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Öğe The Design of Computer Controlled Cold and Hot Therapy Device with Thermoelectric Module(Amer Scientific Publishers, 2013) Yavuz, Celil; Yilmaz, Sezayi; Kaya, MetinIn this paper, a computer controlled cold-hot therapy device with thermoelectric module has been designed. This device is used in order to balance temperature of body in case of injury, fever etc. In this medical device, cold and hot therapy operations have been accomplished by changing the feeding voltage and feeding polarity of thermoelectric modules. Temperature was measured via PIC18F4550 microcontrollers and USB port and AD595AQ Monolithic Thermocouple Amplifiers were used for transferring data of K type temperature sensors to microprocessor. A control interface has been developed in VisualBASIC6.0 to monitor and record the temperature data, and control the device by the computer. All tests were conducted at variable temperature inside a heated chamber to simulate the human body temperature. The computer controlled cold-hot therapy device with thermoelectric module was operated and tested at variable water flow rates and variable voltages by computerized control. As a result of this study, cold and hot therapy operations have been realized via this medical device. Cold therapy with splint is a vital first aid application in Traffic, sports, work accidents etc. According to the literature, cold and hot therapy temperatures range from 0 degrees C to 15 degrees C and from 40 degrees C to 45 degrees C respectively. The study was performed at the simulated body temperature of 37 degrees C. The hot and cold therapy device which was designed was tested at various power values obtained cold surface temperatures from -3.4 degrees C to 5.5 degrees C and hot surface temperatures from 37.8 degrees C to 58.3 degrees C.Öğe EFFECT OF MODULE OPERATING TEMPERATURE ON MODULE EFFICIENCY IN PHOTOVOLTAIC MODULES AND RECOVERY OF PHOTOVOLTAIC MODULE HEAT BY THERMOELECTRIC EFFECT(Yildiz Technical Univ, 2023) Kayabasi, Ramazan; Kaya, MetinOne of the parameters affecting the efficiency of photovoltaic (PV) modules and PV systems is the temperature. The factors that increase the temperature in PV modules cause loss of efficiency. In this study, experiments have been conducted with the aim of reducing the module temperature. For this purpose, four polycrystalline and four monocrystalline PV modules, all with the same features, were used. A pair of polycrystalline and monocrystalline modules were used as reference modules. The aim of this study is to reduce the operating temperature of the modules, while also decreasing the transient temperature fluctuations in the system, in order to prevent the loss of efficiency. For this reason, current, voltage and power values of PV modules have been examined and the relationship between these values and module temperature has been explained. As a result, temperature values were measured at 30-80 degrees C in reference modules, 30-50 degrees C in heat pipe modules, 30-37 degrees C in modules using heat pipes and phase-changing material, and 30-66 degrees C in modules using phase-changing material with flexible surfaces. If the PV module operating temperature is increased by 35 degrees C, the module efficiency decreases by 10%. Heat pipe and PCM balance the temperature in PV/T/PCM monocrystalline and polycrystalline modules. In PV/T/PCM modules, efficiency loss caused by temperature increase is 1%. In addition, electrical energy is produced from the heat accumulated on the surface of the PV module by means of Thermoelectric Generator (TEG). When the temperature difference between the surfaces is 15 degrees C, the naturally cooled TE provides 0.45V energy output, while the forced-cooled TEG provides 0.97V energy output. As the temperature gap between the surfaces increases, the voltage and current values of the TEG also increase. Briefly, TEG's power values increase up to 5W depending on the temperature gap between surfaces.Öğe Energy Analysis of a New Design of a Photovoltaic Cell-Assisted Solar Dryer(Taylor & Francis Inc, 2013) Ceylan, Ilhan; Kaya, Metin; Gurel, Ali Etem; Ergun, AlperIn this study, a new type of solar dryer was designed and manufactured. This new solar dryer is composed of a heat pipe collector, a drying chamber, a load cell, an air circulation fan, photovoltaic cells (PvC), batteries, and halogen lamps. In this experimental study, tomatoes were used to test the drying process. The drying air was heated by the heat pipe collector and forced through the tomatoes by a blower fan during the daytime. The photovoltaic cells, which were used to run the fan, were also used to charge the batteries during the day. These charged batteries were used for running the halogen lamps during the night, when the halogen lamps were used to heat the drying-air-assisted photovoltaic cells. During the drying period, the drying air temperature, relative humidity, air flow rates, solar radiation, and loss of mass were measured in the solar dryer. Then, the measured data were used for energy analysis.Öğe Energy Analysis of Concentrated Photovoltaic/Thermal Panels with Nanofluids(Int Center Applied Thermodynamics, 2021) Dumrul, Hakan; Yilmaz, Sezayi; Kaya, Metin; Ceylan, IlhanIn this study, a prototype system was established for location heating application and electricity generation through utilizing two concentrated photovoltaic thermal panels (CPV/T) possessing flat surface receivers connected in series with each other. The purpose of the system is to supply the heating needs of a room in winter season and to meet the electricity requirement of the equipment used in this system. In the analysis of the installed system, different refrigerants (10% mono propylene glycol + 90% water and 0.5% Al2O3-water nanofluid) were tested at three different flow rates (0.4 m(3)/h, 0.5 m(3)/h, 0.6 m(3)/h). Throughout the experiments, the fan-coil air outlet temperature used to heat the room was adjusted to 35 degrees C with an inverter and a process control device. The results attained from the experiments carried out using different fluids throughout different months and days (April-May) have demonstrated that the thermal and electrical efficiencies of the system are found to be in good agreement with each other when evaluated in terms of the fluids utilized. The highest electrical energy recovery was found as 268 W at 0.6 m(3)/h flow rate for propylene glycol-water mixture and 194 W at 0.5 m(3)/ h flow rate for nanomixture. The total thermal energy efficiency for the system using different fluids was found to be around 22%. The total thermal energy gain of the system was also calculated as 2312 W at 0.6 m(3)/h for the propylene glycol mixture and 2041 W at 0.5 m(3)/h for the nanomixture.Öğe EXPERIMENTAL ANALYSIS OF THE AIR-HANDLING UNIT CAPABLE OF MODULATION CONTROL BASED ON CO2 CONTENT IN THE CLASSROOM(Begell House Inc, 2020) Korkmaz, Murat; Kaya, MetinPeople spend most of their lives indoors today. Therefore, the importance of indoor air quality increases with each passing day, particularly, when the current quality of life expectations is taken into consideration. One of the factors affecting indoor air quality is the amount of CO2 in the air. In this study, by using an air-handling unit (AHU) with plate heat recovery, the correlation of CO2 concentration variations based on the number of students present in a classroom of the university was evaluated. Also, alterations in the energy consumption, depending on the variable mixing unit ratios of AHU, were monitored. In the measurements, the measured CO2 concentration was at its highest level (1350 ppm) while the AHU was not active and 70 students were in the classroom. The CO2 concentration was 1087 ppm when 50 students were in the classroom. When the AHU was operated with 100% fresh air, the CO2 concentrations were 765 ppm and 682 ppm in the experiments with 70 and 50 students, respectively. Besides, when the AHU was operated with 60% fresh air, the measured CO2 concentration in the classroom was 889 ppm for 70 students, and 851 ppm for 50 students. In the experiments, the lowest energy consumption was calculated as 13.1 kW/h when there was no student in the classroom, and the AHU was operated with 60% fresh air. In the experiments, the highest energy consumption was calculated as 15.8 kW/h when there were 70 students in the classroom, and the AHU was operated with 100% fresh air.Öğe An experimental investigation on thermal efficiency of two-phase closed thermosyphon (TPCT) filled with CuO/water nanofluid(Elsevier - Division Reed Elsevier India Pvt Ltd, 2020) Kaya, MetinThe purpose of this study is to experimentally investigate thermal performance of Two Phase Closed Thermosyphon (TPCT) using nanofluid containing CuO nanoparticles at a mass concentration of 1% and 2% wt. For this purpose, an experimental setup was designed and manufactured which contains a copper pipe, 100 cm in length and 18 mm in the inner diameter. TPCT consists of three sections: the evaporator section (40 cm), adiabatic section (20 cm) and condenser section (40 cm). The evaporator section was wrapped with electrical spiral heater to apply heat, and whole section of TPCT was insulated. A cooling water circuit was used to remove the heat from condenser section. The temperatures were measured on the TPCT surface and cooling water inlet and outlet. The inclination angle of the TPCT was fixed at 90 degrees. The effects of various parameters such as heat load (ranging from 200 to 800 W), cooling water flow rate (ranging from 18 to 54 l/h) and type of working fluid on the thermal performance of TPCT were examined. The results were plotted graphically and discussed in detail. As a result, the performance enhancement was established by using CuO/water nanofluids instead of pure water in TPCT. Approximately 10% and 18.5% enhancement were found when 1% CuO/water and 2% CuO/water nanofluids were used, respectively. In addition, TPCT thermal resistance was reduced averagely 25% and 35% with the use of 1% CuO/water and 2%CuO/water working fluids, compared to the base fluid pure water. (C) 2020 Karabuk University. Publishing services by Elsevier B.V.Öğe Fotovoltaik modüllerin atık isılarından termoelektrik jeneratör ile elektrik üretimi(2019) Kayabaşı, Ramazan; Kaya, MetinGünümüz teknolojilerinin temelini enerji ve enerji kaynakları oluşturmaktadır. Gelişmiş dünya ülkeleri, enerji kaynaklarına sahipolmak ve enerji teknolojilerini geliştirmek için yarış halindedir. Ayrıca enerjinin verimli kullanılmasını sağlamak bu ülkelere çevreselve ekonomik olarak avantaj sağlamaktadır. Enerjinin üretimi ve tüketimi esnasında, kaynakların bir kısmı atık ısı olarak alıcı ortamabırakılmaktadır. Endüstride birçok atık ısı kaynağı bulunmaktadır. Atık ısı kaynaklarının sahip olduğu enerjiyi işe dönüştürmek içinaraştırma geliştirme faliyetleri artarak devam etmektedir. Atık ısı kaynaklarından biri fotovoltaik modüllerin yüzeylerinde biriken ısıenerjisidir. Fotovoltaik modüllerde biriken ısı enerjisi modüllerin verimlerini düşürmektedir. Ayrıca yüksek sıcaklık fotovoltaikmodüllerin verimli çalışma sürelerini azaltmaktadır. Bu çalışmada fotovoltaik modüllerin yüzeyinde biriken ısı enerjisi faz değiştirenmadde kullanılarak çekilmiştir. Fotovoltaik modüllerden çekilen ısı enerjisi termoelektrik jenaratörün çalıştırılmasında kullanılmıştır.Fotovoltaik modüllerin yüzey sıcaklığı deneyler esnasında maksimum 90?C’ye ulaşmaktadır. Fotovoltaik modüllere uygulanan ısıborusu ve faz değiştiren madde ile modül yüzeyi 30?C sıcaklığa kadar soğutulabilmektedir. Sonuç olarak fotovoltaik modülünsıcaklığı sabit tutulmakta ve bu nedenle modül verimleri artmaktadır. Termoelektrik modülün yüzey sıcaklıklarına bağlı olaraktermoelektrik jeneratörlerde elektrik üretimi yapılmaktadır. Yüzeyler arasında sıcaklık farkı arttıkça ölçülen gerilim değerleri artışgöstermektedir. Termoelektrik modül yüzey sıcaklığı 80?C ulaştığında 7.80V elektrik enerjisi üretilmektedir. Termoelektrikjeneratörden üretilen güç sıcaklık farkına bağlı olarak 5W olarak belirlenmiştir. Termoelektrik jenaratörün yüzeylerinden biri atık ısıile ısıtılırken, diğer yüzeyi tabii ve cebri olarak havayla soğutulmaktadır. Cebri olarak soğutulan termoelektrik jeneratörün yüzeyleriarasında 51?C sıcaklık farkı oluşrurken, doğal olarak soğutulan termoelektrik jeneratörün yüzeyleri arasında 26?C sıcaklık farkıoluşmaktadır. Atık ısı kaynaklı termoelektrik jeneratör kullanılarak, elektrik enerjisi üretilmektedir. Sistem hibrit olarak çalıştığı içintoplam verim artmaktadır.Öğe Numerical investigation on turbulent convective heat transfer of nanofluid flow in a square cross-sectioned duct(Emerald Group Publishing Ltd, 2019) Senay, Guelbanu; Kaya, Metin; Gedik, Engin; Kayfeci, MuhammetPurpose The purpose of this study is to numerically investigate the heat transfer enhancement by using two different nanofluids flow throughout the square duct under a constant heat flux (500x10(3) W/m(2)). Design/methodology/approach In numerical computations, ANSYS Fluent code based on the finite volume method was used to solve governing equations by iteratively. Water, Al2O3-water and TiO2-water nanofluids were used for different flow velocities changing 1 m/s to 8 m/s (i.e. Reynolds number varying from 3,000 to 100,000). Findings The results were compared with results published previously in the literature and close agreement was observed especially considering Dittus and Boelter correlation for water. It was found that from the obtained results, increasing flow velocity and volume fractions of nanoparticles has caused to increase Nu number for all cases. Besides, variations of pressure drop, Darcy friction factor are presented graphically and discussed in detail. The results are consistent with a deviation of 1.3 to 15 per cent with the results of other researchers. Originality/value The effects of the Re numbers and volume fractions of nanoparticles (0.01 <= Phi <= 0.04) on the heat transfer and fluid flow characteristics such as average Nu number, pressure drop (Delta P) and Darcy friction factor (f) were investigated.Öğe Performance analysis of using CuO-Methanol nanofluid in a hybrid system with concentrated air collector and vacuum tube heat pipe(Pergamon-Elsevier Science Ltd, 2019) Kaya, Metin; Gurel, Ali Etem; Agbulut, Umit; Ceylan, Ilhan; Celik, Selim; Ergun, Alper; Acar, BahadirAn experimental study was conducted to determine the effects of adding copper oxide (CuO) with 50 nm diameter into neat methanol (CH3OH) on the energetic and exergetic analysis of a concentrated air collector with vacuum tube heat pipe at different air velocities (1, 2 and 3 m/s). The experimental results clearly indicated that the nanofluid application enhanced the thermal properties and provided better performance for heat pipe applications. Considering all air velocities together, the average efficiency for neat methanol and CuO-Methanol nanofluid was achieved by 65% and 64%, respectively. Additionally, the average specific exergy outlet values for neat methanol and CuO-Methanol nanofluid were calculated as 206 J/kg and 298 J/kg, respectively. In the experiments, it is seen that the efficiency values of the system using the CuO-Methanol nanofluid reached higher values, as the solar radiation values were higher. In conclusions, this paper distinctly suggests that the presence of copper oxide in the base fluid can be used in a concentrated air collector with vacuum tube heat pipe particularly at the high radiation conditions and positively affects the performance of the system.
