Mechanical Properties of a New Insulation Material Based on Miscanthus x Giganteus

This paper deals with a brand new cost-effective, ecological and energy-efficient insulation material application based on Miscanthus x Giganteus with a reduced cement binder amount enriched with a smaller quantity of zeolite. In order to increase energy efficiency, the use of cement was minimized, as it is considered an extremely energy-inefficient material whose production requires large amounts of thermal energy, accompanied with high carbon dioxide emissions. As the physical-mechanical properties of thermal insulation are of crucial importance the paper deals with physical-mechanical properties of this material. The experimental part consisted of preparation of four mixtures with different component mass ratio, and determination of their physical-mechanical properties. The sample that showed the highest values of compressive and bending strength simultaneously was taken into thermal conductivity control tests. The thermal conductivity was measured by steady state conditions. The proposed composite material showed certain potential for practical and eco-friendly use

Cathode Ray Tube Waste Glass in Concrete Preparation - Increasing Sustainability

The construction sector is responsible for approximately 39% of energy use and process-related carbon dioxide emissions. Mixing waste materials into concrete, as a substitute for cement and/or aggregate, increases energy efficiency and sustainability in general. Additionally, pressure on the environment is decreasing by reducing the amount of exploitation of natural raw materials. On the other hand, the rapid progress of the electronic industry has led to the generation of a large amount of electrical waste before the end of its useful life. Disposal of old monitors and TV screens, i.e. their cathode-ray tubes (CRT), represents a major problem for the environment because CRT waste is classified as hazardous due to its high lead content. This paper deals with an overview of investigations on CRT waste utilization in cement materials in order to increase sustainability and encourage a circular economy in the construction sector

Otpadno staklo katodnih cevi u pripremi betona - povećavanјe održivosti

The construction sector is responsible for approximately 39% of energy use and process-related carbon dioxide emissions. Mixing waste materials into concrete, as a substitute for cement and/or aggregate, increases energy efficiency and sustainability in general. Additionally, pressure on the environment is decreasing by reducing the amount of exploitation of natural raw materials. On the other hand, the rapid progress of the electronic industry has led to the generation of a large amount of electrical waste before the end of its useful life. Disposal of old monitors and TV screens, i.e. their cathode-ray tubes (CRT), represents a major problem for the environment because CRT waste is classified as hazardous due to its high lead content. This paper deals with an overview of investigations on CRT waste utilization in cement materials in order to increase sustainability and encourage a circular economy in the construction sector.Građevinski sektor je odgovoran za približno 39% potrošnje energije i emisija ugljendioksida vezanih za date procese. Mešanje otpadnih materijala u beton, kao zamena za cement i/ili agregat, povećava energetsku efikasnost i održivost uopšteno. Pored toga, smanjuje se i pritisak na životnu sredinu smanjenjem eksploatacije prirodnih sirovina. S druge strane, brzi napredak elektronske industrije doveo je do stvaranja velike količine električnog otpada pre isteka njegovog životnog veka. Odlaganje starih monitora i TV ekrana, odnosno njihovih katodnih cevi (CRT), predstavlja veliki problem za životnu sredinu pošto je otpad od CRT-a klasifikovan kao opasan usled visokog sadržaja olova. Ovaj rad se bavi pregledom istraživanja o korišćenju CRT otpada u cementnim materijalima u cilju povećanja održivosti i podsticanja cirkularne ekonomije u građevinskom sektoru.11th International Conference on Renewable Electrical Power Sources : November 2-3, Belgrade, 2023

Energy Efficiency and Sustainability of Biofibres-Based Thermal Insulation

Energy efficiency of residential and commercial buildings is acutely important as this sector is responsible for approximately 40% of overall energy consumption and around 35% of CO2 emissions (in the European Union). The construction sector has intense environmental footprint due to exploitation of non-renewable material and energy resources, land use and generation of waste materials during construction and demolition. It is therefore important to develop sustainable building structures, practices and materials with minimal resources and energy use. Utilization of energy efficient, sustainable and resource-saving building materials is of particular importance. The study is carried out to investigate possibilities and evaluate effects of application of biofibres-based structures as non-constructive and/or insulating materials in current building practice. Focus is on natural, dominantly cellulose, fibres, traditionally used in the past (hemp, reed, straw, flax, rice hulls, cotton stalks, sunflower, cattail, bagasse, etc) as well as on some promising grass/reed cultures, such as Miscanthus x Giganteus. The experimental examinations of thermal and mechanical properties decisive for the performance of thermal insulation have been undertaken. Expectedly, the thermal conductivity, as the material characteristic primarily responsible for Operational Energy Consumption, has been found mostly worse than in commonly used, mass produced, thermal insulation materials such as expanded or extruded polystyrene, glass or mineral wool, etc. On the other hand, conclusions of Life Cycle Analysis and examination of Embodied Energy advocates the utilization of designated natural biofibres-based thermal insulation as more sustainable and in the long run (Cradle to Grave) energy efficient alternative to the conventional insulation materials

Reuse of Solid Brick Waste Mix in Geopolymerization – a Preliminary Investigation

The applicability of solid bricks waste in geopolymerization technique was considered. Waste samples were characterized in terms of mineralogical composition by XRD prior to mechanical testing. XRD analysis showed that both brick samples contained anorthite, wollastonite, and mullite as the main components. The compressive strength investigation was carried out by screening method with three geopolymer mixtures. Geopolymer mixtures were prepared with alkaline activators; the mixtures were poured into molds and air-dried for 28 days. The compressive strength of samples was measured according to the standard SRPS EN 12390-3:2010 for cubic samples. The compressive strength values ranged from 9.8 MPa for the newer solid brick, 10.2 MPa for the older solid brick, and 10.5 MPa for the solid brick mix waste geopolymer sample. The most likely underlying reason for the higher compressive strength results of the older solid brick and the mixed sample is their mineral composition, i.e. higher proportion of aluminosilicate. However, all samples showed satisfactory compressive strengths, and it represents an excellent basis for further research.SETI V 2023 : International Scientific Conference SCIENCE, EDUCATION, TECHNOLOGY AND INNOVATION : October 14, 2023

Reuse of Solid Brick Waste Mix in Geopolymerization – a Preliminary Investigation

The applicability of solid bricks waste in geopolymerization technique was considered. Waste samples were characterized in terms of mineralogical composition by XRD prior to mechanical testing. XRD analysis showed that both brick samples contained anorthite, wollastonite, and mullite as the main components. The compressive strength investigation was carried out by screening method with three geopolymer mixtures. Geopolymer mixtures were prepared with alkaline activators; the mixtures were poured into molds and air-dried for 28 days. The compressive strength of samples was measured according to the standard SRPS EN 12390-3:2010 for cubic samples. The compressive strength values ranged from 9.8 MPa for the newer solid brick, 10.2 MPa for the older solid brick, and 10.5 MPa for the solid brick mix waste geopolymer sample. The most likely underlying reason for the higher compressive strength results of the older solid brick and the mixed sample is their mineral composition, i.e. higher proportion of aluminosilicate. However, all samples showed satisfactory compressive strengths, and it represents an excellent basis for further research

Carbon dioxide as the replacement for synthetic refrigerants in mobile air conditioning

Based on Kyoto Protocol and the decisions of European Commission R134a refrigerant, currently dominantly used in mobile air conditioning systems, needs to be phased-out. At present automotive industry looks at carbon dioxide (CO2; R744) as the refrigerant of the future. Apart from the environmental benefits discussed are the technical characteristics of carbon dioxide refrigeration cycle and mobile air-conditioning systems in comparison to R134a refrigerant. Analyzed are challenges emerged from the use of CO2 as refrigerant and improvement opportunities in regards to increase of the system performance and efficiency. Particular attention is dedicated to the advantages of CO2 utilization in prospective automotive heat pump systems

Prospects for wider energetic utilization of subgeothermal water resources: Eastern Serbia case study

Intenzivno korišćenje fosilnih goriva širom sveta uzrok je ozbiljnih zagađenja prirode i utiče na globalno zagrevanje. Otuda je jedan od glavnih ciljeva energetske politike evropskih zemalja korišćenje efikasnije 'zelene' energije iz obnovljivih i sopstvenih izvora. Generalno, geotermalna energija predstavlja vid obnovljivih izvora energije. Ipak, i dalje se smatra da korišćenje subgeotermalne energije niske entalpije (temperature podzemnih voda od 30°C i niže) za potrebe grejanja nije u potpunosti ekonomski opravdano. Standardna tehnologija za primenu ovog vida energije zahteva velike površine pod panelima sa cevima koje provode toplu vodu i/ili upotrebu toplotnih pumpi sa visokim stepenom iskorišćenja. Razvoj kaskadne toplotne pumpe i njena šira primena omogućila bi daleko efikasniju upotrebu 'lako' dostupnih podzemnih vodnih resursa temperature između 10-30°C i stoga je u više projekata realizovanih poslednjih godina analizirana i razvijana ova tehnologija. Hidrogeološki uslovi u terenima istočne Srbije, su veoma povoljni sa aspekta eksploatacije subgeotermalnih resursa. Područje se odlikuje značajnim količinama podzemnih voda i terestičnim toplotnim tokom u okviru geoloških formacija u osnovnim geo-strukturnim jedinicama ovog regiona (Karpato-Balkanidi i Dakijski basen). Blizina urbanizovanih naselja i manjih gradova i postojanje razvijenog i centralizovanog grejanja su činjenice koje povoljno utiču na mogućnost eksploatacije subgeotermalnih vodnih resursa. Održivo korišćenje podzemnih vodnih resursa podrazumevalo bi i potrebnu termalnu rekonstrukciju i bolju izolaciju postojećih građevinskih objekata, kao i donošenje novih zakonskih propisa u Srbiji u cilju podsticaja korišćenja obnovljivih izvora energije. U području istočne Srbije, procenjene količine energije koje se mogu dobiti iz subgeotermalnih voda iznose oko 33 MWt, što bi predstavljalo oko 16% ukupnih energetskih potreba nekoliko odabranih većih naselja za koje je ova analiza vršena. I pored činjenice da se ne očekuje potpuno iskorišćenje ovog potencijala, evidentno je da je on daleko veći od 4 % koliko je u planovima energetskog razvoja predviđeno da bi moglo iznositi učešće geotermalnih vodnih resursa na nivou cele Srbije.Extensive worldwide usage of fossil energy sources causes high pollution and contributes to global warming. Hence, achieving energy independence by stimulating efficient use of energy and environmentally friendly exploitation of renewable sources is a main orientation of European countries. Geothermal energy is generally treated as a renewable and inexhaustible energy source. Nonetheless, direct use of low enthalpy subgeothermal resources, i.e. groundwater of 30.C or lower, for heating is commonly viewed as economically unjustified. To enable its usage, large panel surfaces or a high-temperature heat pump with excellent efficiency is required. The development of a cascade type heat pump and its wide application would enable more efficient utilization of widely available and easy replenished groundwater sources with temperatures of 10-30.C. The hydrogeological conditions in eastern Serbia are particularly favourable for exploitation of subgeothermal resources due to rich aquifer systems and notable terrestrial heat flow formed into the main geo-structures of the region (Carpathian-Balkan arch and Dachian basin). More intensive exploitation of subgeothermal sources additionally justifies the existence of a number of urbanized small and medium-size cities with a heating infrastructure already developed and centralized. Sustainable use of groundwater resources should be followed by thermal reconstruction of the previously constructed buildings as well as new legislation which supports and encourages development of renewable energy sources. It is estimated that the total potential thermal power which can be generated from subgeothermal waters in the study area is around 33 MWt, which corresponds to some 16 % of the total heat requirements

Improving the Efficiency of District Heating and Cooling Using a Geothermal Technology: Underground Thermal Energy Storage (UTES)

For efficient operation of heating and cooling grids, underground thermal energy storage (UTES) can be a key element. This is due to its ability to seasonally store heat or cold addressing the large mismatch between supply and demand. This technology is already available and there are many operational examples, both within and outside a district heating network. Given the range of available UTES technologies, they are feasible to install almost everywhere. Compared to other storage systems, UTES have the advantage of being able to manage large quantities and fluxes of heat without occupying much surface area, although the storage characteristics are always site specific and depend on the geological and geothermal characteristics of the subsoil. UTES can manage fluctuating production from renewable energy sources, both in the short and long term, and fluctuating demand. It can be used as an instrument to exploit heat available from various sources, e.g., solar, waste heat from industry, geothermal, within the same district heating system. The optimization of energy production, the reduction in consumption of primary energy and the reduction in emission of greenhouse gases are guaranteed with UTES, especially when coupled with district heating and cooling networks.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Water ResourcesGeo-engineerin