•Developed novel approach based on the optimization and GIS.•Approach considers four groups of biomass conversion technologies.•The objective function maximizes NPVQ and selects the most ...cost-effective investments.•The approach is the basis for long-term planning methodology.
Use of biomass for energy purposes has many advantages, but it is not always profitable due to the characteristics of biomass. In order to improve the utilization of biomass it is necessary to create optimal conditions which require employment of several methods and technologies. This paper describes developed approach for consideration of options for the optimal utilization of available biomass potential under the current conditions (technological, economic, environmental and social). The developed approach is focused on support for decision making process on community level. Proposed approach includes mapping of biomass potential with defining both potential primary storage locations and potential locations of plant using geographic information system technologies. Also, it includes determining the optimal amount of biomass that can be justifiably used for energy purposes under current conditions by using the mathematical optimization with objective function related to maximizing net present value quotient. Four groups of technologies that can be used for biomass valorisation have been considered in the paper; biofuels production, thermal power plants, district heating and cogeneration.
The proposed approach has been applied (as a case study) on Municipality of Ivanjica located in South-West region of Serbia. Municipality of Ivanjica is characterized by both significant forest area and significant forest biomass potential. There are 30 potential primary storages locations and 57 potential plants locations determined by geographic information system. However, only one of potential locations of plant and two of potential primary storage locations (6% of available potential) are determined by mathematical optimization as optimal and could be used under current conditions.
This paper analyzes the potential for deep renovation of an apartment building to the level of a passive house in different contexts in the continental part of Europe. The examined variables include ...different local climatic conditions, levels of economic development, and levels of market development (energy prices, energy footprint, labor prices, etc.) as well as different energy efficiency retrofit scenarios in four different countries. The adequate methodology was developed here in order to obtain an optimal solution for deep renovation in each context. The proposed methodology was based on the interaction of energy simulation and mathematical optimization. In this model, the energy performances of a building are determined with the EnergyPlus package and the optimal solution was obtained by using a mixed-integer non-linear programming model. The results demonstrate that the optimal solution for each analyzed location cannot provide cost-effectiveness over the lifetime of a building, so the introduction of additional subsidies or incentives, such as carbon taxes and upfront subsidies, is necessary.
•Modeling methodology of the residential buildings heating energy consumption is presented.•Methodology is performed on staggered block buildings constructed between 1981 and 1990.•Thermal ...improvements of external walls and windows are investigated.•Heating energy consumption reductions are calculated on the city level.
Understanding of the buildings energy performance at the city level is necessary in order to form a city energy planning policy and make a strategic decision on which buildings should be thermally improved. Energy modeling of the building sector is methodology that estimates energy consumption in buildings and simulates the effects of energy efficiency improvements of building envelopes and systems. In this paper engineering bottom-up method was used for modeling the heating energy consumption of a multi-family residential building sector built before 2012 in the city of Kragujevac in Serbia. The first part of methodology presents the criteria based on which a multi-family residential building sector of the city was described and building types were defined. The second part of methodology investigates the selection of the real buildings, their modeling and heating energy consumption simulation. The modeling method was performed on staggered block buildings constructed between 1981 and 1990, and estimated heating energy consumption was compared to measured consumption. After the simulation of different thickness of polystyrene thermal insulation additions to external walls and simulation of the new windows installation, the reductions of the total annual heating energy consumption were obtained.
Water hydraulic components and systems play pivotal roles in the development of modern hydraulics. Sustainable development and environmental protection cannot be imagined without the use of water as ...a working medium in modern hydraulic systems. An axial piston pump is the main component of these systems. This paper presents analytical and experimental methods for the development of an axial piston pump. The presented mathematical model is rooted in numerous research results in the literature and in our own experience. It is based on mathematical modelling of hydrodynamic processes of a water hydraulic axial piston pump which, combined with experimental research, provides a great tool to analyse the influence of different factors on the operating process and to optimise the pump parameters. The experimental equipment used in our tests simulates a real hydraulic installation, and the obtained results are very close to the actual operating parameters. This research included a modification of the swash plate in order to achieve ideal operating parameters and, thus, extend the service life of the pump. Water has a number of advantages over conventional hydraulic oils. It is a sustainable, environmentally friendly resource, more readily available than oil (lower transportation costs), cheaper to dispose of, non-flammable and non-toxic, and its high thermal conductivity aids in cooling.
LED Corn bulbs are a simple solution to increase the energy efficiency of existing street lighting because their installation does not require the replacement of existing lamps. The paper analyses ...the techno-economic characteristics of LED Corn bulbs that can be used as a replacement for existing inefficient bulbs. Based on the collected data of more than 80 models of LED Corn bulbs, which are available on the European market, the functional dependences of power = f (luminous flux) and price = f (power) of these bulbs were determined using piecewise regression. Besides, based on the obtained functional dependencies, the effects of improving the energy efficiency of street lighting by replacing the existing High Pressure Sodium and High Pressure Mercury light bulbs with LED Corn bulbs in one city in Serbia were analysed.
The procedure of development of energy management system applied to an existing company (Serbian car producer “Zastava”) is shown in the paper. The aim of the paper is to provide a guideline for ...entrepreneurs in metal-working industry in implementing energy management system. First of all, paper includes: critical analysis of existing energy management system (energy matrix), principles of effective energy management organization (with energy manager and energy team in its structure) and energy management politics. Based on the results of energy auditing and performed technological and economical feasibility studies several energy saving measures related to different energy sources (steam, hot water, compressed air, electricity and water) were proposed, implemented and valuated. The proposed measures are not exclusively related to car assembly industry; they can be easily applied to other metal-working facilities with minor modifications. Such energy management system reduces energy costs and increase profitability of a factory.
Co-digestion implementation in wastewater treatment plants enhances biogas yield, so this research investigated the optimal ratio of biodegradable waste and sewage sludge. The increase in biogas ...production was investigated through batch tests using basic BMP equipment, while synergistic effects were evaluated by chemical oxygen demand (COD) balance. Analyses were performed in four volume basis ratios (3/1, 1/1, 1/3, 1/0) of primary sludge and food waste with added low food waste: 3.375%, 4.675%, and 5.35%, respectively. The best proportion was found to be 1/3 with the maximum biogas production (618.7 mL/g VS added) and the organic removal of 52.8% COD elimination. The highest enhancement rate was observed among co-digs 3/1 and 1/1 (105.72 mL/g VS). A positive correlation between biogas yield and COD removal is noticed while microbial flux required an optimal pH, value of 8 significantly decreased daily production rate. COD reductions further supported the synergistic impact; specifically, an additional 7.1%, 12.8%, and 17% of COD were converted into biogas during the co-digestions 1, 2, and 3, respectively. Three mathematical models were applied to estimate the kinetic parameters and check the accuracy of the experiment. The first-order model with a hydrolysis rate of 0.23–0.27 indicated rapidly biodegradable co-/substrates, modified Gompertz confirmed immediate commencement of co-digs through zero lag phase, while the Cone model had the best fit of over 99% for all trials. Finally, the study points out that the COD method based on linear dependence can be used for developing relatively accurate model for biogas potential estimation in anaerobic digestors.
The way citizens perceive air quality has a huge impact on the public's willingness to contribute agendas that promote a sustainable future. Consequently, the scientific community wonders do the ...sudden and short-term shifts in air quality (such as one caused by the COVID-19 pandemic) have the potential to induce long-term changes in community behavior. This study is based on the interpretation and analysis of a facultative survey administered to the student population of a medium-sized university city in the Balkans. The study's goal is to identify the types and strengths of factors that influence students' perceptions of air quality. In this regard, six classification algorithms were compared in order to select the one with the best fit between students' demographics, traveling habits, and air quality perception. Individual variable influence revealed that Weekly lectures attendance and Distances students travel determine the perception of air quality more than Gender and Permanent place of residence. According to the study, potential commuting reorganization should target those living 2-4 km from the faculty building. Students who regularly attend lectures are likely to be willing to rely on better-organized public transport. Those who do not, will generally contribute the initiative once the positive effects are evident.
This paper shows the thermal energy audit of the kindergarten "Zeka", located in the territory of the city of Kragujevac, Serbia. Data of the analyzed building, with an emphasis on the heating ...system, as well as the climate conditions of the location are shown. Analysis of the thermal energy use, done by implementing a software package "URSA-građevinska fizika 2", shows that the analyzed building belongs to the "G" energy efficiency level, which indicates that the heat transfer coefficients are not in the range defined by the Rule book of energy efficiency for buildings. Consequently, the energy conservation measures for increasing the efficiency of thermal energy use are proposed. Besides, for each measure, the techno- economic analysis was done, which includes determination of the investment costs, as well as the payback period. By implementing the appropriate measures in the analyzed building, it was concluded that thermal energy savings of almost 79% can be achieved.
