COMPLETED THESIS

Dokuz Eylül Research and Application Hospital, founded in 1982, is located in İnciraltı place, in Balçova. It is placed at the south of İzmir and between the İzmirÇeşme Highway and İzmir-Çeşme Super Highway. Rather rich geothermal resources found in Balçova, provides the use of geothermal water for heating in the hospital. However, the required cooling capacity for the hospital, which is relatively massive when compared with the residents, has been supplied by conventional compression chillers.
In this study, the aim is to decrease the overall annual costs incurred by cooling of the hospital by implementing an absorption cooling system, which uses geothermal fluid as the heating source. The main idea behind this implementation is that the electricity consumption of an absorption chiller is minimal when compared with a compression chiller. On the other hand, since the source that is going to be used in the system is geothermal energy, there will be an additional cost incurred by the use of geothermal fluid. So, the economic analysis that is going to be conducted involves the comparison of two alternatives, which are leaving the system as is now and implementing an absorption cooling system.
To minimize the costs incurred by the implementation of an absorption cooling system, instead of supplying the full capacity of the hospital, a moderate capacity will be supplied by the absorption chillers, by using the existing compression chillers as the peaking units. Since it is not known which capacity will be suitable for the needs, several absorption cooling machines with various capacities will be examined.
After comparing these mutually exclusive alternatives, the effect of the change in geothermal fluid price on the implementation of an absorption cooling system, and the break-even geothermal water price will be found.
At the end, the investment worth values of the selected absorption cooling machines will be examined to decide whether to implement an absorption cooling system in the hospital or not.

Geothermal energy, which is the Earth’s interior energy, has a broad application area for heating and energy production purposes. To develop healthy geothermal energy projects, conceptual planning study is one of the important tasks which should be done initially. Conceptual planning studies consists of technical, economical and political evaluation of the project showing that whether the project is feasible or not. In this study, conceptual planning study is applied to the Athletes’ Village which has a dwelling area of 97,446 m2. The total peak demand including hot water need for this system design is 11,7 MWt. The existing heating system is fuel-firing system. A comparison between the existing system with geothermal district heating system is done by this study. The hot water at 140 ºC, which is planned to be extracted from new drilled wells, is first cooled down to 120 ºC and afterwards designed to give its energy to the closed city loop. Finally, city loop water will circulate in the buildings within the temperature range of 85 ºC/55 ºC. The economy of the system is studied for two different well locations considering different participating costs and operating costs. The monthly fixed charges which make the internal rate of return positive around 0 % is determined for the investor for different participating costs varying between $ 1250 and $ 2500. At the end, the net present worths for the payments that would be done to the heating systems are calculated for the consumers. As a result of the economic feasibility study, it is determined that geothermal district heating design would be feasible for the consumers when the same comfort conditions are considered for both of the designs.

Conceptual planning (technical, economical and politic feasibility) of geothermal district heating systems is the most important step of these projects. In this study, a conceptual planning model developed for geothermal district heating systems is applied to the project of Balcova (Izmir) System-2 Geothermal District Heating System which is on the agenda nowadays in Balçova and the technical, economic and politic feasibilities are investigated. The city section on which the geothermal district heating system will be constructed has a maximum capacity of dwellings having an area of 391,700 m2 and 80% of them have been built and are in use. The most important parameter that affects the economics of the geothermal district heating systems is the participation ratio of the dwellings in the district. In this study different participation ratio (between 100% and 26%), participation costs (between 1250$ and 1500$) and participation periods (2 or 5 years) are considered and the monthly fixed energy charge which will make the internal rate of return ratio approximately positive values around 0% are calculated.

The main goal of this study is to determine optimum control strategy of Balçova-Narlıdere geothermal district heating system to minimise the energy consumption. First heat demand model of the system was constructed by using statistical method called time series analysis. This model provides the heat demand forecast of next day, by considering ambient temperature forecast of the next day. Then geothermal pipeline system and city distribution system have been modelled in the PIPELAB district heating simulation program. To model the system close to the actual case, database of Balçova geothermal company was used as an input, and the code of PIPELAB program was adapted to be used in geothermal pipeline system. Once the sysem was modelled in PIPELAB, it would be possible to obtain pressure and temperature distribution along the pipe networks in the system. To determine the optimum operation strategy of the wells according to the changing heat demand first the energy consumption of each well pump was defined as a function of their heat production rate. Then these functions were inserted into dynamic programming algorithm which selects the optimum well operation strategy among thousands of options. Also power consumption models of circulation pumps were built and calibrated with actual values. Finally optimum control strategy for the system was determined and the system model was operated by using optimum control strategy according to ambient temperature data of 2001 and 2002. The acual energy consumption values were compared with the optimum energy consumption values and decisive factors in efficient control and operation of  the system have been defined.

Development of a geothermal district heating system covers full range of activities from the determination of geothermal reservoir to the delivery of geothermal energy successfully. Economic assessments are come true in the early stages of geothermal developments. The goal of this thesis is to realize a detailed economic assessment for Balçova – Narlıdere Geothermal District Heating System (GDHS) which is one of the largest district heating systems in Turkey with its current heating capacity of 50 MW_th. Tasks in geothermal district heating investments are looked over at the beginning to make a correct economic evaluation and make future development in this geothermal field easy under the discipline of project management. Internal rate of return method which is commonly used financial tool to find the profitability of investments is applied to this investment. The economic analysis begin with the calculation of end of 2002 values of capital investment costs, revenues and operating costs since the existence of past cash flows. Future operating costs are determined according to the yearly expenditures realized in 2002. Future revenues are determined in accordance with the capacity of current heating system and energy utilization prices valid in 2002-2003 heating season. If the sustainability of a resource is considered in the design, the prospective geothermal district heating system could be operated in a long period. However, long-term period projects contain economic uncertainties for the future cash flows. The overall life of Balçova – Narlıdere GDHS is considered as 20 years after year 2001 and uncertainties are considered in this study. Calculations are realized according to various scenarios in which operating costs are constant throughout 20 years. To determine these scenarios, operating costs in 2002 which reflects the current expenditures are either decreased or increased by some percentages. In addition, 60 different pricing plans have been taken into consideration in these scenarios to demonstrate the effects of energy utilization prices on the profitability of investment. The continuity of current price policy for Balçova – Narlıdere GDHS is discussed and energy utilization prices per 100 m² are suggested for these scenarios. On the other hand, taxes paid to government in Balçova – Narlıdere GDHS investment are investigated to show the benefits of geothermal investments from the viewpoint of government.  Because of the development in production of some equipment like heat exchangers, pipes and changing in marketing strategy, the costs of  these equipment are reduced. At the end,  internal rate of return method is repeated for the current cost of the investment. The energy utilization prices for 13 different scenarios are found for this situation and results are compared with the prices determined to meet the real cost of the investment. 

Izmir Institute of Technology (IZTECH), founded in 1992, is the third state university of İzmir. 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 temperatures 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.