Yıldırım, Nurdan

Profile URL
https://hdl.handle.net/11147/16234
Name Variants
Yildirim Ozcan, N.
Yıldırım Özcan, Nurdan
Yıldırım Özcan, N.
Yıldırım, N.
Yildirim, Nurdan
Job Title
Email Address
Main Affiliation
03.10. Department of Mechanical Engineering
Status
Former Staff
Website
ORCID ID
0000-0001-5140-6340
Scopus Author ID
14061388000
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID

Sustainable Development Goals

NO POVERTY1
NO POVERTY
0
Research Products
ZERO HUNGER2
ZERO HUNGER
0
Research Products
GOOD HEALTH AND WELL-BEING3
GOOD HEALTH AND WELL-BEING
0
Research Products
QUALITY EDUCATION4
QUALITY EDUCATION
2
Research Products
GENDER EQUALITY5
GENDER EQUALITY
0
Research Products
CLEAN WATER AND SANITATION6
CLEAN WATER AND SANITATION
2
Research Products
AFFORDABLE AND CLEAN ENERGY7
AFFORDABLE AND CLEAN ENERGY
6
Research Products
DECENT WORK AND ECONOMIC GROWTH8
DECENT WORK AND ECONOMIC GROWTH
1
Research Products
INDUSTRY, INNOVATION AND INFRASTRUCTURE9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
4
Research Products
REDUCED INEQUALITIES10
REDUCED INEQUALITIES
0
Research Products
SUSTAINABLE CITIES AND COMMUNITIES11
SUSTAINABLE CITIES AND COMMUNITIES
0
Research Products
RESPONSIBLE CONSUMPTION AND PRODUCTION12
RESPONSIBLE CONSUMPTION AND PRODUCTION
2
Research Products
CLIMATE ACTION13
CLIMATE ACTION
3
Research Products
LIFE BELOW WATER14
LIFE BELOW WATER
0
Research Products
LIFE ON LAND15
LIFE ON LAND
0
Research Products
PEACE, JUSTICE AND STRONG INSTITUTIONS16
PEACE, JUSTICE AND STRONG INSTITUTIONS
0
Research Products
PARTNERSHIPS FOR THE GOALS17
PARTNERSHIPS FOR THE GOALS
0
Research Products
Documents

21

Citations

589

h-index

12

Go to Scopus profile
This researcher does not have a WoS ID.
Scholarly Output

13

Articles

7

Views / Downloads

20894/7537

Supervised MSc Theses

2

Supervised PhD Theses

1

WoS Citation Count

165

Scopus Citation Count

201

Patents

0

Projects

0

WoS Citations per Publication

12.69

Scopus Citations per Publication

15.46

Open Access Source

12

Supervised Theses

3

JournalCount
Applied Thermal Engineering1
ECOS 2006: Proceedings of the 19th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems1
Energy1
Energy and Buildings1
Geothermal Energy, Technology and Geology1
Current Page: 1 / 2

Scopus Quartile Distribution

Competency Cloud

GCRIS Competency Cloud

Filters

2003 - 200962010 - 201962020 - 20211

Settings

search.filters.applied.f.isAuthorOfPublication: search.filters.isAuthorOfPublication.249d13f4-7d82-4363-b0d2-1f058c829168

Scholarly Output Search Results

Now showing 1 - 10 of 13
  • Doctoral Thesis
    Modeling, Simulation and Optimization of Flashed-Steam Geothermal Power Plants From the Point of View of Noncondensable Gas Removal Systems
    (Izmir Institute of Technology, 2010) Yıldırım Özcan, Nurdan; Gökçen Akkurt, Gülden
    Geothermal fluids contain noncondensable gases (NCGs) at various amounts. The presence of NCGs in geothermal steam results with a dramatic decrease in net power output increasing condenser pressure and total auxiliary power consumption. Hence, NCGs should be withdrawn by a gas removal equipment to improve the performance of geothermal power plants (GPPs). The flashed-steam GPPs (single-flash, double-flash) are a relatively simple way to convert geothermal energy into electricity when the geothermal wells produce a mixture of steam and liquid. The primary aim of the Thesis is to model and develop a code to simulate flashed-steam GPPs to examine the thermodynamic and economical performance of NCG removal systems, which are major concerns at planning and basic design stages of GPPs. The model is validated comparing model output with Kizildere GPP output, classified as deterministic and static. The model is simulated to identify the effects of input variables which are NCG fraction, separator pressure, condenser pressure, wet bulb temperature, interest rate, tax rate, O&M cost ratio and electricity sales price. Among the variables, NCG fraction is the most significant parameter affecting thermodynamic performance and profitability of flashed-steam GPPs. The net power output and overall exergetic efficiency of singleflash GPP is decreased 0.4% for compressor system (CS), 2.2% for hybrid system (HS), 2.5% for reboiler system (RS) and 2.7% for steam jet ejector system (SJES) by 1% increase in NCG fraction. Based on thermodynamic and economical simulations, SJES, HS and CS can be recommended to be used for a NCG fraction range of 0-2%, 2-10% and >10%, respectively. Furthermore, thermodynamic performance of single-flash plants can be improved by adding second flash by 45.5-127.9%.
  • Article
    Türkiye’nin Farklı İklim Koşullarında Isıl Konfor Sıcaklıklarına Bağlı Olarak Konutların Enerji Performanslarının Değerlendirilmesi
    (2021) Hancıoğlu Kuzgunkaya, Ebru; Yıldırım, Nurdan; Gökçen Akkurt, Gülden
    Isıl konfor, insanın yapısı, yaşı, cinsiyeti gibi kişisel parametrelerin yanı sıra çevresel parametrelere de bağlıdır. Isıtma, soğutma ve havalandırma sistemlerinin çalışma şekli ve dış hava sıcaklıkları ısıl konfor için önemli parametrelerdir. Fanger deneysel çalışmalar sonucu “tahmini ortalama oy (PMV)” olarak adlandırılan bir gösterge oluşturmuş ve PMV=0’ı konfor için en iyi değer olarak belirlemiştir. Bu çalışmada, farklı iklim bölgelerinden dört il seçilerek, her bir il için ısıl konfor sıcaklıkları belirlenmiş ve bu ısıl konfor sıcaklıklarındaki enerji performansları değerlendirilmiştir. Isıtma ve soğutma sistemi için kişisel kontrole izin verilmeyen tam mekanik kontrollü sistem seçilmiş, kesikli ve sürekli rejim için hesaplamalar yapılmıştır. Çalışmada, konfor koşullarının PMV=0 olması durumunda enerji tüketimleri incelenerek iller arasındaki ısıl konfor memnuniyeti ve enerji tüketiminindeki farklılıklar saptanmaya çalışılmıştır. PMV değerlerinin istatistiksel analizinde, İzmir ili için kesikli rejimde çalışmanın sürekli rejime göre daha iyi olmasına rağmen İstanbul için sürekli rejimde konfor koşulları açısından daha iyi sonuçlar alınmıştır. Tüm illerde sürekli rejim uygulandığında birim enerji tüketiminde artış olduğu belirlenmiştir. Sürekli rejim, kesikli rejime göre ısıtma enerji tüketiminde % 4,5-6,2, soğutma enerji tüketiminde ise % 9,1-23,2 daha yüksektir.
  • Master Thesis
    Thermodynamic Optimization of Downhole Heat Exchangers for Geothermal Power Generation
    (Izmir Institute of Technology, 2016) Parmanto, Slamet; Gökçen Akkurt, Gülden; Yıldırım Özcan, Nurdan
    Geothermal reservoirs have various thermodynamic and physical properties. The heat extraction and power generation from the geothermal reservoirs depend on the reservoir properties. Downhole heat exchangers (DHEs) are designed to move the heat extraction process into the geothermal well. The working fluid is injected to the DHE which suspends in the geothermal well, heated by geothermal fluid and then returned to the surface through the inner pipe. DHEs have been used for heating purposes widely but there is no application for electricity generation. Because of the natural convection on the geothermal fluid side, convective heat transfer coefficient is low and simultaneously the heat extraction rate is low comparing with extracting geothermal fluid by downhole pumps. Therefore if the temperature is high but flowrate is low in a geothermal well, DHEs are good alternatives to harness the energy from that well. Considering the number of wells with abovementioned conditions in the World, there is a potential for electricity generation coupling geothermal power plants with DHEs. The main purpose of the Thesis is to develop a thermodynamic and economic evaluation model of DHEs for power generation and to examine the feasibility of the model. The thermodynamic model is developed by EES software and over 300 simulations have been conducted to identify the effects of the insulation, geothermal well conditions, geometry of DHE, mass flowrate and the type of working fluids to the performance of DHE system. The economic analyses are conducted to evaluate the thermodynamic results regarding the economic consideration such as Net Present Value (NPV), simple payback time and electricity production rate. The results show that the insulation on the inner pipe is desirable to prevent heat loss along DHEs. The best design of the DHE is a design with deeper the depth, larger the diameter of the inner pipe, and higher mass flowrate for a specific geothermal heat source. The best design for the case study resulted as a work output of 3152 kW with annual net revenue and payback time of $1.75 million and 2.24 years, respectively. Besides, the economic evaluation gives positive value for NPV which means investment in DHE for geothermal power generation is acceptable.
  • Article
    Citation - WoS: 33
    Citation - Scopus: 42
    Thermodynamic Assessment of Downhole Heat Exchangers for Geothermal Power Generation
    (Elsevier, 2019) Yıldırım, Nurdan; Parmanto, Slamet; Akkurt, Gülden Gökçen
    Downhole heat exchanger is a device to extract heat from geothermal fluid. While it is widely used for heating purposes, its use for power generation has not been reported. The aim of this study is to examine the feasibility of power generation from a 2500 m deep existing geothermal well with high temperature gradient and insufficient flowrate by using a downhole heat exchanger. For this purpose, a thermodynamic and an economic evaluation model are developed by the use of Engineering Equation Solver software. Additionally, the parametric studies have been carried out to identify the effects of insulation, geothermal well conditions, geometry of downhole heat exchanger, mass flowrate and type of working fluids on the performance of downhole heat exchanger system. Consequently, work output of the best alternative is computed as 2511 kW(e) with 64 kg/s mass flowrate of R-134a for 2500 m-deep downhole heat exchanger having inner pipe diameter of 0.127 m. Electricity generation cost and simple payback time are calculated as 46 $/MWh and 2.25 years, respectively. The obtained results showed that the downhole heat exchanger system can be a feasible alternative for wells with very low geothermal flowrate to generate power. (C) 2019 Elsevier Ltd. All rights reserved.
  • Article
    Isıl Konfor Sıcaklıklarına Bağlı Olarak Bir Konutun Enerji Performansının Değerlendirmesi: Izmir Örneği
    (Sakarya Üniversitesi, 2018) Yıldırım, Nurdan; Kuzgunkaya, Ebru; Gökçen Akkurt, Gülden
    Türkiye’de enerji tüketiminin yaklaşık %34’ü binalarda ve bunun %85 kadarı da ısıtma ve soğutma amaçlı kullanılmaktadır. Binalarda bulunan HVAC sistemlerinin işletme özellikleri, hem binanın ısıl konforunu hem de enerji tüketimlerini doğrudan etkilemektedir. Bu çalışmada, HVAC sistemlerinin işletme şartlarının, ısıl konfor koşulları ile enerji tüketimlerine olan etkisinin belirlenmesi amaçlanmaktadır. Bu amaçla İzmir ilindeki 100 m2’lik bir konut için öngörülen HVAC sisteminin kesikli ve sürekli rejimde, tek ve çift sıcaklık set değerleri ile tam mekanik kontrollü veya doğal havalandırmalı olarak çalıştırılması durumları incelenmiştir. Isıl konfordan olan memnuniyet; Tahmini Ortalama Oy (Predicted Mean Vote - PMV) değeri ile ifade edilmektedir. Bu kapsamda öncelikle, Design Builder yazılımı kullanılarak en iyi duruma karşılık gelen PMV=0’a göre HVAC sisteminin set sıcaklıları belirlenmiştir. Bu sıcaklık set değerlerinin kullanılması ile ele alınan 5 farklı durumda konut için yıllık birim ısıtma/soğutma enerji tüketimleri, birim birincil enerji tüketimi, yıl boyunca ailenin evde bulunduğu saatlerde sağlanan PMV değerleri ve PMV değerlerinin istatistiksel değerlendirilmesi gerçekleştirilmiştir. Elde edilen sonuçlara göre, incelenen 5 durum arasında normal beklenti seviyesinde % 99,6 kümülatif frekans yüzdesi ile ısıl konforu en çok sağlayan tam mekanik kontrollü, sürekli rejim, aylık çift ısıtma/soğutma operatif sıcaklık set değerli durumdur. Tam mekanik kontrollü, kesikli rejim, aylık tek ısıtma/soğutma hava sıcaklığı set değerli durum ise 2,04 kWh/m2/%KF birim memnuniyet enerji tüketimi değeri ile en az enerji tüketen durum olmaktadır.
  • Article
    Citation - WoS: 25
    Citation - Scopus: 32
    District Heating System Design for a University Campus
    (Elsevier Ltd., 2006) Yıldırım, Nurdan; Toksoy, Macit; Gökçen Akkurt, Gülden
    İzmir Institute of Technology campus is in use since 2000 and still under development. At present, heating is provided by individual fuel boilers. On the other hand, the campus has a geothermal resource in its borders with a temperature of 33 °C. Because of this low geothermal fluid temperature; heat pump district heating system is considered for the campus. As an alternative, fuel boiler district heating system is studied. Each heating system is simulated using hourly outdoor temperature data. For the simulations, a control system with constant flow rate and variable return water temperature is used and the main control parameter is the indoor temperature. Various heating regime alternatives have been studied for heat pump district heating system for the various condenser outlet temperature and geothermal fluid flow rate, and two of these alternatives are given in this study. Furthermore, economic analysis has also been done for each heating system alternative based on investment and operational costs. Results indicate that heat pump district heating system has the highest investment but lowest operational cost. The alternatives are evaluated according to internal rate of return method, which shows the profit of the investment and resulted that, the heat pump district heating system has minimum 3.02% profit comparing with the fuel boiler district heating system at the end of the 20-year period.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 19
    Effect of Non-Condensable Gases on Geothermal Power Plant Performance. Case Study: Kızıldere Geothermal Power Plant-Turkey
    (Inderscience Enterprises Ltd., 2008) Gökçen Akkurt, Gülden; Yıldırım, Nurdan
    Non-Condensable Gases (NCGs) are natural components of geothermal fluids, and they are a source of considerable capital and operating costs for power plants. The NCG content of geothermal steam varies over the world from almost zero to as much as 25% (wt). In this work, the influence of NCGs on the thermodynamic performance of geothermal power plants is analysed for various NCG content and turbine inlet temperatures. The results obtained can be useful on the feasibility study of single flash geothermal power plants. Depending on the NCG content of the field, the performance of the power plant can be determined roughly. © 2008, Inderscience Publishers.
  • Book Part
    Citation - Scopus: 3
    Performance Analysis of Single-Flash Geothermal Power Plants: Gas Removal Systems Point of View
    (Nova Science Publishers, Inc., 2012) Yıldırım Özcan, Nurdan; Gökçen, Gülden
    Non-condensable gases (NCGs), natural components of geothermal fluids, affect the performance of a geothermal power plant (GPP) significantly. Therefore, the NCGs should be removed from the process to optimise the thermodynamic efficiency of the plant. GPPs require large capacity NCG removal systems that occupy large portion in the total plant cost and auxiliary power consumption. The flashed-steam GPPs, which are commonly used in the World, are a relatively simple way to convert geothermal energy into electricity when the geothermal wells produce a mixture of steam and liquid. The primary aim of this study is to develop a code for simulating flashed-steam GPPs to examine the thermodynamic performance of NCG removal systems, which represent major concerns at planning and basic design stages of GPPs. A single-flash GPP model is developed and simulated to identify the effects of input variables, such as NCG fraction, separator pressure and condenser pressure. Among the variables, NCG fraction is the most significant parameter affecting thermodynamic performance of single-flash GPPs. The net power output and overall exergetic efficiency of single-flash GPP are decreased 0.4% for compressor system (CS), 2.2% for hybrid system (HS), 2.5% for reboiler system (RS), and 2.7% for steam jet ejector system (SJES) by 1% increase in NCG fraction.
  • Conference Object
    Citation - WoS: 7
    Modeling of Low Temperature Geothermal District Heating Systems
    (Taylor and Francis Ltd., 2004) Yıldırım, Nurdan; Gökçen, Gülden
    In this work, low temperature geothermal district heating systems with heat pumps have been studied and compared with fuel-oil boiler heating systems for intermittent and continuous regimes according to the optimum indoor air temperature and operational cost. Izmir Institute of Technology (IZTECH) Campus is taken as a case study. Various heat pump and boiler configurations are studied to meet required duty. Operational cost analysis for each alternative is conducted. According to the results, for IZTECH Campus the best alternative, which gives the optimum indoor air temperature and the lowest operational cost, is heat pump continuous regime.
  • Master Thesis
    District Heting System of Iztech Campus and Its Integration To the Existing System
    (Izmir Institute of Technology, 2003) Yıldırım, Nurdan; Gökçen Akkurt, Gülden
    Izmir Institute of Technology (IZTECH), founded in 1992, is the third state university of Izmir. At present IZTECH Campus has individual fuel boiler heating systems for each faculty building and the Campus is still under development. But the Campus has also a geothermal source. In 2002, 5 gradient wells were drilled. Of these, one well has a geothermal fluid of 33°C is obtained but the actual flowrate of the geothermal fluid has not been measured yet. The aim of this Thesis is to investigate this source whether it can be used for district heating application for IZTECH Campus. Mainly two heating system types have been considered;. Heat pump heating system (HPHS) (using a renewable energy source, geothermal energy), . Fuel boiler heating system (FBHS) (using a conventional energy source, fuel-oil). HPHS is considered as HPO type since the existing geothermal fluid temperature is low. While HPHS is considered only as district, FBHS is considered as district and individual. Each heating system is simulated using hourly outdoor temperature data. For these heating simulations, the main control parameter is the indoor temperature of the buildings. Mathematical models are derived using Matlab [16] and EES [17] programs. Various heating regime alternatives have been studied for HPHS for the various condenser outlet temperature and geothermal fluid flowrate. Consequently, the heating regime with 35°C condenser inlet and 45°C condenser outlet temperature with 120 kg/s geothermal fluid flowrate considered to be the best option. FBHSs are also simulated for various boiler set temperatures. Boiler set emperatures have been recommended by Demirdöküm [39], is the best alternative with the least fuel consumption and best indoor temperature around 20°C. Besides heating system simulations, piping network simulation is made using the software Pipelab [18]. The piping network of the Campus has been considered with two loops as geothermal and Campus. Each loop contains supply and return main. The location of the heat centre and the pressure loss per unit length are common design parameters for economy of the system. Therefore, several alternatives have been studied and because of the lowest investment and operational cost, Alternative 3, where the heat centre is in the middle of the Campus, is considered to be the best option with target pressure loss of 150 Pa/m. For installation type of piping network, underground (buried) pipeline installation is selected. Furthermore, economic analysis has also been done for each heating system alternative depending on investment and operational costs. For operational cost, 3 heating scenarios are considered depending on the heating period of the buildings in the Campus. According to the results of economical analyses, while heat pump district heating system (HPDHS) has the biggest investment cost with 3,040,125 US$, it has minimum operational cost. The alternatives are evaluated according to internal rate of return (IRR) method, which shows the profit of the investment. The results indicate that, the HPDHS has minimum 3.02% profit according to the fuel boiler district heating system (FBDHS) at the end of the 20-year period. The profit increases with increasing operating period of the heating systems.