The heat transfer from walls has a significant role in the correct estimation of temperature distribution in order to investigate the thermal stresses and low cycle fatigue in the engine liner. Therefore, it is necessary to investigate the details of the flow and heat transfer over a wide range of engine operation in the design and exact simulation of the cooling jacket. An efficient approach to study the cooling system is to simulate using Computational Fluid Dynamics (CFD) as a three-dimensional model by simultaneously solving the structure and fluid, which leads to accurate prediction of wall temperature and heat flux. In the present paper, the distribution of heat transfer coefficients (HTC) in the cooling jacket of a 16-cylinder heavyduty diesel engine has been calculated, using ANSYS/Fluent based on 3D-CFD method. Also, equations of subcooled boiling phenomenon have been solved based on two commonly used patterns of Chen and BDL, and the effects of fluid pressure, velocity, and temperature at the time of the phenomenon of boiling on the heat transfer of cooling jacket wall have been studied. The results indicate that the best condition for a cooling jacket is when the coolant flow in critical heat points reaches to a velocity so that subcooled nucleate boiling occurs.

One of the main parameters of climate determinant in every region is “temperature”, that they estimate of needs will supplying by natural gas in cold season, that need to heating and cooling and it monthly and annual changes for household and on the other hand they climate classification is very important to calculation amount of natural gas consumption. In this research, mean total of HDD and CDD monthly, seasonal and annual in Guilan by using of HDD and CDD studiedly index according to temperature threshold between 18.3 to 23.9 oC calculation, drawing and were analyzed. Database included mean daily temperature and relative humidity for selected stations of Guilan during available statistical period. At first, from total of seasonal mean, present the total inaps of seasonal necessary energy, and from total of annual mean, the total maps of annual necessary energy, too. Then, the region has been classified from viewpoint of beating, cooling and humidity factor and finally, calculating the cost of heating climate classifying according to necessary natural gas of a standard unit.

Dwellings in rural areas of the developing countries do not have artificial systems of cooling or heating. These buildings, especially in hot-dry climate, are provided with natural cooling systems. Parameters which influence natural cooling of such buildings can be classified as (i) surrounding environmental factors and (ii) parameters associated with the buildings. Present paper describes influence of above parameters in providing natural cooling of residential buildings in general and in hot-dry climate in particular. These effects are supported by case studies of few residential buildings.          

The rapid development of gas distribution in Iran causes considerable dependence of consuming sectors on Natural Gas production .The share of South Pars Gas Field from the entire gas production in the end of sixth Five-Year Iranian Economic Plan will be over 62%. The pressure of reservoir gradually reduces and subsequently the volume of gas production declines in the production period due to the natural technical condition of South Pars reservoir. Installation of gas compressor platform is necessary in order to delay the reduction of the production. In spite of installation of these platforms, unofficial announcements indicate that production from South Pars field will decrease significantly in the twenty–year prospect and supply of new gas fields cannot compensate this reduction. Hence, in order to prevent gas shortage crisis in the coming years, it is required to predict some strategic actions and prioritize the supply of gas for new demand sectors. The "AHP" model has been applied to determine the priorities for this purpose. The relevant calculations have been carried out for solving the model by selecting a total of 8 options and 6 criteria by using the Expert Choice Software. The priorities of this study for each option are as follows respectively: Injection into Oil Reservoirs, Gas supply to Power Plants, Export, Feedstock for Petrochemical Units, Gas supply to Industries, Gas supply to Residential& Commercial, Transportation.

In this research, a combined cooling system of heating and electricity is proposed and a complete thermodynamic analysis is presented. The system includes a gas turbine, a heat cooling system, a cogeneration system and a hot water heat exchanger. The basis of the work is that by using the recovery of waste gases in the gas turbine can be generated by a steam turbine and, with the help of an absorption chiller, can recover the waste heat in the steam turbine and provide the required cooling. The cogeneration system saves energy consumption, and reduces environmental pollution. In this study, we have tried to increase the economic justification of using the cogeneration system under study by using up-to-date cost functions. The energy efficiency and exergy efficiency of the studied system are 20 and 21%, respectively, which is a reasonable amount. The results of the economic analysis show that with a total cost of $ 93.56 per second and a total investment and maintenance cost of $ 1732 per second, the proposed system is highly economical and profitable in practice. This may provide a new way to increase the efficiency and effectiveness of thermodynamic performance of cogeneration systems.

Turbine blades are one of the most sensitive and important hot parts of gas turbines, so that the efficiency and life of turbines are directly related to the operation of these components. Therefore, to prevent damage caused by high temperatures, they must be properly cooled. The common method of cooling these parts is to pass the cooling fluid through their complex internal channels. Nondestructive testing of thermography, is one of the new methods for detecting imperfections in these cooling paths which is considered in this article. Thermal loading is applied in an active manner by hot steam generator system. In order to identify the capability of this system in the detection of the residuals in the cooling system of blades, 3 kinds of different blades are studied and tested using active thermography. Results show the appropriateness of the system in detection of the blockages in all three blades. But it worth to notify that the success of the system is strongly related to the best detection of the system parameters as steam pressure, temperature and Fluid flow. So, the best parameters are chosen as: pressure of 2bars, ambient temperature of 25 oC and the maximum fluid of the hot steam.

According to the forecasts of reputable international centers, natural gas will play the most effective role in the future of world energy. Because Iran has one of the largest natural gas reserves in the world,This energy source can be considered as the main advantage of Iran in the domestic & international arena. In the meantime, one of the options facing the country is the export of this energy source. Considering that the export of natural gas, in addition to economic benefits, has many political-security benefits for the country,Determining the goals & scenarios for the advancement of natural gas exports has always been one of the main issues facing the country's energy sector. Target countries are interested in not limiting the source of their natural gas supply to fixed & specific sources,Therefore, they have long paid special attention to Iran. Therefore, it is important to study the future status of Iran's natural gas exports. The purpose of this study is to design scenarios for the country's natural gas exports until 2050 using the opinion of the elite & the method used in the research is a combination of the Delphi method & interaction analysis method. The three factors of Iran's isolation from the world trade & financial system, the political influence of powerful countries in the target country & the status of natural gas resources, their production & development in the target countries have been identified as key factors & based on future trends Three key effective factors, four compatible natural gas export scenarios were identified. Finally, after explaining each of these scenarios, policy recommendations have been made to achieve a favorable situation in Iran's natural gas exports.

Natural gas compressor stations in gas transmission industries cause to increase gas pressure and discharge to gas transmission pipeline. Air coolers in compressor station, have high electrical energy consumption and pressure drop. In this investigation, the application of heat pipe heat exchangers (HPHE) in a case study of the gas compressor station is evaluated to use instead of air coolers. The result of the investigation shows that applying 620 heat pipes with a 50% filling ratio, working fluid R134 and arranged triangularly, can reduce the compressed natural gas temperature. Energy performance analysis shows that using this method improves total, thermal, and electrical energy performance indicators (3%, 2.4 %, and 78%, respectively). Also simulating process demonstrate that using HPHE cause to save 1,115,000 SCM fuel in gas turbine and 3,800 MWh electrical saving in air coolers. In addition, results show with using HPHE 2,615,000 $ cost saving is available and project payback period value less than 1 year evaluated, and avoiding 1652 ton CO2 emission estimated annually.

The compressor inlet air cooling, especially in hot climates, has a significant effect on the power output augmentation of the gas turbines. The water consumption in evaporative cooling and fogging systems and power consumption and investment cost in vapor absorption and compression refrigeration systems are high. So, the purpose of this article is to investigate the possibility of using the night sky radiative cooling system for cooling the intake air of the compressor. In this method, the circulating water used to cool the intake air of the compressor, at night and in the exchange of radiation with the sky, is cooled using glassless flat plate collectors and returns to the storage tank for reuse on the next day. The effect of parameters such as the number and arrangement of collectors in series or parallel on the cooling capacity is investigated. Also, the required storage tank volume for returned water from collectors is calculated. The results show that the compressor’s intake air cooling for six hours a day needs a storage tank with a minimum capacity of 1000 m3. Also, by using 400 parallel collectors and a 1000 m3 storage tank, the power production increases by an average of 2 MWh.

The present sought to draw a comparison between Model Predictive Control performance and two other controllers named Simple PI and Selective PI in controlling large-scale natural gas transport networks. A nonlinear dynamic model of representative gas pipeline was derived from pipeline governing rules and simulated in SIMULINKâ environment of MATLABâ. Control schemes were designed to provide a suitable pressure at consumers’ nodes by varying the refinery production rate and compressor station output pressure in the middle of pipeline. The results showed that the model predictive control significantly outperformed the other two methods in economic controlling of pipeline by using less energy in compressor station and simultaneously rejecting disturbances. Although MPC controller performed better, it had a more complicated structure and difficult design procedure than PI controllers.