Sharif Digital Repository

Nowadays, cooling towers are widely used in power plants, refineries, petrochemicals and ventilation industries, but the water consumption of these towers is high and because of water crisis in Middle East and Iran, it is necessary to devise in order to reduce the water consumption of these towers. In this study separated hybrid cooling tower are used to investigate the water consumption at power plants. The rigorous Poppe method are used in order to estimate the exact amount of water loss due to evaporation in wet cooling towers. First, the effect of ambient condition, wet cooling tower cells and dry cooling tower size on the performance of hybrid cooling tower are investigated, then the... 

Hybrid Solid Oxide Fuel Cell-Micro Gas Turbine systems(SOFC-MGT) present opportunities for improvement over conventional systems, including high efficiency, cogeneration, and the potential for low carbon emmisions. In order to advance toward commercialization, Hybrid systems need to model under design point and off-design situations that maintain safe and efficient operations, also exhibiting favorable exergetic and economic performance. The present work investigates the hybrid SOFC-MGT performance and effects of steam injection, humidity effect, and fuel change in the system. The 1-D model of SOFC stack has been developed in EES Code and then coupled with a microturbine’s components with... 

Considering the increasing growth of population and the economical development in our country, the need to drinking water as well as agricultural water sources is felt more. In this respect and with regard to the lack of water sources in central and southern parts of our country, the present project suggests a system which can be used in south of the country to produce desalinated water from the salt water of sea. This system is recommended due to the comparative advantages of the southern part of the country including the prevalence of gas turbine plants, proper solar insulation and the access to salt water. The system is suggested with the presupposition of accessibility to a working gas... 

In the present study, for cost-effective brine elimination of desalination plants, a hybrid system consisting of a multiple-effect distillation unit and a humidification-dehumidification unit is proposed. The development process of the hybrid system was carried out in two main steps: 1) evaluation of electricity-driven and heat-driven humidification-dehumidification brine concentrators 2) redesigning the humidification-dehumidification unit according to the results of step one and hybridization the unit with a multiple-effect distillation system. All the steps are assessed using the energy, exergy, exergoeconomics, and exergoenvironmental tools.Among the three heat-driven and... 

According to Iran’s energy policies, the natural gas transmission pipeline has expanded significantly over the last decade. Moreover, improving energy efficiency is known as a key strategy in energy policies and programs. Therefore, the need for expansion and development of the rational use of energy has received more and more attention. The use of technologies aimed at energy recovery will be an effective step in this regard. Pressure regulators are most commonly used to reduce this pressure in Iran as one of the significant sources of exergy destruction in Iranian gas transmission system. The turbo-expander system is a kind of technology applied in gas pressure reduction stations to...