Showing 4 results for Abravesh
Volume 6, Issue 4 (2016 2017)
Abstract
Mahdieh Abravesh, ,
Volume 12, Issue 3 (8-2012)
Abstract
The amount of energy consumption in a building is affected not only by the components’ performance, but also by the building envelope components’ installation method. The negligence of the good practice methodology can have a huge impact on the thermal bridges, increasing the average thermal transmittance up to 40%. In this paper, the thermal performance corresponding to different positions of the fixed frame, without sub-frame and with different sub-frame materials including wood and steel for double-glazed windows has been analyzed. Besides, in these cases, different configurations of thermal insulation has been considered. The evaluation of thermal bridges due to different models in a sample wall, insulated externally, has been carried out using THERM program. The linear heat transfer coefficient has been calculated for each model and the impact of each parameter on the thermal performance has been evaluated. The results show that the position of the frame, the sub-frame material and the configuration of the thermal insulation around the window frame affects considerably the thermal performance.
Mahdieh Abravesh, Behrouz Mohammad Kari, Shahin Heidari,
Volume 15, Issue 8 (10-2015)
Abstract
Considering the determinant role of glazing systems in energy consumption, it is imperative to survey the thermal performance of double coated glazing systems in accordance with the harsh climatic conditions and available local and foreign products' situation. In this paper, the radiative properties of local coated and non-coated glazing units are measured by the spectrophotometer and emissometer apparatus. These thermal and solar properties were not available in any datasheet. In the second step, through the accurate calculation method of EnergyPlus software, the amount of energy loss due to the radiative properties of glazing units was simulated in two extreme climates (very hot and humid climate and cold climate). By choosing the simulation method instead of real measurements in this step, it became possible to evaluate the effect of different parameters (such as climate, orientation and glazing specification) on the annual energy loss through the glazing units by eliminating other factors like energy transfer through opaque surfaces and ventilation. The simulation results indicate that using double glazing unit with low-E coating on the third surface (from the exterior) of the double glazing, significantly reduces energy consumption of the glass unit (up to 97 percent) for all orientations in the cold climate. In hot climates like Bandarabbas, using reflective coatings (with dark blue color) in double glazing units is the best possible alternative since it lessens the energy transfer through the glass unit (up to 70 percent) compared to the clear double glazed ones.
M. Akbari Paydar, B. Mohammad Kari, M. Maerefat, M. Abravesh,
Volume 19, Issue 6 (June 2019)
Abstract
The optimal insulation thickness is a function of the insulation initial cost and the cost of energy carriers for the internal space heating and cooling due to heat transfer from the wall. In Iran, by allocating subsidies to the energy sector, tariffs for energy carriers are sensibly lower than global prices. In order to determine the insulation optimal thickness, energy carrier tariffs were considered variable according to consumption. Electricity and gas costs were divided into 4 ascending tariffs for low, moderate, high, and very high consumption cases. In addition, the case of energy carriers without subsidies was also examined the 5 . The outer wall consists of a typical hollow with 20cm thickness, insulated with an expanded polystyrene layer, placed the outside. Heat load due to heat transfer from the external wall was calculated by using EnergyPlus simulation software in different geographical directions and different thermal insulation thicknesses in Tehran climate. The optimum insulation thickness was determined based on the total cost over the lifetime of 30 years. According to the results, in the first tariff, which refers to low-cost subscribers, the use of thermal insulation in some geographic directions does not allow the payback period over a lifetime. In other directions, economic savings are low and . For higher tariffs, the optimum insulation thickness increases. In the 2 5 , the thermal insulation thickness from 6 to 18 cm. Also, the calculated payback periods of these configurations are between 6 and 28 years.
