The investigation of district heating by steam extraction from Çatalağzı Thermal Electricity Power Plant

In a conventional coal-fired power plant, which is only designed for electricity generation, while nearly 1/3 of fuel energy can be converted to useful energy, the other part of the energy is wasted as stack gases and cooling water of condensers. This waste energy could be recovered by modifying the plant as cogeneration system. It is possible to employ district heating by cogeneration system which generates both electricity and useful heat at the same time. In this study, the possibility of employing district heating in Zonguldak has been researched in order to reduce waste energy amount that is transferred to the cooling water of condensers in Çatalağzı Thermal Electricity Power Plant. The heat demand of district heating system has been met by steam extraction from turbine. To simply the steam extraction point, four different cycle model have been developed and the most appropriate steam extraction point has been identified. To specify heat demand of the location, two types of building have been modelled as isolated and unisolated and the total heat demand of the location has been determined. The most economical pre-isolated pipe diameter which is used for transporting the hot fluid between the location and the plant and the heat losses at these pipes have been calculated. The unit cost of heat energy has been determined in order to compare district heating and heating with natural gas. In order to specify the unit cost of heat energy; the decrease of the electricity generation as the steam extraction takes place, the first investment cost, the need of electricity for pumps, maintaning and repairing costs have been considered. Results have indicated that employing district heating system by the way of steam extraction from Çatalağzı Thermal Electricity Power Plant is a useful heating system from the view of energy efficiency and economy.