<abstract><title style='display:none'>Abstract</title>The tremendous growth in the transportation sector as a result of changes in our ways of transport and a rise in the level of prosperity was reflected directly by the intensification of energy needs. Thus, electric vehicles (EV) have been produced to minimise the energy consumption of conventional vehicles. Although the EV motor is more efficient than the internal combustion engine, the well to wheel (WTW) efficiency should be investigated in terms of determining the overall energy efficiency. In simple words, this study will try to answer the basic question – is the electric car really energy efficient compared with ICE-powered vehicles? This study investigates the WTW efficiency of conventional internal combustion engine vehicles ICEVs (gasoline, diesel), compressed natural gas vehicles (CNGV) and EVs. The results show that power plant efficiency has a significant consequence on WTW efficiency. The total WTW efficiency of gasoline ICEV ranges between 11–27 %, diesel ICEV ranges from 25 % to 37 % and CNGV ranges from 12 % to 22 %. The EV fed by a natural gas power plant shows the highest WTW efficiency which ranges from 13 % to 31 %. While the EV supplied by coal-fired and diesel power plants have approximately the same WTW efficiency ranging between 13 % to 27 % and 12 % to 25 %, respectively. If renewable energy is used, the losses will drop significantly and the overall efficiency for electric cars will be around 40–70% depending on the source and the location of the renewable energy systems.</abstract>

Comparison of the Overall Energy Efficiency for Internal Combustion Engine Vehicles and Electric Vehicles

<abstract xml:lang="en"><title style='display:none'>Heat and Mass Transfer Processes in Scrubber of Flue Gas Heat Recovery Device</title>The paper deals with the heat and mass transfer process research in a flue gas heat recovery device, where complicated cooling, evaporation and condensation processes are taking place simultaneously. The analogy between heat and mass transfer is used during the process of analysis. In order to prepare a detailed process analysis based on heat and mass process descriptive equations, as well as the correlation for wet gas parameter calculation, software in the <italic>Microsoft Office Excel</italic> environment is being developed.</abstract>

Institute of Energy Systems and Enviroment, Riga Technical University

Heat and Mass Transfer Processes in Scrubber of Flue Gas Heat Recovery Device

<abstract><title style='display:none'>Abstract</title>The present work aims to analyse the environmental advantages of a production process that applies circular economy. The study examines a product that is generated through the use of a certain percentage of recovered secondary materials, thus helping to avoid impacts related to the disposal of these materials and preserving the ecosystems from indiscriminate excessive natural resources extraction. The product analysed is an ecological detergent (“Ri-Detersivo” – Re-Detergent), produced by the company Tea Natura, mainly composed of regenerated vegetable oils coming from food industry. The methodology used in this paper is Life Cycle Assessment (LCA). A partial LCA will be carried out here, arriving at the saponification phase, and comparing the environmental impacts deriving from the Re-Detergent production process with those of a traditional soap, comparable to that studied in terms of function. The analysis of the case study found that the use of regenerated vegetable oils for the production of soap allows to significantly reduce the environmental impacts compared to the use of coconut oil imported from third countries.</abstract>

The Role of Environmental Evaluation within Circular Economy: An Application of Life Cycle Assessment (LCA) Method in the Detergents Sector

<abstract>
<title style='display:none'>Abstract</title>
The paper examines the role and place of green enterprises, green jobs and the environmentally sound activities of society in waste management, taking into account the waste management hierarchy with an emphasis on waste reduction and prevention. In the course of the work, a questionnaire was prepared on the role green enterprises, green jobs and the environmentally friendly activities of society play in the development of a waste management system. The TOPSIS method of multi-criteria analysis was used to assess these roles in the development of a circular economy, including in relation to a waste management system. Through the assessment of the roles of these green measures in the field of waste management, the results clearly show that the most effective of the selected alternatives in the circular economy model in the field of separate collection and recycling of waste can be achieved via measure exercised by green enterprises, followed by green jobs and finally – the role of environmentally sound activities taken by the public, which play an important role as well.
</abstract>

Role of Green Jobs in the Reduction of Waste and Waste Management

<abstract><title style='display:none'>Abstract</title>The importance of the honey bee lays in its huge role in pollination and, as a result, maintaining the flora of the environment and also increasing agricultural production. Temperature is the most important element of the atmosphere affecting beekeeping. Results of stationary conclusions are generalized to the area of Fars province by using geographical information system (GIS) according to direct relationship between elevation changes and temperature variations. A beekeeping capability map was then drawn for the Fars province by months of the year. The results showed that heat conditions in four months of the year, from December to March, are not suitable in most of the northern and eastern parts of the province. The southern regions with an altitude of less than 1100 meters above sea level are considered as a suitable place for deployment, wintering and beginning of bee colony activities. The most optimal months of the year for honey bee activities are May and October. For fixed beekeeping, the central strip of the province with an average height of 1500 meters above sea level is the most suitable places.</abstract>

Temperature Conditions for Determination of Beekeeping Regions in the Light of Climate Change. Case study: Fars Province

<abstract><title style='display:none'>Abstract</title>The aim of this study is to identify the factors affecting behavioural intention in buying energy-efficient household products in Malaysia. The extended Theory of Planned Behaviour (TPB) was tested in this research. Five hypotheses were tested using data derived from 336 residences in Malaysia. The hypothesized model incorporates knowledge and reasonable price into the conventional (TPB) model. Multiple regression analysis was used to examine the relationship between the independent and dependent variables. The results of the multiple regression analysis show that attitude, subjective norm, perceived behavioural control, knowledge and reasonable price have significant and positive effect on energy-efficient household product buying intention among residences in Malaysia. This research results provide insights for companies for promotion of green technological products and in strategizing to motivate residence in Malaysia to embrace green consumption behaviour.</abstract>

Factors Affecting Energy-Efficient Household Products Buying Intention: Empirical Study

<abstract>
<title style='display:none'>Abstract</title>
The article analyses the thermodynamic conditions for long-term storage of hydrates and proposes a methodology for calculating the main thermodynamic parameters that ensure long-term stability of the structure of gas hydrates. A criterion for optimizing thermodynamic parameters and heat and mass transfer parameters for effective introduction of new technology
</abstract>

Application of Synthesized Hydrates in the National Economy

<abstract>
<title style='display:none'>Abstract</title>
The EU countries are implementing biomethane production projects from biogas, supplying it to the natural gas distribution grid, or using it as motor fuel. It is also extremely relevant for Ukraine, supposing the problems with gas import due to Russian aggression. Biogas production from landfills, agriculture waste, and sewage is already implemented in Ukraine, so the next step must be biomethane production on an industrial scale and the selection of biogas separation technology is important. Using 11 years of industrial experience in biogas production from landfills, wide experience of the different methane-containing gases separations, and small companies’ industrial possibilities, the most applicable separation technologies for Ukraine were selected: amine, water, and combined water amine carbon dioxide separation. These technologies had compared using computer simulation with real landfill biogas flow rate debt. Results of a software simulation of the most applicable water-amine absorption technology were verified using a laboratory setup. For carbon dioxide concentration in biogas at 32–42 % vol., the specific energy consumption when using water absorption is on average 2 times less compared to amine absorption, but at the same time, the loss of methane due to its solubility in water during water absorption amounted to 7.1–7.6 %, with practically no losses in amine absorption, and minor losses at 0.17–2.8 % in combined water-amine technology. The energy consumption of combined water-amine absorption is comparable to that of water absorption due to: a) reduction of heat losses for the regeneration process of saturated amine absorbent, as part of carbon dioxide has already been removed with water technology; b) using the methane excess to compensate power consumption of the biogas compressor during the preliminary water absorption of carbon dioxide and/or to compensate heat costs of the saturated amine absorbent regeneration
</abstract>

Effectiveness of Water-Amine Combined Process for CO2 Extraction from Biogas

<abstract>
<title style='display:none'>Abstract</title>
In this study, the insertion loss of devulcanized waste rubber baffles were evaluated. Acoustic baffles are suitable to reduce noise from the devices or machines by interfering with their emitting sound waves. Knowledge of the acoustic properties of the material used is of significant importance in ensuring the effectiveness of the acoustic properties of the baffle. Basic properties include airborne sound insulation, which is usually determined during laboratory tests. Baffles consists of sound absorbing and sound insulating materials. In this study, plasterboards were used as sound insulating material and devulcanized waste rubber as sound absorbing material. During the devulcanization process, porous granules are obtained, which can be used as an acoustic material. In this study, two types of rubber granules were devulcanized by grinding method and one other type was chemically devulcanized. Three types of rubber granules were mixed together in increasing 25 % proportion steps and glued with patented polyurethane glue. A total of 15 different composition devulcanized waste rubber granule boards were made. Rubber boards were attached together with the plasterboards. Insertion loss of the different composite baffles was measured in semi-anechoic chamber in a purposefully designed stand in 1/3rd octave bands. The results showed that the insertion loss of the baffles was mostly dependent on the rubber granule board density. When the density of the rubber board increased, the insertion loss also increased. The 5–6 dB insertion loss difference was measured between the most and least dense rubber granule board baffles.
</abstract>

Research of Insertion Loss of Multilayered Construction with Devulcanized Waste Rubber

<abstract>
<title style='display:none'>Abstract</title>
With the integration of wind power into the power system, dispatch becomes more complex and existing algorithms are no longer applicable. This paper focuses on optimizing carbon emissions in wind farm generation while considering issues related to wind power integration and carbon trading. An optimal dispatch algorithm was designed with the objective of minimizing total costs, which was then solved using the cuckoo search (CS) algorithm. Additionally, an adaptive improvement was made to the CS algorithm to obtain the improved cuckoo search (ICS) algorithm. An analysis was conducted on a case study with 10 units. The ICS algorithm obtained higher quality solutions, with a total cost of $ 632 719 and a calculation time of 0.51 minutes, which was superior to the solutions obtained by the particle swarm optimization and CS algorithms. Fluctuations in the confidence level of system rotation reserve capacity could lead to variations in the final system cost, which needs to be adjusted according to actual conditions. The dispatch scheme obtained by the ICS algorithm showed reduced carbon emissions, total costs, and better performance when compared with the optimal dispatch algorithm in different scenarios. The results show that the proposed methods are reliable and practical.
</abstract>

Optimization Study of Carbon Emissions in Wind Power Integrated Systems Based on Optimal Dispatch Algorithm

<abstract>
<title style='display:none'>Abstract</title>
Fly ashes as a residue from combustion processes of coal in coal-fired power stations can be applied for zeolite formation. The zeolite synthesis has considerable effect on their structure following further catalytic use. The formation of analcime is guided by the operation of the silicate framework in the company of Na+, [Al(OH)4]−, [H2SiO4]2− species, coming from fly ash processing. Here, we have highlighted the importance of conducting the coal fly ash waste management towards monomineralic zeolite synthesis, in the form of powder analcime. It is the first report on powder analcime production without fly ash residues, confirmed by SEM and XRD analysis. The obtained analcime-zeolite was further explored as biodiesel catalyst based on base-catalyzed transesterification process. The effect of analcime catalyst usage on the biodiesel yield was determined with observed 97.2 % conversion efficiency under the concentration of 4%wt at 230 °C, with three times reusable analcime catalysts. Coal fly ash-derived monominerals on a large scale can significantly contribute to the sustainability goals and efficient waste management.
</abstract>

Hydrothermal Conversion of Fly Ash into Monomineralic Zeolite Synthesis for Biodiesel Production

<abstract>
<title style='display:none'>Abstract</title>
Two case studies are reported in the present work. They regard municipal solid waste (MSW) management trends in the last decades in two Italian provinces selected to analyse some issues of waste management in mountainous areas. The first case study refers to a selective collection (SC) rate expected to reach 80 % soon. This scenario assumes SC mainly in kerbside mode. The scenario is based on specific local conditions: the absence of a thermo-chemical plant in the territory (but with a part of the residual MSW burnt in a neighbour province), the presence of local plant of anaerobic, and a sanitary landfill for pre-treated residual MSW. The adopted tariff helped increasing the SC rate: indeed, since 2013, a tariff calculated at user level, depending on the behaviour of each user, has been adopted. This is called punctual tariff. The second case study concerns an area where SC reached about 75 %. The punctual tariff has been recently introduced. In this scenario, an incineration plant and a Solid Recovered Fuel (SRF) plant allow implementing an industrial symbiosis solution in conjunction with a cement factory. The work demonstrates that SC can be the core of a correct MSW management and that kerbside collection is fully compatible with mountainous area. However, other issues remain to be optimized yet: the low density of mountain areas makes difficult to implement enhanced solutions of SC (e.g. for diapers) and increases costs for light packaging collection; moreover, the presence of tourist fluxes can significantly affect SC efficiency.
</abstract>

MSW Management in Two Italian Mountainous Areas

<abstract><title style='display:none'>Abstract</title>Multi-criteria decision analysis (MCDA) is widely used to solve various decision problems through alternative evaluation. MCDA methods can be used in every field that can define a problem, alternatives and criteria. However, finding the appropriate method can influence the results, in this research five MCDA methods have been tested on the renewable energy sector in Latvia to find the best alternative. The main results showed that TOPSIS, VIKOR and PROMETHEE-GAIA have similar priority selection and the highest ranking was selected for hydropower plant, but MULTIMOORA and COPRAS results were beneficial to Solar PV.</abstract>

Multi-Criteria Decision Analysis Methods Comparison

<abstract><title style='display:none'>Abstract</title> Environmental impacts of the mineral extraction have been a public concern. Presently, there is widespread global interest in the area of mining and its sustainability that focused on the need to shift mining industry to a more sustainable framework. The aim of this study was to systematically assess all possible environmental and climate change related impacts of the limestone quarrying operation in Thailand. By considering the life cycle assessment method, the production processes were divided into three phases: raw material extraction, transportation, and comminution. Both IMPACT 2002+ and the Greenhouse Gas Protocol methods were used. Results of IMPACT 2002+ analysis showed that per 1 ton crushed limestone rock production, the total depletion of resource and GHGs emissions were 79.6 MJ and 2.76 kg CO2 eq., respectively. Regarding to the four damage categories, ‘resources’ and ‘climate change’ categories were the two greatest environmental impacts of the limestone rock production. Diesel fuel and electricity consumption in the mining processes were the main causes of those impacts. For climate change, the unit of CO2 eq. was expressed to quantify the total GHGs emissions. Estimated result was about 3.13 kg CO2 eq. per ton limestone rock product. The results obtained by the Greenhouse Gas Protocol were also similar to IMPACT 2002+ method. Electrical energy consumption was considered as the main driver of GHGs, accounting for approximately 46.8 % of total fossil fuel CO2 emissions. A final point should be noted that data uncertainties in environmental assessment over the complete life cycle of limestone quarrying operation have to be carefully considered.</abstract>

Assessment of Environmental Impacts of Limestone Quarrying Operations in Thailand

<abstract><title style='display:none'>Abstract</title> A kinetic study of pyrolysis process of Parthenium hysterophorous is carried out by using thermogravimetric analysis (TGA) equipment. The present study investigates the thermal degradation and determination of the kinetic parameters such as activation E and the frequency factor A using model-free methods given by Flynn Wall and Ozawa (FWO), Kissinger-Akahira-Sonuse (KAS) and Kissinger, and model-fitting (Coats Redfern). The results derived from thermal decomposition process demarcate decomposition of Parthenium hysterophorous among the three main stages, such as dehydration, active and passive pyrolysis. It is shown through DTG thermograms that the increase in the heating rate caused temperature peaks at maximum weight loss rate to shift towards higher temperature regime. The results are compared with Coats Redfern (Integral method) and experimental results have shown that values of kinetic parameters obtained from model-free methods are in good agreement. Whereas the results obtained through Coats Redfern model at different heating rates are not promising, however, the diffusion models provided the good fitting with the experimental data. </abstract>

Determination of Kinetic Parameters for the Thermal Decomposition of Parthenium hysterophorus

<abstract><title style='display:none'>Abstract</title> Eastern Europe today is confronted with an unavoidable problem - the multifamily apartment building stock is deteriorating but apartment owners do not have sufficient access to resources be they organizational, financial, technical or legal. In addition, destructive myths have grown about the Soviet era buildings despite their continued resilience or the ex- GDR experience in the 90s with the same buildings. Further, without resources, decision making in residential apartments is seen as a major obstacle and used as an explanation why renovation has not taken place in Latvia. This is important not only in the context of a potential housing crisis but also because the renovation of the apartment buildings is an effective solution to significantly reduce the energy consumption and greenhouse gas emissions. It has a proven potential to effectively finance the long term renovation of these buildings. This paper summarizes the first findings of a comprehensive and in-depth study of apartment buildings, their owners and the processes relating to renovation, combining social and environmental engineering research methods. It seeks to understand how owners of multi-family buildings in Eastern Europe understand their buildings and then to answer two questions - how to motivate owners to renovate their homes and increase energy efficiency and what business models should be used to implement economically viable and high quality projects.</abstract>

NGO “Building and Energy Conservation Bureau”, Baznīcas iela 8-22, Rīga, LV-1010,

Institute of Energy Systems and Environment, Riga Technical University, Azenes iela 12/1, Riga, LV-1048,

NGO "CBNRM Networking", P.O. Box 1600, NO-4688 Kristiansand,

Climate Change and Buildings Energy Efficiency – the Key Role of Residents

<abstract>
<title style='display:none'>Abstract</title>
In this paper, optimal coordination of the demand side under uncertainty of the energy price in energy market is studied. The consumers by demand response programs (DRPs) have optimal role in minimization of the energy generation costs in multiple energy system. The consumers can participate via local generation strategy (LGS) and demand curtailment strategy (DCS). The optimal coordination is considered as two stage optimization, in which minimization of the consumers’ bills is done in first stage. In following, the minimization of the generation costs is performed in second stage optimization. The LGS is taken into accounted through optimal discharging of plug electric vehicles (PEVs). Finally, numerical simulation is implemented to show superiority of the proposed approach to minimization of the energy generation costs.
</abstract>

Operation of the Multiple Energy System with Optimal Coordination of the Consumers in Energy Market

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Environmental and Climate Technologies

The Journal of Riga Technical University

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Volume 28 (2024): Issue 1 (January 2024)

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Volume 24 (2020): Issue 3 (November 2020) SPECIAL ISSUE OF ENVIRONMENTAL AND CLIMATE TECHNOLOGIES PART II: The Green Deal Umbrella for Environmental and Climate Technologies

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Volume 23 (2019): Issue 3 (December 2019) “Special Issue of Environmental and Climate Technologies Part II: Energy, bioeconomy, climate changes and environment nexus”

Volume 23 (2019): Issue 2 (November 2019) Special Issue of Environmental and Climate Technologies Part I: Energy, bioeconomy, climate changes and environment nexus