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Hospitals with high energy consumption are among the places where cogeneration and trigeneration systems, called combined heat and power systems, should be applied. In this study, the applicability of cogeneration and trigeneration systems in a 276-bed university hospital in Kars was investigated. Due to the continuity of the electricity need and the high unit price, the system was selected according to the electricity need of the hospital. The planning of both systems has been designed in a way that will meet all the electricity needs and with the heating and cooling outputs resulting from this production, some of the heat needed by the hospital will be met. It has been determined that a net profit of 1,649,142 TL per year with the implementation of the cogeneration system and 1,661,105 TL per year with the trigeneration application will be made. The static payback period was calculated as 2.41 years in the cogeneration system, 3.86 years in the trigeneration system, and the dynamic payback period was calculated as 2.85 years for the cogeneration system and 3.13 years for the trigeneration system. As a result, it has been determined that both systems will benefit the hospitals in the regions with Kars climate characteristics, but it may be more advantageous to apply a cogeneration system for the hospital examined due to the high initial investment costs in trigeneration systems. [ABSTRACT FROM AUTHOR]

Surface temperatures of photovoltaic (PV) panels increase with solar radiation and ambient temperature. This temperature increase negatively affects the PV cell, causing the electrical efficiency of the system to decrease. Photovoltaic-thermal (PV/T) systems also provide thermal energy gain by cooling PV cells, increasing electrical conversion efficiency and lifespan. Integrating porous material into cooling pipes offers an important innovation in terms of the cooling techniques of PV panels. This study emphasizes the positive effects of porous materials by innovative approaches in this field. For this reason, in order to increase the electrical and thermal efficiency of PV cells, a porous material-supported cooling system was designed for the PV/T system and the effects of using porous materials with different properties were examined with Ansys Fluent software. As the porous density and porosity ratio of the porous material used throughout the pipe decreased, the average cell temperature decreased and the water outlet temperature increased. At a low flow rate of 0.3 L/min, it achieved an improvement of approximately 118% in thermal efficiency compared to the pipe without porous material. The porous structure containing 0.9 and 30 PPI pore density reached the highest efficiency value of 96.56% with a flow rate of 1.71 L/min. [ABSTRACT FROM AUTHOR]

In this study, the simulation of hydrogen production system demonstrated with electrolysis of water by hybrid solar collector. The mathematical model created by in accordance with the system flowchart. For this numerical study, three cities located in west, middle and east of Turkey, were considered which are Istanbul, Konya and Erzurum. Borland Delphi 7 programming language used for numerical analyses. The insolation and solar irradiance of these cities were taken into consideration and the values of the solar irradiance of the cities compared to each other. For each case, a simulation of the system made keeping temperature constant (373 K) and increasing the pressure up to 0.1 MPa and 0.5 MPa. In the other case, the pressure kept at constant (0.1 MPa), the temperature increased up to 573 K. It observed that City of Konya was quite convenient in terms of hydrogen and oxygen production compared to Istanbul and Erzurum, and the pressure had a very low effect on hydrogen and oxygen production; but the temperature is an important component in hydrogen and oxygen production system. The results for hydrogen production compared to literature and found a difference around 1.08%. [ABSTRACT FROM AUTHOR]

In this study, a semi-spherical porous metal matrix burner was developed for boiler combies and other combustion systems. Unlike the conventional ceramic porous medium, metal matrix has been used as porous medium. Experimental investigations on performance of the burner have been carried out. Burner was tested at four different flow rates (0,048 kg/s, 0,075 kg/s, 0,105 kg/s and 0,125 kg/s). Tests showed the temperature on the burner surface has reached up to 1174 K. Value of CO emission dropped under the limit values, and the value of 99,2% was obtained for the efficiency of combustion. As a result, because of excellent combustion, the emission values reduced, and the energy saving was obtained. [ABSTRACT FROM AUTHOR]

In this study, the waste heat loss of flue gases from the boilers of Kafkas University district heating system has been calculated between 6-8% according to the combustion analysis and the annual cost of this heat loss has been found as $58,658.79. In terms of energy efficiency and the national economy, we think that this lost energy should be recovered as much as possible and fuel and energy savings should be achieved. In the paper, the effects of variants such as air excess coefficient, flue gas temperature, boiler capacity and fuel consumption on the heat recovery from flue gas have been presented in detail. The heat recovery scenarios have been presented for reusing this waste energy for space heating, domestic hot water, and preheating combustion air and the applicability of these scenarios has been investigated in terms of thermodynamics and economics. According to the results of the study, in the second scenario examined to cover the domestic hot water need of the guest house building, the energy savings of the scenario can be provided during 20 years of economic life is $122,820.83, and it has the highest savings income among the scenarios. In addition, it is possible to recover approximately 50% of the flue gas loss with thanks to the scenario. On the other hand, the third scenario of heating the boiler combustion air with waste heat is the easiest and most economical scenario because its payback period is only one year, and there are no extra excavation and pipe costs. [ABSTRACT FROM AUTHOR]

Exhaust after treatment systems have become a necessity to eliminate pollutant emissions as required by standard. Nowadays, DOC and SCR are widely used after treatment technologies in diesel vehicles. In this experimental study carried on DOC and SCR systems, two different catalysts as Al 2 O 3 -TiO 2 /Fe 2 O 3 and Al 2 O 3 -Pt/Fe 2 O 3 were produced with impregnation method. The catalysts were characterized by Field Emission-Scanning Electron Microscope (FE-SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF) and Brauner–Emmett–Teller (BET). Each catalyst was tested as DOC and SCR in real working state to see the effect of catalyst on pollutant emissions in diesel engine. Results showed that the use catalysts as DOC led to significant decrease in CO, HC, NO and smoke emissions. The exhaust temperature rose up to 50 °C after DOC. The use of catalysts in SCR system eliminated NO x emission by high rates. Furthermore; the use of catalysts in emission control systems led to an increase in specific fuel consumption and a decrease in excess air coefficient of engine. [ABSTRACT FROM AUTHOR]