Advanced Energy Technologies
Negin Maftouni; Minoo Askari
Abstract
Both energy and environmental criticisms push a society toward energy-efficient buildings with green technologies. Green roofs are of significant importance due to their remarkable role in decreasing the thermal loads ofbuildings, especially in summer, and also in sound insulation. Here in, the thermal ...
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Both energy and environmental criticisms push a society toward energy-efficient buildings with green technologies. Green roofs are of significant importance due to their remarkable role in decreasing the thermal loads ofbuildings, especially in summer, and also in sound insulation. Here in, the thermal loads of a residential building were calculated, and then, an optimized green roof was designed for it in three different cities of Tehran, Rasht, and Tabriz. The energy saving was analyzed in each case, and proper plants and roof thickness were selected to achieve both comfortable air conditioning and energy optimization. It is also important to use water resources in an optimized manner. Considering the annual mean rain magnitude, here, a suitable system is designed to harvest rainwater for watering the plants. Results indicate that a sedum grass-based green roof with the thickness of 10 cm leads to a 21.3 % reduction in the annual total thermal loads in Tehran; one with thickness of 8 cm in Tabriz will result in a 11.7 % thermal load reduction per year; a green roof with 9 cm thickness in Rasht, Iran shows 13.2 % energy saving per year. Therefore, Tehran is the best option here to integrate the green roof into the structure of the building. The patterns of the obtained data indicate that the reduction of cooling loads is more noticeable when implementing a green roof in comparison with heating loads. Moreover, it has been revealed that harvested rainwater is sufficient to support about 72 % of required water in Tehran, 81 % of it in Tabriz, and 93 % in Rasht.
Renewable Energy Resources and Technologies
Negin Maftouni; Kiana Motaghedi
Abstract
Traditional fossil fuels, which are also depleting cause environmental problems. A significant portion of global energy consumption is due to building air conditioning systems. Nowadays, considerable attention is drawn to renewable and sustainable energy sources to support the energy requirements of ...
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Traditional fossil fuels, which are also depleting cause environmental problems. A significant portion of global energy consumption is due to building air conditioning systems. Nowadays, considerable attention is drawn to renewable and sustainable energy sources to support the energy requirements of buildings. In this study, a solar absorption chiller was designed for a three-floor residential building in hot and arid climate. At first, thermal loads in the building were calculated using Carrier software. The material and color of the exterior walls, as well as window types, were changed to reduce the heat transfer coefficient and get an optimum design. Results indicate that by using the optimum design, maximum heating load reduction and maximum cooling load reduction can be achieved with approximate rates of 37 % and 12 %, respectively. Considering safety factor and based on the maximum cooling load, a single-effect LiBr-water solar absorption chiller was designed for the optimum building. Two different scenarios were suggested using two types of flat plate and evacuated tube collector. Results show that in the case of evacuated tube collector the net collector area of 254.18 m2 is sufficient to supply the cooling power. Implementing flat plate collectors would result in occupying an area of 398.5 m2. Regarding the limitation of total area of roof and efficiency issues, the evacuated tube collector is the best option.