Browsing by Author "Turhan, Cihan"

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Citation Count: 1
AKILLI BİNA UYGULAMALARINDAKİ HAVALANDIRMA SISTEMI KONTROL STRATEJILERINDE KULLANICI SAYISI TESPITI TEMELLI YENI BIR YAKLAŞIM
(2021) Turhan, Cihan; Çeter, Aydın Ege; Energy Systems Engineering
Binalarda kullanılan geleneksel havalandırma sistemleri tutarlı bir şekilde işlevini yerine getirmesine karşın, iç ortamda yeterli konforu sağlamamaktadır. Akıllı havalandırma sistemleri ise enerji tüketimini en aza indirirken, istenilen iç hava kalitesini sağlamak için iç ortam parametrelerini isteğe bağlı olarak kullanıcı sayısı tespiti ile ayarlamaktadır. Kabul edilebilir iç hava kalitesi için havalandırma gereksinimlerini düzenleyen ASHRAE 62 standardı, zamandan bağımsız kullanıcı sayısı tespit algoritmaları kullanmaktadır. Ancak bu tip simülasyon çalışmalarında dinamik metot ve algoritmaların kullanılması gerekmektedir. Bu amaç doğrultusunda, Ankara ATILIM Üniversitesi Mühendislik Fakültesi’nde yer alan bir ofis alanında, kullanıcı sayısı tespiti ile yeni bir dinamik havalandırma sistemi kontrol stratejisi geliştirilmiştir. Bu algoritma, karbondioksit konsantrasyonu, iç hava sıcaklığı ve kapı konumunu tespit eden bir dizi sensör yardımı ile elde edilmiştir. Üretilen prototip, HVAC sistemin hava akışını düzenlemektedir ve gerçek koşullarda test edilmiştir. Geliştirilen yeni yöntemin testleri 1 Ocak 2020 – 15 Ağustos 2020 tarihleri arasında yapılmış olup, termal konfor ve enerji tüketimi bağlamında geleneksel HVAC yönetim sistemi ile karşılaştırılmıştır. Elde edilen sonuçlara göre yeni kontrol stratejisi ve prototipin enerji tüketimini %16 azalttığını, aynı zamanda kişilerin %94’ünün ısıl konforu sağladığı tespit edilmiştir.
Bir eğitim binasının termal konfor incelenmesi ve güçlendirilmesi stratejileri
(2022) Rashıd, Sanarya Ghazı Rashıd; Turhan, Cihan; Energy Systems Engineering
Binaların, küresel sürdürülebilir kalkınma açısından en büyük enerji tüketicilerinden biri olduğu bilinmektedir. Teknolojik gelişmeler çevre dostu binaların inşasına aktif olarak yardımcı olsa da, mevcut binalar da önemli miktarda enerji tüketiyor. En önemli yapı türlerinden biri de inceleyeceğimiz eğitimdir. Gelecek nesillere kaliteli bir eğitim verebilmek için kaliteli okul yapılarına sahip olunması gerekmektedir. Binayı birçok faktör etkilerken, ısıl konfor öğrencileri etkileyen en etkili faktördür. Termal konfor, bir insanın termal çevresi ile olan zevkini ifade eder. Hoş bir termal ortam, fiziksel ve zihinsel sağlığı destekler. Bu çalışma, bu faktörü dikkate almakta ve tasarımı yeniden inşa etmeden farklı iyileştirmeler ekleyerek eğitim binalarında ısıl konforu iyileştirme potansiyelini incelemeye çalışmaktadır. Halihazırda mevcut bir binanın analiz modeli Atılım Üniversitesi, Ankara Design Builder yazılımı kullanılarak yapılmıştır. İlk olarak orijinal kasa binası üzerinde simülasyon yapılmıştır. Daha sonra binanın modifiye edilmiş kasaları üzerinde, toplamda yedi kasa simülasyonu yapılmıştır. pencere ve çerçeve tiplerini değiştirmeyi, bir Trombe duvarı eklemeyi içerir. Yalıtım malzemesinin her seferinde üç farklı malzeme ile değiştirilmesi, güneş kollektörü eklenmesi, ayarlanan sıcaklık ve hava sızdırmazlığının değiştirilmesi ve ışık sistemlerinin led tipine dönüştürülmesi. Model, yıllık enerji tüketimi için simüle edilmiş ve sonuçlar kaydedilmiştir Bu, ilk vi güçlendirme senaryosu seçeneğiydi. Bina yöneliminin revizyonunu dikkate alan teorik bir yeniden tasarım senaryosu da oluşturuldu. Vakalar arasında karşılaştırmalı bir analiz yapılmış ve çalışma, hava sızdırmazlığının hiçbir vakadan etkilenmediğini, öğrenci ısıl konforu için en etkili durumun ise öğrenci rahatsızlık saatlerini %17 azaltan Taşyünü yalıtım malzemesi uygulaması olduğunu göstermiştir. CO2 emisyonlarını azaltmak ve enerji tüketimini azaltmak için en etkili olurken, hava sızdırmazlığı hiçbir durumdan etkilenmedi. ve güneş kollektörü uygulamak en pahalı durumdu.
Citation Count: 0
A case study on measuring course learning outcomes in software engineering education;
(CEUR-WS, 2017) Karakaya,M.; Turhan,C.; Yazici,A.; Energy Systems Engineering; Computer Engineering; Software Engineering
One of the most critical outcomes in the MÜDEK accreditation system which plays an important role in the evaluation and assessment of the quality of education in higher education institutions is evaluating how much students have achieved the course outcomes. This study aims to compare two methods utilized to measure course outcomes in the Software Engineering department of Atilim University. In the most general sense, these two methods are based on indirect and direct measurement techniques. The results of the analysis show a high degree of differentiation between the direct measurement and indirect measurement results. In light of the results obtained, some recommendations have been offered for course outcome assessment methods to be developed in the scope of MÜDEK accreditation.
Citation Count: 0
A Case Study on the Assumption of Mean Radiant Temperature Equals to Indoor Air Temperature in a Free-Running Building
(2021) Özbey, Mehmet Furkan; Turhan, Cihan; Energy Systems Engineering; Mechanical Engineering
Thermal comfort is basically affected by environmental (mean radiant temperature, indoor air temperature and relative humidity and air velocity) and personal parameters (clothing value and activity level). Mean Radiant Temperature is the most complicated parameter among all thermal comfort parameters due to the difficulty of measurement and calculation processes. Calculation methods are not preferred by the researchers because of the complexity of obtaining angle factors while the measurement methods require very expensive devices such as globe thermometers and radiometers. On the other hand, assumptions are commonly used in thermal comfort studies because of their simplicities. One of the most frequently used assumptions expresses the equality of mean radiant temperature to indoor air temperature. However, the accuracy of this assumption needs further experimental research in order to evaluate thermal comfort, especially in free-running buildings. To this aim, this study proposes to determine the accuracy of the assumption of mean radiant temperature equals to indoor air temperature in a free-running building where Adaptive Thermal Comfort approach is applied in summer condition. Environmental parameters are measured via objective sensors, while adaptive thermal comfort is assessed by a software program. The statistical results show that there are significant deviations between two parameters in summer conditions for a free-running building.
Citation Count: 1
Comfort based investigation on historic libraries for user satisfaction and preservation of paper-based collections
(IOP Publishing Ltd, 2021) Turhan,C.; Topan,C.; Durmus Arsan,Z.; Goksal Ozbalta,T.; Gok en Akkurt,G.; Software Engineering; Energy Systems Engineering
Historic libraries preserve cultural heritage values while housing rare manuscripts and paper-based collections. The collections in the libraries are deteriorated chemically, biologically and mechanically due to inappropriate indoor environment conditions such as temperature and relative humidity fluctuations and microbiological conditions. Apart from preserving vulnerable paper-based collections, accommodating of a considerable thermal comfort level for visitors is essential in historic libraries. The aim of this study is to analyse indoor environment of a historic library in terms of thermal comfort and preventive conservation of paper-based collections. Izmir National Library, built in 1933, is selected as a case study. Indoor air temperature, relative humidity and air velocity in the library were monitored with a one-year measurement campaign. Meanwhile, thermal comfort of the visitors was assessed with PMV/PPD indices and thermal sensation surveys. The results show that high chemical degradation risk is detected in the library while biological and mechanical degradations are in the low risk zone. On the other hand, 87% and 93% of the visitors feel thermally satisfied in heating and cooling seasons, respectively. © Published under licence by IOP Publishing Ltd.
Citation Count: 10
A comprehensive assessment plan for accreditation in engineering education: A case study in Turkey
(Tempus Publications, 2015) Turhan,C.; Sengul,G.; Koyuncu,M.; Energy Systems Engineering; Information Systems Engineering; Computer Engineering
This paper describes the procedure followed by Computer Engineering and Software Engineering programs at Atilim University, Ankara, Turkey, which led to the granting of five years of accreditation by MUDEK, the local accreditation body authorized by The European Network for Accreditation of Engineering Education (ENAEE) to award the EUR-ACElabel, and a full member signatory of Washington Accord of International Engineering Alliance(IEA). It explains the organizational structure established for preparation, determination and measurement of the educational objectives, program outcomes, course outcomes, and the continuous improvement cycle carried out during the preparation period. The aim of the paper is to share methods and experiences which may be beneficial for the other programs that are intended for accreditation. © 2015 TEMPUS Publications.
Citation Count: 11
A comprehensive comparison and accuracy of different methods to obtain mean radiant temperature in indoor environment
(Elsevier, 2022) Ozbey, Mehmet Furkan; Turhan, Cihan; Energy Systems Engineering; Mechanical Engineering
Thermal comfort is defined as "the state of mind which expresses satisfaction with the thermal environment" by the American Society of Heating, Refrigerating and Air Conditioning Engineers in the standard of the ASHRAE55. Thermal comfort is affected by six main parameters which are split into two categories; personal (basic clothing insulation value and metabolic rate) and environmental (air temperature, relative humidity, air velocity, and mean radiant temperature) parameters. The mean radiant temperature is a problematic parameter in thermal comfort studies due to its complexity. The mean radiant temperature approaches are based on different techniques such as calculation methods, measurement methods, and assumptions. Although the assumptions are utilized by researchers to abstain complexity, their accuracies are uncertain. To this aim, this study purposes to find the accuracies of calculation and assumption methods by comparing with reference measurement method. An office building in a temperate climate zone is selected as a case study. Two calculation methods and eight assumptions on obtaining mean radiant temperature are compared via in-situ measurements. The results revealed that using assumptions or calculation methods to obtain the mean radiant temperature caused a significant error compared to the reference method and researchers should consider accuracies of these methods before utilizing them in their applications.
Citation Count: 31
A comprehensive evaluation of the most suitable HVAC system for an industrial building by using a hybrid building energy simulation and multi criteria decision making framework
(Elsevier, 2021) Bac, Ugur; Alaloosi, Khalid Abdulwahab Mohamed Saed; Turhan, Cihan; Energy Systems Engineering; Industrial Engineering
Great demand for energy and growing trend in the use of energy-efficient HVAC systems force researchers to focus on the importance of choosing the most appropriate HVAC system for industrial buildings during design process. Therefore, developing a model to select the most suitable HVAC system is vital for industrial buildings. To this aim, this study provides a comprehensive evaluation of different HVAC systems for an industrial building by using hybrid multi criteria decision making (MCDM) method. An industrial building in Ankara/Turkey is selected as a case building. Eleven HVAC systems are evaluated based on twenty seven criteria, which are determined as a result of extensive literature research, and are grouped under six categories including ergonomic, environmental, reliability, technical, and economical aspects. A hybrid application of building energy simulation (BES) integrated modified Stepwise Weight Assessment Ratio Analysis (SWARA) and Weighted Additive Sum Product Assessment (WASPAS) framework is developed for supporting the decision making process. The novelty of the study is integrating the objective results of a well-calibrated dynamic BES tool with subjective criteria which are collected from expert opinions by applying questionnaires with face-to-face interview method. The results of MCDM framework and sensitivity analysis showed that the water-source heat pump is the best and suitable alternative for the industrial building. The outcome of this study would benefit the HVAC engineers and specialists in order to design the best HVAC systems in industrial buildings while providing an insight into different criteria. Moreover, key contribution to the literature is the usage of hybrid MCDM framework integrated with BES tool in the building sector.
Citation Count: 6
Cutting Force Prediction in Ultrasonic-Assisted Milling of Ti-6al With Different Machining Conditions Using Artificial Neural Network
(Cambridge University Press, 2021) Namlu,R.H.; Turhan,C.; Sadigh,B.L.; Kiliç,S.E.; Energy Systems Engineering; Mechanical Engineering; Manufacturing Engineering
Ti-6Al-4V alloy has superior material properties such as high strength-to-weight ratio, good corrosion resistance, and excellent fracture toughness. Therefore, it is widely used in aerospace, medical, and automotive industries where machining is an essential process for these industries. However, machining of Ti-6Al-4V is a material with extremely low machinability characteristics; thus, conventional machining methods are not appropriate to machine such materials. Ultrasonic-assisted machining (UAM) is a novel hybrid machining method which has numerous advantages over conventional machining processes. In addition, minimum quantity lubrication (MQL) is an alternative type of metal cutting fluid application that is being used instead of conventional lubrication in machining. One of the parameters which could be used to measure the performance of the machining process is the amount of cutting force. Nevertheless, there is a number of limited studies to compare the changes in cutting forces by using UAM and MQL together which are time-consuming and not cost-effective. Artificial neural network (ANN) is an alternative method that may eliminate the limitations mentioned above by estimating the outputs with the limited number of data. In this study, a model was developed and coded in Python programming environment in order to predict cutting forces using ANN. The results showed that experimental cutting forces were estimated with a successful prediction rate of 0.99 with mean absolute percentage error and mean squared error of 1.85% and 13.1, respectively. Moreover, considering too limited experimental data, ANN provided acceptable results in a cost-and time-effective way. Copyright © The Author(s), 2020. Published by Cambridge University Press.
Citation Count: 3
Design and Validation of a Fault Tolerant Fuzzy Control for a Wind Park High-Fidelity Simulator
(Ieee, 2021) Simani, Silvio; Turhan, Cihan; Farsoni, Saverio; Energy Systems Engineering
To enhance both the safety and the efficiency of offshore wind park systems, faults must be accommodated in their earlier occurrence, in order to avoid costly unplanned maintenance. Therefore, this paper aims at implementing a fault tolerant control strategy by means of a data-driven approach relying on fuzzy logic. In particular, fuzzy modelling is considered here as it enables to approximate unknown nonlinear relations, while managing uncertain measurements and disturbance. On the other hand, the model of the fuzzy controller is directly estimated from the input-output signals acquired from the wind farm system, with fault tolerant capabilities. In general, the use of purely nonlinear relations and analytic methods would require more complex design tools. The design is therefore enhanced by the use of fuzzy model prototypes obtained via a data-driven approach, thus representing the key point if real-time solutions have to implement the proposed fault tolerant control strategy. Finally, a high-fidelity simulator including hardware-in-the-loop modules is exploited to validate the reliability and robustness characteristics of the developed methodologies also for on-line implementations.
Citation Count: 0
Determination of Metabolic Rate from Physical Measurements of Heart Rate, Mean Skin Temperature and Carbon Dioxide Variation
(2022) Özbey, Mehmet Furkan; Çeter, Aydın Ege; Turhan, Cihan; Energy Systems Engineering; Mechanical Engineering
Thermal comfort depends on four environmental parameters such as air temperature, mean radiant temperature, air velocity and relative humidity and two personal parameters, including clothing insulation and metabolic rate. Environmental parameters can be measured via objective sensors. However, personal parameters can be merely estimated in most of the studies. Metabolic rate is one of the problematic personal parameters that affect the accuracy of thermal comfort models. International thermal comfort standards still use a conventional metabolic rate table which is tabulated according to different activity tasks. On the other hand, ISO 8996 underestimates metabolic rates, especially when the time of activity level is short and rest time is long. To this aim, this paper aims to determine metabolic rates from physical measurements of heart rate, mean skin temperature and carbon dioxide variation by means of nineteen sample activities. 21 male and 17 female subjects with different body mass indices, sex and age are used in the study. The occupants are subjected to different activity tasks while heart rate, skin temperature and carbon dioxide variation are measured via objective sensors. The results show that the metabolic rate can be estimated with a multivariable non-linear regression equation with high accuracy of 0.97.
Citation Count: 23
Development of a personalized thermal comfort driven controller for HVAC systems
(Pergamon-elsevier Science Ltd, 2021) Turhan, Cihan; Simani, Silvio; Akkurt, Gulden Gokcen; Energy Systems Engineering
Increasing thermal comfort and reducing energy consumption are two main objectives of advanced HVAC control systems. In this study, a thermal comfort driven control (PTC-DC) algorithm was developed to improve HVAC control systems with no need of retrofitting HVAC system components. A case building located in Izmir Institute of Technology Campus-Izmir-Turkey was selected to test the developed system. First, wireless sensors were installed to the building and a mobile application was developed to monitor/ collect temperature, relative humidity and thermal comfort data of an occupant. Then, the PTC-DC algorithm was developed to meet the highest occupant thermal comfort as well as saving energy. The prototypes of the controller were tested on the case building from July 3rd, 2017 to November 1st, 2018 and compared with a conventional PID controller. The results showed that the developed control algorithm and conventional controller satisfy neutral thermal comfort for 92 % and 6 % of total measurement days, respectively. From energy consumption point of view, the PTC-DC decreased energy consumption by 13.2 % compared to the conventional controller. Consequently, the PTC-DC differs from other works in the literature that the prototype of PTC-DC can be easily deployed in real environments. Moreover, the PTC-DC is low-cost and user-friendly. (c) 2021 Elsevier Ltd. All rights reserved.
Citation Count: 91
Dynamic thermal and hygrometric simulation of historical buildings: Critical factors and possible solutions
(Pergamon-elsevier Science Ltd, 2020) Akkurt, G. G.; Aste, N.; Borderon, J.; Buda, A.; Calzolari, M.; Chung, D.; Turhan, C.; Energy Systems Engineering; Software Engineering
Building dynamic simulation tools, traditionally used to study the hygrothermal performance of new buildings during the preliminary design steps, have been recently adopted also in historical buildings, as a tool to investigate possible strategies for their conservation and the suitability of energy retrofit scenarios, according to the boundary conditions. However, designers often face with the lack of reliable thermophysical input data for various envelope components as well as with some intrinsic limitations in the simulation models, especially to describe the geometric features and peculiarities of the heritage buildings. This paper attempts to bridge this knowledge gap, providing critical factors and possible solutions to support hygrothermal simulations of historical buildings. The information collected in the present work could be used by researchers, specialists and policy-makers involved in the conservation of building's heritage, who need to address a detailed study of the hygrothermal performance of historical buildings thorugh dynamic simulation tools.
Citation Count: 10
Effect of pre-and post-exam stress levels on thermal sensation of students
(Elsevier Science Sa, 2021) Turhan, Cihan; Ozbey, Mehmet Furkan; Energy Systems Engineering; Mechanical Engineering
The Predicted Mean Vote and Predicted Percentage of Dissatisfied (PMV/PPD) method is used worldwide to assess thermal comfort. The PMV/PPD method traditionally depends on four environmental parameters; air temperature, relative humidity, mean radiant temperature and air velocity, and two personal parameters; metabolic rate and clothing insulation. However, accurate modelling of thermal comfort requires consideration of psychological impacts, as well as associated physical responses to the environment. This paper investigates the effect of one of the psychological parameters; stress level on the thermal sensation of students for male and female which can be a sufficient limitation of the accuracy of thermal comfort/sensation models. Actual Thermal Sensation (ATS) and Profile of Mood States (POMS) are used to examine the effect of stress level on the thermal sensation. Pre-test-Post-test Control (PPC) experimental design is conducted on the students in a university, Ankara, Turkey, which has a Csb type climate zone according to Koppen-Geiger climate classification. First, students are split into two random groups; control and experimental groups. The students in experimental group are requested to attend exam while the students in control group read their favourite books. Then, students are subjected to pre-and post-exam surveys in order to understand the relationship between stress level and ATS. As a supportive analysis, Heart Rate (HR) and Skin Temperature (ST) are also included in the study as sympathetic responses of occupants to the thermal discomfort due to stress. Smart wristbands and infrared thermometers are used to measure Heart Rate and Skin Temperature of the students. Results showed that there is a difference between control group and experimental group before the exam (pre-test) except the ST of females. After the exam (post-test), there are no significant differences between two groups. (C) 2020 Elsevier B.V. All rights reserved.
Citation Count: 0
Emotion Analysis on Turkish Texts: A Systematic Mapping Study
(Institute of Electrical and Electronics Engineers Inc., 2022) Altmay,G.; Turhan,C.; Software Engineering; Energy Systems Engineering
In recent years, the increase in internet usage also led to an increase in data. Therefore, the importance of classification has increased to understand and analyze the data more easily, and this made emotion analysis a necessity. Research in this area shows that emotion is a key tool in analyzing texts. However, there are very limited studies conducted on the text in Turkish language. The purpose of this study is to detect emotions in Turkish texts by analyzing the results of earlier studies in this scope. The following research questions are aimed to be answered: What are the years and count of publications What are the techniques used in the emotion analysis on texts What are the main data sets Which types of emotion are detected Which tools are used in emotion analysis For this reason, a systematic mapping study is performed to categorize and summarize the existing literature on emotion analysis. To ensure relevant papers in this field, an automated search process is performed for this study. Web of Science and Scopus databases are used for searching current and past research in emotion analysis on texts. There are 66 articles found on this subject. Then, by using filtering, irrelevant studies are removed. According to a set of inclusion and exclusion criteria, 9 relevant papers are selected in this field. The machine learning method is used for text analysis that automatically identifies the patterns and makes decisions about emotions. © 2022 IEEE.
Citation Count: 12
Gender inequity in thermal sensation based on emotional intensity for participants in a warm mediterranean climate zone
(Elsevier France-editions Scientifiques Medicales Elsevier, 2023) Ceter, Aydin Ege; Ozbey, Mehmet Furkan; Turhan, Cihan; Energy Systems Engineering; Mechanical Engineering
The deficiencies of the one of the most preferred conventional thermal comfort models, the Predicted Mean Vote/ Percentage of Predicted Dissatisfied (PMV/PPD) method have emerged over time since the model does not take psychological parameters such as personal traits, mood states and adaptation into account. Therefore, re-searchers have focused on Adaptive Thermal Comfort models that integrate human behaviours into the model for better prediction of thermal comfort. In addition to the influence of the behaviours of occupants, thermal comfort may be evaluated as a subjective term, thus, the effect of one of the psychological parameters, current mood state, on thermal sensation cannot be ignored for predictions. Although, the effect of current mood state on thermal sensation is a vital concept, the findings of the studies are not effective and comprehensive in the literature. For this reason, the aim of this study is to examine the relationship between current mood state and thermal sensation in gender difference aspect. Therefore, a series of experiments were conducted in a university study hall between August 16th, 2021 and August 1st, 2022. The current mood states of the participants were evaluated with the Profile of Mood States (POMS) questionnaire and the results were represented by a novel approach called Emotional Intensity Score (EIS). One tailed t-test was applied for investigating the relationship between the EIS and the thermal sensation. Findings of the research showed that a significant association exists between the EIS and thermal sensation for male participants while no relationship was found for female.
Citation Count: 0
Hardware-In-The-Loop Assessment of a Fault Tolerant Fuzzy Control Scheme for an Offshore Wind Farm Simulator
(Elsevier, 2022) Simani, Silvio; Farsoni, Saverio; Turhan, Cihan; Energy Systems Engineering
To enhance both the safety and the efficiency of offshore wind park systems, faults must be accommodated in their earlier occurrence, in order to avoid costly unplanned maintenance. Therefore, this paper aims at implementing a fault tolerant control strategy by means of a data-driven approach relying on fuzzy logic. In particular, fuzzy modelling is considered here as it enables to approximate unknown nonlinear relations, while managing uncertain measurements and disturbance. On the other hand, the model of the fuzzy controller is directly estimated from the input-output signals acquired from the wind farm system, with fault tolerant capabilities. In general, the use of purely nonlinear relations and analytic methods would require more complex design tools. The design is therefore enhanced by the use of fuzzy model prototypes obtained via a data-driven approach, thus representing the key point if real-time solutions have to implement the proposed fault tolerant control strategy. Finally, a high-fidelity simulator relying on a hardware-in-the-loop tool is exploited to verify and validate the reliability and robustness characteristics of the developed methodology also for on-line and more realistic implementations. Copyright (C) 2022 The Authors.
İç ortamda ortalama radyan sıcaklığını elde etmek için farklı yöntemlerin doğruluğunun karşılaştırılması
(2021) Özbey, Mehmet Furkan; Turhan, Cihan; Lotfısadıgh, Bahram; Energy Systems Engineering; Mechanical Engineering
Amerikan Isıtma Soğutma ve Klima Mühendisleri Birliği (ASHRAE), ısıl konforu bir kişinin bulunduğu ortamdaki memnuniyetini ifade eden öznel ve zihinsel değerlendirme ile elde edilen zihin koşulları olarak tanımlanmıştır. Isıl konfor, geleneksel olarak Fanger'in Ortalama Tahmini Oy (PMV) / Memnuniyetsizliklerin Tahmini Yüzdesi (PPD) metodu ve kişilerin davranışlarını da içeren adaptif ısıl konfor metotları ile elde edilmektedir. Isıl konfor parametreleri kişisel parametreler (giysi değeri ve metabolizma hızı) ve çevresel parametreler (hava sıcaklığı, bağıl nem, hava hızı ve ortalama radyan sıcaklığı) olarak üzere iki farklı kategoride ele almaktadır. Bu parametreler arasında, Ortalama Radyan Sıcaklık ölçülmesinin ve hesaplanmasının karmaşık olmasından dolayı elde edilmesi zor bir faktördür. İç ortamlarda ortalama radyan sıcaklığı elde etme yaklaşımları hesaplama yöntemleri, ölçüm yöntemleri ve varsayımlar gibi farklı yöntemlere dayanmaktadır. Ancak hesaplama yöntemlerinin karmaşık olması ve ölçüm yöntemleri için kullanılacak ölçüm aletlerinin pahalı ve elde edilmesi zor araçlar olması araştırmacıları doğruluğu kesin olmayan varsayımlara yönlendirmektedir. Bu nedenle, bu çalışmanın amacı ortalama radyan sıcaklığın elde edilme yöntemlerinin ölçüm yöntemlerinden birisi olan ve bu çalışma için üretilen küre termometresini referans alıp diğer metotlar ile karşılaştırılarak tüm yöntemlerin doğruluğunu bulmaktır. Bu çalışmada Köppen- Geiger sınıflandırmasına göre Csb tipi iklim bölgesinde bulunan bir test odası seçilmiştir ve ortalama radyatif sıcaklığı elde etmek için kullanılan 2 farklı hesaplama yöntemi ve 8 farklı varsayım yerinde ölçümle referans metodu ile karşılaştırılmıştır. Sonuçlar, ortalama radyan sıcaklığı elde etmek için varsayımların veya hesaplama yöntemlerinin kullanılmasının, referans yönteme kıyasla %9,1'e varan bir hataya neden olduğunu ortaya koydu.
Citation Count: 5
The importance of the calculation of angle factors to determine the mean radiant temperature in temperate climate zone: A university office building case
(Sage Publications Ltd, 2022) Ozbey, Mehmet Furkan; Turhan, Cihan; Energy Systems Engineering; Mechanical Engineering
Thermal comfort depends on four environmental (air velocity, relative humidity, air temperature, mean radiant temperature) and two personal (clothing insulation and metabolic rate) parameters. Among all parameters, the mean radiant temperature (t(r)) is the most problematic variable in thermal comfort studies due to its complexity. Measurement methods, calculation methods and assumptions are mostly used to obtain the t(r). Researchers mainly prefer to obtain the t(r) via measurement methods or assumptions due to their easiness compared to the calculation methods. Besides, some researchers use constant values of angle factors in calculation methods. However, using constant values is not proper for every indoor environment, and it causes wrong estimations in the t(r) and thus the thermal comfort. This paper gives the importance of calculation of angle factors, with an example of a university office building in temperate climate zone, according to the ISO 7726. The angle factors of the room were calculated for a seated occupant from the centre of gravity in three different locations and compared with the constant angle factors. The results indicate that a significant difference (MAPE of 1.02) was found in the t(r) values, which were obtained by calculation of constant values of angle factors.
Citation Count: 8
The Influence of Meteorological Parameters on PM₁₀: A Statistical Analysis of an Urban and Rural Environment in Izmir/Turkiye
(Mdpi, 2023) Birim, Necmiye Gulin; Turhan, Cihan; Atalay, Ali Serdar; Gokcen Akkurt, Gulden; Energy Systems Engineering
Air pollution is a substantial menace, especially in industrialized urban zones, which affects the balance of the environment, life of vital organisms and human health. Besides the main causes of air pollution such as dense urbanization, poor quality fuels and vehicle emissions, physical environment characteristics play an important role on air quality. Therefore, it is vital to understand the relationship between the characteristics of the natural environment and air quality. This study examines the correlations between the PM10 pollutant data and meteorological parameters such as temperature (T-air), relative humidity (RH), and wind speed (WS) and direction (WD) under the European Union's Horizon 2020 project. Two different zones (Vilayetler Evi as an urban zone and Sasali Natural Life Park as a rural zone) of Izmir Province in Turkiye are used as a case study and the PM10 data is evaluated between 1 January 2017 and 31 December 2021. A one-tailed t-test is used in order to statistically determine the relationships between the PM10 pollutant data and meteorological parameters. As a further study, practical significance of the parameters is investigated via the effect size method and the results show that the RH is found to be the most influencing parameter on the PM10 for both zones, while T-air is found to be statistically non-significant.