Reşat Selbaş

COMPARATIVE ANALYSIS OF NEURAL NETWORK AND NEURO-FUZZY SYSTEM FOR THERMODYNAMIC PROPERTIES OF REFRIGERANTS

Fast and simple determination of the thermodynamic properties of refrigerants is very important for analysis of vapor compression refrigeration systems. Although tables are available for refrigerants, limited data of tables are not useful in the simulation of refrigeration systems. The aim of this study is to determine the thermodynamic properties such as enthalpy, entropy, specific volume of the R413A, R417A, R422D, and R423A by means of the artificial neural networks (ANN) and adaptive neuro-fuzzy (ANFIS) system. The results of the ANN are compared with the ANFIS, in which the same data sets are used. The ANFIS model is slightly better than ANN. Therefore, instead of limited data as found in the literature, thermodynamic properties for every temperature and pressure value with the ANFIS are easily estimated.

Prediction of Thermodynamic and Thermophysical Properties of Carbon Dioxide

CO2 may be an important alternative refrigerant to hydrofluorocarbons in commercial refrigeration systems. CO2 is one of the few natural refrigerants that is neither flammable nor toxic. It is inexpensive, widely available, and does not affect the global environment as do many other refrigerants. In this study, alternative methods are presented using artificial neural networks and adaptive neurofuzzy inference systems to determine thermodynamic and thermophysical properties of CO2. The results of the artificial neural network model are compared with those of the adaptive neurofuzzy inference system model in which the same datasets are used. The artificial neural network model is much better than the adaptive neurofuzzy inference system model. A new formulation is presented for the determination of the thermodynamic and thermophysical properties of CO2. The results of this study show that the artificial neural network model is an excellent alternative method for the calculation of thermodynamic and thermop...

Environmental Impact Assessment of Electricity Production, A Case Study of Turkey

For at least the next few decades, fossil fuels will use for global energy demand and without a proper control atmospheric emissions. Therefore greenhouse gas (GHG) emissions continue to increase and pose even more serious problems for environment and also human health. Beyond this point, the combustion products of fossil fuels are the main cause of environmental issues such as acid rains, ozone depletion and global warming.

Chapter 2.17 – Design, Energy and Exergy Analyses of Linear Fresnel Reflector

Abstract Lighting, heating, transport, industrial output: without energy we would have none of these essential day-to-day services without which we and our businesses cannot function. Renewable energy refers to natural energy resource (solar, wind, biogas, tidal, geothermal, etc.) alternatives to fossil and nuclear fuels. All renewable energy sources like solar, wind, geothermal, hydropower, and wave and tidal power are forms of sustainable energy. Solar energy is the most important part of the renewable energy resources such that it is an essential building block for our future global sustainable energy system. Solar energy technologies are divided into two groups: photovoltaic power systems and thermal power systems. The linear Fresnel reflector (LFR) is a thermal power system. The LFR collects the suns rays through reflective surfaces and then transfers the energy to the fluid in the receiver located at the focal point. The heated fluid is provided with thermal energy conversion thanks to the LFR. It is converted to electrical energy from the thermal energy generated by various transducer equipment. In this chapter, we researched design and performance analysis of LFR. System efficiency has been shown to vary with design and incoming radiation intensity.

Enhanced exergy analysis of a waste heat powered ejector refrigeration system for different working fluids

Conventional and enhanced exergy analyses of a waste heat powered ejector refrigeration system using exhausted gas from rotary kiln were carried out. Isentropic (R290, R141b and R142b), wet (R134a and R152a) and dry fluids (R600a) were considered in the cycle in terms of avoidable-unavoidable parts of the exergy destruction to decide improvement potentials of the overall system. The results indicate a significant issue; the importance of component can change regarding refrigerant. The ejector comes into view as an important component to improve the overall cycle performance for R134a while the generator shows the best improvement potential for R600a.

Performance Analyses of CO 2 -N 2 O Cascade System for Cooling

The excess usage of many refrigerants which includes chlorofluorocarbons (CFC) and hydro chlorofluorocarbons (HCFC) in cooling systems causes several environmental issues such as acid rain, stratospheric ozone depletion and global climate change. Therefore, the usage of these refrigerants is restricted. In this context, an increase occurs in the usage of the alternative refrigerants.