Geothermal energy in Turkey: 2008 update

Geological studies indicate that the most important geothermal systems of western Turkey are located in the major grabens of the Menderes Metamorphic Massif, while those that are associated with local volcanism are more common in the central and eastern parts of the country. The present (2008) installed geothermal power generation capacity in Turkey is about 32.65 MWe, while that of direct use projects is around 795 MWt. Eleven major, high-to-medium enthalpy fields in western part of the country have 570 MWe of proven, 905 MWe of probable and 1389 MWe of possible geothermal reserves for power generation. In spite of the complex legal issues related to the development of Turkey's geothermal resources, their use is expected to increase in the future, particularly for electricity generation and for greenhouse heating.     

Energy and exergy analysis of Salihli geothermal district heating system in Manisa,Turkey

This study deals with an energy and exergy analysis of Salihli geothermal district heating system (SGDHS) in Manisa, Turkey. In the analysis, actual system data are used to assess the district heating system performance, energy and exergy efficiencies, specific exergy index, exergetic improvement potential and exergy losses. Energy and exergy losses throughout the SGDHS are quantified and illustrated in the flow diagram. The exergy losses in the system, particularly due to the fluid flow, take place in the pumps and the heat exchanger, as well as the exergy losses of the thermal water (e.g. geothermal fluid) and the natural direct discharge of the system. As a result, the total exergy losses account for 2.22, 17.88 and 20.44%, respectively, of the total exergy input to the entire SGDHS. The overall energy and exergy efficiencies of the SGDHS components are also studied to evaluate their individual performances and determined to be 55.5 and 59.4%, respectively. Copyright © 2005 John Wiley & Sons, Ltd.     

Geothermal applications in Turkey

Geothermal energy is mostly utilised in direct applications in Turkey. The equivalent of 61,000 residences are currently heated by geothermal fluids. A total of 665 MW_t is utilised for space heating of residential, public and private property, and 565,000 m² of greenhouses. Geothermal fluids are also used in 195 spas (327 MW_t), bringing the total direct use capacity to 992 MW_t. ORME Geothermal Inc. has completed the engineering design of a geothermal district heating system that serves the equivalent of nearly 300,000 residences. A total of 170 geothermal fields have been explored so far in Turkey. At Kizildere a single-flash power plant with 20.4 MW_e installed capacity is integrated with a factory producing liquid CO₂ and dry-ice. A binary cycle power plant with an installed capacity of 25 MW_e will be constructed shortly at Aydin/Germencik. The proven geothermal heat capacity, according to data from existing geothermal wells and natural discharges, is 3132 MW_t (I. Akkus, MTA General Directorate, oral communication, January 2003).     

A renewable energy system in Frederikshavn using low-temperature geothermal energy for district heating

The Danish city Frederikshavn is aiming at becoming a 100% renewable energy city. The city has a number of energy resources including a potential for off-shore wind power, waste and low-temperature geothermal energy usable as heat source for heat pumps producing district heating.     

Coefficient of performance (COP) analysis of geothermal district heating systems (GDHSs): Salihli GDHS case study

The purpose of this survey is about to analyze the heating coefficient of performance (COP) of geothermal district heating systems. Actual system data are taken from the Salihli GDHS, Turkey. The collected data are quantified and illustrated in tables, particularly for a reference temperature for comparison purposes. In this study, firstly energy and COP analysis of the GDHSs is introduced and then Salihli GDHS coefficient of performance results is given as a case study. Moreover, this paper offers an interesting empirical study of certain geothermal systems.     

Geothermal exploration using geoelectric methods in Kestanbol, Turkey

A self-potential survey was carried out in the Kestanbol area in order to investigate the fault zones that might be associated with geothermal activity. Two fault zones, which could be interpreted as planes electrically polarized by geothermal activity, have been detected by compilation of a self-potential map. A resistivity survey, using the Wenner configuration, was able to identify the geoelectrical structures that are caused by different rocks with variable degrees of fracturation and also affected by geothermal activity. The resistivity maps and two-dimensional geoelectric models indicated a good conductive region (<10 ohm-m) in the southwest part of Kestanbol. On the basis of the results of both methods, a new location is proposed for drilling in this conductive zone.     

Solar district heating and cooling: A review

Both district heating and solar collector systems have been known and implemented for many years. However, the combination of the two, with solar collectors supplying heat to the district heating network, is relatively new, and no comprehensive review of scientific publications on this topic could be found. Thus, this paper summarizes the literature available on solar district heating and presents the state of the art and real experiences in this field. Given the lack of a generally accepted convention on the classification of solar district heating systems, this paper distinguishes centralized and decentralized solar district heating as well as block heating. For the different technologies, the paper describes commonly adopted control strategies, system configurations, types of installation, and integration. Real‐world examples are also given to provide a more detailed insight into how solar thermal technology can be integrated with district heating. Solar thermal technology combined with thermally driven chillers to provide cooling for cooling networks is also included in this paper. In order for a technology to spread successfully, not only technical but also economic issues need to be tackled. Hence, the paper identifies and describes different types of ownership and financing schemes currently used in this field.     

Innovation diffusion,public policy,and local initiative: The case of wood-fuelled district heating systems in Austria

This paper comprises a three-level study on wood fuel utilisation for district heating in Austria. First, we discuss the framework conditions for the diffusion in Austria of rural biomass district heating (BDH) plants, an energy conversion plant type which constituted a real innovation in the 1980s. Second, we describe the diffusion of BDH systems in the Austrian province of Vorarlberg, where a variety of biomass energy systems have been promoted by capital grants since 1993, as part of a dedicated bioenergy promotion programme. Third, the paper contains a case study of a 2 MW BDH plant put into operation in 2000 in Rankweil, a small market town located in Vorarlberg on the east side of the Rhine Valley. Analysis of the plant history reveals that an oversupply of forest residues, caused by devastating storms and forest diseases, together with the more general need to rejuvenate severely over-aged forest stands, created strong incentives to form local actor networks and initiatives to push for the adoption and diffusion of centralised biomass heating systems in rural areas. In addition, intensive lobbying and strong political and public support were necessary to successfully combat interventions by both the natural gas industry and influential gas-supplied industrial enterprises. Finally, a capital grant of 45% of eligible investment costs as well as careful capacity expansion and other planning significantly improved and safeguarded the economic viability of the plant. These considerations, combined with a dedicated forest-restructuring programme, render the plant one of the most successful integrated forestry and BDH projects in Vorarlberg, and an important model for later adopters. Overall, the analysis sheds some light on the role of public policy, local actors, and economic and other framework conditions on the market diffusion dynamics of BDH in Austria.     

Metamorphoses of cogeneration-based district heating in Romania: A case study

The paper presents the birth and evolution of the cogeneration-based district heating (DH) system in a medium size city in Romania (Targoviste). The evolution of the industrialization degree was the main factor which controlled the population growth and led to a continuous reconfiguration of the DH system. The DH system assisted by cogeneration emerged as a solution in a certain phase of the demographic development of the city. The political and social changes occurring in Romania after 1990 have had important negative consequences on the DH systems in small towns. In Targoviste the DH system survived but in 2001 the solution based on cogeneration became economically inefficient, due to the low technical quality of the existing equipment and the low gas prices, to the procedure of setting the DH tariffs and the service cost at consumer’s level and to some bureaucratic problems. Energy policy measures taken at national and local levels in 2003 and 2005 led to the re-establishment of the cogeneration-based district heating in 2005. However, a different technical solution has been adopted. Details about the present (2009) cogeneration-based DH system in Targoviste are presented together with several technical and economical indicators. The main conclusion is that by a proper amendment of the technical solutions, cogeneration could be a viable solution for DH even in case of abrupt social and demographic changes, such as those occurring in Romania after 1990.     

Regulating district heating in Romania: Legislative challenges and energy efficiency barriers

Many states in Eastern and Central Europe (ECE) possess extensive district heating (DH) networks that were constructed during the days of communist rule in order to provide a universally accessible energy service that supported Soviet development policies. But the post-communist transition was marked by the exacerbation of the sector’s numerous technical, economic, regulatory and environmental problems, accompanied by its abandonment in favour of alternative methods of domestic heating. Recent efforts to increase the use of DH in ECE as a result of environmental and energy security concerns have taken place in an absence of critical, context-sensitive research.     

Piping network design of geothermal district heating systems: Case study for a university campus

Geothermal 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.     

Barriers and enablers to geothermal district heating system development in the United States

According to the US Energy Information Administration, space and hot water heating represented about 20% of total US energy demand in 2006. Given that most of this demand is met by burning natural gas, propane, and fuel oil, an enormous opportunity exists for directly utilizing indigenous geothermal energy as a cleaner, nearly emissions-free renewable alternative. Although the US is rich in geothermal energy resources, they have been frequently undervalued in America's portfolio of options as a means of offsetting fossil fuel emissions while providing a local, reliable energy source for communities. Currently, there are only 21 operating GDHS in the US with a capacity of about 100 MW thermal. Interviews with current US district heating operators were used to collect data on and analyze the development of these systems. This article presents the current structure of the US regulatory and market environment for GDHS along with a comparative study of district heating in Iceland where geothermal energy is extensively utilized. It goes on to review the barriers and enablers to utilizing geothermal district heating systems (GDHS) in the US for space and hot water heating and provides policy recommendations on how to advance this energy sector in the US.     

The role of district heating in future renewable energy systems

Based on the case of Denmark, this paper analyses the role of district heating in future Renewable Energy Systems. At present, the share of renewable energy is coming close to 20 per cent. From such point of departure, the paper defines a scenario framework in which the Danish system is converted to 100 per cent Renewable Energy Sources (RES) in the year 2060 including reductions in space heating demands by 75 per cent. By use of a detailed energy system analysis of the complete national energy system, the consequences in relation to fuel demand, CO₂ emissions and cost are calculated for various heating options, including district heating as well as individual heat pumps and micro CHPs (Combined Heat and Power). The study includes almost 25 per cent of the Danish building stock, namely those buildings which have individual gas or oil boilers today and could be substituted by district heating or a more efficient individual heat source. In such overall perspective, the best solution will be to combine a gradual expansion of district heating with individual heat pumps in the remaining houses. Such conclusion is valid in the present systems, which are mainly based on fossil fuels, as well as in a potential future system based 100 per cent on renewable energy.     

散热器与低温地板辐射联网供暖系统设计

针对单热源且同时存在散热器供暖与低温地板辐射供暖联网的供暖系统,分析了混水泵并联管网和带旁通的串联管网两种不同形式的供暖系统各自的结构特点、参数选择和优缺点,并给出了两种系统的适用情况。     

Proliferation of district heating using local energy resources through strategic building-stock management: A case study in Fukushima,Japan

District heating systems using cogeneration technology and renewable resources are considered as an effective approach to resources conservation and reduction of greenhouse gas (GHG) emissions. However, widespread aging and depopulation problems, as well as the popularization of energy-saving technologies in buildings, are estimated to greatly decrease energy consumption, leading to inefficiency in district heating and barriers to technology proliferation. From a long-term perspective, land use changes, especially the progression of compact city plans, have the potential to offset the decrement in energy consumption that maintains the efficiency of district heating systems. An integrated model is developed in this paper based on building cohort analysis to evaluate the economic feasibility and environmental impact of introducing district heating systems to a long-term compact city plan. As applied to a case in the Soma Region of Fukushima, Japan, potential migration from the suburbs to the central station districts is simulated, where district heating based on gas-fired cogeneration is expected to be introduced. The results indicate that guided migration to produce concentrated centers of population can substantially increase the heat demand density, which supports a wider application of district heating systems and better low-carbon performance. These results are further discussed in relation to technology innovation and related policies. It is concluded that policies related to urban land use planning and energy management should be integrated and quantitatively evaluated over the long-term with the aim of supporting urban low-carbon sustainable development.     

Do liberalised electricity markets help or hinder CHP and district heating? The case of the UK

This paper investigates whether and how Danish-style combined heat and power (CHP) and district heating (DH) can be implemented in the UK in the context of a liberalised electricity market. There is currently an absence, in the UK, of the Danish system of planning rules and also good tariffs for CHP electricity exports to the grid that led to the development of the Danish system of CHP and DH. However, there are some changes in UK planning practice that may help CHP and DH. These would need to be strengthened, but it is also the case that the way the liberalised electricity market operates in the UK effectively discriminates against small CHP plant selling their electricity to the grid. A Danish system of ‘aggregating’ CHP–DH plant using thermal stores could help to overcome this problem. However, an alternative strategy would be to establish feed-in tariffs for CHP units that are linked to DH modelled on the Danish ‘triple tariff’. This could help the UK's long-term objective of absorbing high levels of fluctuating renewable energy sources.     

Improvement of a district heating network through thermoeconomic approach

This paper reports a procedure to optimise district heating networks on the basis of second law analysis. The approach is derived from the exergonomic theory. A cost function has been set up and an iterative procedure was employed to determine the minimum value corresponding to the optimal pipe size and insulation thickness. Such a method was used to analyse an existing district network in Italy. The results show that significant savings could be obtained by using the proposed approach.     

Exergetic assessment of EAHEs for building heating in Turkey: A greenhouse case study

The present study undertakes an exergy analysis of earth to air heat exchanger (EAHE) and applies to a local one in Turkey. Namely, the exergy performance of an EAHE has been evaluated in a demonstration in Solar Energy Institute of Ege University, Izmir, Turkey. Exergetic efficiencies of the system components are determined as an attempt to assess their individual performances. The daily maximum heating coefficient of performance (COP) value for the system is obtained to be 6.18. The total average COP in the experimental period is found to be 4.74.     

Analysis of variable-base heating and cooling degree-days for Turkey

The degree-day method is one of the well-known and the simplest methods used in the Heating, Ventilating and Air-Conditioning industry to estimate heating and cooling energy requirements. In this study, the heating and cooling degree-days for Turkey are determined by using long-term recent measured data. Five different base temperatures ranging from 14 to 22°C are chosen in the calculation of heating degree-days. In the case of cooling degree-days, 6 different base temperatures in the range 18 to 28°C are used. Yearly heating and cooling degree-days are given both in tabular form and as counter maps for all the provinces of Turkey (78 weather stations).     

A simplified quadratic expression for the approximate estimation of heating degree-days to any base temperature

A simplified second-degree expression is developed for the approximate estimation of annual heating degree-days to various base temperatures. The only data needed for the application of this relation is the degree-days value to some reference base temperature and the mean annual temperature of the location. No statistical analysis is required for the identification of the parameters of the suggested relation, and so it is location insensitive. The quadratic relation proved to be quite accurate when applied to data from many cities from Greece and other Countries. Apart from the estimation of heating degree-days, the suggested expression can be useful for analytical purposes, due to its explicit and simple form.