Solar energy is one of the renewable energy sources that has been in high demand in the last decades. With the increasing penetration of photovoltaic (PV) systems in around the world, accurate estimation of the power output of PV systems has become an important issue. Since PV systems directly convert sunlight into electrical energy, PV power output varies depending on environmental conditions. In order to deal with the periodic and non-stationary problems of PV output power, modelling methods are widely use for forecasting. The main purpose of this study is to lead an assessment of forecasting of the PV power outputs in short-time. For this purpose, data are obtained from experimental activities carried out on a real 250 kWp PV stystem, which is located in T.C Tekirdağ Namık Kemal University, Süleymanpaşa district of Tekirdağ province. All parametres are measured hourly with three times according to inclination of the panel setups (0˚, 30˚,60˚). In this sense, this study differs from the previously studies in literature, as it expands the forecasting model with considering of different panel angle. In the first stage, the significant variables for predicting PV power output are identified based on both correlation analysis and stepwise regression analysis. The findings are shown that solar radiation and angle of inclination of the panel are significant predictors of the generation of PV power. In the second stage, three different model are proposed based on Time Series Analysis (TSA) and Artificial Neural Network (ANN) approaches in order to predict power production of PV system. Furthermore, the accuracies of the models are analyzed in order to better understand the intrinsic errors caused and to evaluate its potential in energy forecasting applications. All models are compared in terms of the correlation coefficient (R), coefficient of determination (R2), mean absolute percentage error (MAPE). The results of analyses show that the ANN models have higher accuracy than the TSA model for forecasting PV power.

This research was carried out in farms which have 100 and more cows with commercial biogas production capacity, in 2019 in Tekirdağ. This is because it is stated that if the livestock enterprises have at least 100 animals, biogas production can be realized economically. The distribution and number of farms with this feature in districts were provided from Tekirdağ Food, Agriculture and Livestock Provincial Directorate. Biogas is generally used by converting it to heat and electrical energy. While it is used mostly for heating purposes in small farms, electricity and heat energy are provided in CHP units in large farms. Total methane production potential and energy value were calculated as 22466 Nm3day-1 and 81756.4 MWhyear-1, respectively. The highest methane production potential and energy value is in Muratlı district and the least is in Çerkezköy district. It was determined that 42512.48 MWhyear-1 useful heat energy and in CHP unit 28614.17 MWhyear-1 electricity energy and 19784.65 MWhyear-1additional heat energy could be obtained from methane produced by anaerobic fermentation. It is determined that 19067.56 tonsCO2eyear-1 of methane will be released if the manure is stored outdoors. It was determined that methane emission could be reduced by 1087.13 tons CO2eyear-1 if the nitrogen was used in fermentation residues instead of the chemical fertilizer. Total methane retention in the use of methane for heat purposes will be 31590.55 tons CO2eyear-1. Methane emissions will be reduced by 12522.99 tons CO2eyear-1 when used for heat purposes, than the conditions in which the manure is stored outdoors. When methane is used in the CHP unit to provide electricity and heat energy, total methane retention is calculated as 38467.6 tons CO2eyear-1, and the decrease in methane emission is calculated as 19400 tons CO2eyear-1. In animal husbandry enterprises that are located in Tekirdağ and are commercially producing, evaluation of manure without long-term storage by means of anaerobic digestion is important in terms of meeting of the energy requirement and reducing methane emission and the government should encourage enterprises in this regard.

As a result of the rapid decrease in fossil fuels and increasing energy demand, countries have turned to alternative energy sources. Renewable resources, which are alternative to fossil resources and are environmentally friendly, are clean and inexhaustible energy resources. Solar energy is one of these alternative energy sources This study; With the RetScreen program, it is aimed to analyze the suitability of the system and observe its performance before the PV system is installed. Features affecting the performance of PV systems; It has been designed by considering factors such as the position of the panel, the angle of inclination, shading and panel type. Shadow analysis was performed with the Helioscope program. In the shadow analysis, firstly, the geographical location is defined and the determined parameters are entered into the system. Technical, energy and economic analysis of the 14 kW solar system for the Ziraatbiyotek building was made. The analysis was made in 2 different scenarios and the positive and negative aspects of the solar system to be installed in the building were revealed. The Ziraatbiyotek building, where the study was carried out, was established in the Naip District of the Suleymanpasa district of Tekirdag province. For the Ziraatbiyotek laboratory building, 60 panels of the GES power plant with an area of 405 m(2) were used. The brand of the selected panel is Astronergy Solar and each has a power capacity of 240 W. The panel inclination is 30 degrees and the azimuth angle is 0 degrees in the RetScreen program. Polycrystalline was used as the panel type in two different scenarios. In the first scenario, emission reduction support was not included and the payback period of the system was 10.4 years, and in the other, $15 tCO(2)(-1) and annual support of $142 were included and the payback period of the system was 9.8 years. According to the results obtained with the program, 20.1 Wh energy produced by the solar panel system decreased 9.5 tCO(2) greenhouse gas emissions. It has been obtained that if a 14 kW solar energy system is installed in the Ziraatbiyotek building, approximately 40% of the annual electricity need will be met from solar energy.

Gasification is the process of obtaining syngas containing combustible gases such as H2, CO and small amounts of CH4 from biomass by performing partial combustion with a limited oxygen supply or with the help of suitable oxidants such as CO2 and water vapor. The efficiency of the gasification process is the most important parameter that determines the success of the system. In this study, the performance of the system in the gasification of palm pruning residues was evaluated by energy and exergy analysis methods. The gasification process was carried out at 7.6 Nm3/h and 10.2 Nm3/h air flow rates in the laboratory type fixed bed downdraft gasification unit manufactured in the Biosystems Engineering Department. The lower heating value of the syngas obtained as a result of gasification was found to be 4.09 MJ/Nm3 at 7.6 Nm3/h air flow rate and 3.76 MJ/Nm3 at 10.2 Nm3/h air flow rate. It has been observed that the lower heating value of the syngas is lower at high air flow rate. Energy efficiencies of the gasification system at 7.6 and 10.2 Nm3/h air flow rate were calculated as 47.6% and 52.8%, and exergy efficiencies were calculated as 43.7% and 48.1%, respectively. Exergy efficiencies were found to be lower than energy efficiencies in both air flow rates. However, as the air flow rate increased, the energy and exergy efficiencies also increased. The results obtained are similar to the results of previous studies on gasification of biomass.

In solar energy systems that use solar panels, it's important to know the best tilt angle to optimize solar energy production. Monthly, seasonal, and annual optimum tilt angles were determined in this study using meteorological insolation data from many years in the provinces of Tekirdag and Konya, which are located in different regions of Turkey. At optimum tilt angles, monthly, seasonal, and annual total radiation on the tilted surface were 1516.7 kWh m-2 year-1, 1504.1 kWh m-2 year-1 and 1448.1 kWh m-2 year-1 in Tekirdag, respectively. In Konya, these values were 1851.4 kWh m-2 year-1, 1833.51 kWh m-2 year-1 and kWh m-2 year-1, respectively. In the seasonal and annual optimum tilt angles, there was an approximately 1% and 5% loss in the total radiation values on the tilted surface, respectively, according to the monthly optimum tilt angle. In addition, the coefficients of the relationship between the monthly mean daily radiation on the tilted surface and the tilt angles were determined for each month using the cubic regression model in both provinces. The Cubic regression model coefficients are computed for each month in the provinces of Tekirdag and Konya. All months in both provinces had R2 (Coefficient of determination) values of 0.999 for the Cubic model. To determine whether there is a difference between the total amounts of radiation reaching the tilted surface for each month at the best tilt angles obtained by the two methods, the t-test was used. The monthly average daily radiation values on the tilted surface obtained by the two methods at the best tilt angles in both provinces have not been found to differ statistically (p>0.05; t=0.001).

Hasat – Harman Makinalarının Tarihsel GelişimiAbdullah SESSİZAhmet İNCE Bitki Yapısı ve Kesme MekaniğiAbdullah SESSİZBirol KAYIŞOĞLUYılmaz BAYHAN Kesme Düzenleri Ve MakinalarıAbdullah SESSİZDeniz YILMAZ Tahıl Hasat-Harman MakinalarıYılmaz BAYHAN BiçerdöverlerAbdullah SESSİZAhmet İNCEBirol KAYIŞOĞLU Pamuk Hasat MakinalarıAbdullah SESSİZAhmet İNCE Yerfıstığı Hasat ve Harmanlama MakinalarıAhmet İNCE Şeker Pancarı Hasat MakinalarıAbdullah SESSİZReşat ESGICI Tıbbi ve Aromatik Bitkiler Hasat MakinalarıDeniz YILMAZMehmet Emin GÖKDUMAN