نشریه انرژی ایران
سال هجدهم شماره 2 (پیاپی 67، تابستان 1394)

The main issue of the study of solar energy potential which could be used for agro-food industrial consumption is the thermal efficiency modeling of these systems. A novel calculation algorithm based on steady state thermal analysis is presented for thermal performance study of a typical Flat Plate Solar Air Heater (FPSAH) in Urmia climate all the year around in 2009. Hence, the Urmia climate condition in 2009 was selected as work condition of FPSAH in modeling. The real and hourly data of ambient temperature and solar radiation which was recorded in Urmia airport meteorological station were used. The optimum tilt angles of FPSAH were applied in model. A calculating algorithm was developed for modeling and ran in MATLAB. The useful thermal gain, the thermal efficiency and the outlet temperature of FPSAH were considered as three parameters representing the thermal performance of a FPSAH. The result was presented as monthly averaged values at different radiation hour during the day, in the form of diagram and color counters. Some estimations of the extractable heat in different months of year, was achieved. This research results will be the first step of an optimized design and construction of a FPSAH supporting the real annual heat demand in Urmia climate.

In this article, for the purpose of developing energy efficiency in building, it is required to recognize key elements of success in optimization of energy consumption. Therefore, energy management system implemented according to international standard ISO 50001:2011 and all energy parameters in building measured through performing energy auditing. Then, while using energy auditing results, and measurement of energy consumption carriers as per bills and also distributing questionnaire and also interview with experts in order to Verification of energy auditing results, all effective factors in optimization of energy consumption are recognized. In the next stage, through modeling while using modern methods in data analysis, effective main factors in municipality buildings are identified. On the other side, influence portion and amount of each energy consumption elements in percent are recognized while using obtained results from energy auditing and measurement of all energy consuming parameters. As a Result, uncontrolled wall indexes, wall thickness, roof layer, window and net wall thickness as effective main variables in optimization of energy consumption in two parts of heating and cooling energies in buildings of municipality district 7 of Tehran city are recognized.

Among the mid term actions of National Strategy of Iran Fuel Cell Technology Development, is designing and manufacturing polymer fuel cell system with the power of 10KW. However, this measure was performed before the commencement of this period. This article presents, in separate chapters, the steps of designing, manufacturing and testing the components, stack and the system of a 10 KW PEMFC. Finally, the advantages of this sample will be investigated in comparison with the first system made in Iran with the capacity of 5KW.

Energy as one of the major issues of concern to human society in many countries and saving energy is important. Energy consumption in the country buildings as a non-productive part, are located the largest share among all consumer segments. A series of factors that determines the amount of energy consumption in buildings can be classified as follows: 1- Weather conditions and climate of building construction site. 2- Materials used on the external walls of the building. 3- Architectural and structural building. 4- Central Utility Building (heating, cooling, ventilation and lighting). 5- Consumer equipment (electrical appliances and office equipment). In this project I will audit a building in a given geographical conditions in terms of cooling load, In order compute Q refrigerating, then obtain the sensible colling load.

Developing energy estimation models is one of the most important steps in macro-planning for providing sustainable energy with the purpose of economic development and social welfare. Also, it has always been noted by energy policymakers and analysts. Residential and commercial sectors are the largest energy consumers in Iran and it is very important to estimate energy demand of the sectors. In the present study energy demand of residential and commercial sectors of Iran has been estimated using linear and exponential functions and the coefficients are obtained from genetic algorithm. 54 different scenarios with various inputs have been investigated. Data from the years 1968 to 2011 are used to develop models and select the suitable scenario. Results show that an exponential model with inputs including total value added minus that of the oil sector, value of made buildings, total number of households and consumer energy price index is the most suitable model. Using the selected scenario, energy demand of residential and commercial sectors is estimated up to the year 2032. The results show that the energy demand of the sectors will achieve a level of about 1180 million barrel of oil equivalent per year by 2023.

This paper reviews the performance of various fluids in a coupled power and refrigeration cycle has been studied.exergy is used to assessment and optimize the energy system with more detailed useful information than energy analysis.indeed exergy analysis includes implement the first and second thermodynamic rules, and analysis of Energy and exergy various fluid of coupled power and refrigeration cycle EES software is used in this article. R134a, R134a_mh, R12, R22 and R290 is the use of the working fluid in this paper. Based on the results, the most exergy efficiency and COP of the fluid is R290 and R12.

This paper presents a hierarchical control structure that has been applied to control the outlet oil temperature of solar parabolic trough plants. This should be achieved through changes in the field oil flow, non-manipulated energy source, the physical constraints of the system and multiple input disturbances such as solar radiation, inlet oil temperature and ambient temperature. These factors also are in the system model parameters that are changing constantly, so the system will be varying time. In lower layer for temperature control, the mathematical model is obtained by differential equations and then the model system being piecewise linear and finally linearization model is discretized and the linearization model is used based on the model predictive control method for control the temperature of the solar collectors. Another major challenges in solar power plants, regulate to reference temperature related to effective factors of the system is due enhancing the efficiency and reducing the human error. Therefore the fuzzy logic controller has been utilized for this purpose in the upper layer. The control algorithm is validated with real data taken from the Alice springs Airport station in springs (Australia). The simulation results show the performance of fuzzy logic in the creation of the reference temperature and model predictive controller in tracking the reference temperature.

This study examines the dynamic relationship between gas consumption (GC) and economic growth (EG) in Iran by using a multivariate model and including capital stock and labor as other explainatory variables for the period between 1972Q1 and 2012Q4. The results of the bound test demonstrate the presence of co-integration relationships among the variables. The estimated long-run impact of GC on EG is greater than other factor inputs suggest that energy is an important driver of production and growth in Iran. Furthermore, the results of causality test suggest that GC and EG are supplement. Given that GC is the most important source of energy in Iran, the entailment of this study is that gas conservation policies might harm growth and, therefore, the policy makers should improve the energy (gas) supply efficiency as well as formulate appropriate policies to attract foreign direct investment and establish private initiatives.