simulations is Aversa, Italy. Results include wall temperature distributions, air velocity and temperature fields, transversal profiles in the channel, liquid fractions, and stream function fields for the phase change material. The evaluation of thermal and fluid dynamic behaviours aims to provide insights for enhancing the energy conversion system and understanding the thermal differences between the different phase change materials with metal foam.

Presenting Author: Maria Rita Golia Università degli studi della Campania "Luigi Vanvitelli"

Presenting Author Biography: PhD student at Università degli studi della Campania "Luigi Vanvitelli". My research focus on Thermal Energy Storage Systems and Solar Chimney, with a specific emphasis on numerical simulations in the field of thermofluid dynamics.

Authors:

Bernardo Buonomo Università degli studi della Campania "Luigi Vanvitelli"
Tommaso Antonio Famoso Università degli studi della Campania "Luigi Vanvitelli"
Maria Rita Golia Università degli studi della Campania "Luigi Vanvitelli"
Oronzio Manca Università degli studi della Campania "Luigi Vanvitelli"
Sergio Nardini Università degli studi della Campania "Luigi Vanvitelli"
Renato Elpidio Plomitallo Università degli studi della Campania "Luigi Vanvitelli"