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Binary geothermal power plants (GPP) always attract researchers' attention as they are renewable-energy operated, low-temperature, high-performance, environmentally-friendly, and baseload power plants. In addition, they need to be monitored, controlled and optimized due to their complex structure and functioning. This article presents the application of the Simulated Annealing (SA) algorithm for the thermodynamic performance optimization on the verified thermodynamic model of the SINEM GPP operating in Aydın, Turkey. This algorithm is also compared to the Gravitational Search Algorithm (GSA). By using these methods, 17 optimization parameters in the plant model are simultaneously optimized for maximum exergy efficiency. Study results show that the exergy analysis, gravitational search algorithm and simulated annealing algorithm respectively determined the exergy efficiency of the plant as 14.48%, 30.62%, and 38.49%. The SA algorithm has a better performance compared to the other two methods. System components such as condensers, vaporizers, and pumps are made more efficient using the SA algorithm. In addition, the most effective parameters of the plant are evaporator pressure differences and the mass flow of ORC's working fluid. By using GSA and SA algorithm, the gross electricity generation in the power plant can be increased by 2.11 MW and 3.15 MW, respectively. While GSA uses the procedure of reducing the amount of component exergy destruction, the SA algorithm uses the procedure of reducing the amount of electricity spent in the operation of the plant equipment. The rate of non-condensing gas (NCG) outlet, which is harmful to the environment, can be reduced by using SA algorithm. In this way, a power plant can be operated more economically and in a more environmentally friendly manner. • It is used a simulated annealing (SA) algorithm for maximizing performance of a real GPP. • A comprehensive research and real-world constraints are conducted for design and off-design. • Simulation programs (SA and GSA) are compared with each other for a parametric study. • The gross electricity generation in GPP is increased by 2.11 MW and 3.15 MW with GSA and SA. • The release of non-condensing gas (NCG) can be reduced by using SA algorithm. [ABSTRACT FROM AUTHOR]

• Exergy-based degree-hour (DH) method is supposed in predicting energy requirements. • It employs solar-air temperature, accounting for solar impact, not environmental temperature. • This method can be widely used across different climates and countries. • It is demonstrated practical benefits through a case study. • The exergy-based heating and cooling DHs enhances energy efficiency. This study presents an innovative exergy-based methodology to revolutionize the assessment of heating and cooling energy utilization, transcending the limitations of traditional heating and cooling degree-hours (HDH and CDH) analyses. The study's distinctiveness stems from its investigation into variations in HDH and CDH concerning critical parameters such as ambient temperature, solar-air temperature, solar absorptivity, surface emissivity, and total heat transfer coefficient. This fosters a profound comprehension of the thermodynamic performance of building heating and cooling systems, empowering decision-makers with the insights needed to optimize energy utilization effectively. As demonstrated through a case study conducted in Antalya, Turkey, this study uncovers significant findings. A mere 1 °C increase in ambient temperature results in an average 14 % surge in heating demand and an average 17 % decline in cooling demand, leading to a substantial 1000°-h discrepancy between heating and cooling requirements. Furthermore, we underscore the sensitivity of energy demand to temperature fluctuations, the substantial impact of design temperature on energy consumption, the notable influence of solar effects on environmental conditions, and the potential for optimization in parameters such as solar absorptivity, surface emissivity, and total heat transfer coefficient. These insights underscore the significance of exergy-based systems, offering heightened energy efficiency, swift adaptability to temperature changes, integration of renewable energy sources, and intelligent control features that contribute to sustainability and energy savings. [ABSTRACT FROM AUTHOR]

In the context of increasing awareness of climate change, the performance and environmental impacts (EIs) of heat exchangers (HEs) have become crucial. Traditional approaches have often overlooked the comprehensive evaluation of EI due to the absence of a universal criterion. Adressing this gap, this study introduces an innovative methodology for assessing both performance and EI in HEs, focusing on heat transfer and pressure drop across various types. The proposed methodology leverages exergoenvironmental analysis to optimize HEs handling liquid and gaseous fluids on both hot and cold sides with pumps and fans. Validation of this approach is conducted using experimental data from compact plate HEs (CPHEs) produced by additive manufacturing. The results highlight the influence of material choice on the EI of CPHEs, with a particular emphasis on the comparative significance of exergy destruction-related EI versus component-related EI. Notably, the EI on the cold side is consistently higher than that on the hot side. The study also delves into the role of pressure drop as a critical factor in HE enhancement techniques and discusses the variations in EI under different ambient conditions, inlet temperatures, and pressures. Consequently, this study presents a powerful model that serves as both an EI criterian and an optimization tool for HEs, offering valuable insights for environmentally conscious improvements in HE design and operation. • A novel methodology is proposed for environmental impact (EI) of heat exchangers (HEs). • The methodology is based on exergoenvironmental analysis combining exergy and LCA. • Compact plate HEs produced by additive manufacturing is an example application of it. • It successfully met the criteria in increasing performance and reducing EIs. • This determines optimum heat transfer and pressure drop for low EI on hot and cold side. [ABSTRACT FROM AUTHOR]

Highlights • It is focused on improving thermodynamic performance for a binary geothermal power plant. • An accurate modelled system simulating a real operating system is developed. • It is used the gravitational search algorithm to maximize its exergy efficiency. • System exergy efficiency can be maximized from 14% to 31% using gravitational search algorithm. • Thus, a more compatible operating strategy between system components is ensured. Abstract The limited energy resources globally, low efficiency of renewable energies, complicated and costly energy conversion systems and environmental pollution have significantly increased scholar's interest in innovative and efficient systems and their improvement studies. Therefore, it is necessary to increase the efficiency of power generation systems used in geothermal sources of medium or low enthalpy. This study aims to improve the thermodynamic performance of an existing binary geothermal system with organic Rankine cycle and its system components while trying to comprehend the physical events/changes during these improvement processes. A model has been developed that simulates the system completely and accurately. Seventeen system parameters which were considered as crucial to maximize the exergy efficiency of the system like turbine inlet, condenser temperature and so on, are optimized using a gravitational search algorithm. The results of the study show that the exergy efficiency of the system is 14% and thus it can be maximized to 31% with optimization. During the optimization process, the pressure of work fluid on the evaporator line is increased and thus 2.1 MW more power is produced compared to normal power production. The condenser, with the highest exergy destruction in the system, has performance improvements of 75%. As a result, with the optimization process, a more compatible operating strategy between system components is ensured. This will allow the system and its components to run for longer and without failures. [ABSTRACT FROM AUTHOR]

In this study, the thermodynamic performance of a binary geothermal power plant (GPP) is comparatively evaluated using the exergy analysis and optimization method. Thus, in addition to routes to improve the thermodynamic performance of the system, the thermodynamic relationships between the system components and improvement performances of the components are determined. With this aim, the Sinem GPP located in Aydın province in Turkey as a real system is selected. All data from the system are collected and a numerical model simulating the real system is developed. On the developed model, the conventional and advanced exergy analyses for exergy analysis and the artificial bee colony (ABC) method for optimization process are performed. The results of the study show that total exergy efficiencies of the conventional exergy analysis, advanced exergy analysis and artificial bee colony are determined as 39.1%, 43.1% and 42.8%, respectively. The exergy efficiency obtained from advanced exergy analysis is higher compared to the other two methods. This is due to the fact that theoretical and unavoidable operation assumptions in advanced exergy analysis are arbitrary as a single value depending on the decision maker. However, decision variables in the ABC method are within certain constraints chosen by the decision maker. It is better to select constraint limits instead of an arbitrary single value selection. Therefore, its arbitrary values should be confirmed with any optimization method. Additionally, the highest exergy destruction identified in the three methods is occurred in heat exchangers as the condenser and vaporizer. [ABSTRACT FROM AUTHOR]

Due to environmental and economic reasons, thermal energy saving has gained more importance especially in industry. This study is concerned with the application of insulation to improve thermal energy storage in spherical shaped containers positioned high above the ground. For this purpose, the thickness of the insulation applied to spherical containers of different diameters was optimized for convection and radiation heat transfer using life cycle cost analysis. In Turkey, the mechanism of storing the thermal energy of water at different temperatures in four different climatic conditions in Turkey (Ankara, Antalya, Erzurum, and Istanbul) in a container has been investigated. The results of the study show that the optimum insulation thickness and energy savings rise as the water storage temperature and the diameter of the container increase. While there is a 46% increase in the optimum insulation thickness for the vessel diameter from 0.5m to 3m in 20 °C water, a 69% increase is achieved in 100 °C water. Similarly, 85% and 114% increases were found for the optimum insulation thickness from 20 °C to 100 °C for 0.5m and 3m, respectively. In climates with the lowest heating degree-hours (Antalya), the highest energy savings are achieved with the lowest insulation thickness. To accurately determine seasonal storage heat load, a revised heating degree-hour method using hourly solar-air temperature data is recommended. This provides a 13% increase in energy savings. • With LCC, insulation subject in above-ground spherical container is investigated. • Heating degree-hour method is used to determine annual heat load of spherical container. • Insulated container is evaluated for different storage temperatures and climatic conditions. • The use of sun-air temperature instead of ambient temperature is more sensitive to heat load. • The study can draw a clear picture about insulation of above-ground container in storage processes. [ABSTRACT FROM AUTHOR]

Energy sources are of great importance in relation to pollution of the world. The use of renewable energy resources and the creation of more efficient energy systems make great contributions to the prevention of greenhouse gases. Recently, many studies indicate that the energy conversion systems have many advantages in terms of technical and economic point of view. In near future, environmental impact is going to play an important role in the selection/design of such energy resources and systems. In this study, the Afyon GDHS (geothermal district heating system) having actual operating conditions is investigated at the component level in terms of environmental impact by using exergoenvironmental analysis. Moreover, the effects of ambient and wellhead temperatures on the environmental impacts of the system are discussed. The results show that a great part of total environmental impact of the system occurs from the exergy destructions of the components. Therefore, the environmental impacts can be reduced by improving their exergetic efficiencies instead of design changes of the system components. The environmental impacts of the system are reduced when the ambient temperature decreases and the wellhead temperature increases. Thus, it might not be necessary to conduct separately the exergoenvironmental analysis for different ambient temperatures. [ABSTRACT FROM AUTHOR]

The energy saving and the environmental impacts’ reduction in the world building sector have gained great importance. Therefore, great efforts have been invested to create energy-saving green buildings. To do so, one of the many things to be done is the insulation of cylindrical pipes, canals and tanks. In the current study, the main focus is on the determination of the optimum insulation thickness of the pipes with varying diameters when different fuels are used. Therefore, through a new method combining exergy analysis and life cycle assessment, optimum insulation thickness of the pipes, total exergetic environmental impact, net saving and payback period were calculated. The effects of the insulation thickness on environmental and combustion parameters were analyzed in a detailed manner. The results revealed that optimum insulation thickness was affected by the temperature of the fuel when it enters into the combustion chamber, the temperature of the stack gas and the temperature of the combustion chamber. Under these optimum effects, the optimum insulation thickness of a 100 mm pipe was determined to be 55.7 cm, 57.2 cm and 59.3 cm for coal, natural gas and fuel–oil, respectively with the ratios of 76.32%, 81.84% and 84.04% net savings in the exergetic environmental impact. As the environmental impacts of the fuels and their products are bigger than those of the insulation material, the values of the optimum insulation thickness of the method used this study was found greater. Moreover, in the pipes with greater diameters, through the use of optimum insulation thickness, very high net savings and low payback periods were to be obtained. [ABSTRACT FROM AUTHOR]

As a result of decreasing fossil fuel resources and their adverse impacts on the environment, interest in renewable energy resources, particularly geothermal energy, has been revived. Finding approaches that are more accurate and systematic to the energy system development is of great importance for the exploitation of geothermal energy. The aim of this study was to carry out both conventional and advanced exergy analyses of an existing geothermal binary power system. In this way, in-depth information was collected about the exergy destroyed in the system and its parts. Through advanced analysis, it became possible to investigate the interactions between the system components and the actual performance of the reasonable improvements. The results show that the order of the primary improved components is CON 1, TURB 1 and VAP 2 for the conventional analysis and CON 1, CON 2 and PRE-HE 1 for the advanced analysis. The results of the advanced analysis were found to be more qualified than the results of the conventional one. The improvements made to the system, increased the modified exergy efficiency to 18.26%, while the total system efficiency was found to be 9.60% in the real conditions. [ABSTRACT FROM AUTHOR]

The fact that diffusion absorption refrigeration (DAR) systems can also work with low power plants has increased the interest in these cooling systems again. The DAR systems are mostly analyzed using energy analysis. Although, energy analysis is not adequate itself, so exergy analysis is required. In this study, the effects of nanofluid use on the DAR system performance are investigated by performing exergy and thermoeconomic analyses. Some nanoparticles like MgOAl 2 O 3 , ZnOAl 2 O 3 and TiO 2 in various weight ratios are used in the DAR system. In experiments with different nanoparticles, the effect of utilizing hybrid nanoparticles on enhancing system performance is also evaluated. The highest exergy destruction rate occurs in the solution heat exchanger, although the lowest exergy destruction rate happens in the condenser. The highest exergy efficiency with 0.798 is found in the base fluid (25% NH 3 –H 2 O). Besides, it is clearly observed that exergy efficiency decreased in the DAR systems using nanofluids. Moreover, the economic analysis of the DAR system is added to the study in order to evaluate the relationship between the exergy destruction rate and initial investment costs. It is found that the DAR system with ZnOAl 2 O 3 (2 wt%) is preferable compared to other DAR systems. • Exergy and thermoeconomic analyses of the DAR system with different nanoparticles is evaluated. • Performances of various DAR systems with different weight ratios comparies to each other. • The use of nanofluids in the DARs system reduces the exergy efficiency; however, they are more economical. • The largest part of the exergy destruction is in the solution heat exchanger and the rectifier. • With levelized cost of cooling, the DAR system with ZnOAl2O3 (2 wt%) is more preferable. [ABSTRACT FROM AUTHOR]

Highlights: [•] Comprehensive advanced exergoeconomic assessment of GDHSs for the first time. [•] Determining conventional exergoeconomic factor to be 5.53%. [•] Calculating modified exergoeconomic factor to be 9.49%. [•] Deducting inefficiencies of the system components for possible improvements. [ABSTRACT FROM AUTHOR]

Highlights: [•] Evaluation of a GDHS using advanced exergy-based methods. [•] Comparison of the results of the conventional and advanced exergy-based methods. [•] The modified exergetic efficiency and exergoeconomic factor are found as 45% and 13%. [•] Improvement and total cost-savings potentials are found to be 3% and 14%. [•] All the pumps have the highest improvement potential and total cost-savings potential. [Copyright &y& Elsevier]

Abstract: This study presents the exergoeconomic analysis and evaluation in order to provide cost based information and suggests possible locations/components in a GDHS (geothermal district heating system) for improving the cost effectiveness. The analysis is based on the SPECO (specific exergy costing) method, and used to calculate exergy-related parameters and display cost flows for all streams and components. As a real case study, the Afyon GDHS in Turkey is considered based on actual operational data. The obtained results show that the unit exergy cost of heat produced by the Afyon GDHS is calculated as average 5624 $/h. The HEX (heat exchanger)-III among all components should be improved quickly due to the high total operating cost rate and relative cost difference. The HEX-I and PM (pump)-V have the highest exergoeconomic factors among all other system components due to the high owning and operating costs of these components. The heat production costs per exergy unit for all the HEXs decrease due to the high exergy destruction cost rate of the system, while the well head temperature and ambient temperature increase. The SPECO method may be used to improve the cost effectiveness according to exergy rates in GDHSs as a thermal system. [Copyright &y& Elsevier]

Abstract: The exergy cost structure of the geothermal district heating system (GDHS) is investigated by using an exergoeconomic method called as the modified productive structure analysis (MOPSA). A parametric study is also conducted to show how exergy cost flow rates change with the reference state (ambient temperature). As a comprehensive case study, the Afyon GDHS in Afyonkarahisar, Turkey is considered. The actual thermal data taken from the technical staffs as 2.3°C for January (case 1) and 10.2°C for February (case 2), 2010 in 100% load condition are collected for this study. Mechanical and thermal exergy flow rates, entropy production rates and exergy cost flow rates for each component in the Afyon GDHS are calculated using these two actual data sets. The results show that the exergy efficiencies of the overall system for these two cases are found to be 25.34% and 22.78%, respectively. And, the largest exergy cost loss occurs in the heat exchangers with 52.49% and 64.91% for cases 1 and 2, respectively. The unit exergy costs are found as c P >c T >c S >c Q for the actual data sets in each case. In addition, ambient temperature has a big impact on the exergies and costs of GDHSs. [Copyright &y& Elsevier]

Highlights: [•] The ExEBCS for exergy efficiency maximization in real GDHS is economically evaluated. [•] The initial cost for ExEBCS is more expensive than that for old one by 6.33kUS$/year. [•] The cost saving makes the ExEBCS profitable by up to 7% of annual energy saving. [•] This results in a short payback period of 3.8years. [•] The use of newly ExEBCS in GDHSs is quite suitable. [ABSTRACT FROM AUTHOR]

Abstract: This paper comparatively evaluates exergy destructions of a geothermal district heating system (GDHS) using both conventional and advanced exergetic analysis methods to identify the potential for improvement and the interactions among the components. As a real case study, the Afyon GDHS in Afyonkarahisar, Turkey, is considered based on actual operational data. For the first time, advanced exergetic analysis is applied to the GDHSs, in which the exergy destruction rate within each component is split into unavoidable/avoidable and endogenous/exogenous parts. The results indicate that the interconnections among all the components are not very strong. Thus, one should focus on how to reduce the internal inefficiency (destruction) rates of the components. The highest priority for improvement in the advanced exergetic analysis is in the re-injection pump (PM-IX), while it is the heat exchanger (HEX-III) in the conventional analysis. In addition, there is a substantial influence on the overall system as the total avoidable exergy destruction rate of the heat exchanger (HEX-V) has the highest value. On the overall system basis, the value for the conventional exergetic efficiency is determined to be 29.29% while that for the modified exergetic efficiency is calculated to be 34.46% through improving the overall components. [Copyright &y& Elsevier]

Abstract: This study deals with an energetic and exergetic analysis as well as economic and environmental evaluations of Afyon geothermal district heating system (AGDHS) in Afyon, Turkey. In the analysis, actual system data are used to assess the district heating system performance, energy and exergy efficiencies, specific exergy index, exergetic improvement potential and exergy losses. And, for economic and environmental evaluations, actual data are obtained from the Technical Departments. The energy and exergy flow diagrams are clearly drawn to illustrate how much destructions/losses take place in addition to the inputs and outputs. For system performance analysis and improvement, both energy and exergy efficiencies of the overall AGDHS are determined to be 34.86% and 48.78%, respectively. The efficiency improvements in heat and power systems can help achieving energy security in an environmentally acceptable way by reducing the emissions that might otherwise occur. Present application has shown that in Turkey, geothermal energy is much cheaper than the other energy sources, like fossil fuels, and makes a significant contribution towards reducing the emissions of air pollution. [Copyright &y& Elsevier]

Abstract: This paper deals with an artificial neural network (ANN) modeling to predict the exergy efficiency of geothermal district heating system under a broad range of operating conditions. As a case study, the Afyonkarahisar geothermal district heating system (AGDHS) in Turkey is considered. The average daily actual thermal data acquired from the AGDHS in the 2009–2010 heating season are collected and employed for exergy analysis. An ANN modeling is developed based on backpropagation learning algorithm for predicting the exergy efficiency of the system according to parameters of the system, namely the ambient temperature, flow rate and well head temperature. Then, the recorded and calculated data conducted in the AGDHS at different dates are used for training the network. The results showed that the network yields a maximum correlation coefficient with minimum coefficient of variance and root mean square values. The results confirmed that the ANN modeling can be applied successfully and can provide high accuracy and reliability for predicting the exergy performance of geothermal district heating systems. [Copyright &y& Elsevier]

Abstract: This paper deals with determine the energy and exergy efficiencies and exergy destructions for thermal optimization of a geothermal district heating system by using artificial neural network (ANN) technique. As a comprehensive case study, the Afyonkarahisar geothermal district heating system (AGDHS) in Afyonkarahisar/Turkey is considered and its actual thermal data as of average weekly data are collected in heating seasons during the period 2006–2010 for ANN based monitoring and thermal optimization. The measured data and calculated values are used at the design of Levenberg-Marquardt (LM) based multi-layer perceptron (MLP) in Matlab program. The results of the study are described graphically. The results show that the developed model is found to quickly predict the thermal performance and exergy destructions of the AGDHS with good accuracy. In addition, two main factors play important roles in the thermal optimization: (i) ambient temperature and (ii) flow rates in energy distribution cycle of the AGDHS. Various cases are investigated to determine how to change the energy and exergy efficiencies of the AGDHS for the temperature and flow rate. Finally, a monitoring and performance evaluation of a geothermal district heating system and its components by ANN will reduce the losses and human involvement and make the system more effective and efficient. [Copyright &y& Elsevier]

Abstract: Energy consumptions in buildings can be reduced considerably using insulation materials. Even in well-insulated buildings energy consumption can be reduced further by insulating transmission pipes. For this reason, the energy savings can be obtained by using proper thickness of insulation in these areas. In this study, insulation thickness has been optimized by using exergy method and life-cycle cost concept for the case of using various fuels such as coal, natural gas and fuel–oil. This analysis is based on the exergetic cost of insulation materials and fuel. As a result, combustion parameters such as excess air, stack gas temperature, and combustion chamber parameters are much more effective on optimum insulation thickness. The optimum insulation thickness decreases with the increasing of inlet temperature of fuel, and with the decreasing of excess air coefficient, temperatures of stack gases and combustion chamber. Under this effects, the optimum insulation thicknesses determine as 0.065, 0.071, 0.099m with a rate of 68.27%, 71.54% and 77.85% in the exergetic saving for natural gas, coal and fuel–oil fuels, respectively. The optimum insulation thickness, total annual exergetic cost, exergy saving, and exergy losses depending on heat transfer increase with the increase of heating degree-days, while they decrease by increasing the temperature of outside air (reference state). In addition, the optimum insulation thickness for the exergoeconomic optimization is higher than that of energoeconomic optimization. [Copyright &y& Elsevier]

Abstract: The determination of optimum thickness of insulation is often applied to energy technologies and building projects. In this study, the energy, economic and environmental evaluations of thermal insulation in district heating pipeline are discussed. The optimum insulation thickness, energy saving over a lifetime of 10 years, payback period and emissions of CO2, CO and SO2 are calculated for nominal pipe sizes and fuel types based on heating loads in Afyonkarahisar/Turkey. The life cycle cost analysis is used to determine the optimum thickness of the pipeline material in order to take into account the change in inflation that directly affect both the cost of pipeline material and fuels depending on fuel type. The results show that the highest value of optimum insulation thickness, energy savings, emissions and the lowest payback period are reached for a nominal pipe size of 200 mm. About three times more energy saving results by making 200 mm nominal pipe instead of 50 mm. Considering the economical and environmental advantages, the geothermal energy is a better choice and then fuel-oil. When thermal insulation is done in a district heating pipeline, there will be a significant reduction of 21% in the amount of CO2 emitted to the atmosphere. [Copyright &y& Elsevier]

Abstract: In this study energy, exergy and exergoeconomic analysis of the Afyon geothermal district heating system (AGDHS) in Afyon, Turkey is performed through thermodynamic performances and thermo-economic assessments. In the analysis, actual system data are used to assess the district heating system performance, energy and exergy efficiencies, exergy losses and loss cost rates. Energy and exergy losses throughout the AGDHS are quantified and illustrated in the flow diagram. The energy and exergy efficiencies of the overall system are found to be 37.59% and 47.54%, respectively. The largest exergy loss occurs in the heat exchangers with 14.59% and then in the reinjection wells with 14.09%. Besides, thermo-economic evaluations of the AGDHS are given in table. Energy and exergy loss rates for the AGDHS are estimated to be 5.36kW/$ and 0.2 kW/$, respectively. [Copyright &y& Elsevier]

• It is focused on thermal insulation of residential- and population-sourced energy demands and emission in future. • The proposed new method can be extended to other cities around the world. • The carbon footprints will respectively be 233 kg/person-year with an increase of 44% for coal of Ankara city in 2040. • The sulfur dioxide amount is 0.460 kg/year for a 41% increase in coal use in 2040. • The study can draw a clear picture for policy makers concerned about the future of the world. This study predicts the effect of insulation thickness on residential- and population-sourced energy demands and emission amounts in the future with a new method. Attempts are made to determine the future population increase amounts with the graphic method for 2018-2040. The current population of 5,600,386 in Ankara/Turkey is predicted to rise to 8,043,717 people in 2040. Additionally, the number of residences is predicted to be 1,608,743 and wall area will be 160,874,330 m2. The total annual carbon dioxide amount for natural gas, coal and fuel oil is estimated to reach 916,179,309 kg/year, 1,304,690,816 kg/year, and 1,818,523,426 kg/year with 44% increase from 2018 to 2040, respectively. In 2018, the city-based heading period carbon footprints (CBHPCF) are 113.9, 162.2 and 226 kg/person-year for natural gas, coal and fuel oil, respectively. It is calculated that the CBHPCF will respectively be 163.56, 232.92 and 324.54 kg/person-year for the three fuels in 2040. The city-based heating period sulfur dioxide amount is estimated to be 0.460 kg/year for coal and 1,751 kg/person for fuel oil in 2040. Thus, the study can provide a clear picture for policy makers concerned about the future of the world. [ABSTRACT FROM AUTHOR]

In this study, advanced exergoeconomic analysis is performed for a gas turbine cycle located in Inchon/South Korea. In addition, an approach combining advanced exergy analysis with modified productive structure analysis is applied to the system and the results are compared. Both methods showed that higher part of exergy destruction cost rate for overall system was unavoidable. The investment cost rate of system equipment was also unavoidable. Avoidable exergy destruction cost rate was higher than unavoidable part only for gas turbine. The exergy destruction cost rates obtained with approach are considerably lower than the results obtained with the advanced exergoeconomic analysis. This situation affected the strategies developed to obtain a cost-effective system for gas turbine. Advanced exergoeconomic analysis proposed reducing the exergy destruction cost rate for gas turbine. However, for gas turbine, the approach proposed reducing the investment cost rate. The sum of exergy destruction cost rate of system equipment was higher than that of overall system in advanced exergoeconomic analysis. However, the exergy destruction cost rate of overall system was equal to the sum of exergy destruction cost rate of system equipment in the approach. Finally, it can be concluded that the results obtained with the approach were more compatible. • Advanced exergoeconomic analysis was performed on gas turbine cycle. • MOPSA method was combined with advanced exergy analysis. • The method using MOPSA provided considerably lower exergy destruction cost rates. • Both methods pointed out to the same equipment for system modification. [ABSTRACT FROM AUTHOR]

• The effect of lightning strike on PV arrays were investigated with simulation. • Three parameters, PV array number, cable sectional area and cable length were changed. • Real data was taken from the solar power plant was used in simulation study. Solar power plants are installed in high and open places to receive high solar radiation. However, this leaves them vulnerable to lightning strike. Lightning strike affects power plants in two ways, directly and indirectly. Direct lightning strikes can be prevented by using lightning protection systems. However, under the indirect effect of a lightning strike, the surrounding electronic devices may be damaged due to the induced voltage. In a solar power plant with a lightning protection system in Turkey, it was stated that the bypass diodes failed after a lightning strike. In this study, it is aimed to examine the effects of indirect lightning strike on the PV module. For this reason, different lightning pulse amplitudes were injected into the system and the effects of three parameters on the induced voltage were investigated with an EMT type program. These parameters were the cable lengths, cable cross-sections and the number of PV arrays. Four different panel configurations were performed in the EMT type program. Data was taken from the solar power plant in Turkey was used in fourth configuration. It was concluded that when the lightning strike fell on the air termination bar, bypass diodes in the nearest PV array were affected, and this effect decreased as the array distance increased. However, as the amplitude of the lightning strike increased, arrays in the far-distance were also affected. It has been seen that the results obtained were compatible with the malfunction information received from the solar power plant. [ABSTRACT FROM AUTHOR]

Geothermal driven power plants (GPPs) with two-stage ORC are mostly used in low-temperature geothermal fields around the World. The environmental impacts of these GPPs create a gap in the literature. In this study, enhanced exergo-environmental analysis for the GPP and its components is conducted as a case study. With the analysis, the component-related, exergy degradation-related, and pollution formation-related environmental impacts (EIs) are separated endogenous/exogenous and avoidable/unavoidable parts. In this way, detailed information about the interaction and improvement potential between components is acquired by using the recommended performance indicators. The results of the study show that for the enhanced exergo-environmental analysis, EI related to exergy destruction of components is predominated. In the traditional exergo-environmental analysis the total amount of EI is condenser with 1.386 Pt/h while in the enhanced one the highest avoidable-endogenous exergy destruction is condenser with 716 Pt/h. The value of EI which is caused by electricity generation is 0.108 Pts/kWh. The EI value of geothermal fluid is 11.8 Pt/GJ. The EI value of the plant's avoidable-endogenous pollution formation is 8 Pt/h. As the reason for this, the mass flow rate of the geothermal fluid steam and the amount of NCG gas in it are effective. Eventually, if the plant could be operated under enhanced analysis' operation conditions, the EI of released CO 2 value can be reduced by 8.4% by carbon capture and storage. Thus, the details of the analyzes performed for the plant are expected to guide the researchers. • Enhanced exergo-environmental analysis is conducted for geothermal driven power plant (GPP) with dual-loop ORC. • The study splits equipment-related, exergy destruction-related and pollution formation-related environmental impacts (EIs). • EIs of generated electricity, geothermal fluid and NCG (CO2) release for the GPP are investigated in detail. • The GPP has more EI of 0.108 Pts/kWh (0.099 Pts/kWh of enhanced one) than that of 0.061 Pts/kWh in Greece. • Compared to the traditional analysis, the EI of NCG release for the enhanced analysis can diminish by 8.4%. [ABSTRACT FROM AUTHOR]

Abstract Since the industrial revolution to nowadays, many waste gases have been produced in iron-steel facilities. These gases increased the amount of energy consumption and risky by CO 2 emissions. For these reasons, the useful waste gases, energy saving and decreased emissions technology are made. In this study, a collection of real operating data has been performed in an existing steam power plant using the useful waste gas that has occurred in iron and steel production facilities according to their nature, traditional and enhanced exergy analyses of it. The thermodynamic performance of the system is evaluated by improvement potential of the system components and by the interaction between the components. Useful waste gases produced in the facility consist of blast furnace gas, coke oven gas and converter gas. These gases are used for boosting the pressure and temperature of the circulation water by means of the heat of the exhaust gas produced by burning them at the steam-powered Rankine cycle's boiler and its subcomponents. The results of the study showed that the traditional and the enhanced exergy efficiencies of the system are respectively 60.7% and 83.7%. Potential improvement of the system and the interaction between the components are determined as 24.8% (low) and 74.5% (high). System components with improvement priority are condenser; combustion chamber, turbine, first super-heater and economizer at the traditional exergy analysis; whereas a combustion chamber, turbine, first super-heater, economizer and second super-heater at the enhanced exergy analysis. Thus, as a similar result to those for all conversion thermal systems, combustion chamber is a component that always needs to be improved. Highlights • It is focused to thermodynamic performance of a waste gas-fired steam power plant in iron-steel facilities. • The traditional and enhanced exergy analyses are performed using actual system data. • The potential to improvement and the interaction between components are evaluated for the first time. • Their values are determined as 24.8% and 74.5%, respectively, and thus there is no urgency to improve the system. • Exergy efficiency is found as 60.7% and 83.7% for the traditional and enhanced exergy analyses. [ABSTRACT FROM AUTHOR]

This paper presents a comparison between empirical models in the literature and the development of new models for estimating global solar radiation on the horizontal surface in the city of Muğla/Turkey. The necessary meteorological data are collected using a Kipp and Zonen pyranometer installed at the University Campus of the Muğla Sıtkı Koçman University and the records are available from 2007 to 2015, inclusive. In total 105 literature models are assessed to estimate global solar radiation in the Muğla Province using MATLAB software program on the basis of statistical tests such as mean bias error (MBE), mean percentage error (MPE), mean absolute percentage error (MAPE), mean absolute bias error (MABE), root mean squared error (RMSE) and coefficient of determination (R 2 ). The results indicate that only two models (Veeran and Kumar/model 24, Chegaar and Chibani/model 35) are within the ±10% acceptable statistical error limits. In this paper, 7 new models are calibrated in the same manner leading to less than 0.8 error values as high R 2 values. In order to reduce the error values of these models data sets are divided into two semesters (January–June and July–December). In addition, Benson's model is investigated and compared with the previous models. Finally, it is found that the cubic and quadratic models are appropriate for January–June and July–December periods, respectively. [ABSTRACT FROM AUTHOR]

In this study, a coal-fired stoker boiler and a beta-type rhombic-drive Stirling engine were manufactured and tested. The performance of the coal boiler with a Stirling engine has been investigated experimentally for the heating system of a three-storey house. The aims of this study are to investigate the Stirling engine's electricity generation potential and thermal energy production. Also, energy and exergy analyses of the micro-CHP system were performed to evaluate thermodynamic performance. Measurements were taken at 10-min intervals for three months. Thus, the temperature values, thermal power, thermal performance, efficiency, energy rates, exergy rates, and electrical parameters of the micro-CHP system can be monitored. The heating demand of the building was covered totally by the micro-CHP system, and the thermal power of the stoker boiler was reduced by approximately 1.29 kW due to the integration of the Stirling engine. The daily total of 2.6 kWh of electricity was generated with the Stirling engine and stored in the battery, and the rest of the electrical energy demand was taken from the grid. If the heating system is supported by PV, it can be operated off-grid. This study will provide insight into the usage of micro-CHP systems in residential applications. • An experimental set up of a coal-fired boiler with a Stirling engine for heating. • The analysis is based on long-term real-time measurements in a district heating. • Performance analysis with and without the Stirling engine. • Investigation of the electricity production potential of the Stirling engine. [ABSTRACT FROM AUTHOR]

This article reports the effects of air gap on insulation thickness and life cycle costs for different diameter steel pipes. The life cycle cost analysis based on heat degree days is used as a calculation method. Under climatic conditions in Afyonkarahisar, Turkey, using several fuel types and various insulation materials, the annual total costs, energy saving and payback period are evaluated for the insulation of different diameter pipes and also for use of an air gap. The results show that under all conditions, the lowest optimum insulation thickness was found for natural gas and XPS insulation material. Considering all variable parameters in the analysis, optimum insulation thickness, energy cost savings and payback periods for all air gap values varied within the intervals 0.3–25 cm, 20 to 423 $/m-yr and 0.8–2.2 years, respectively. In conclusion, in terms of the effect of air gap on insulation thickness and life cycle costs, for small diameter pipes air gap is effective, whereas for large diameter pipes the insulation thickness plays significant role. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to quantitatively evaluate thermodynamic performance of a geothermal power plant (GPP) from potential for improvement point of view. Thus, sources of inefficiency and irreversibilities can be determined through exergy analysis. The advanced exergy analysis is more appropriate to determine real potential for thermodynamic improvements of the system by splitting exergy destruction into unavoidable and avoidable portions. The performance critical components and the potential for exergy efficiency improvement of a GPP were determined by means of the advanced exergy analysis. This plant is the Bereket GPP in Denizli/Turkey as a current operating system. The results show that the avoidable portion of exergy destruction in all components except for the turbines is higher than the unavoidable value. Therefore, much can be made to lessen the irreversibilities for components of the Bereket GPP. The total exergy efficiency of the system is found to be 9.60%. Its efficiency can be increased up to 15.40% by making improvements in the overall components. Although the heat exchangers had lower exergy and modified exergy efficiencies, their exergy improvement potentials were high. Finally, in the plant, the old technology is believed to be one of the main reasons for low efficiencies. [ABSTRACT FROM AUTHOR]

The plate heat exchanger (PHE) is an important component for parameters such as size, weight, high temperature and high pressure in many nanotechnological applications. Improving the thermo-hydraulic performance of PHEs along with technological developments are among the major challenges. The performance of PHEs can be improved by design, fabrication according to design, and the use of nanofluids. This causes economic problems. However, it can be compensated by improving the performance. In this study, inspired by fish gill shapes, fish gill grooves are designed on the plate surface of a PHE. This is a compact PHE that can be produced by additive manufacturing. It is compared to the performance of commercial Chevron angled PHE to verify the performance improvement under the same conditions. In addition, 0.5 vol% and 1 vol% concentrations of Cu and Al 2 O 3 nanoparticle and water mixtures in hot and cold flow sides are used to increase the heat transfer according to the pressure drop of the fish-gill embossed PHE. The results of the study show that for water and 0.5 vol% Cu/water, its heat transfer rates are respectively 17.5% and 41% higher compared to the Chevron angled PHE. According to water usage in the fish-gill embossed PHE, the use of 0.5 vol% Cu/water nanofluid increases the heat transfer rate by 19.9% and the effectiveness by 24.5%. The narrow flow channels of the fins added to the plate surface cause an increase in the pressure drop of the fish-gill embossed PHE. As a result, nanofluid can be used to reduce the pressure drop compared to water usage. • Inspired by fish gill, grooves are designed on plate for mini-channel flow of PHEs for the first time. •Comparing performance of the novel PHE for nanofluids with different concentration ratios. •Compared to water, PHE with nanofluid reduces pressure drop despite increasing heat transfer. •For nanofluid use, mini-channel flow can be preferred over Chevron trough flow. •The usability of single-pass PHEs instead of multi-pass PHEs is recommended. [ABSTRACT FROM AUTHOR]

• Additive manufacturing method is used for lung patterned compact PHE for the first time. • Experimental tests of a lung pattern on plate surface have been successfully performed. • The novel PHE guides in reducing the number of plates and volume. • It shows superior hot-side performance over reference studies. Today, compact PHEs produced by additive manufacturing method have emerged when high heat transfer and low-pressure drop are required from PHEs under high temperature and pressure operating conditions. This has resulted in attention to the design of the plate surface geometry. In this study, a PHE of compact class of which plate surface has a lung pattern was fabricated by additive manufacturing method for their purpose of pressure drop reduction and improvement of heat transfer. The novel compact PHE was tested under single-phase water flow conditions. In addition, the thermal performance of the designed PHE was investigated numerically. As a result of the study, the hot side heat transfer rate of the lung patterned PHE was reported as 3206.06W and 2891.36W, with a 10% deviation according to the experimental and numerical results, respectively. For a water-to-water PHE, a good performance and pressure drop has been achieved by using the geometric features of the existing commercial PHEs, such as the minimum plate thickness (0.5mm) and the distance between two plates (1.5mm), in the developed design. Thus, the number of plates and the volume of the PHE can be reduced for the same amount of heat transfer in commercial PHEs. In addition, this study provides indications of the importance of plate surface geometry design for compact PHEs produced by additive manufacturing. [ABSTRACT FROM AUTHOR]

Since both heat and electricity are produced in the cogeneration system, residential heating can be done independently from the grid. Stirling engine is proposed to use for rural areas where electricity cannot reach. It can be used also for independence from power cuts and increasing energy security and distributed energy production. In this study a novel micro-combined heat and power production system (μ-CHP) which consisted of photovoltaic modules (PV), Beta type Stirling engine and coal-fired boiler was designed and manufactured to heating of multi-family house in Muğla, Turkey. Performance and economic analyses of μ-CHP system were performed. The daily average electricity production of Stirling engine and PV was 3.126 kWh. The daily average heat production of Stirling engine and coal boiler was 985.97 kWh. Average thermal efficiencies of the μ-CHP system with and without Stirling engine were 31.78% and 30.78%, respectively. Average Carnot efficiency of the Stirling engine was 30.2%. Electricity was charged in battery. Electricity need of auxiliary equipment of the heating system was met from battery. Thus, μ-CHP system can be used for residential heating independently from the grid, especially in rural areas. This study will provide insight using μ-CHP systems in residential heating and real conditions. • The novel micro-CHP system was compared with conventional coal boiler system. • Micro-CHP system can be used in residential heating independently from the grid. • Electrical energy was produced with photovoltaic module and Stirling engine. • Thermal energy production with and without Stirling engine was investigated. [ABSTRACT FROM AUTHOR]

Abstract: Concerns about fossil fuel consumption increase daily because of the limited nature of the reserves and its impact on the environment. Research and Development studies suggest an optimistic future for the use of renewable energy sources. To create such a bright future, however, renewable energy education must be quickly and efficiently spread to future generations. The current study explores Turkish university students’ levels of awareness regarding renewable energy sources. For this purpose, a questionnaire was given to students in Turkish universities. The questionnaire comprised questions that address students’ personal and demographic characteristics levels of awareness levels regarding renewable energy sources. The data obtained from the questionnaire were evaluated using the SPSS program. Finally, actions that should be taken to increase university students’ awareness levels are described. [Copyright &y& Elsevier]

Abstract: In the present study, to discover how teaching of renewable energy sources in Turkey is carried out at the university level, a questionnaire was developed and applied at different universities in Turkey. The analyses conducted on the data obtained from the questionnaire revealed that education about geothermal, solar and wind energy is given at master’s level, other renewable energy sources are taught at the undergraduate level within the curriculum of some engineering courses. The teaching performed about renewable energy sources is in Turkish and at encyclopedic level. As preparing and obtaining the required materials are costly, some problems are encountered in the teaching of renewable sources. In Turkish universities, no degree about renewable energy sources is granted. Hence, the country must make use of the people having engineering degree to capitalize on its renewable energy sources. As there is no program specializing on providing training about the renewable energy sources, it seems to be difficult to find experts about this issue. The current state of renewable energy sources education seems to be inadequate and it should be expanded and strengthened. [ABSTRACT FROM AUTHOR]

Abstract: In this study, two types of solar air collectors are constructed and examined experimentally. The types are called as zigzagged absorber surface type and flat absorber surface type called Model I and Model II respectively. Experiments are carried out between 10.00 and 17.00h in August and September under the prevailing weather conditions of Karabuk (city of the Turkey) for 5days. Then, thermal performances belongs to experimental systems are calculated by using data obtained from experiments. To estimate thermal performances of solar air collectors an artificial neural network (ANN) model is designed. The measured data and calculated performance values are used at the design of Levenberg–Marquardt (LM) based multi-layer perceptron (MLP) in Matlab nftool module. Calculated values of thermal performances are compared to predicted values. Statistical error analysis is used to evaluate results. Comparing and statistical results demonstrate effectiveness of the proposed ANN. Also reliability of ANN and meaningfulness of input variables are tested via applying stepwise regression method to the data used in designing ANN. [ABSTRACT FROM AUTHOR]

The control strategy insures the efficiency, increased production and safety in new and complicated energy conversion systems. To this end, a thermodynamic model that simulates a real geothermal power plant is developed, and a new and optimal control strategy to increase exergy efficiency is presented on this model. In this study, real average daily data obtained during 2016 are used to verify the thermodynamic model of Sinem geothermal power plant in Turkey (S-GPP) and its control strategy. Thus, exergy efficiency of the system is maximized even under different and changed conditions by controlling flow rate, pressure and NCG percent content parameters in certain locations of S-GPP. Consequently, a new control strategy based on PID is developed. At the same time, different working conditions are provided by assigning disruptive values to these parameters. The thermodynamic model of S-GPP is used as a test system to demonstrate the efficiency of the proposed control strategy under various operating conditions. The results of the study prove that the model has a good statistical performance in terms of maximum exergy efficiency values. In addition, the proposed PID controller has a better performance compared to manual control, even in the presence of S-GPP. The effectiveness of the proposed control strategy is demonstrated by this case study, in which exergy efficiency of the system increased by 25% and power generation by 23%. Therefore, the proposed control strategy has the potential to create more reliable and controlled systems for geothermal and other power plants. • A thermodynamic model has been developed that can simulate an existing operating GPP in real time. • An exergy-based PID control strategy is used for the first time in the GPP under various operating conditions. • Maximum exergy efficiency of the GPP is ensured with control of flow rate, pressure and percent content. • The strategy has better control performance compared to the uncontrolled one in the GPP. • With the proposed strategy, its exergy efficiency and power rate can be increased by 25% and 23%, respectively. [ABSTRACT FROM AUTHOR]

This study investigates the effect of using a latent heat storage unit (LHSU) equipped with fins and nanoparticles (NAPs) on the performance of a photovoltaic (PV) system. Various PV systems were assessed for their economic viability and environmental impact. Initially, three different PV systems were designed and analyzed: a conventional PV, a PV with a paraffin-containing LHSU, and a PV with LHSU integrating 3 fins and paraffin. Results from the first set of experiments indicated that the fin-integrated system delivered the best performance. In the second phase, the most effective system from the initial stage (PV with 3 fins-added LHSU) was compared to systems with 6 fins-integrated LHSU and LHSUs integrating 6 fins and iron (Fe) NAPs. The stage specifically examined the effects of doubling the number of fins and adding NAPs to the paraffin on performance. It was found that increasing the number of fins resulted in a levelized cost of electricity (LCOE) of 0.69 USD/kWh. The electrical (module) efficiency of the system incorporating 6 fins and NAPs improved by 15.51 % compared to the conventional system. Moreover, the surface temperature of the PV panel was reduced by 7.28–17.93 % using these modifications. Performance ratio values for the five different analyzed PV systems ranged between 0.597 and 0.689. From an environmental perspective, integrating aluminum into PV systems lead to a total environmental impact of 4.73 Pt/h and an environmental impact of electricity produced (EIE) of 0.90 mPts/kWh. However, introduction of NAPs significantly increased these values to 17.76 Pt/h and 3.09 mPts/kWh, respectively. This study highlights the potential of the proposed passive cooling technique for enhancing PV system efficiency while also pointing out the necessity for design improvements to optimize economic and environmental impacts. • Innovative use of fins and NAPs in LHSUs significantly improves PV system efficiency. • Increased fin count and NAP integration result in notable electrical efficiency gains. • Significant reduction in PV panel surface temperature achieved through design modifications. • Comprehensive environmental and economic impact assessment of PV cooling techniques. • Study strikes a balance between enhancing PV system performance and economic feasibility. [ABSTRACT FROM AUTHOR]

• Lung-inspired CPHE was created to optimize heat transfer and pressure drop. • CPHEs with the same geometry and roughness were produced by additive manufacturing from different material powders. • Compared to a brazed PHE, max 75% superior heat transfer occurred in aluminum CPHE. • According to that, a decreasing pressure drop of max 32% was achieved in titanium CPHE. • Material selection can be considered in performance improvement of CPHEs. The selection of material for compact plate heat exchangers (CPHEs) is of increasing importance due to global economic and supply constraints. Additionally, the influence of material selection on the thermo-hydraulic characteristics of CPHEs is an area of ongoing research. This study aims to address these issues by analyzing the thermo-hydraulic performance of CPHEs made from steel, aluminum, and titanium materials with small, complex channels. Using an additive manufacturing method (specifically Direct Metal Laser Sintering), lung-inspired CPHEs of identical geometry and roughness were manufactured from steel, aluminum and titanium powders. The thermo-hydraulic characteristics of CPHEs as well as that of a traditional one with Chevron-type, were investigated using both experimental and numerical techniques under specific operating conditions to determine the optimum between maximum heat transfer and minimum pressure drop. The findings of this study reveal that as the temperature difference between the inlet on the hot and cold sides, as well as the flow rate, were increased, there was a corresponding increase in both amount of heat transferred and loss of pressure across all investigated CPHEs. Compared to the chevron type brazed plate heat exchanger, the CPHE made from aluminum showed a 75.2 % and 11.2 % increase in heat transfer and a 31.8 % and 10.9 % reduction in pressure drop at 3 and 6 L/min, respectively, for a temperature difference of 90–40 °C. This study suggests that the use of materials with different thermal conductivities in CPHEs may offer a promising solution to achieve elevated heat transfer rates while minimizing pressure drop. [ABSTRACT FROM AUTHOR]

Burning chicken manure (CM) with lignites may be a promising method to ensure waste management. In this study, a circulating fluidized bed boiler (CFBB) system was designed, manufactured, and tested for the disposal of CM in poultry farming. Combustion and co-combustion tests of CM and Kale Lignite (L) were carried out in the CFBB to determine the effect of excess air ratio and CM share in the fuel mixture on combustion efficiency and flue gas emissions. As the CM share in the mixture increased, the combustion efficiency increased from 86 % to 95 %. It was observed that while CO emissions increased, SO 2 and NO x emissions decreased with respect to CM share. CO emissions ranged from 726 to 2241 mg/Nm3 for 100%L and between 838 and 2450 mg/Nm3 for 100%CM. The NO x emissions changed between 177.5 and 240 mg/Nm3 for 100%CM; however, it was 276.3 mg/Nm3 for 100%L. While SO 2 emissions (average) for 100%L were around 5200 mg/Nm3, as the CM share in the fuel mixture increased, emissions decreased, and when they became zero for 100%CM. CO emissions decreased as the excess air ratio increased. SO 2 and NO x emissions increased as the excess air ratio increased in almost all fuel mixtures. This combustion system was proposed for waste disposal, emission reduction, and usage of domestic sources. Photovoltaic panels can support this system and meet farms' operational energy requirements away from the grid. Combustion efficiency can be increased by operating the system at oxy-firing mode instead of air-firing. • Co-combustion of biomass and lignite in different ratios was investigated. • Optimum combustion conditions with various excess air ratios were examined. • CO, NO x , and SO 2 emissions were measured. • Waste management with the disposal of chicken manure can be ensured. [ABSTRACT FROM AUTHOR]

Increasing worldwide demand for chicken and chicken products has led to increased production of chicken manure. Therefore, chicken manure has an important application potential in the energy industry. This study aims to dispose of chicken manure, which is harmful to soil and groundwater, for thermal energy purposes and to reduce the emissions of lignite coal. For this purpose, it concerns the design and manufacture of a Circulating Fluidized Bed Boiler (CFBB) with a novel combustion chamber for burning chicken manure (CM) and lignite (L) fuels and their mixtures. The combustion behaviors and contaminating emissions of the mentioned fuels in such a CFBB are investigated experimentally and numerically. Emissions of major gaseous pollutants, including CO, SO 2 and NO, and the temperature distribution throughout the combustion chamber are measured during the tests. Experimental results show that increasing the amount of CM in the mixture increases CO and reduces SO 2. For this condition, NO emission either increases or decreases. According to the numerical results, the temperature of the combustion chamber decreases with the increase of the CM fraction. In the CFBB, the CO emission decreases in the CM fraction up to 25 %, while it increases in the CM fraction above 25 %. For increasing CM fraction, NO emission decreases in the cyclone while it increases in the evaporator. In the experimental and numerical results, the CO 2 emission for the L, CM and CM fractions are observed to be equivalent to each other. In conclusion, this study clearly shows that in situ burning of chicken manure or lignite and chicken manure mixtures reduces lignite emissions and meets the heat requirement and disposal of waste in chicken processing plants. • Lignite, chicken manure and their mixtures were burned on-site experimentally and numerically. • CFBB with a novel combustion chamber were manufactured, tested and simulated. • Temperature distribution, emissions and waste heat criteria were evaluated for fuels. • CM and CM fractions successfully met the criteria in reducing lignite emissions. • The developed CFBB met heat demand and waste disposal in chicken processing plants. [ABSTRACT FROM AUTHOR]

In this work, it is aimed to improve the performance of a photovoltaic-thermal (PVT) air collector using finned latent heat thermal energy storage unit. In this regard, four different types of parallel-flow PVT (PPVT) systems have been designed, manufactured and tested including a conventional PPVT, a PPVT with paraffin-based thermal energy storage unit, a PPVT with 3-finned storage unit and a PPVT with 6-finned storage unit. A parallel-flow collector geometry has been designed to convey excess heat from both surfaces of the photovoltaic panel in the systems. Moreover, the effect of increasing the number of fins in the storage system in the PPVT on the performance has been analyzed within the scope of this work and the developed systems have been tested simultaneously. According to the experimentally obtained findings, overall efficiency value of the PPVT was improved from 55.83% to 76.79% using thermal energy storage with 6-fins. The performance ratio and sustainability index values were obtained between 0.64-0.76 and 1.0277–1.0474, respectively. Enviro-economic analysis has been performed and payback periods of the systems were attained between 0.991 and 1.146 years. Also, employing 6-finned storage unit in the PPVT upgraded the annual carbon dioxide savings as 33.71% in comparison to the unmodified PPVT. [ABSTRACT FROM AUTHOR]

In the current article, it is intended to improve the performance of an unglazed solar air collector using mesh tubes as extended heat transfer surfaces and nano-enhanced black paint as a thermal conductivity booster of the absorber coating material. In this regard, three types of unglazed solar air collectors have been designed, produced and simultaneously tested containing a conventional (unmodified) system, a system with only mesh tube modification and a system with combined usage of mesh tubes and nano-enhanced absorber coating. It should be stated that Fe 3 O 4 nanoparticles have been utilized within the scope of this work. Integrating nanoparticles to the absorber coating material (industrial matt black paint) averagely improved the thermal conductivity as 0.031 W/mK. The experimental process was tested at fixed air flow rate (0.0115 kg/s) in winter climatic conditions. As result of the experimental analysis, average thermal efficiency values were attained between 45.11 and 63.36%. Combined usage of mesh tubes and nano-enhanced black paint upgraded the mean thermal performance as 40.45% in comparison to the unmodified system. Also, obtained exergetic efficiencies are in the range of 5.49–9.96%. In addition to the energy-exergy analysis, enviro-economic survey was performed within the scope of the current work. Payback periods of the analyzed systems were found between 0.31 and 0.34 years. • The effects of combined usage of mesh tubes and nano-enhanced black paint in an unglazed SAC were investigated. • Experimental analysis of three USACs with various configurations. • Mean thermal energies for USAC, USAC/MT and USAC/MT-NP were found 56.28 W, 68.81 W and 78.87 W, respectively. • The LCOH value of USAC/MT-NP decreased 7.22% in comparison to the USAC. [ABSTRACT FROM AUTHOR]

Highlights: [•] Economic evaluation of GDHS using advanced exergoeconomic analysis for the first time. [•] The results obtained for two different GDHSs are compared under same condition. [•] Each component of the Sarayköy GDHS is to operate more economically. [•] The usefulness of this analysis was clearly demonstrated comparing both the systems. [ABSTRACT FROM AUTHOR]