Miroslav Lambic

Global Trends on Production and Utilization of Biodiesel

This work represents a review of biodiesel production in the world. European Union policy and aims are to reduce increased emission of gases, carbon dioxide in particular, which cause the greenhouse effect due to an increase in demand and use of fossil fuels. A graphical display is given showing the production of oilseed plants: sunflower, soybean, and oilseed rape, with a special overview of the countries which are leading producers of this alternative fuel. Studies are made for biodiesel, showing that the total energy balance is positive, and for this reason give the material and energy the balance of biodiesel production. Regulations and aims directed to increase the production of biodiesel are also shown as well as possibilities for obtaining and using this ecological fuel.

The increase of exploitability of renewable energy sources

ABSTRACT The article stresses the significance of the use of renewable energy sources (RES) regarding the fact that the climate changes are a real problem and RES are a real solution. The article also shows the potential of biomass, solar energy, hydro energy, wind energy, and geothermal energy, as well as the actual state of exploitability of these RES in Serbia. There are identified barriers to RES implementation and proposed measures to overcome them. There are present strategies for improvement and an increase of exploitability of RES potential in compliance with the world policy in this regard. The aim of this article is to point out the necessity of creating an enabling environment for promoting RES and the gradual removal of barriers to stronger penetration in the energy market.

Estimation of Indoor Temperature for a Direct-Gain Passive Solar Building

AbstractThis paper examines the effects of passive solar heating produced by a direct passive solar system consisting of windows for direct insolation in a residential building located in Nis, Serbia. A mathematical model is presented to calculate the temperature in the room of a building with a direct passive solar system, depending on the size of the opening, window slope (slanting or vertical position), orientation of the room, and the size of the eave above the window (if it is installed). Using the proposed mathematical model, the inner air temperatures of a thermally insulated residential building with a direct passive solar system are analyzed for different building orientations during the period between January and March of 2008. Two software packages are developed to support the proposed mathematical model.

Measures for increasing consumption of natural gas

ABSTRACT This paper provides an overview and analysis of the structure of the energy system and consumers of natural gas on the territory of the Serbia with special attention to one category of consumers – households. It gives an overview of data on the energy system of Serbia – the natural gas sector, concepts, and directions of the development with projections until 2030. In addition to the projection of consumption of natural gas, it also gives the legal framework in force in the field of energy sector in Serbia. It presents data on natural gas consumption in Serbia in the period from 2010 to 2015, with projections of future consumption until year 2030.

Estimating the Effects of Environmental Conditions on Active Solar Wall Air Heating System Efficiency

AbstractThis study analyzed the effect of the environmental conditions on the thermal efficiency of an active solar wall with forced convection. The analyzed system is comprised of a double glass glazing and a massive wall with an opening and central channel in it. In order to increase the efficiency, we provided a fan at the bottom vent of the wall. The active solar wall is more advanced compared to the simple Trombe solar wall with a relatively low thermal resistance, which we took as a reference in our experimental analysis. This paper presents a one-dimensional steady-state mathematical model for simplified analysis of the efficiency of active solar wall air heating systems. We analyzed the obtained results in order to predict the effects of environmental parameter variations, such as solar radiation, ambient temperature, and wind velocity, on thermal efficiency.

Some aspects of the use of solar energy in Serbia

ABSTRACT This article presents the aspects of solar radiation and the use of solar energy in Serbia. It also considers why Serbia does not use thermal conversion of solar radiation in spite of much greater potential comparing to the countries of the Western and Central Europe, which are leading in the use of solar energy. The low standard of living, low electricity prices, the low level of energy efficiency in all areas of energy use, lack of knowledge, and political decisions are the main causes of insufficient use of renewable energy sources in Serbia.

Increasing the efficiency by retrofitting gas boilers into a condensing heat exchanger

ABSTRACT When trying to reduce energy consumption in a central heating system or in a domestic water heating system, it is necessary to consider the annual operating efficiency of the heating and the domestic hot water heating system. A boiler operates under dynamic conditions, so it essential to know the methodology and the model of annual operating efficiency calculation for thermo technical systems. The outlet temperature of the flue gases with conventional gas boilers is considerably higher than the ambient temperature and consequently the heat loss occurs; it is then vented off into the environment as a result of heat transfer. The heat loss may be reduced if a condensing heat exchanger is installed, which will, on the other hand, increase the boiler efficiency by more than 10%. This paper studies the relations between combustion and heat transfer, which will enable the appraisal of a gas boiler efficiency increase and possible ways of energy savings. The method for cost-effectiveness of the investment is used to perform a feasibility study of retrofitting a conventional boiler into a condensing boiler with necessary details. The results of the investigation show that the most cost-effective temperature range of the flue gases is 40–60°C. The use of a working fluid in the heating system or the domestic cold water results in cooling the condensing heat exchanger. The temperature of the return water or the domestic cold water is lower than the water vapor dew point in the flue gases during most of the heating period in almost all parts of the Republic of Serbia where natural gas is used.

Solar energy in Vojvodina (Serbia): Potential, scope of use, and development perspective

ABSTRACT In this article, the solar radiation in Vojvodina (a region which is located on the north of Republic of Serbia) is discussed. Its application up until now in this region and possible additional applications of solar energy in the future are reviewed. The aim of this work is to overview the energy and exploitation possibility in using solar energy in all of the segments of energy consumption of Vojvodina and to present to potential investors relevant base for future decision-making of application of these technologies.