<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 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 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 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>Atrium is a popular architectural feature utilized widely by building designers and owners to bring various benefits such as adequate daylight, circulation spaces and surfaces for landscape applications. But atrium problems in tropical climates such as excessive daylight, glare and high temperature, which lead to increase building energy demand, have been reported. To avoid and reduce these unpleasant features, a side-lit atrium has been suggested. Although researchers proposed side-lit atrium to prevent common problems of atria, the lack of precedent research on this issue compels these authors to study atrium performance in hot and humid climate. So the research aims to examine two different atrium roof form types in terms of temperature and ventilation impacts in hot and humid climate of Malaysia using DesignBuilder as a simulation program. The results indicate lower temperature of side-lit model with better airflow pattern in comparison with top-lit model while the top-lit model provides higher air velocity at the air inlet and outlet.</abstract>

Thermal Performance of Tropical Atrium

<abstract>
<title style='display:none'>Abstract</title>
According to the Waste Management Policy of the European Union, the recycling and reuse of various wastes is considered the most environmentally friendly and advanced waste disposal technology that has the least impact on the environment. By applying the principles of the Circular Economy, plastic waste will extend its life cycle and will be used as secondary materials to create metamaterial structures with improved sound absorption and insulation properties. The aim of this study was to determine plastic potential for use in acoustic structures. Acoustic metamaterial resonators, created from plastic, were measured in an impedance tube according to standards ISO 10534-2 for their sound absorbing and ASTM E2611 for their insulating properties. Two types of plastic, PLA and recycled PET-G, were used in acoustic metamaterial 3D printing process. For sound insulation, combined resonator systems were used to control symmetrical wall sound resonance. Sound absorption of both PLA and PET-G metamaterials were peaking at 1600 Hz with 0.93 and 0.89 sound absorption coefficient, respectfully. The results showed that combined constructions with plastic metamaterials can be integrated into building structures and used as an alternative for improving building acoustics, reducing indoor noise and reverberation time.
</abstract>

Integration of Acoustic Metamaterials Made of Plastic to Improve Building Acoustics

<abstract>
<title style='display:none'>Abstract</title>
Portland cement (PC) is the most commonly used binder material for producing concrete. Nonetheless, increasing concerns have been attached to its manufacture which is highly energy-intensive and generates a large quantity of greenhouse gases. Developing alkali-activated materials as eco-binders is a sustainable replacement for PC and many investigations have been reported successfully utilizing industrial wastes as precursors. However, owing to the low reactivity, studies regarding biomass wood ashes (BWA) are still limited. To produce a green cementless alkali-activated mortar material, in this study, biomass fuel by-products – biomass wood bottom ash and biomass wood fly ash – were binarily used as precursors. Sodium hydroxide NaOH at 10 mol/L and calcium hydroxide Ca(OH)2 at 20 % by binder mass were applied as alkali activators. Recycled sand, substituting natural sand, was adopted as fine aggregate with an aggregate/binder ratio of 2 to reduce the consumption of non-renewable natural resources. Compressive and flexural strength were tested to evaluate the mechanical performance. A cradle-to-gate lifecycle assessment was conducted to analyse the environmental impacts. The results reveal that the alkali-activated mortar has less environmental impact compared to the traditional PC mortar. NaOH solution is the primary source of environmental influence and BWA only contributes to very limited impacts. The usage of Ca(OH)2 effectively improves the mechanical strength and compared to NaOH, it leads to decreased energy demand, requires fewer preparation steps and is less dangerous for operation.
</abstract>

Mechanical Properties and Lifecycle Assessment of a Green Alkali-Activated Mortar Based on Biomass Wood Ash

<abstract>
<title style='display:none'>Abstract</title>
This study aims to present computational technology that can be used to evaluate numerically the harmful environmental consequences caused by an accidental hydrogen release from failed high-pressure dispensing cylinders and its explosion at a vehicle hydrogen filling station. A coupled problem of a hydrogen explosion products expansion in the atmospheric ground layer and a harmful explosion pressure wave shock impact on service personnel and infrastructure buildings at an accident site is solved by means of computer experiment simulation series. A spatial time-dependent model of compressible hydrogen-air mixture flow is used to obtain pressure history in calculation area in order to assess maximum overpressure in control points of human possible locations and on building surfaces exposed to hydrogen blast wave impact. A deterministic impact consequences model is based on comparing maximum overpressure values extracted from the mathematical model with threshold ranges corresponding to certain degrees of human damage and infrastructure destruction. The presented computer technology allows safety experts to identify potentially dangerous zones by means of mathematical modelling and recommend effective protection measures to mitigate negative consequences of explosions.
</abstract>

Numerical Evaluation of Harmful Consequences after Accidental Explosion at a Hydrogen Filling Station

<abstract>
<title style='display:none'>Abstract</title>
Over the past two decades, there has been an increasing use of biofuels worldwide, especially in Europe. The main objective is to reduce greenhouse gas emissions, particularly carbon dioxide (CO2), from transportation. The regulation of fuels produced from biomass and other renewable sources at the EU level is primarily governed by the Renewable Energy Directive (RED). As of today, RED III directive has come into effect, significantly altering the EU fuel market by 2030. The main change involves an increase in the share of renewable fuels in transport and the non-use of first-generation fuels. Since all EU member states are obliged to comply with the RED III directive, it is essential to assess the current status of each member state in meeting the requirements for transport fuels. Therefore, the aim of this article is to analyse the impact of the RED III directive on the use of renewable fuels in the transport sector. Specifically, it provides an overview of various RED directives’ requirements, analyses the shares of renewable fuels in fossil diesel in Estonia under different RED III compliance scenarios, and presents an overview of the situation regarding the use of renewable fuels in Estonia. The article is based on a literature review, and fuel share calculations are based on RED III directive calculation methodologies. The results of the study indicate that if the requirement for the share of renewable energy used in transport is 29 %, using only HVO (Hydrotreated Vegetable Oil) to achieve this goal would require replacing 30.3 % of diesel with HVO. In cases where there is a requirement to reduce the greenhouse gas emission intensity of fuels in the transport sector by at least 14.5 % by 2030, the volumetric share of HVO fuel must meet certain criteria based on the raw material. For example, fuel produced from residues must contain a minimal amount of biocomponents. In this context, biologically derived oil is initially used, such as in food preparation. Subsequently, after its use in food preparation, it is processed into fuel. The article also addresses cases where biogas is introduced as a renewable component in replacing diesel.
</abstract>

The Impact of RED III Directive on the Use of Renewable Fuels in Transport on the Example of Estonia

<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>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>
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

<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

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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

Volume 24 (2020): Issue 2 (September 2020) SPECIAL ISSUE OF ENVIRONMENTAL AND CLIMATE TECHNOLOGIES PART I: 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