Numerical investigation on the convection heat transfer and drag reduction by utilizing the designed flow controlling blades on a smart sustainable house

Abstract

The development of the boundary layer leading to separation of the flow from the surface along with the formation of the wake regions dramatically increases the overall convective heat transfer coefficient and the exerted drag force on the body. Sustainable building designs are usually encountered with energy issues mainly related to heat loss through the facades due to convective heat transfer and aerodynamic loading problems on the structure due to severe drag forces on facades. Flow control has been demonstrated as a promising tool for reducing wake intensity and preventing flow separation in different areas of aerospace and mechanical engineering. This paper numerically investigates the feasibility and efficiency of utilizing a novel idea based on locating flow controlling blades (FCBs), designed by the Department of Building Aerodynamics of the Solar Decathlon China 2013 (SDC 2013) Team of Iran, in the periphery of the external facades of the house in order to control the external flow and make it more streamlined than the real case of wind around approximately cubic shaped houses, while the objective is to reduce the convection heat loss from the walls and drag force exerted on them. As a case study, the smart sustainable house (Shāremān) was designed by the RTEOPT (Research Team for Energy Optimization and Passive-house Technologies) and participated in the SDC 2013 held by the U.S. DOE and National Energy Administration of China is presented. A 2D incompressible steady computational fluid dynamics solver, based on the finite volume method in the available commercial software package Fluent, is employed, and wind directions varying from 0 to 330 are resolved. The numerical results show an average reduction of about 15.6% for convective heat transfer coefficient over 12 different conditions; also, a decrease of about 4.8% is observed for the pressure difference between the stagnation point and the opposing corresponding point behind the body of the house.