Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
A CONSTRUCTAL DESIGN OF EARTH-AIR HEAT EXCHANGERS COMPOSED BY FOUR DUCTS
Submission Author:
Ruth Brum , RS
Co-Authors:
Liércio Isoldi, Jairo Ramalho, Luiz Alberto Oliveira Rocha, Elizaldo dos Santos
Presenter: Luiz Alberto Oliveira Rocha
doi://10.26678/ABCM.ENCIT2016.CIT2016-0168
Abstract
The Earth-Air Heat Exchangers (EAHE) systems offer an environmental friendly way to reduce the use of non-renewable energy for air conditioning by taking advantage of the thermal inertia of the ground, where the temperatures lag those on the surface, mainly in the summer and winter. For this, the EAHE make use of underground ducts where the ambient air is blown, to receive or lose part of its heat from/to the surrounding soil, and, finally, enter a building as conditioned air. Many works in the literature have focused in the thermal performance of EAHE composed by only one duct, and it is well known, for instance, that it can be improved to some extent by increasing the ducts size and/or reducing their diameter. However, to use the results of those papers, one needs to take the ducts far apart from each other, to avoid their mutual thermal influences. Taking a different approach, this article aims to explore new layouts to build EAHE with four ducts. Employing the constructal design method, this work presents as results the best spacings among the ducts in order to improve the heat transfer between soil and air, increasing the EAHE thermal potential. This is done varying the ratio between the vertical and horizontal spaces among the ducts, up to limiting global constraints, and using several simulations of the temperature fields in the ducts, with a verified and validated three-dimensional computational model.
Keywords
Constructal Design, Earth-Air Heat Exchangers (EAHE), Renewable Energy Devices, air conditioning
