WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 23Multiple Regression Analysis of Performance Parameters of a Binary Cycle Geothermal Power Plant(Elsevier Ltd., 2015) Karadas, Murat; Çelik, H. Murat; Serpen, Umran; Toksoy, MacitRegression analysis of a 7.35 MWe existing binary geothermal power plant is conducted using actual plant data to assess the plant performance. The thermo physical properties of geothermal fluid and ambient conditions, which are brine (geothermal water) temperature and flow rate, steam and NCGs (non-condensable gases) flow rates and ambient air temperature, directly affect power generation from a geothermal power plant. Generally, amount of power generated is calculated by deterministic formulations of thermodynamics. However, the data would be probabilistic because inputs may be measured by uncalibrated devices or some parameters may be neglected during the calculation. In these cases, the performance of power plant may be estimated by using regression analysis and then changing of plant performance may be monitored overtime. All measured parameters on DORA-1 Geothermal Power Plant from 2006 to 2012 and 49,411 hourly time series data are used in this study. A review of the available literature indicates this paper is the first study to focus on the prediction of power generation of a geothermal power plant by using multiple linear regression analysis. In this study, annual multiple linear regression models are developed to estimate the performance of a geothermal power plant. These models are tested by using classical assumptions of linear regressions and positive serial autocorrelation is found in all models. Autocorrelations are eliminated by using Orcutt-Cochran method. Although the performance model trends, from 2006 to 2008, are found to be close, the performance status of the plant is generally variable from year to year. According to annual regression models, since 2009, the plant performance started to decline with 270 kW(e) electricity generation capacity. The total degradation of the plant performance reached 760 kW(e) capacity by 2012. (C) 2014 Elsevier Ltd. All rights reserved.Article Citation - WoS: 66Citation - Scopus: 79Piping Network Design of Geothermal District Heating Systems: Case Study for a University Campus(Elsevier Ltd., 2010) Yıldırım, Nurdan; Toksoy, Macit; Gökçen, GüldenGeothermal district heating system design consists of two parts: heating system and piping network design. District heating system design and a case study for a university campus is given in Yildirim et al. [1] in detail. In this study, piping network design optimisation is evaluated based on heat centre location depending upon the cost and common design parameters of piping networks which are pipe materials, target pressure loss (TPL) per unit length of pipes and installation type. Then a case study for the same campus is presented. © 2010 Elsevier Ltd.Article Citation - WoS: 39Citation - Scopus: 41Economic Assessment of Geothermal District Heating Systems: a Case Study of Balçova-Narlıdere, Turkey(Elsevier Ltd., 2006) Erdoğmuş, Berkan; Toksoy, Macit; Özerdem, Barış; Aksoy, NiyaziGeothermal energy is an important renewable energy resource in Turkey. The aim of this research is to evaluate the Balcova-Narlidere geothermal district heating system from an economic perspective. The system is the largest one in Turkey in terms of heating capacity and located in Izmir. Although there are some assessments regarding energy and exergy analysis for the Balcova-Narlidere geothermal district heating system, an economic assessment was not performed, previously. The profitability of the investment is investigated by using internal rate of return method. Seven hundred and eighty different scenarios are developed in this assessment. In order to estimate the potential cash flows in the remaining project life, operating cost in 2002 is decreased and increased, alternatively, between 5% and 30% by 5% in each step, while monthly energy utilization price is changed between US$ 17 and 72 in those scenarios. The energy utilization prices are suggested according to zero IRR value for all scenarios due to the consideration of social and environmental concerns in this investment. It is found that, the proper monthly energy utilization price for a 100 m2 household would be US$ 55.5 when the operating cost and heating capacity in 2002 were remained constant.Article Citation - WoS: 25Citation - Scopus: 32District Heating System Design for a University Campus(Elsevier Ltd., 2006) Yıldırım, Nurdan; Toksoy, Macit; Gökçen Akkurt, Güldenİzmir 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.