The Impact of External Shading Design on the Building Energy Consumption
In this paper, the effect of an exterior shading element (Iwan) on energy consumption in four different climatic regions, and for different geographical directions, has been investigated numerically and experimentally. By applying different materials and techniques and creating various elements and spaces, architects make hard climatic conditions more tolerable for residents. Iwan is one of the cooling elements which is used in different forms and dimensions in the Islamic architecture. In the present research, Iwan has been introduced as a climatic element in traditional and contemporary architectures and its role in reducing the energy consumption in buildings has ben studied. In this respect, first, the thermal loads of a building without Iwan are computed by means of EnergyPlus software. Then, four different forms of Iwan are added to the abovementioned structure along the four principal geographical directions, and the effect of Iwan on the reduction of thermal loads is analyzed for four different climates. Finally, the design parameters of Iwan, in terms of depth and form, that can help reduce the thermal loads in different climatic conditions are presented. The results show that the best position for using an Iwan is the south direction and the use of Iwan in temperate & humid, hot & humid, cold & mountainous and hot & dry climates could reduce the energy consumption in buildings by 32%, 26%, 14%, and 29%, respectively.
An experimental and numerical investigation of Shovadan heating and cooling operation
Abstract Shovadan is the underground room which, for a long time, has been used in several areas of Iran for heating and cooling purposes. In the present work, Shovadan heating and cooling performance is experimentally investigated during a year. In the sample studied, when the ambient temperature is 7 °C in January and 47 °C in July, Shovadan average temperature is 17 °C and 23 °C, respectively. The suitable Shovadan temperature range proves the ability of this space in architecture optimization for saving energy. Next, in order to save time and cost to study more Shovadans in other locations, a three-dimensional model is simulated in real size. Then, Navier–Stokes and energy equations have been numerically solved and the temperature distribution within a Shovadan has been calculated. Numerical results are in good agreement with the experimental data. Finally, ventilation effectiveness was evaluated in the coldest and warmest months.
Thermotropic glass with active dimming control for solar shading and daylighting
The effectiveness of an autonomous responsive dimming (thermotropic) glass panel fabricated with a transparent heating layer and an electrochromic layer to provide additional active dimming control is examined through preliminary experiments and simulations. Thermotropic glass consists of two panes of glass sandwiching a polymer gel that undergoes a transition from clear to cloudy at a threshold temperature. Winter temperatures can thus prevent the glass from dimming when required for solar shading. With appropriate control of the heating layer, however, the performance of the panel with respect to office solar-shading requirements is demonstrated to be superior to that without the heating layer, despite the simplicity of the system. The configuration requires relatively low electric power, utilizing solar radiation energy to maintain the cloudy state as required. In a different approach, application of electrochromic layer for active dimming control is proposed and verified in various aspects with wavelength characteristics considering simulation.