Energy

Increase of greenhouse gases concentration in the atmosphere, mainly carbon dioxide, which leads to global warming, indicates the need to take actions to reduce use of energy from carbon sources. The building sector is the largest consumer of energy, and thereby the largest emitter of greenhouse gases. In this paper the possibilities of achieving "near net zero emission" vision, in the residential sector, by the year 2050, were analysed. The necessary policies and technical energy efficiency measures were analysed, that could be applied in the building sector in Bosnia and Herzegovina by 2050. Large amount of energy is used for space heating and hot water, mainly from fossil fuels, which significantly contributes to air pollution and global warming. Specific energy consumption for space heating in Bosnia and Herzegovina is several times higher than in EU countries with the similar climate conditions. Therefore, it is necessary to reduce energy consumption significantly, ie to increase energy efficiency. It is also necessary to deploy the potential of renewable energy use in buildings and to use buildings as energy producers. In this way, in the long term, energy costs in buildings would be significantly reduced, as well as dependence on energy imports and the need for building of new capacities for energy generation. From other side, employment would be increased while emissions of pollutants and greenhouse gases would be reduced. In this paper, due to the availability of reliable data on energy consumption for the Sarajevo Canton, the necessary policies and measures to promote energy efficiency were analysed, that could be applied in the residential sector in the Sarajevo Canton.

Increase of greenhouse gases concentration in the atmosphere, mainly carbon dioxide, which leads to global warming, indicates the need to take actions to reduce use of energy from carbon sources. The building sector is the largest consumer of energy, and thereby the largest emitter of greenhouse gases. In this paper the possibilities of achieving "near net zero emission" vision, in the residential sector, by the year 2050, were analysed. The necessary policies and technical energy efficiency measures were analysed, that could be applied in the building sector in Bosnia and Herzegovina by 2050. Large amount of energy is used for space heating and hot water, mainly from fossil fuels, which significantly contributes to air pollution and global warming. Specific energy consumption for space heating in Bosnia and Herzegovina is several times higher than in EU countries with the similar climate conditions. Therefore, it is necessary to reduce energy consumption significantly, ie to increase energy efficiency. It is also necessary to deploy the potential of renewable energy use in buildings and to use buildings as energy producers. In this way, in the long term, energy costs in buildings would be significantly reduced, as well as dependence on energy imports and the need for building of new capacities for energy generation. From other side, employment would be increased while emissions of pollutants and greenhouse gases would be reduced. In this paper, due to the availability of reliable data on energy consumption for the Sarajevo Canton, the necessary policies and measures to promote energy efficiency were analysed, that could be applied in the residential sector in the Sarajevo Canton.

In this paper, wind energy potential in Sarajevo area, Bosnia and Herzegovina, was analyzed statistically. The analysis of wind energy potential was performed based on measured wind data in a one-year period from 1 January to 31 December 2019. Measured data were obtained on the basis of a meteorological station installed on the roof of the building of the Faculty of Mechanical Engineering in Sarajevo at 30 m height. Measured wind characteristics were statistically analyzed using the Weibull and Rayleigh distribution functions. The Weibull parameters were obtained using two methods, the energy pattern factor method and the maximum likelihood method, and both methods were used to find the Weibull parameters and the wind power density. The results of this investigation showed that the analyzed place falls under Class 1 of the international system of wind classification as the mean annual wind velocity recorded in the analyzed area was 1.215 m/s and the corresponding annual mean power density was estimated to be 6.7 W/m2 at 30 m height. The results show that the available wind energy potential to generate electricity in Sarajevo is low and wind power cannot be used to meet the energy needs in that region.

Global temperature increase on Earth, due to climate change, indicates the need for a data revision pertaining to outdoor design temperature and number of degree – days. In this paper, based on the relevant data pertaining to tempereture mesurements in Sarajevo for a period of ten years (since 2001 to 2010), new outdoor design temperature- 13°C is defined, instead of applicable temperature-18°C and number of degree days 2381°C-ann, instead of applicable 3077°C-ann. The results of calculation show that requirement for thermal energy is 22 % less for outdoor design temperature of-13°C. Therefore, there is the need for data revision pertaining to outdoor design temperature and number of degree – days, wich could lead to a correction in the heating systems. As a consequence, atmospheric CO2 emmision will be less in the building sector, which can play a key role in combating climate change.

Global temperature increase on Earth, due to climate change, indicates the need for a data revision pertaining to outdoor design temperature and number of degree-days. In this paper, based on the relevant data pertaining to tempereture mesurements in Sarajevo for a period of ten years (since 2001 to 2010), new outdoor design temperature-13°C is defined, instead of applicable temperature-18°C and number of degree days 2381°C-ann, instead of applicable 3077°C-ann. The results of calculation show that requirement for thermal energy is 22% less for outdoor design temperature of-13°C. Therefore, there is the need for data revision pertaining to outdoor design temperature and number of degree-days, wich could lead to a correction in the heating systems. As a consequence, atmospheric CO 2 emmision will be less in the building sector, which can play a key role in combating climate change.

The paper presents results of the inventory of refrigerants in use in Bosnia and Herzegovina and a discussion on their impact on the environment. Data on types, quantities and numbers of refrigerants in use, a type of a user and a purpose of the use were collected through the survey. The research sample included 297 facilities with 745 samples of refrigeration equipment covering the facilities from different sectors such as: banks, industry, shopping centres and stores, hotels and hospitals. Findings of this research are important for analysis of a level of the application of environmentally friendly refrigerants. The research showed that in Bosnia and Herzegovina HFC coolants are mostly used with a share of 62%, followed by 37% of natural refrigerants. The use of other types of refrigerants is negligible. Refrigerants that have the ozone depletion potential equal to zero are mainly used. Natural refrigerant R-717 has the largest share of 36.3%, followed by HFC R-134A with share of 24.9%. Refrigerant R-404A has the highest global warming potential (GWP) of 4210 and share in the total mass of 16.8%. Refrigerant R-410A has a share of 16.5% in the total mass and GWP of 2080. The work identifies promising alternative refrigerants with the lower GWP as potential environmental substitute for the refrigerants under control R-404A, R-410A and R-134.

This paper aims to assess the perception of residents about the level of noise caused by indoor and outdoor activities. The survey was also conducted to assess the level and type of negative emotions caused by noise. The survey included different groups of residents, as well as different types of buildings in which they live. 201 respondents were included in the survey, and the survey focused on outdoor sources of noise such as traffic, children's playgrounds, sports fields and cafes and restaurants, and indoor types of noise such as loud music, renovation of apartments, family quarrels and children's games. 72 respondents stated that they were most irritated by noise from construction work in neighbouring apartments, 51 of them cited arguments and noise from neighbouring apartments and 29 respondents mentioned loud music. However, the respondents express empathy towards children, because the noise caused by children's play does not bother them.

Strategic renovation of existing building stock is strongly promoted in Energy Efficiency Directive and Energy Performance of buildings directive. Measures at the envelope are usually combined with replacement of existing heating system. This paper deals with situation where existing radiator system are connected to heat pump instead of previously installed old boiler for heating. Designers of these systems rely on bin method which is well designed for new systems. However, in case of existing systems several factors determine the available power from heat pumps such as: oversized radiators, over-or under flow of hot water in existing systemboth influencing the return temperature or inlet temperature to heat pump. It is demonstrated that in some cases available and declared capacity of the pump is overestimated which is result of neglecting previously mentioned factors. In this paper the adaptation of existing bin method according to standard EN 14825 is proposed which fits any existing system. Calculations are performed and results are presented for the baseline condition and three scenariostwo with radiator system and one with underfloor heating. Advances of improved methodology for calculation are highlighted and the conclusions are presented at the end.

A mathematical model and robust numerical solution algorithm for radiator heating of an arbitrary room is presented in this paper. Three separate and coupled transient thermal energy equations are solved. A modified transient heat conduction equation is used for solving the heat transfer at multi-layer outer walls and room assembly. Heat exchange between the inner walls and the observed room are represented with their own transport equation and the transient thermal energy equation is solved for radiators as well. Explicit coupling of equations and linearization of source terms result in a simple, accurate, and stabile solution algorithm. Verification of the developed methodology is demonstrated on three carefully selected test cases for which an analytical solution can be found. The obtained results show that even for the small temperature differences between inner walls and room air, the corresponding heat flux can be larger than the transmission heat flux through outer walls or windows. The benefits of the current approach are stressed, while the plans for the further development and application of the methodology are highlighted at the end.

In this paper analysis wind velocity data in the area of the city of Sarajevo in period 1980 to 1990. Data obtained from the Federal Hydrometeorological Institute of Bosnia and Herzegovina. After analysis wind velocity data in the area of the city of Sarajevo in period 1980 to 1990 are compared with the results obtained from the analysis of wind velocity data in the area of the city of Sarajevo in period 2000 to 2010. After that analysis, given more precise assessment of wind energy potential in the area of the city of Sarajevo.

The main goal of this paper is to evaluate and discuss the energy potential of wind in the mountain area around Sarajevo. The analysis of wind energy potential was performed based on measured wind data for Bjelasnica in a period from 2000 to 2017. Measured data for wind velocity were obtained from the Federal Hydrometeorological Institute of Bosnia and Herzegovina. The results of this investigation showed that the analysed place falls under Class 7 according to the international system of wind classification, as the mean long term wind velocity recorded in the analysed area was 11 m/s and the corresponding mean long term power density was estimated about 2013 W/m 2 at 10 m height. Taking into account the power coefficient of the wind turbine as well as the utilization factor of the turbine and generator, it is obtained that the mean long term electrical power density is about 624 W/m 2. For a better insight into the characteristics of the occurrence of high-wind velocity, the calculation of expected maximum wind velocity for a return period of 50 years was carried out. It was shown that for the return period of 50 years, the reference extreme wind velocity is 64.6 m/s.

Variable flow distribution systems are promoted in complex heating and cooling systems as energy efficient solutions for new systems and as an upgrade of the existing constant distribution flow systems. In the case of variable flow, the pumping energy costs decreases and the preferable return temperature can be achieved which is beneficial for operation of the condensing boilers or district heating connection. As a result of different demand in heating/cooling zones, the pressure variations in the system can lead to hydraulic problems of single zones/consumers, which at the end result in control stability problems and decrease of thermal comfort for end users. High differential pressures at zones connections can in case of mixing circuits lead to back flows in the bypass ports of the three-way valves or backflow at the injection circuits with two port valves are used, increasing the return temperature and preventing the work of control valves in the full stroke. In these cases, the differential pressure controllers are necessary in order to stabilize the strong variation of differential pressure by preserving the high value of the regulating valve authority which guaranties the stable control over the entire stroke of the control valves, very close to the nominal conditions for which they are designed. This paper presents the simple algebraic model of the differential pressure controller as part of the hydraulic system and demonstrates the use of the proposed model at four characteristic examples applied at three different systems: Fixed flow radiators system, variable flow for injection circuit consumer connection and variable flow connection of indirect heating substation. The results of calculations demonstrate the applicability of the developed model for calculation of more complex cases.

In modern society, when people spend most of their time in indoor environment, it is very important to ensure the best possible indoor climate in order to achieve general satisfaction with the users of the space. The paper provides an overview and description of the key parameters required for achieving a quality indoor climate. Also, the measurement of indoor air quality (IAQ) parameters was performed in one of the classrooms in the building of the Faculty of Mechanical Engineering in Sarajevo in the period from May 7 2019 till May 24 2019. The results obtained by measurement are compared with the values prescribed according to EN 15251, EN 16798, EN 13779 and ASHRAE 62.1 standards in order to determine the level of air quality in the room.

A major problem in the area of the city of Sarajevo is that during the winter period there is an increase in the concentration of harmful gases in the atmosphere (primarily CO2), as a result of the intensive use of fossil fuels. Constant growth of energy sources, then the increase in the price of electricity and the intensification of the effects of greenhouse gases is the main reason for the analysis of wind potential in the area of the city of Sarajevo. In this paper analyzes and processes wind velocity data for the period from 2001 to 2010 for the area of Sarajevo, obtained from the Federal Hydrometeorological Institute of Bosnia and Hezegovina. After analyzing and processing wind velocity, a more precise assessment of wind potential in the Sarajevo area was given and guidelines for further research.

One of the major problems the city of Sarajevo is currently facing is the fact that in winter months the atmosphere is very polluted, mainly because of enormous usage of fossil fuels, primarily for heating. The other issue is the fact that it is extremely energy dependent, only a small portion of it's energy needs is currently produced within the area of the city. These are the two main reasons for the analysis of the solar energy potential in Sarajevo. This paper focuses on analysing the available solar irradiance data obtained from several sources and on providing the exact mathematical method of the analysis, as well as on the results themselves. Furthermore, it also focuses on the effect of the surface tilt angle on the overall amount of the solar irradiance received by the tilted surface. After analysing and processing al the data, a more precise assessment of solar energy potential and the effect of the tilt angle on the overall irradiance received by the tilted surface in Sarajevo is given, as well as the guidelines for further research.

Constant growth of energy sources, then the increase in the price of electricity and the intensification of the effects of greenhouse gases is the main reason for the analysis of wind potential in the area of the Canton Sarajevo. In this paper analysis wind velocity data for the period from 2000 to 2010 for Bjelasnica, obtained from the Federal Hydrometeorological Institute of Bosnia and Herzegovina. After analysis wind velocity, a more precise assessment of wind potential in the Bjelasnica area was given and guidelines for further research.

The building sector in Bosnia and Herzegovina is a major energy consumer due to the age, inadequate maintenance, and poor energy characteristics of the majority of buildings. More than 90% of the residential buildings are categorized as individual, single-family houses, accounting for more than 80% of energy consumption. It is of great importance to model the impact of architectural, construction elements, and other relevant parameters on the building's energy consumption. Using the statistical method of design of experiments, a mathematical model is developed a model for the annual energy consumption of a typical residential building based on the building's relevant parameters. The model considers climatic conditions, architectural and construction features, and the characteristics of the installed heating system. This model enables identification of key factors influencing energy consumption and a rapid evaluation of potential energy savings through the implementation of energy efficiency measures. The model is developed for a typical building from the Typology of Residential Buildings of Bosnia and Herzegovina, specifically in the category of single-family houses constructed between 1981 and 1990, representing more than 200000 buildings. The validation of the model demonstrated its effectiveness in predicting the energy consumption of a representative building, therefore the analysis results can be extrapolated to all buildings within the same category.