The electric power system of the Republic of Serbia relies mostly on lignite-fired thermal power plants, with 70% of the total electricity generation. Most of these plants are over 30 years old, and investment in their modernization is necessary. The energy efficiency of the 110 MW coal-fired power plant in which the condenser is cooled by the mechanical draught wet cooling towers system is analyzed in this paper. Attention is primarily devoted to operating conditions of the cold end of the plant, i.e. to the interrelationship of the condenser and cooling towers. Most important parameters that affect the operation of the cooling towers system are ambient air temperature and relative humidity, specific mass flow rate, and temperature of cooled water. With the existing cooling system, the overall energy efficiency of the plant is low, especially in the summer months, even less than 30%, due to adverse weather conditions. By upgrading existing cooling tower system by adaptation of two additional cooling tower cells, overall energy efficiency can be increased by 1.5%. The cooling tower system rehabilitation investments payback period is estimated to be less than one year. Static method for economic and financial assessment is used.

Abstract. Electricity is a key energy source in each country and an important condition for economic development. It is necessary to use modern methods and tools to predict

A large number of producers offer a wide choice of various types of industrial cooling towers. Usually, a proper choice of pre-fabricated cooling tower satisfies end-user needs. However, if there are specific end-user requirements, it is necessary to design cooling tower according to those requirements. For the adhesive factory located in southern region of Serbia, 350 kW mechanical draught wet cooling tower was designed and built. Dimensioning of the cooling tower was done according to parameters of the ambient air, higher than the standard recommendations given in the literature. In this paper, the reasons for deviation from recommendations are given. The analysis of the cooling tower operation based on real meteorological parameters for 2015 is also shown in this paper. According to this analysis, cooling tower provides required water temperature in any season, and gives opportunity for energy savings in winter, with opportunity for heat capacity enlargement if production capacity is raised as it is planned in the factory.

A thermal power plant (TPP) uses large amounts of fresh water, mostly for cooling purposes. Among different types of cooling systems, once-through cooling is the most water-intensive and has the greatest environmental impacts. From the viewpoint of the steam cycle efficiency, this type of cooling still provides the most efficient electricity production, and therefore is widely used. Water is withdrawn from nearby water bodies, absorbs heat from the steam in a condenser, and then discharged back to its original source at higher temperatures causing severe environmental impacts, including fish killing, disturbing ecosystems, and heating-up natural water bodies. The total installed capacity of almost 1100 MW on the right bank of the Danube in Serbia threatens the ecosystem of this large international river due to thermal pollution. This problem will be even more pronounced in the near future, due to an inevitable increase in production capacity for new 350 MW, currently under construction. Herein, analysis of the legal framework for the protection of water from thermal pollution as well as analysis of the actual situation on the site of the TPP "Kostolac" in Serbia are presented. Based on meteorological and hydrological parameters, configuration and operation parameters of the plant, the numerical simulation of the condenser was carried on. The temperature of the water leaving condenser and amount of heat discharged back to the river are obtained. According to those results, the analysis of the existing thermal pollution of the Danube River in the flow through Serbia is given by numerical simulation using software ANSYS CFX. Analysis of thermal discharge into the Danube for the five-year period has been carried out. The cooling water effluent causes a temperature increase in the area of the right bank of the Danube, and this thermal disturbance extends along the right river bank for kilometers. Note that the flow rate of the Danube is currently large enough to compensate this thermal disturbance, but for a smaller river and/or larger electricity production capacities, this influence would have even more significant consequences on the ecosystem, making those results even more useful for further analysis.

Daily emissions of greenhouse gasses have a negative impact on the quality of the atmosphere. In almost every sector there is a certain emission of these gasses. This means that every sector, whether it is the energy, industry, transport sector or the household has a part in the degradation of the environment. In this connection, many models have been developed, whose task is to reduce greenhouse gas emissions and carbon dioxide as well to improve the environmental quality. This paper will discuss the carbon footprint model. A carbon footprint is the set of greenhouse gas emissions caused by something. It can be calculated for a product, service, person or even a country, and is used to understand the impact of human activity on the earth's climate. Also, an analysis of carbon footprint using different types of fuel for heating households will be presented.