نشریه فناوری های نوین در سیستم های انرژی
سال یکم شماره 1 (پیاپی 104، زمستان 1394)

In this study, the compression cooling cycle was simulated by EES software for the purpose of cooling at the hot climate regions of Iran. In these simulations, different compressors with different efficiencies were considered. The working fluid was R134a which is more compatible with the environment. The calculations were conducted for the compression cooling cycle and both the coefficient of performance (COP) and the consumption of electrical energy in the compressors were determined for a four-story building located at Bandar Abass with the construction area of 300m2. At the second step, the possibility of substitution of compression cooling cycle with a solar absorption cooling cycle was studied and the required surface of solar collectors to supply the required heat for the generator in the absorption chiller was calculated. The calculations showed that with the utilization of solar collectors with appropriate surfaces and supplying the required thermal energy for the absorption cooling cycle with the free of cost solar energy, it is possible to decrease the consumption of electrical energy for the cooling of buildings at the hot climate regions of Iran to zero.

Axial flow micro hydro turbines are suitable for use in a large percentage of micro hydro potentials in Iran. The turbine under the study is an axial flow micro hydro of Kaplan type, with its main shaft subtending 45 º to the line of horizon. However the turbine was originally designed to operate without any guide vanes but due to its low performance a number of guide blades were included to the original design and so the operating conditions of the turbine were improved. The turbine was tested according to standard turbine tests. In order to study the performance of the turbine all the standard performance curves such as the operating curves were constructed. Operating curves help determine the operating point of the turbine under certain heads and flow rates. This work consists of appraisal of the operating characteristics of the turbine including a comparative study of the operating points for various blades settings.

Energy consumption is one of the most important factors that reveals development situation of the countries. Management and optimization of energy consumption due to both conservation of energy resources and reduction of environmental pollution is also very important. In Iran Among the four major sectors of industry, agriculture, construction and transportation, energy consumption of buildings with the highest consumption accounted for about 42 percent. In this paper in order to optimize energy consumption, the impact of changes in effective parameters on heating and cooling load of buildings in the consumption and cost of electricity and fuel has been studied by HAP Carrier software. According to simulation results, the costs of electricity and fuel to the building by taking steps such as changing the internal design temperature within one degree Celsius, 7.7 and 3.4 percent , lower infiltration rate to zero, 2.6 and 18.6 percent, the use of 10 cm thick polystyrene insulation in roof and exterior walls, 4.5 and 15.3 percent, change from single-glazed windows to double with vinyl frame, 5.8 and 6.8 percent, using 20 cm thick leca blocks instead of 10.5 cm thick solid brick, 3.9 and 11.9 percent has been reduced. Also, reducing hot water output temperature from package to 10 degree Celsius reduces gas costs to 11.9 percent. The most appropriate orientation for achieving the lowest cost of electricity and fuel is when the biggest wall towards the north, use the package system and radiator and evaporative cooler would lower the cost of electricity and fuel as well. In addition, the simultaneous application of all proceedings, the annual cost of electricity and fuel is reduced to 21.1 and 40.7 % respectively.

In the present numerical study, the effect of inlet flow rate, equivalence ratio and inlet temperature are investigated on temperature, thermal efficiency and pollutant emission in the multi hole premixed burner. This burner is used in condensing boiler which is named premixed multi-hole flat flame burner. Due to decreasing of heat loss, Temperature increases by increasing of inlet flow rate. It caused to emitting more pollution from the burner. The maximum temperature is occurred in 0.9 equivalence ratio from interaction between reaction rate and heat loss from the burner. Increase of equivalence ratio to 0.9, causes increasing temperature and consequently NOx emissions from burner. An increase of equivalence ratio of 0.9, the temperature is reduced due to heat loss overcoming. On the other hand, CO Pollutant increases with increase of equivalence ratio. The effect of inlet temperature of fuel- air mixture is studied. It is observed, which by increasing of inlet temperature, pollutants (i.e. NOx and CO) and temperature is reduced. Finally, flow rate from 14.5 to 17.5 lit/s, range of 0.7 to 0.8 for equivalence ratio and inlet mixture with 400K are choosing the optimal operating range.

Using the energy of the high-temperature flows, one of the most effective ways to save the ‎energy in industries. In this paper, the technology of combined heat and power generation in the ‎cement industry was investigated. For this purpose, the thermal energy in the hot exhaust gases ‎from the furnace clinker was used. The results showed that when using the hot exhaust gases ‎from the furnace with a temperature of 570 C, 57.9 kJ/s works was done by turbine. In addition, ‎the temperature of the hot exhaust gases from the process reached to 100 C and this could be ‎used in heating purposes such as: production of hot water, space heating and dehumidification of ‎cement.‎

Nowadays, The hydrogen engines are widely used in machinery. Adding small and controllable amounts of the hydrogen in the main fuels such as gasoline can be used to complete the combustion, to produce higher efficiency and lower emissions. In this research, a four stroke SI engine operation is modeled using GMDH type of the neural networks and an evolutionary method to make the network structure, so that the percent of the hydrogen are added to the gasoline and then, the brake power and thermal efficiency of the engine are obtained as the functions of the engine speed and the fuel mass flow rate. Based on obtained results, these functions accurately evaluated the operation of the research engine. The modeling results also showed that the brake power has more dependency on the engine speed and the thermal efficiency has more dependency on the mass flow rate.