The simplified scheme of power plant 

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... U cilju smanjenja ukupnih troškova proizvodnje elektri č ne energije potrebno je obezbediti efikasan rad termoelektrane. Za energetski efikasan rad termoelektrane neophodno je da se omogu ć i sinhronizovan rad svih delova. U ovom radu izvršen je izbor potrebne površine kondenzatora za dato termoenergetsko postrojenje sa proto č nim sistemom hla đ enja kondenzatora, kako bi se održala minimalna specifi č na potrošnja toplote. Prora č un potrebne površine kondenzatora ura đ en je na osnovu parametara realnog termoenergetskog postrojenja, na osnovu standardne projektne temperature rashladne vode. Za na taj na č in usvojenu potrebnu površinu razmene toplote u kondenzatoru izvršena je analiza rada postrojenja u smislu njegove energetske efikasnosti. Kao pokazatelj energetske efikasnosti rada postrojenja razmatrana je specifi č na potrošnja toplote. Zatim je kao projektna temperatura rashladne vode usvojena viša temperatura. Za tako dobijeni kondenzator ve ć e površine izvršena je analiza energetske efikasnosti. Na kraju, dato je pore đ enje dobijenih vrednosti specifi č ne potrošnje toplote za usvojene vrednosti u cilju izbora odgovaraju ć e površine kondenzatora. Abstract: In order to minimize total cost of electricity production it is necessary to provide efficient operation of thermal power plants. For an energy efficient work of thermal power plants it is necessary to maintain synchronized work of all its parts. In this paper, the calculation of required heat exchange surface of the condenser with the constant cooling water flow was done, in order to maintain minimal specific heat consumption. Calculation of required condenser surface was made based on parameters of real power plant on the so far applied standard for the design temperature of the cooling water. For the calculated heat exchange surface of the condenser, an analysis of the power plant in terms of its energy efficiency was made. As an indicator of the power plant energy efficiency specific heat consumption is considered. The calculation of the condenser heat exchange surface was also done for higher design temperature of the cooling water. For the power plant with new, larger condenser, an analysis of the energy efficiency was also done. Finally, the comparison of the obtained values of specific heat consumption of the power plant in both study cases is given, in order of choosing appropriate heat exchange surface of the power plant condenser. The largest electricity producers are thermal power plant. Electricity consumption is changeable on a daily, weekly and annual basis. Beside the outer consumers, part of generating power is used inside of the power plant and part is losing in a process of transfer. Due to the higher energy consumption, in the process of designing power plants, it tends to be the higher efficiency degree, reliability, and lower cost per unit of installed capacity. Energy efficient operation of the power plant can be provided by proper selection of the equipment and by appropriate handling of the power plant. A part with a great influence on power plant operation is the condenser. The main condenser task is to condense steam using water. Proper selection and operation of the water cooling system is of great importance for the energy efficient operation of the power plant. Which cooling system will be in use it depends on the available amount of water, it can be once - through (open - cycle) system and recirculation (closed - cycle) system with cooling towers. When there is enough amount of cooling water it can be used once - through system, but if there is no required amount of water closed - cycle system is in use. Regardless of which cooling water system is in use, significant influence on the operation of condenser has a temperature of cooling water and the state of atmospheric air. [1] Operation of the condenser at thermal power plants with once - through (open - cycle) water cooling system depends on the temperature of the cooling water at the inlet of the condenser and heat exchange surface of the installed condenser. The problem with the thermal power plants, especially during the summer months when the temperature of the cooling water is rising, is impossibility to achieve designed power, which leads to reduction of energy efficiency. As a reference power plant it was taken facility of the same configuration and the same operating parameters as TPP "Kostolac B", of 348.5 MW. This power plant with once – through cooling system is using water from the Danube with temperatures from 4 °C in winter to 26 °C in summer. The aim of this paper is to determine a proper heat exchange surface to the purpose of energy efficient operation of the power plant. This calculation was done based on next parameters: pressure of condensation and temperature of the cooling water at the inlet of the condenser. [2] Thermal power plants are very complex facilities with a large number of mutually related factors that affect proper operation. Before the start of calculation some restrictions are introduced related to the power plant and the flow of the cooling water. This restrictions are considered constant in the whole calculation. Nominal output power is 348.5 MW, flow of the cooling water is 13 m 3 / s . This restrictions have been introduced in order to be more clearly spotted the effects of cooling water temperature change to the specific heat consumption. Compared to the reference power plant observed power plant contains simplifications which are introduced in order to reduce the volume of calculation. This simplifications are related to the thermal plant scheme, but do not have a significant impact on the result of the calculation. The main components of power plant (Figure 1.) are steam boiler (SB), high pressure turbine (HPT), intermediate pressure turbine (IPT), low pressure turbine (LPT), two surface low pressure regenerative heaters (LPH 1 and LPH 2), regenerative feedwater heater high pressure (HPH), condenser and pumps. In addition to these components, the turbine is equipped with four ports (EP1,..., EP4) for steam subtraction, which are used to supply the regenerative heater high and low pressure and deaerator (DA). Function of deaerator (DA) is to remove the non - condensing gases from the steam cycle. Characteristics of the turbine as well as the efficiency of these components are given in Table 1. In order to determine the necessary heat exchange surface of condenser, which allows normal operation of the power plant, two calculations were carried out with different design temperatures of cooling water. The obtained values show the operation of the condenser depending on changes of temperature of the cooling water at the inlet of the condenser at constant power of power plant and the constant flow of cooling water. Mathematical model of condenser is based on the equations of heat transfer (1) and equations of mass and energy balance ...