Energy efficiency in buildings: Thermophysical characterization of building materials

Introduction:The lack of treatment of construction demolition waste (CDW) is a problem that must be solved immediately. It is estimated that the unused CDW generates an increase in the use of new materials close to 20% of the total materials consumed worldwide. Because of that, the use of CDW in building materials is an interesting alternative to guarantee their application. In the last years, many research works are being carried out in order to analyze the viability of using CDW as a substitute for the traditional raw materials that cause high environmental impact.However, much remains to be done, because these works generally characterize materials but not specific applications that allow the agents of construction to provide assurance required by the projects.Aim:The research group TEMA from the School of Building Construction (UPM) is working on this topic with the University of Seville, University of Burgos and the University of Zaragoza, developing a research project called "Waste to resources (W2R)". The main goal of the project is to develop new materials, elements and construction systems, manufactured with CDW generated in building retrofitting works, to be used in improving the energy efficiency of buildings.Results:In this article, some of the results of the W2R project are presented, namely the identification, quantification and characterization of the types of waste generated in renovation works to improve the energy efficiency of buildings and their possible applications as fillers in plasters to improve the performance of the original materials with a significant reduction in raw material, and thus reduce the environmental impact.Conclusions:Concrete and ceramics are the most commonly generated waste categories in building rehabilitation works to improve the energy efficiency of the buildings. These waste categories are generated during the preparation of the surface prior to the execution of the works. Also, mixed waste from insulation materials can be highlighted due to its volume.

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Thermal Characterization of Recycled Materials for Building Insulation

Energies ◽

10.3390/en14123564 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3564

Author(s):

Arnas Majumder ◽

Laura Canale ◽

Costantino Carlo Mastino ◽

Antonio Pacitto ◽

Andrea Frattolillo ◽

...

Keyword(s):

Environmental Impact ◽

Environmental Sustainability ◽

Building Materials ◽

Raw Materials ◽

Natural Fibers ◽

Thermal Characterization ◽

Recycled Materials ◽

Building Insulation ◽

Operational Phase

The building sector is known to have a significant environmental impact, considering that it is the largest contributor to global greenhouse gas emissions of around 36% and is also responsible for about 40% of global energy consumption. Of this, about 50% takes place during the building operational phase, while around 10–20% is consumed in materials manufacturing, transport and building construction, maintenance, and demolition. Increasing the necessity of reducing the environmental impact of buildings has led to enhancing not only the thermal performances of building materials, but also the environmental sustainability of their production chains and waste prevention. As a consequence, novel thermo-insulating building materials or products have been developed by using both locally produced natural and waste/recycled materials that are able to provide good thermal performances while also having a lower environmental impact. In this context, the aim of this work is to provide a detailed analysis for the thermal characterization of recycled materials for building insulation. To this end, the thermal behavior of different materials representing industrial residual or wastes collected or recycled using Sardinian zero-km locally available raw materials was investigated, namely: (1) plasters with recycled materials; (2) plasters with natural fibers; and (3) building insulation materials with natural fibers. Results indicate that the investigated materials were able to improve not only the energy performances but also the environmental comfort in both new and in existing buildings. In particular, plasters and mortars with recycled materials and with natural fibers showed, respectively, values of thermal conductivity (at 20 °C) lower than 0.475 and 0.272 W/(m⋅K), while that of building materials with natural fibers was always lower than 0.162 W/(m⋅K) with lower values for compounds with recycled materials (0.107 W/(m⋅K)). Further developments are underway to analyze the mechanical properties of these materials.

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Sustainability Investigation of Vehicles’ CO2 Emission in Hungary

Sustainability ◽

10.3390/su13158237 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8237

Author(s):

István Árpád ◽

Judit T. Kiss ◽

Gábor Bellér ◽

Dénes Kocsis

Keyword(s):

Energy Efficiency ◽

Co2 Emissions ◽

Energy Supply ◽

Internal Combustion Engines ◽

Combustion Engines ◽

The European Union ◽

New Approach ◽

Technology System ◽

Low Co2

The regulation of vehicular CO2 emissions determines the permissible emissions of vehicles in units of g CO2/km. However, these values only partially provide adequate information because they characterize only the vehicle but not the emission of the associated energy supply technology system. The energy needed for the motion of vehicles is generated in several ways by the energy industry, depending on how the vehicles are driven. These methods of energy generation consist of different series of energy source conversions, where the last technological step is the vehicle itself, and the result is the motion. In addition, sustainability characterization of vehicles cannot be determined by the vehicle’s CO2 emissions alone because it is a more complex notion. The new approach investigates the entire energy technology system associated with the generation of motion, which of course includes the vehicle. The total CO2 emissions and the resulting energy efficiency have been determined. For this, it was necessary to systematize (collect) the energy supply technology lines of the vehicles. The emission results are not given in g CO2/km but in g CO2/J, which is defined in the paper. This new method is complementary to the European Union regulative one, but it allows more complex evaluations of sustainability. The calculations were performed based on Hungarian data. Finally, using the resulting energy efficiency values, the emission results were evaluated by constructing a sustainability matrix similar to the risk matrix. If only the vehicle is investigated, low CO2 emissions can be achieved with vehicles using internal combustion engines. However, taking into consideration present technologies, in terms of sustainability, the spread of electric-only vehicles using renewable energies can result in improvement in the future. This proposal was supported by the combined analysis of the energy-specific CO2 emissions and the energy efficiency of vehicles with different power-driven systems.

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Hot Box Investigations of a Ventilated Bioclimatic Wall for NZEB Building Façade

Energies ◽

10.3390/en14051327 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1327

Author(s):

Dwinanto Sukamto ◽

Monica Siroux ◽

Francois Gloriant

Keyword(s):

Energy Efficiency ◽

Flow Rate ◽

Experimental Setup ◽

Air Flow Rate ◽

Space Thickness ◽

Zero Energy ◽

Interior Space ◽

Air Space ◽

Thermal Metrology

The building sector is the largest consumer of energy, but there are still major scientific challenges in this field. The façade, being the interface between the exterior and interior space, plays a key role in the energy efficiency of a building. In this context, this paper focuses on a ventilated bioclimatic wall for nearly zero-energy buildings (NZEB). The aim of this study is to investigate an experimental setup based on a hot box for the characterization of the thermal performances of the ventilated wall. A specific ventilated prototype and an original thermal metrology are developed. This paper presents the ventilated prototype, the experimental setup, and the experimental results on the thermal performances of the ventilated wall. The influence of the air space thickness and the air flow rate on the thermal performances of the ventilated wall is studied.

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Characterization of a Novel CaCO3-Forming Alkali-Tolerant Rhodococcus erythreus S26 as a Filling Agent for Repairing Concrete Cracks

Molecules ◽

10.3390/molecules26102967 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2967

Author(s):

Seunghoon Choi ◽

Sungjin Park ◽

Minjoo Park ◽

Yerin Kim ◽

Kwang Min Lee ◽

...

Keyword(s):

Building Materials ◽

Culture Fluid ◽

Natural Phenomenon ◽

Environment Friendly ◽

Wide Range ◽

Filling Agent ◽

Calcium Source ◽

Alkali Tolerance ◽

High Alkali

Biomineralization, a well-known natural phenomenon associated with various microbial species, is being studied to protect and strengthen building materials such as concrete. We characterized Rhodococcus erythreus S26, a novel urease-producing bacterium exhibiting CaCO3-forming activity, and investigated its ability in repairing concrete cracks for the development of environment-friendly sealants. Strain S26 grown in solid medium formed spherical and polygonal CaCO3 crystals. The S26 cells grown in a urea-containing liquid medium caused culture fluid alkalinization and increased CaCO3 levels, indicating that ureolysis was responsible for CaCO3 formation. Urease activity and CaCO3 formation increased with incubation time, reaching a maximum of 2054 U/min/mL and 3.83 g/L, respectively, at day four. The maximum CaCO3 formation was achieved when calcium lactate was used as the calcium source, followed by calcium gluconate. Although cell growth was observed after the induction period at pH 10.5, strain S26 could grow at a wide range of pH 4–10.5, showing its high alkali tolerance. FESEM showed rhombohedral crystals of 20–60 µm in size. EDX analysis indicated the presence of calcium, carbon, and oxygen in the crystals. XRD confirmed these crystals as CaCO3 containing calcite and vaterite. Furthermore, R. erythreus S26 successfully repaired the artificially induced large cracks of 0.4–0.6 mm width.

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The Influence of Cement Substitution by Biomass Fly Ash on the Polymer–Cement Composites Properties

Materials ◽

10.3390/ma14113079 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3079

Author(s):

Beata Jaworska ◽

Dominika Stańczak ◽

Joanna Tarańska ◽

Jerzy Jaworski

Keyword(s):

Fly Ash ◽

Building Materials ◽

Raw Materials ◽

Combustion Process ◽

Biomass Combustion ◽

Cement Composites ◽

Cement Mortars ◽

Mineral Additive ◽

Biomass Fly Ash

The generation of energy for the needs of the population is currently a problem. In consideration of that, the biomass combustion process has started to be implemented as a new source of energy. The dynamic increase in the use of biomass for energy generation also resulted in the formation of waste in the form of fly ash. This paper presents an efficient way to manage this troublesome material in the polymer–cement composites (PCC), which have investigated to a lesser extent. The research outlined in this article consists of the characterization of biomass fly ash (BFA) as well as PCC containing this waste. The characteristics of PCC with BFA after 3, 7, 14, and 28 days of curing were analyzed. Our main findings are that biomass fly ash is suitable as a mineral additive in polymer–cement composites. The most interesting result is that the addition of biomass fly ash did not affect the rheological properties of the polymer–cement mortars, but it especially influenced its compressive strength. Most importantly, our findings can help prevent this byproduct from being placed in landfills, prevent the mining of new raw materials, and promote the manufacture of durable building materials.

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Specific Electrical Energy Consumption and CO2 Emissions Assessment of Agrifood Industries in the Central Region of Portugal

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.675-677.1880 ◽

2014 ◽

Vol 675-677 ◽

pp. 1880-1886 ◽

Cited By ~ 5

Author(s):

Pedro D. Silva ◽

Pedro Dinis Gaspar ◽

J. Nunes ◽

L.P.A Andrade

Keyword(s):

Energy Efficiency ◽

Energy Consumption ◽

Food Safety ◽

Central Region ◽

Electrical Energy ◽

Electrical Energy Consumption ◽

Reference Levels ◽

Energy Characteristics ◽

Result Analysis

This paper provides a characterization of the electrical energy consumption of agrifood industries located in the central region of Portugal that use refrigeration systems to ensure the food safety. The study is based on the result analysis of survey data and energy characteristics of the participating companies belonging to the following agrifood sectors: meat, dairy, horticultural, distribution and wine. Through the quantification of energy consumption of companies is possible to determine the amount of greenhouse gases (GHGs) emissions indexed to its manufacturing process. Comparing the energy and GHGs emissions indexes of companies of a sector and between sectors is possible to create reference levels. With the results of this work is possible to rating the companies in relation to reference levels of energy and GHGs emissions and thus promote the rational use of energy by the application of practice measures for the improvement of the energy efficiency and the reduction of GHGs emissions.

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