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Öğe Assessment of Energy Efficient HVAC Systems for Office Buildings(Bursa Teknik Üniversitesi, 2022) Özpolat, Yunus Emre; Kara, Yusuf AliAs a result of economic and political requirements, renewable energy investments are supported with various incentives all over the world, while fossil fuel systems are restricted by regulations. This article aims to make conventional heating, cooling and power systems more efficient or to develop an alternative system based on renewable energy by modeling an office building. Considering three scenarios - classical heating-cooling system, combined cooling-heating-power system and zero energy building, the test building’s energy estimation analysis and life-cycle cost analysis have been conducted and 3 different sub-scenarios for renewable energy scenarios have been generated. As a result of the Hourly Analysis Program (HAP), the building’s cooling design load was found to be 742.7 kW, and the heating design load was 439.8 kW. The required borehole length for ground source heat pump is determined as 20,371 m for cooling and 9,137 m for heating, while the heat is discharged into the borehole with a rate of -44.3 W / m and extracted with a rate of 34 W / m. Annual energy generation of the photovoltaic plant was determined as 607.639 kWh and installed power of for this plant was calculated as 463 kWp. Lifecycle cost analyses were performed by using P1-P2 method and according to the calculations, the payback period for the extra investment cost is 37 months for the combined cooling-heating-power plant, whereas it is 94 months for the improved zero energy building design. Similarly, the payback period for the full investment cost is determined as 58 months for the combined cooling-heating-power plant, and 127 months for the improved zero energy building design. As a result, a hybrid zero energy building (air source condenser + ground source heat pump, photovoltaic panels) is proposed as the best design option for the office building identity.Öğe Assessment of wind energy potential: a case study(Bellwether Publishing, Ltd., 2021) Düzcan, Abdullah; Kara, Yusuf AliUtilization and investments of wind energy have been speedily rising in the world due to harmful side of the fossil fuels. Assessment of wind energy potential analysis is a must before making investment decision of wind farm. Due to high capacity factor of Aegean Sea, Gökçeada location is chosen for wind energy potential analysis. One year hourly measured wind velocity and direction data supplied by Turkish State Meteorological Service (TSMS) is used to assess the wind potential in the terrain. Two different approaches are used for the assessment, the former employs power-law method for calculating wind velocity field while the latter employs Windsim software based on Computational Fluid Dynamics (CFD) method. After calculating wind velocity field, Weibull method is used for energy analysis in both approaches. Results from each approach are compared. The roughness is attained at only two points that are measurement site and turbine site in power-law method while it is taken into account for the whole domain in CFD method. Besides, unlike CFD method, wind direction is not considered in power-law method. The velocity profile is calculated at the height of 60 m and considered the same everywhere depend on the roughness in power-law method. On the other hand, Windsim calculates velocity profile over the terrain in consideration by solving Reynolds-averaged Navier-Stokes (RANS) equations. In this assessment, seven Vestas V90 2 MW wind turbines are employed. According to the results of power-law method and CFD method, the capacity factor is calculated as 31.67 and 49.5%, respectively. Windsim results indicate that annual energy production (AEP) is 60.2 GWh/y regarding wake loss, and the shape factor ranges from 1.57 to 1.64 whereas scale factor ranges from 9.49 to 10.77 m/s for the locations of turbines. It is strongly advised to build a wind farm in Gökçeada location according to the results from the analysis.Öğe Diurnal performance analysis of phase change material walls(Pergamon-Elsevier Science Ltd, 2016) Kara, Yusuf AliA research study was conducted to investigate the thermal performance of phase change material (PCM) walls. The south-facing external wall of a test room was constructed using PCM walls composed of brick walls, plasterboards containing PCMs, and novel triple glass. The thermal performance of the PCM walls was experimentally determined on a daily basis. The ratio of the solar energy gain provided by the PCM walls to the heat load of the test room on a daily basis varied from 12% to 25%; daily overall efficiency of the coupled novel triple glass and PCM walls varied from 17% to 20%; and solar transmittance of the novel triple glass varied from 45% to 55% during the heating period. (C) 2016 Elsevier Ltd. All rights reserved.Öğe ENERGY AND ENVIRONMENTAL EVALUATION OF A PCM WALL COVERED WITH NOVEL TRIPLE GLASS(2018) Seyhan, Aslıhan Kurnuç; Kara, Yusuf AliResearch was conducted to investigate the performance of phase change material (PCM) walls for solar space heating. The PCM walls were consisted of brick walls, plasterboards containing PCMs and novel triple glazing units. South façade of a test room was constructed using the PCM walls for heating the test room with solar thermal energy. The overall efficiency of the PCM walls was experimentally determined on a monthly basis. In addition to experimental analysis, a theoretical energy analysis of the PCM walls based on 10-year mean meteorological data was performed to provide a more general conclusion about the performances of the PCM walls. Besides, reduction in CO2 from the test room owing to PCM wall was also calculated. Theoretical analysis results showed that, the reduction of CO2 emission on a monthly basis varied from 57 to 7% during the heating period. Heating period is from October through May. Reduction of CO2 emission was 16% on an annual basis.Öğe Exergoeconomic and exergoenvironmental analysis of a coal-fired thermal power plant(Springer Science and Business Media Deutschland GmbH, 2021) Düzcan, Abdullah; Kara, Yusuf AliWhen evaluating a thermal system, exergy analysis is performed in addition to energy analysis to determine the location and quantity of losses in the system. In this study, energy, exergy, exergoeconomic and exergoenvironmental analyses of Orhaneli thermal power plant located in Bursa are carried out. In exergy analysis, physical and chemical exergies are taken into consideration and potential and kinetic exergies are neglected. Exergoeconomic analysis is conducted by using specific exergy costing (SPECO) method and cost values corresponding to each exergy flows are calculated. According to exergoeconomic analysis, unit exergy cost and exergy cost of steam sent to high-pressure turbine are calculated as 17.94 $/GJ and 22,854 $/h, respectively. The highest exergoeconomic factor is measured in pump (P2) and followed by P3. For the life cycle assessment (LCA) analysis, eco-indicator 99 impact assessment method is selected. LCA results are transferred to exergy flows and then exergoenvironmental analysis is performed. Environmental impact per exergy unit and exergetic environmental impact rate of the steam sent to high-pressure turbine are calculated as 14,680 mPts/GJ and 18,700 Pts/h, respectively. The highest exergoenvironmental factor is measured in pump (P2) and followed by P3.Öğe Investigation of the usage potential of the evacuated tube and the flat plate collectors to assist an absorption chiller(Elsevier Ltd, 2021) Düzcan, Ahmed; Kara, Yusuf AliIn this study, the usage potential of the evacuated tube collectors (ETCs) and the flat plate collectors (FPCs) for assisting an absorption chiller (AC) are comparatively investigated by using TRNSYS software. ETC and FPC are examined under different load conditions and scenarios to see if the collectors satisfy the required source temperature for an absorption chiller system (ACS) with LiBr – H2O pair. Daily and seasonal analyses are carried out. Daily analyses consist of three scenarios: both the auxiliary heater and the load are turned off in the first scenario while only the load is turned on in the second; both the auxiliary heater and the load are turned on in the third scenario that is also performed for summer season as a fourth scenario. The working fluid in all scenarios is a heat transfer fluid (HTF). In the third scenario at 250 kg/h load, the maximum collector outlet temperature is 113 °C and 99 °C, the daily solar fraction (SF) is 83% and 57%, the temperature to load is 106 °C and 86 °C for ETC and FPC, respectively. In the seasonal analysis, the seasonal SF is 81% and 20.19% at 250 kg/h load for ETC and FPC, respectively. Higher temperature and SF are obtained when HTF is used instead of water. It has been observed that the required source temperature for ACS can be provided with ETC.Öğe Optimization of a multi-generation renewable energy supply system for a net-zero energy building with PCM-integrated Trombe wall(Elsevier, 2025) Duzcan, Abdullah; Kara, Yusuf AliThis study aims to perform the thermal performance and economic optimization of a phase change material (PCM)-integrated Trombe wall to achieve a zero energy building (ZEB) to reduce overheating in summer. For this purpose, a ground source heat pump (GSHP) is used to condition a 120 m(2) single-family building by providing both heating and cooling. Also, three different building configurations are investigated for three different climate zones of T & uuml;rkiye. Of these configurations, the shaded PCM-integrated Trombe wall building (TWB) has the lowest annual energy consumption compared to the standard building (SB). The performance of the Trombe wall is assessed using thermal efficiency, effectiveness and energy reduction rate; the thermal comfort of the building is evaluated using the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) indices; and the economic performance is analyzed through the Levelized Cost of Energy (LCOE) and payback period. On-grid photovoltaic-thermal (PV/T) and wind turbine (WT) provide the annual electricity consumption of building, resulting in a net ZEB in TRNSYS software. The particle swarm optimization (PSO) algorithm in the GenOpt software is then used to economically optimize the size of PV/T and WT system that satisfies the annual energy need and domestic hot water (DHW) requirements of building. Accordingly, the annual electrical energy reduction rate of the PCM-integrated TWB compared to the SB is 11.9 %, 18.0 %, and 34.3 % for Bursa, Ankara, and Erzurum provinces, respectively. While the effectiveness is calculated as 24.7 %, 44.1 % and 34.9 %, the efficiency is also calculated as 65.8 %, 61.9 % and 58.4 % for Bursa, Ankara, and Erzurum provinces, respectively for the PCM-integrated TWB. Hourly levelized total capital investment cost rate of PV/T and WT systems are 0.35 $/h, 0.42 $/h, and 0.40 $/h whereas LCOE are 0.05 $/kWh, 0.07 $/kWh, and 0.03 $/kWh in Bursa, Ankara and Erzurum, respectively.Öğe Thermal performance evaluation of PCM-integrated interior shading devices in building glass facades(Elsevier, 2025) Celik, Ali; Mandev, Emre; Ersan, Orhan; Muratcobanoglu, Burak; Ceviz, Mehmet Akif; Kara, Yusuf AliThis study investigates the thermal performance and energy efficiency potential of Phase Change Material (PCM)-integrated interior shading devices installed within double and triple-glazed facades. The primary aim is to explore how these systems can enhance indoor thermal comfort, reduce energy consumption, and impact natural lighting levels. A test cabin was designed to evaluate these parameters, featuring double and triple-glazed panels with integrated shading devices containing microencapsulated PCMs. The PCMs, known for their ability to store and release thermal energy through phase changes, were utilized to mitigate indoor temperature fluctuations by absorbing excess solar heat during the heating period and releasing it during the cooling period. Experimental results revealed that the combination of triple glazing, shading devices, and PCM led to significant improvements in thermal performance, reducing temperature peaks and extending the cooling period compared to systems without PCM. The integration of PCM reduced the maximum temperature difference caused by heating and cooling cycles from 26.9 degrees C to 20.1 degrees C in double-glazed windows and from 19.8 degrees C to 12.4 degrees C in triple-glazed windows. Furthermore, PCM integration was shown to delay temperature rises by acting as a thermal buffer, thus stabilizing indoor conditions and reducing the load on cooling systems. Additionally, light intensity measurements were conducted to assess the impact of the shading devices on natural daylight levels. Despite the 35 % reduction in natural lighting caused by the shading devices, the overall thermal performance and energy saving potentials were substantial, highlighting the effectiveness of PCM as a passive thermal regulation material. This study provides valuable insights into the potential of PCM-enhanced shading devices as a solution for improving energy efficiency and occupant comfort in modern buildings.Öğe Thermal performance investigation of microencapsulated phase change material enhanced with graphene nanoplatelets in double-glazing applications(Elsevier Science Sa, 2024) Celik, Ali; Ceviz, Mehmet Akif; Kara, Yusuf Ali; Mandev, Emre; Muratcobanoglu, Burak; Afshari, Faraz; Manay, EyuphanEffective heat energy storage is crucial for thermal energy management. The utilization of latent heat storage methods is widely prevalent across various engineering applications for enhancing energy efficiency. In this study, the energy storage performances of Phase Change Materials (PCMs) achieved by incorporating graphene nanoplatelets into a microencapsulated PCM were experimentally analyzed for double-glazing applications. Changes in thermal energy storage and heat transfer performance by incorporating graphene nanoplatelets into the PCM at two different mass ratios (1 % and 0.1 %) were investigated. The results obtained from light intensity and temperature measurements, as well as thermal camera imaging, were evaluated together. The results support the contribution of graphene nanoplatelets addition to microencapsulated PCMs in enhancing thermal performance during both heating and cooling periods. Among the investigated cases, the highest mass ratio of 1 % graphene nanoplatelets addition led to a major 10 degrees C increase in peak temperature compared to the reference condition. In contrast, this increase in peak temperature was accompanied by a mere 14 % decrease in average light levels. This research underlines the potential of graphene-enhanced microencapsulated PCMs in optimizing thermal management systems for double-glazing applications, offering a promising pathway towards enhancing energy efficiency and thermal comfort in building environments.Öğe Transient thermodynamic and parametric analysis of solar-assisted Rankine cycle(Sage Publications Ltd, 2025) Duzcan, Ahmed; Arslanoglu, Nurullah; Coskun, Salih; Kara, Yusuf AliIn this study, the parabolic solar collector supported Rankine cycle is thermodynamically and parametrically conducted using the TRNSYS program. The system contains a collector cycle, an auxiliary heater cycle and a Rankine cycle. In the Rankine cycle, water vapor is employed as the heat transfer fluid, whereas in the other two cycles, heat transfer fluid with a boiling temperature of 359 degrees C is utilized. In the system, an auxiliary heater is configured to maintain a source-side temperature of 250 degrees C prior to entering the steam boiler. The whole system is analyzed throughout the year for different collector tilt angles. In addition, nine different scenarios are designed so that the collector area, tank volume, turbine and condenser pressures in the Rankine cycle, flow rate in both collector and auxiliary heater cycle and three different provinces are analyzed. Collector outlet temperature, collector efficiency, SF, Rankine cycle efficiency, system thermal efficiency and utilization factor are analyzed. The maximum values observed in the analyses are as follows: the overall system efficiency of 5.46% in Scenario 5; the Rankine cycle efficiency of 24.1% in Scenarios 8 and 9; the utilization factor of 24.03% in Scenario 5; SF of 100% except Scenario 4 and 9; the collector efficiency of 28.96% in Scenario 4; and the collector outlet temperature of 303 degrees C in Scenario 7. In Scenario 5, the turbine delivers its peak performance at roughly 346 MWh, resulting in a net energy of approximately 157 MWh, the highest among all cases.
