Numerical simulation of a combination of a new solar ventilator and geothermal heat exchanger for natural ventilation and space cooling

In this article, cooling and ventilating performance of the passive cooling system is investigated numerically. This system consists of a novel vertical solar chimney with fins and an earth-air heat exchanger to work as an alternative ventilation, and air-conditioning system during the summer in a hot and arid climate (Yazd, Iran). In this study, the RNG K-ε\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K-\varepsilon$$\end{document} turbulence model was utilized to simulate the internal fluid flow. Geometric parameters of the solar chimney such as its height, diameter, number of fins, the depth, length, and diameter of the Earth-air heat exchanger 's pipes were studied. The optimum geometry performance during different day times is also investigated numerically by ANSYS Fluent 18.2 on the hottest day of the year. Given the numerical study, the optimum geometry consists of (a) solar chimney with 6 m height, 1 m diameter, and 3 fins, and (b) Earth-air heat exchanger’s pipes with 7 m depth, 360 m length, and 0.2 m diameter. The best performance for the hottest day of the year reached at 14:00 when the indoor temperature experienced 295.07 K, solar chimney and Earth-air heat exchanger outlet temperature was 306.18 and 288.18 K, respectively. Besides, this system satisfied the ventilation requirements for laboratories and residential sectors and was able to save 85% of energy consumption at the best performance point.