Makine Mühendisliği Bölümü Yayın Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/263

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Citation - Scopus: 1
A Droplet Based Multi-Drug Screening System Controlled With Electrostatic Microvalves
(Chemical and Biological Microsystems Society, 2012) Yildirim, E.; Yıldırım, Ender; Özgür, E.; Külah, H.; 31835; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This paper presents a droplet-based drug effect analysis system utilizing electrostatically-actuated normallyclosed microvalves to screen the effect of multiple drugs on a single type of cell. Proposed system minimizes the need for off-chip equipment by utilizing parylene based electrostatic microvalves. Prototypes of the system were fabricated and tested using colored DI water and 3 μm diameter micro beads, emulating drugs and cells respectively. During the tests, micro beads could be successfully entrapped in 137 pl droplets. Tests carried out with yeast cells also yielded successful encapsulation of the cells. It was shown that, switching between the drugs could be achieved by applying 200 V dc to operate the microvalves.
Droplet Based Cell Screening System Integrated With Cmos Image Sensor and Android-Based Application
(Chemical and Biological Microsystems Society, 2020) Yıldırım, Ender; Özkan, M.D.; Aslan, M.K.; Atik, A.C.; Özgür, E.; Yıldırım, E.; Külah, H.; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This paper presents a droplet based single cell screening concept, where the cells encapsulated in microdroplets are monitored by integrating a commercial CMOS image sensor to the microfluidic chip. The images acquired through the image sensor are streamed and processed via an Android-based application on smartphone. This integrated system offers microscope-free screening of cells within the droplets based on their shapes. © 17CBMS-0001.
Citation - WoS: 7
Citation - Scopus: 7
Development and Experimental Investigation of Electrochemical Drilling Method Using Rotary Tube Tool
(Gazi Univ, Fac Engineering Architecture, 2013) Ozerkan, H. Bekir; Çoğun, Can; Cogun, Can; 132262; 3837; Mekatronik Mühendisliği; 06.08. Mekatronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this study, a new hybrid electrochemical drilling (ECD) method, based on electrochemical machining in nonconventional machining processes, was developed. In the developed method, tube tool makes rotary motion together with inner through hole flushing. A small scale prototype ECD machine has been designed and manufactured to test the developed method. One of the important features of the new system is the regulation of tool feed rate using current feedback control. The Hadfield (manganese) steel, whose strain hardening behavior makes it very difficult to machine with conventional methods, and AISI 1040 steel, whose machinability is fairly good, were drilled using the prototype machine and results were compared. Workpiece material removal rate increased with the increasing machining voltage, tool rotational speed, electrolyte concentration and flushing pressure in both types of steels. Average radial overcut values increased with the rotational speed of the tool. The AISI 1040 steel hole geometries were regular than that of Hadfield steel. Experimental results showed that deep holes can be drilled successfully with the proposed hybrid ECD method.
Citation - Scopus: 4
Small-Scale Mechanical Properties of Additively Manufactured Ti-6al
(The University of Texas at Austin, 2020) Totuk, Onat Halis; Haghshenas, M.; Totuk, O.; Masoomi, M.; Thompson, S.M.; Shamsaei, N.; 284521; Mekatronik Mühendisliği; 06.08. Mekatronik Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This article aims at studying microstructure and nano/micro-scale mechanical responses of Ti-6Al4V fabricated using a Laser-based Powder Bed Fusion (L-PBF) method. To this end, an instrumented depth-sensing nanoindentation system has been used to assess hardness, Young's modulus, strain rate sensitivity and rate dependent plastic deformation of the alloy at different build Orientations (in the Z-plane and X-plane) at ambient temperature. Indentation tests were conducted at constant proportional loading rate of 15 mN/s in a depth-controlled (hind=2000 nm) testing regime. The Microstructure characterizations were performed using optical and scanning electron microscopy to assess the correlations to the mechanical properties achieved by the nanoindentation testing to better establish structure-property relationships for L-PBF Ti-6Al-4V. It is expected that the fine microstructure, developed by fast solidification during the L-PBF process, to directly contribute to the nanoindentation measurements at different strain rates. Copyright © SFF 2017.All rights reserved.
Citation - WoS: 1
Numerical Analysis of Pulsating Circular Impinging Laminar Jet on a Planar Disc
(Turkish Soc thermal Sciences Technology, 2017) Kahroba, Mitra; Türkoğlu, Haşmet; Turkoglu, Hasmet; 12941; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this study, the flow and heat transfer characteristics of pulsating circular air jets impinging on a flat surface were numerically analyzed. The jet velocity pulsated in time. The objective of the work is to investigate the influence of the jet Reynolds number, pulsation amplitude and pulsation frequency on the rate of heat transfer from the target hot surface. For the analysis, a computer program, based on the control volume method and SIMPLE algorithm, was developed. Laminar flow with the time averaged jet Reynolds numbers between 300 and 700 were analyzed. The pulsation amplitude is ranged between 0.0V(0) (steady jet) and 0.8V(0) (m/s) (V-0 is period averaged jet velocity), and the frequency is ranged between 1 and 6 Hz. The nozzle-to-plate distance was kept constant at H/d=3. From the simulation results, it was observed that at any instant of the pulsation period, the local Nusselt number is maximum at the stagnation point, and it decreases along the plate. This decrease in the local Nusselt number is not monatomic as in the steady jet cases. It has local maximum and minimum values (fluctuations) due to the moving recirculating flow regions along the bottom plate. At low frequencies, the time (period) averaged stagnation point Nusselt numbers are lower than the corresponding steady jet Nusselt numbers. However, with the increasing frequency, the stagnation point Nusselt number increases and become higher than the steady jet Nusselt number.
Experimental Study and Theoretical Investigation of High Temperature Proton Exchange Membrane Fuel Cell Micro-Cogeneration Application
(Turkish Soc thermal Sciences Technology, 2018) Yapıcı, Ekin; Devrim, Yilser; Ozgirgin Yapici, Ekin; 31329; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this study, a house hold micro-cogeneration system is designed using high temperature proton exchange membrane (HTPEM) fuel cell. HTPEM type fuel cells gain the highest interest lately, due to their advantages in terms of increasing efficiency and power quality, reducing harmful emissions and flexibility of operation with respect to the other fuels. The micro-cogeneration system involves producing both electrical energy and hot water and/or vapor together in an economical way, utilizing single fuel (HTPEM fuel cells) for household applications. During the operation of the fuel cell, for high efficiency and stable power production, the access heat of the stack should be removed constantly and the temperature of the stack should be held stable. Heat recovered from the designed innovative cooling system is used for acquiring energy for heating water. This way, thermal efficiency is almost doubled compared to simple cycle. In the scope of this study, 225 W HTPEM fuel cell stack is designed and tested at 160 degrees C operation temperature with hydrogen gas and air. During operation, for homogenous distribution of temperature among the cells, for a short start up period leading to a fast required steady state temperature and for constantly removing the access heat produced in the cell, the cell stack is cooled by using a cooling fluid (Heat Transfer Oil 32- Petrol Ofisi). Selection of insulation material type and thickness for the cell stack is done using natural convection and radiation loss calculations. For the most efficient operating conditions, micro-cogeneration system water inlet and exit temperatures, water and cooling fluid flow rates, convenient pipe diameter and pump power calculations are done to finalize the design. With the cogeneration system designed during the studies, by recovering the access heat of the insulated HTPEM cell stack, district water with initial temperature of 15-20 degrees C is heated around 50 degrees C. Data gathered during studies indicate that fuel cell micro-cogeneration application is highly viable.
Fluorescent On-Chip Imager by Using a Tunable Absorption Filter
(Ieee, 2017) Arpali, Caglar; Yıldırım, Ender; Yildirim, Ender; Arpali, Çağlar; Arpali, Serap Altay; Arpali, Serap; 20809; 31835; 51304; Makine Mühendisliği; Mekatronik Mühendisliği; Elektronik ve Haberleşme Mühendisliği; 06.06. Makine Mühendisliği; 06.08. Mekatronik Mühendisliği; 06.02. Elektronik ve Haberleşme Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Citation - WoS: 12
Citation - Scopus: 13
A Reconfigurable Microfluidic Transmitarray Unit Cell
(Ieee, 2013) Erdil, Emre; Yıldırım, Ender; Topalli, Kagan; Zorlu, Ozge; Toral, Taylan; Yildirim, Ender; Kulah, Haluk; Civi, Ozlem Aydin; 31835); Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This paper presents a novel microfluidics based approach to develop a reconfigurable circularly polarized transmitarray unit cell. The unit cell comprises double layer nested split ring slots formed as microfluidic channels that can be filled by fluids. Split regions in the slots are realized by injecting liquid metal into the channels. Beam steering is obtained by implementing rotational phase shifting via manipulating the liquid metal in the slots. X-band unit cell prototypes are fabricated on glass substrate carrying a patterned metal film, and the slot channels are formed by Polydimethylsiloxane (PDMS) using soft lithography techniques.
Neck Protection in Autonomous Car Crashes
(Kauno Technologijos Universitetas, 2020) Yavuz, Samet; Yavuz, S.; Himmetoglu, S.; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Autonomous cars which are expected to be on the market in the upcoming years, present new challenges to restraint system design since unconventional seating plans can put the occupants at more risk. For instance, an occupant sitting on a rear facing seat can experience higher risk of whiplash in a frontal impact considering the fact that statistically frontal impacts do happen at higher severities than rear impacts as seen in the crash test conditions of US NCAP. In this study, an improvement to car seat design is presented in which the seatback is automatically rotated into a more upright position prior to impact in order to increase the energy absorbing potential of the seatback. The study involves computer simulation of a seat-occupant system to demonstrate the benefits of the proposed system. © 2020 Kaunas University of Technology. All rights reserved.
Citation - WoS: 3
Citation - Scopus: 3
Empirical and Statistical Modeling of Heat Loss From Surface of a Cement Rotary Kiln System
(Gazi Univ, Fac Engineering Architecture, 2013) Simsek, Baris; Altunok, Taner; Simsek, Emir H.; Altunok, Taner; 220872; 8009; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In branches of industry too much energy consuming such as cement sector, controlled use of energy, only it is possible to know how energy is distributed in the system. In cement production process, a large portion of the heat losses which is due to energy consumption consist of convection and radiation heat losses from the surface of rotary kiln. In this study, empirical equation was derived for heat loss from surface of rotary kiln in a cement factory using empirical equations and statistical modeling techniques by the help of temperatures measured surface of rotary kiln. Measured with thermal cameras and the data necessary for experimental modeling was obtained the factory central control room. Total heat loss of system was calculated using Matlab. Statistical analysis related to results was carried out by Minitab 15.1.1 program. It was concluded that heat losses throughout rotary kiln increased toward the center of the kiln.
Citation - WoS: 5
Citation - Scopus: 5
Ann and Anfis Performance Prediction Models for Francis Type Turbines
(Turkish Soc thermal Sciences Technology, 2020) Aylı, Ülkü Ece; Ayli, Ece; Ulucak, Oguzhan; 265836; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Turbines can be operated under partial loading conditions due to the seasonal precipitation fluctuations and due to the needed electrical demand over time. According to this partial working need, designers generate hill chart diagrams to observe the system behavior under different flow rates and head values. In order to generate a hill chart, several numerical or experimental studies have been performed at different guide vane openings and head values which are very time consuming and expensive. In this study, the efficiency prediction of Francis turbines has been performed with ANN and ANFIS methods under different operating conditions and compared with simulation results. The obtained results indicate that it is possible to obtain a hill chart using ANFIS method instead of a costly experimental or numerical tests. ANN and ANFIS parameters which effect the output, have been optimized with trying 100 different cases. 75% of the numerical data set is used for training and 25 % is used for validation as testing data. To asses and compare the performance of multiple ANN and ANFIS models several statistical indicators have been used. Insight to the performance evaluation, it is seen that ANFIS can predict the efficiency distribution with higher accuracy than the ANN model. The developed ANFIS model predicts the efficiency with 1.41% mean average percentage error and 0.999 R-2 value. To the best of the author's knowledge, this is the first study in the literature that ANN and ANFIS are used in order to predict the efficiency distribution of the turbines at different loading conditions.
Phaseguide Assisted Liquid Lamination for Magnetic Bead-Based Assays
(Chemical and Biological Microsystems Society, 2013) Phurimsak, C.; Yıldırım, Ender; Yildirim, E.; Trietsch, S.J.; Hankemeier, T.; Tarn, M.D.; Pamme, N.; Vulto, P.; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
We demonstrate a simple, pump-free platform for performing rapid magnetic bead-based processes via their transfer through sequentially laminated liquid streams, made possible by the use of phaseguide technology. We have applied this strategy to two on-chip assays: (i) a streptavidin-biotin binding assay, and (ii) a sandwich immunoassay for the detection of C-reactive protein (CRP). Here, functionalized magnetic beads were pulled through alternating lanes of reagents and buffer solution, allowing multiple binding and washing processes to be reduced into a single step, significantly shortening procedural times compared to conventional multi-step bead-based assays.
Citation - WoS: 3
Citation - Scopus: 4
Numerical Analysis of a Commercial Display Cabinet With Air Curtain
(Gazi Univ, Fac Engineering Architecture, 2011) Caliskan, Sinan; Altunok, Taner; Altunok, Taner; Baskaya, Senol; Gungunes, H. Murat; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Maintaining food temperatures below critical values is the important maximising the high quality display life of chilled foods. Air curtains are especially used in stores and retailer supermarkets as barrier systems to seperate inner and outer spaces from each other. For both air quality and energy saving, it is crucial that the air transfer between these two spaces are at minimum. Minimization of air transfer between inner and outer spaces, not only decreases heat transfer but also stabilizes the humidity balance. In this study, numerical analysis of a commercial display cabinet has been carried out. For this purpose PHOENICS, a computational fluid dynamics code, is utilized. Optimum jet system conditions for each of the one jet, two jet and there jet systems has been modified according to temperature change of the air, and comparisons among them have been made. The results indicate that, the results the both CFD analysis and experimental results are almost equal and refrigeration systems with three jets is required to obtain the necessary temperature values to keep products fresh in display cabinets, especially because they can distribute temperature in a homogeneous way, meaning that the temperature value is the best ideal system at every point in the cabinet with three jets.
Citation - Scopus: 1
Effects of Earthquake Motion on Mechanism Operation: an Experimental Approach
(Levrotto and Bella, 2015) Selvi, Ö.; Selvi, Özgün; Ceccarelli, M.; Aytar, E.B.; 46949; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This paper presents an experimental characterization of the effects of earthquakes on the operation of mechanical systems with the help of CaPaMan (Cassino Parallel Manipulator), which is a 3 DOF robot that can fairly well simulate 3D earthquake motion. The sensitivity of operation characteristics of machinery to earthquake disturbance is identified and characterized through experimental tests. Experimental tests have been carried out by using a slider-crank linkage, a small car model, and LARM Hand as test-bed mechanisms that have been sensored with proper acceleration or force sensors. Results are reported and discussed to describe the effects of earthquake motion on the characteristics of mechanism operation as a service application of the robotic CaPaMan system.
Clean Energy Generation in Residential Green Buildings
(inst Engineering Tech-iet, 2019) Aylı, Ülkü Ece; Yapici, Ekin Ozgirgin; Ayli, Ece; Makine Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Due to the recent investigations, buildings consume a considerable amount of the electricity, drinking water, global final energy use and as a result are responsible for one third of the global carbon emissions. Therefore, building sector has a key role to reach global energy targets. In this sight, this study draws attention to the sustainable energy performances of green buildings (GBs) and aims towards the GBs concept which includes renewable sources in the construction and lifetime utilization. The remainder of the chapter is subjected as follows: Section 2.1 gives a brief information about residential GBs, and in Section 2.2, certification systems for sustainability ratings of residential GBs are given. This is followed by case studies related to the certification systems in Section 2.3 part. In Section 2.4, GBs incentives are summarized. Section 2.5 provides information about energy demand modelling for residential GBs, and in Section 2.6, clean energy generation systems in residential GBs are described in detail. Finally, outlook for the works that is performed up to now and the outlook for the future is given.
Citation - Scopus: 3
Fused Filament Fabrication in Cad Education: a Closed-Loop Approach
(Sage Publications inc, 2025) Totuk, Onat Halis; Selvi, Ozguen; Akar, Samet; 315516; 06.08. Mekatronik Mühendisliği; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Integrating low-cost fused filament fabrication 3D printing as a foundation for learning 3D modelling is explored. This method blends traditional computer aided design (CAD) instruction with additive manufacturing possibilities. Experimental results demonstrate increased comprehension speed and reduced learning time. This hands-on approach empowers students by enabling direct engagement with the modelling process. Analogous to reverse engineering, the strategy instructs engineering students from final product to model creation, closing the gap between theory and practice. Incorporating 3D printing bridges this divide, enhancing understanding, creativity and problem-solving. The study underscores technology's influence on learning strategies, aligning with the surge of 3D printing in education. Results link advanced design technology usage to improved student performance, with 3D-printed materials yielding 45% higher grades and 30% faster task completion. This study advocates curricular advancement for design-focused careers through enhanced technology integration and favourable 3D printing model reception.
Citation - WoS: 2
Citation - Scopus: 1
Exploring the Potential of Artificial Intelligence Tools in Enhancing the Performance of an Inline Pipe Turbine
(Sage Publications Ltd, 2024) Celebioglu, Kutay; Ayli, Ece; Cetinturk, Huseyin; Tascioglu, Yigit; Aradag, Selin; 265836; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
In this study, investigations were conducted using computational fluid dynamics (CFD) to assess the applicability of a Francis-type water turbine within a pipe. The objective of the study is to determine the feasibility of implementing a turbine within a pipe and enhance its performance values within the operating range. The turbine within the pipe occupies significantly less space in hydroelectric power plants since a spiral casing is not used to distribute the flow to stationary vanes. Consequently, production and assembly costs can be reduced. Hence, there is a broad scope for application, particularly in small and medium-scale hydroelectric power plants. According to the results, the efficiency value increases on average by approximately 1.5% compared to conventional design, and it operates with higher efficiencies over a wider flow rate range. In the second part of the study, machine learning was employed for the efficiency prediction of an inline-type turbine. An appropriate Artificial Neural Network (ANN) architecture was initially obtained, with the Bayesian Regularization training algorithm proving to be the best approach for this type of problem. When the suitable ANN architecture was utilized, the prediction was found to be in good agreement with CFD, with an root mean squared error value of 0.194. An R2 value of 0.99631 was achieved with the appropriate ANN architecture.
Citation - WoS: 6
Citation - Scopus: 7
Analysis of Heat Transfer Enhancement of Passive Methods in Tubes With Machine Learning
(Sage Publications Ltd, 2024) Ayli, Ece; Turkoglu, Hasmet; Yapici, Ekin Ozgirgin; 31329; 265836; 12941; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This study investigates the efficacy of machine learning techniques and correlation methods for predicting heat transfer performance in a dimpled tube under varying flow conditions, including the presence of nanoparticles. A comprehensive numerical analysis involving 120 cases was conducted to obtain Nusselt numbers and friction factors, considering different dimple depths and velocities for both pure water and water-Al2O3 nanofluid at 1%, 2%, and 3% volume concentrations. Utilizing the data acquired from the numerical simulations, a correlation equation, SVM ANN architectures were developed. The predictive capabilities of the statistical approach, ANN, and SVM models for Nusselt number distribution and friction factor were meticulously assessed through mean average percentage error (MAPE) and correlation coefficients (R2). The research findings reveal that machine learning techniques offer a highly effective approach for accurately predicting heat transfer performance in a dimpled tube, with results closely aligned with Computational Fluid Dynamics (CFD) simulations. Particularly noteworthy is the superior performance of the ANN model, demonstrating the most precise predictions with an error rate of 2.54% and an impressive R2 value of 0.9978 for Nusselt number prediction. In comparison, the regression model achieved an average error rate of 6.14% with an R2 value of 0.8623, and the SVM model yielded an RMSE value of 2.984% with an R2 value of 0.9154 for Nusselt number prediction. These outcomes underscore the ANN model's ability to effectively capture complex patterns within the data, resulting in highly accurate predictions. In conclusion, this research showcases the promising potential of machine learning techniques in accurately forecasting heat transfer performance in dimpled tubes. The developed ANN model exhibits notable superiority in predicting Nusselt numbers, making it a valuable tool for enhancing thermal system analyses and engineering design optimization.
Citation - WoS: 9
Citation - Scopus: 8
A Novel Cfd-Ann Approach for Plunger Valve Optimization: Cost-Effective Performance Enhancement
(Elsevier Sci Ltd, 2024) Kaak, Abdul Rahman Sabra; Celebiog, Kutay; Bozkus, Zafer; Ulucak, Oguzhan; Ayli, Ece; 265836; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
This paper introduces a novel computational fluid dynamics-artificial neural network (CFD-ANN) approach that has been devised to enhance the efficiency of plunger valves. The primary emphasis of this research is to achieve an optimal equilibrium between hydraulic flow and geometric configuration. This study is a novel contribution to the field as it explores the flow dynamics of plunger valves using Computational Fluid Dynamics (CFD) and proposes a unique methodology by incorporating Machine Learning (ML) for performance forecasting. An artificial neural network (ANN) architecture was developed using a thorough comprehension of flow physics and the impact of geometric parameters acquired through computational fluid dynamics (CFD). Using optimization, the primary aspects of the Artificial Neural Network (ANN), including the learning algorithm and the number of hidden layers, have been modified. This refinement has resulted in the development of an architecture exhibiting a remarkably high R2 value of 0.987. This architectural design was employed to optimize the plunger valve. By utilizing Artificial Neural Networks (ANN), a comprehensive analysis comprising 1000 distinct configurations was effectively performed, resulting in a significant reduction in time expenditure compared to relying on Computational Fluid Dynamics (CFD). The result was a refined arrangement that achieved maximum head loss, subsequently verified using computational fluid dynamics (CFD) simulations, resulting in a minimal discrepancy of 2.66%. The efficacy of artificial neural networks (ANN) becomes apparent due to their notable cost-efficiency, along with their capacity to produce outcomes that are arduous and expensive to get through conventional optimization research utilizing computational fluid dynamics (CFD).
Soğutma Yüküne Bağlı Olarak Set Sıcaklığı Değişen Hava Soğutmalı Soğutma Grubunun Performansının Deneysel İncelenmesi
(2017) Erşahin, Yasin; Türkoğlu, Haşmet; 12941; 06.06. Makine Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Alışılmış enerji kaynaklarının global enerji ihtiyacını karşılamadaki yetersizliği, her geçen gün enerji ihtiya- cının artması ve enerji üretiminden kaynaklanan çevre kirliliği gibi sebepler enerji verimliliğinin önemini artır- maktadır. Günümüzde bütün sektörlerde, enerjiyi ola- bildiğince verimli kullanabilecek teknikler geliştirilmeye çalışılmaktadır. Gelişmiş ülkeleri incelediğimizde, ısıt- ma ve soğutma alanındaki önceliklerde ilk sırayı enerji verimliliği almaktadır. Merkezi yaşam alanları için gerekli olan soğutma ih- tiyacı, gün veya sezon içerisinde sürekli değişiklik gös- termektedir. Mahaldeki insan sayısının ve hava hare- ketliliğinin değişmesiyle ihtiyaç olan soğutma yükü de değişmektedir. Mahale bağlı bulunan soğutma grubu- nun bu değişken soğutma yüküne göre kendini ayar- layıp, hızlı bir şekilde reaksiyon vermesi enerjinin daha verimli kullanılmasını sağlamaktadır. Bu çalışmada, standart soğutma grubu kontrol tekniği ve adaptif algoritmalı kontrol tekniği ile kontrol edilen bir soğutma grubunun performansı ve enerji tüketimi, deneysel olarak incelenmiş ve sonuçlar karşılaştırma- lı olarak sunulmuştur. Testlerde, her iki kontrol sistemi için değişken soğutma yükü sağlanması amacıyla ciha- zın evaporatör su giriş sıcaklığı 12-7°C arasında de- ğiştirilerek, soğutma grubu kompresörlerinin devreye girmesi ve devreden çıkması sağlanmıştır. Tam ve kıs- mi soğutma yükleri altında yapılan ölçümlerde, adap- tif kontrol sistemi ile kontrol edilen soğutma grubunun, standart kontrol sistemine göre ortalama %10,72 daha az enerji tükettiği ve toplam ekserji yıkımının ise orta- lama % 6,23 daha az olduğu görülmüştür.

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