The characterization and porous structure of raw and modified clinoptilolite as a sorbent has been investigated by nitrogen adsorption, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, differential thermal analysis, scanning electron microscopy and atomic force microscopy methods. The nitrogen adsorption data revealed that the total pore volume and specific surface area were increased after modification. The nitrogen adsorption was used to determine percent of mesoporosity. The TG data show that 14 wt. % of clinoptilolite is lost after heating up to 1200 °C. Two types of porosities-primary porosity (microporosity) and secondary one (meso-and macroporosity) have been observed.

Abstract:The thermodynamic performance of a regenerative organic Rankine cycle that utilizes low temperature heat sources to facilitate the selection of proper organic working fluids is simulated. Thermodynamic models are used to investigate thermodynamic parameters such as output power, and energy efficiency of the ORC (Organic Rankine Cycle). In addition, the cost rate of electricity is examined with exergo-economic analysis. Nine working fluids are considered as part of the investigation to assess which yields the highest output power and exergy efficiency, within system constraints. Exergy efficiency and cost rate of electricity are used as objective functions for system optimization, and each fluid is assessed in terms of the optimal operating condition. The degree of superheat and the pressure ratio are independent variables in the optimization. R134a and iso-butane are found to exhibit the highest energy and exergy efficiencies, while they have output powers in between the systems using other working fluids. For a source temperature was equal to 120 °C, the exergy efficiencies for the systems using R134a and iso-butane are observed to be 19.6% and 20.3%, respectively. The largest exergy destructions occur in the boiler and the expander. The electricity cost rates for the system vary from 0.08 USD/kWh to 0.12 USD/kWh, depending on the fuel input cost, for the system using R134a as a working fluid. OPEN ACCESSSustainability 2015, 7 15363

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The graphene nanosheets (GNS) have been considered as a support for the synthesis of catalysts applied in various catalytic reactions. In this research, the hydrocracking (HCK) of n-hexadecane as a model component of the long chain paraffin was carried out using synthesized Ni-Mo/GNS and commercial Ni-Mo/Al2O3-SiO2 catalysts in a fixed-bed reactor. The physico-chemical properties of catalysts were determined using XRF, TEM, XRD, TGA and NH3-TPD analysis. The effect of support on the conversion and product distribution in HCK of n-hexadecane was investigated. The stability of the catalysts in the presence of water and coke deposition was examined for the HCK of nonconventional feeds. The obtained results revealed that the active metals were anchored on the functionalized GNS and the stability of Ni-Mo/GNS was significantly increased compared to commercial catalyst. The obtained results indicated that the GNS-supported catalysts have a higher potential for HCK of n-hexadecane in comparison to commercial Ni-Mo/ Al2O3-SiO2 catalysts.

Around the globe, developing countries have reported different cases of successfully implemented Renewable Energy (RE) program supported by bilateral or multilateral funding. In developing countries subsidy has played a big role in RE program marketing and whether this will lead to sustainable development is yet to be determined. The adoption of implementation strategies that will support sustainable development and overcoming barriers that hinder expansion of Renewable Energy Technologies (RETs) still remains as a big challenge to stakeholders involved in promotion of RE resources in developing countries. In this respect, developing countries need to reexamine their environmental policy for promotion of RETs in order to define its role in revitalization of their economies. This paper reviews the policy incentives for promotion of RETs in the Islamic Republic of Iran. Setting-up international collaborative business ventures between local industry in Iran and RE companies in developed countries is proposed as an implementation strategy that will appropriate diffusion of RETs in the country. An organizational framework that may help to attain this objective is discussed and a structural model for RE business partnership is presented. It is concluded that with appropriate policy formulations and strategies, RETs can bring about the required socioeconomic development in Iran.

In this research, a genetic algorithm has been used to optimize the focal area of the parabolic trough concentration photovoltaic/thermal. First, based on the physical and thermodynamic variables, the system modeling was performed; then, by changing the variables were calculated the effect of these parameters on the electrical and thermal efficiencies. In the next step, the optimization was conducted by the mentioned algorithms. The objective function consists of two targets of electrical efficiency combined with thermal efficiency. The optimization variables include the length of the system, the pipe diameter, the collector diameter, mass flow rate, and the photovoltaic cell width. After running the program in the normal mode, the highest electrical and thermal efficiencies were 0.2063 and 0.4473 for the length of 10 m, the collector diameter of 1.2 m, the flow rate of 0.15 kg/s, the pipe diameter of 0.03 m, and the photovoltaic cell width of 0.02 m. According to the genetic algorithm, the optimal answer for the total efficiency of this system is 0.84737.

Iran as an energy-rich country faces many challenges in the optimal utilization of its vast resources. High rates of population and economic growth, a generous subsidies program, and poor resource management have contributed to rapidly growing energy consumption and high energy intensity over the past decades. The continuing trend of rising energy consumption will bring about new challenges as it will shrink oil export revenues restraining economic activities.This calls for a study to explore alternative scenarios for the utilization of energy resources in Iran. In this study, we model demand for different types of energy in Iran using a technoeconomic or end-use approach and develop two business-as-usual and efficiency scenarios for the period 2005-2030.The results indicate that Iran has a huge potential for energy savings. Specifically, under the efficiency scenario, Iran will be able to reduce its energy consumption 40 percent by 2030.The energy intensity can also be reduced by about 60 percent to a level lower than the world average today. Furthermore, the energy savings under the efficiency scenario will generate significant additional revenues and will lead to a 45 percent reduction in CO 2 equivalent emissions by 2030 as compared to the BAU trend.

In this research, a parabolic trough concentrating photovoltaic thermal (CPVT) was used to provide the energy needed for a residential building. In order to do this, the required amount of heating and cooling and electrical energy was first obtained using Carrier software, then the electrical demand was obtained according to the standard model and governing relations. In the next step, the CPVT as a source of heat and cooling, and electrical energy for the building, was simulated in TRNSYS software. In order to achieve the highest reliability in terms of heat supply and reduction of thermal losses in the whole system, phase‐change material was used as a heat storage source. Mehrabad (Tehran) was considered as the target area in simulation. For this area the highest radiation intensity is 7.79 kWh/m2·day, which shows the potential of the region. The simulation results of the studied system showed that the highest output temperature and solar fraction for total load in building from CPVT was 150°C and 0.0.2926. © 2019 American Institute of Chemical Engineers Environ Prog, 38: e13220, 2019