Energy Efficient Materials Research Articles

Thermal properties of calcium sulfoaluminate cement-based mortars incorporated with expanded perlite cured at cold temperatures

Reducing the thermal conductivity of cement-based building materials can alleviate the energy consumption and carbon dioxide (CO2) emissions that are related to space heating in buildings. The objective of this study is to incorporate expanded perlite into calcium sulfoaluminate (CSA) cement-based mortars to develop a novel building material that has low thermal conductivity for applications in cold regions. These mortars were cured at 23 °C and cold temperatures (0 °C and −10 °C), and experiments were conducted for thermal properties (i.e., thermal conductivity, thermal diffusivity, and heat capacity), unconfined compressive strength (UCS), density, ultrasonic pulse velocity (UPV), and thermogravimetric analysis (TGA). The results showed that CSA cement-based mortars gained UCS rapidly even at −10 °C owing to a fast hydration reaction, and an exponential decrease was found in UCS with an increase of the aggregate replacement ratio by expanded perlite. Thermal properties of CSA cement-based mortars were mainly affected by aggregate replacement ratios, while curing temperatures and ages had a negligible influence. For example, thermal conductivity decreased exponentially from 0.97 ± 0.01 to 0.13 ± 0.002 W/mK when the aggregate replacement ratio increased from 0% to 100%. It is of note that the thermal conductivity of CSA cement-based mortar without expanded perlite was 0.97 W/mK, being 47% lower than that of ordinary Portland cement-based mortar (1.83 W/mK). In summary, incorporating expanded perlite into CSA cement-based mortars reduced their thermal conductivity, showing their huge potential as energy-efficient and environmentally-friendly building materials.

Experimental Investigation of a Direct Evaporative Cooling System for Year-Round Thermal Management with Solar-Assisted Dryer

Building cooling is achieved by the extensive use of air conditioners. These mechanically driven devices provide thermal comfort by deteriorating the environment with increased energy consumption. To alleviate environmental degradation, the need for energy-efficient and eco-friendly systems for building cooling becomes essential. Evaporative cooling, a typical passive cooling technique, could meet the energy demand and global climatic issues. In conventional direct evaporative cooling, the sensible cooling of air is achieved by continuous water circulation over the cooling pad. Despite its simple operation, the problem of the pad material and water stagnation in the sump limits its usage. Moreover, the continuous pump operation increases the electrical energy consumption. In the present work, a porous material is used as the water storage medium eliminating the pump and sump. An experimental investigation is performed on the developed setup, and experiments are conducted for three different RH conditions (low, medium, and high) to assess the porous material’s ability as a cooling medium. Cooling capacity, effectiveness, and water evaporation rate are determined to evaluate the direct evaporative cooling system’s performance. The material that replaces the pump and sump is vermicompost due to its excellent water retention characteristics. There is no necessity to change material each time. However, the vermicompost is regenerated at the end of the experiment using a solar dryer. The passing of hot air over the vermicompost also avoids mould spores’ transmission, if any, present through the air. The results show that vermicompost produces an average temperature drop of 9.5°C during low RH conditions. Besides, vermicompost helps with the energy savings of 21.7% by eliminating the pump. Hence, vermicompost could be an alternate energy-efficient material to replace the pad-pump-sump of the conventional evaporative cooling system. Further, if this direct evaporative cooling system is integrated with solar-assisted drying of vermicompost, it is possible to provide a clean and sustainable indoor environment. This system could pave the way for year-round thermal management of building cooling applications with environmental safety.

Geopolymer mortar integrated with phase change materials for improvement of thermal efficiency in buildings: A review

The integration of Phase Change Materials (PCMs) in buildings as an energy efficient material has gained interest in construction industry. This review mainly discusses the effect of incorporation of PCM on the thermal and mechanical properties of geopolymer mortar. The study also reviews the properties of PCM when incorporated into mortar based on different binders such as cement, lime and gypsum. Based on the reviewed literature, it is evident that integration of PCM in geopolymer materials is economical and environment-friendly; contributing to better mechanical and thermal properties than PCM integrated conventional mortar.

STATE INNOVATION POLICY FOR GREEN TECHNOLOGIES SUPPORT IN CONSTRUCTION

The purpose of the paper is to determine the status and areas of improvement of state policy to support the development of green technologies in construction. Methodology. This review is based on the characteristics of individual areas of implementation of green technologies in construction. Possibilities of using renewable sources in the process of construction and operation of buildings are considered. It is established that different methods of energy production are used in energy efficient houses. These include photovoltaic solar panels, heat pumps, photothermal collectors, geothermal waters, mini hydroelectric power plants. It is emphasized that the energy consumption of such buildings should also be reduced; for the reason of special architectural design solutions, the energy-efficient materials with high thermal insulation properties are used. The peculiarities of the policy of stimulating the increase of energy efficiency of buildings in Ukraine are considered, the conclusion on its insufficient efficiency is given. The reason for ineffectiveness of the incentive policy is figured out. The directions for reduction of air and water pollution by filtration and use of rain and melt water for household needs are considered. It is established that the active implementation of innovation is impossible mainly due to obsolete housing and worn-out utilities. Eco-design is also used to increase energy efficiency in construction and architects must actively use passive and active methods of designing houses in different climatic conditions. Green construction also involves recycling of construction waste. Improving the environmental efficiency of buildings and structures involves the use of modern insulation materials, coatings. Currently, nanomaterials with unique properties are becoming widespread in construction. They have increased physical characteristics, in particular, accumulated thermal radiation, provided significant energy savings in winter and summer. The results of the study showed that the state regulatory policy (innovation policy, support of science and R&D, technology transfer, price policy regulation, updating of technological regulations) has an extremely important role in stimulating the spread of green technologies in construction. Practical implications. The most important areas of public policy in construction are: the implementation of environmental energy and quality international standards for construction products; stimulating consumer demand for environmentally friendly innovative solutions, including through “green” public procurement, setting reasonable prices for energy resources, stimulating the implementation of a holistic concept of product life cycle; development of financial mechanisms to support the demand for cleaner technologies and innovations.

Application of AHP and GRA methods in energy efficiency potential’s assessment of envelopes from natural materials

The best choice of energy efficient envelope from variety of available materials is still the challenge. Therefore, the attempt of thermal performance multi-criteria evaluation of some building materials of natural origin for energy-efficient envelopes is conducted in present paper. Such types of walls from natural energy-efficient materials are considered in comparison assessment: hempcrete, adobe, strawbale panel, earthbag, cordwood, SIP (plywood+ecofiber), hempcrete+straw and energy efficient block. The influence of thermal inertia time, internal areal heat capacity, as well dimensionless index of thermal inertia D, the total thermal resistance of the walls Rtot-value, mass of the wall assembly and its cost have been taken into consideration as important influence factors. The multi-criteria numerical assessment of envelope’s energy efficiency potential was performed by two popular methods – Analytic Hierarchy Process (AHP) as the subjective weighting method and Grey Relation Analysis (GRA) as the objective weighting method. Both of methods allow to arrange the alternatives and could be applied as decision support tools in decision making (DM) process of choosing the best alternative in terms of multi-criteria assessment. For more objective analysis, by taking into account the variety of physical and physical-mechanical parameters of the wall assembly material, the concept of generalized index of the envelope energy efficiency potential is proposed. Conducted research has shown that the best envelope type in terms of of generalized index of energy efficiency potential has the hempcrete wall and hemcrete+straw wall, almost three times smaller has the wall of the earthbags. The walls from adobe, cordwood and strawbale panels have practically the equal value of generalized index of energy efficiency potential. It could be observed that AHP method shown more inhomogeneous results, than GRA. The possible reason for that is the difference in evaluation attitude in techniques - AHP is considered as the subjective method with pairwise comparison matrixes, while GRA is objective method of comparison.

Preparation of a Cellulose Column for Enhancing the Sensing Efficiency of the Biocide 2-n-Octyl-4-Isothiazolin-3-One.

In this study, a cellulose acetate (CA) membrane with pores generated by a water pressure treatment was investigated for its ability to serve as a pretreatment filter device for the detection of 2-n-octyl-4-isothiazolin-3-one (OIT). Pores were generated by applying a water pressure of 8 bar to a membrane manufactured using a CA-based polymer solution. The CA used for the manufacturing was an environment-friendly, low-cost and highly energy-efficient material. Furthermore, since the fabricated porous CA polymeric film possessed many hydrophilic functional groups, it could strongly bind hydrophilic substances while avoiding interaction with hydrophobic substances. OIT, which comprises a hydrophobic bond that forms weak bonds over time, can break down more easily than hydrophilic impurities. The different extents of interaction occurring between either the toxic fungicide OIT or the hydrophilic impurities and the CA film were determined by Fourier-transform infrared (FT-IR) spectroscopy. The physicochemical changes in the resulting membrane, which occurred when the pores were generated, were investigated through scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).

Stabilization of sand using energy efficient materials under normal and extreme hot weathers

This study employs the byproducts of petroleum hydrocarbons, available in abundance locally, such as polymer and polypropylene (PP) fibers and natural hemp fibers obtained from the discarded ropes for the stabilization of sand. The test parameters included polymer content, fiber type, fiber percentage, and weather temperature. The polymer percentages used for the stabilization of sand were: 1.5%, 1.75%, 2.00%, and 2.25% by weight of sand. The percentages of PP fibers were 0.5% and 1%, whereas the percentages of recycled hemp fibers were 1% and 2% by weight. The direct shear, unconfined compressive strength (UCS), and modulus rupture tests were used for the assessment of the performance of the modified sand. The effect of exposure to the elevated weather temperature and subsequent cooling was also investigated for a selected polymer content. A total of 210 specimens were tested for different tests. The optimal percentages of polymer and fibers are obtained experimentally for achieving the best performance of the polymer modified fiber reinforced soil. The PP fibers are found to outperform the recycled hemp fibers in terms of the shear strength characteristics of the modified sand. The loss in UCS of polymer modified fiber reinforced sand due to the exposure to the elevated temperature of 80 °C is regained on cooling by 85%–100%.

A brief review on high-performance nano materials in solar desalination

Abstract The solar power is most prominent energy source for the solar desalination processes and the productivity of the distilled water depends upon the proper utilization of solar energy into useful form of heat. To absorb maximum solar radiation, energy efficient nano materials were developed and used in renewable and sustainable energy applications like solar stills and solar steam generation etc. Recently the nano materials with energy storage, maximum energy transfer, and high broadband absorption characteristics exhibited accelerating evaporation rate in solar desalination. In this current review paper, energy exchange and energy storage materials including nano embodied PCMs (phase change materials), nano fluids and nano particles, nano structures with efficient steam generation and sensible heat storage materials for solar desalination were discussed.

A Novel Building Information Modeling-based Method for Improving Cost and Energy Performance of the Building Envelope

Building envelopes and regional conditions can significantly contribute to the cost and energy performance of the buildings. Structured methods that take into account the impacts of both the envelope materials and the regional conditions to find the most feasible envelope materials within a region, however, are still missing. This study responds to this need by proposing a novel method using the capabilities of Building Information Modeling (BIM). The proposed method is used for identifying cost- and energy-efficient building envelope materials within a region over the life cycle. First, commonly used envelope materials in a region are identified. Then, BIM is employed for simulating the energy performance and evaluating the life cycle cost of the materials. The method was implemented in Tehran, Iran. It was successfully utilized for improving the cost and energy performance of a nine-story residential building case. The achieved results indicated a potential energy performance enhancement of 31%, and the life cycle cost improvement of 28% by replacing conventionally used envelope materials with the available high-performance building materials. The proposed method can benefit various stakeholders in the building construction industry, including municipalities, owners, contractors, and consumers, by enhancing the cost and energy performance of the buildings.

Experimental and theoretical analysis of a new kind of building envelope

A huge amount of money spent worldwide to attain thermal comfort in residential and commercial buildings throughout the year. The selection of proper insulation material for the building envelope is a very important factor in reducing the cooling and heating load of the building. Presently, authors have proposed a new wall panel namely Ferro Cellular Lightweight Concrete Insulated Panel (FCIP) for a building envelope. FCIP has been analyzed experimentally to study its energy-efficient behavior in the form of a small scale cubical and found to be an energy-efficient material. The same panel has been analyzed theoretically for its energy efficiency on a full-scale cubical model using ‘eQUEST’ an energy simulation program. In this process, walls and roof components of the cubical have been modeled with brick masonry and FCIP. The results of the simulation show that the cubical made of brick masonry walls with a concrete roof consume 10,190 kWh electrical energy in a year, whereas these masonry walls when replaced by FCIP with an insulated roof, the yearly electricity consumption reduced to 2383 kWh. Moreover, the results of cost and benefit analysis show a huge amount of reduction in the lifetime running cost of the building when the traditional construction through brick masonry was replaced by an FCIP envelope.

Comparison of Energy Efficiency of traditional Brick Wall and Inco- Panel Wall: A Case Study of Hotel Sarowar in Pokhara

Energy efficiency is understood to mean the utilization of energy in the most cost-effective manner to carry out process or provide a service, whereby energy waste is minimized, and the overall consumption of primary energy resources is reduced. Various measures can be employed to attain energy efficiency in building such as reducing demands for heating, cooling, lighting, consumption for office equipment and appliances demand, reducing energy requirement for ventilation, using energy efficient building materials.
 An energy efficient home is designed to keep out the wind and rain while reducing energy waste. Modern homes are built with variety of different materials. They are no longer built using only bricks and mortar. A wide variety of energy efficient building materials are now available. Recycled Steel, Insulating Concrete Forms, Plant-based Polyurethane Foam, Straw Bales, Structural Insulated Panels, Plastic Composite Lumber, Vacuum Insulation Panels, Inco-panel are among alternatives available.
 Among those various wall materials, energy performance analysis in terms of heating and cooling load is done in this thesis. For this study, under construction Hotel Sarowar is chosen for analysis. This study compares heat transfer on the building when Inco-panel is used as wall material and conventional brick masonry is used as wall material. The heat transfers through those walls are calculated using MS Excel and ANSYS Software.

Functional Principles of Morphological and Anatomical Structures in Pinecones.

In order to better understand the functions of plants, it is important to analyze the internal structure of plants with a complex structure, as well as to efficiently monitor the morphology of plants altered by their external environment. This anatomical study investigated structural characteristics of pinecones to provide detailed descriptions of morphological specifications of complex cone scales. We analyzed cross-sectional image data and internal movement patterns in the opening and closing motions of pinecones, which change according to the moisture content of its external environment. It is possible to propose a scientific system for the deformation of complex pinecone for the variable structures due to changes in relative humidity, as well as the application of technology. This study provided a functional principle for a multidisciplinary approach by exploring the morphological properties and anatomical structures of pinecones. Therefore, the results suggest a potential application for use in energy-efficient materials by incorporating hygroscopic principles into engineering technology and also providing basic data for biomimicry research.

Thermophysical properties of sustainable cement mortar containing oil palm boiler clinker (OPBC) as a fine aggregate

This study investigated the thermophysical properties in terms of thermal conductivity, heat capacity, thermal diffusivity, density, compressive strength, water absorption, and sorptivity of cement mortars containing different percentages of oil palm boiler clinker (OPBC). The normal sand was replaced by 25%, 50%, 75%, and 100% of OPBC. Furthermore, the relation between the thermal properties of mortar containing various amounts of OPBC with its physical properties has been discussed. The results indicated that 100% replacement of sand by OPBC decreases the density, thermal conductivity, and thermal diffusivity of cement mortar around 16%, 72%, and 76%, respectively. Moreover, the findings revealed that the specific heat capacity of the mortar increases by around 41%, while the sand is replaced by OPBC in 100%. Based on the findings, the usage of OPBC as fine aggregate affects the thermophysical properties of cement mortar due to the higher porosity of OPBC in comparison with normal sand. Therefore, it can be concluded that OPBC mortar can be used as a sustainable and energy-efficient building material due to its decent thermal properties.

Electrochemical approaches to room temperature magnetoelectric materials

Electrochemical voltage control of magnetism is an emerging approach for energy-efficient magnetoelectric materials. In contrast to conventional magnetoelectric concepts, which are typically restricted to low temperatures, low magnetization, or complex heterostructures, electrochemical routines can be efficiently applied to magnetic oxides and metals with high magnetization at room temperature. Potential-induced faradaic reactions, such as interfacial oxidation/reduction, electrochemical hydrogenation, and ion intercalation are used to set different magnetic states at the interface and beyond. Recent advances include the reversible, redox-based ON/OFF switching of magnetization and change of the exchange bias in metal oxide/metal nanostructures, and the fast spin reorientation upon hydrogenation of Pd/Co films. The modulations can be nonvolatile and open a path toward voltage-reprogrammable magnets for spintronics, actuation and sensor applications. • Electrochemistry is a route to room temperature magnetoelectric metals and oxides. • Redox reactions and ion intercalation tune magnetism at the interface and beyond. • Advances in the magneto-ionic mechanism involve oxygen, hydrogen, and lithium ions. • Oxygen-based redox reactions control complex magnetic phenomena in metal films. • Electrochemical hydrogenation offers fast magneto-ionic switching.

Diammonium-Pillared MOPS with Dynamic CO2 Selectivity

Summary The climate challenge calls for the design of energy-efficient CO2-separation materials. CO2-selective solid physisorbents are characterized by a low energy penalty and enable the most promising and energy-efficient CO2 separation technologies by applying vacuum swing adsorption (VSA). Here, we show that a diammonium-pillared microporous organically pillared layered silicate 7 (MOPS-7) represents a CO2-selective physisorbent, synthesized by simple ion exchange of an inexpensive clay. This MOPS provides high dynamic, reversible, and reproducible CO2 uptakes and selectivities proven in dynamic breakthrough experiments mimicking flue gas, natural gas, and biogas conditions. The selective interaction with CO2 is dominated by the multipole interactions with the microporous hybrid material. Thus, the energy penalty attributed to regeneration is intrinsically reduced. The simplicity and modularity of pillaring low-budget and environmentally friendly clays, combined with industrially capable performance with respect to thermal stability, high dynamic CO2 adsorption selectivity, and energy-efficient restoration renders MOPS-7 a highly attractive CO2 adsorbent.

AERATED CONCRETE AS AN ENERGY-EFFICIENT MATERIAL FOR WALLS

Abstract. In the context of tightening the thermo-technical requirements for building envelopes, the benefits and advantages of energy-efficient wall material of autoclaved aerated concrete and aerated concrete products are shown. Domestic and foreign researches in the field of rational use of autoclaved aerated concrete for external walls in modern construction of energy-efficient buildings and optimization of structural solutions of aerated concrete walls are generalized. The most important thermos-physical characteristic for assessing the thermal resistance of external walls made of aerated concrete is the value of the thermal conductivity coefficient. The moisture content of aerated concrete has a significant effect on thermal conductivity, the release moisture is several times higher than the calculated moisture content stipulated by the standards for construction heat engineering and operating conditions. In the initial stages of construction, the moisture content of aerated concrete exceeds the moisture content established in the normative documentation by operating conditions, which requires recalculation of the thermal resistance of the walls of buildings taking into account the real moisture content of aerated concrete used during construction. A detailed explanation of the dependence of the heat flow through the enclosing structure on its resistance to heat transfer, established in the form of a hyperbola, is given, and the dependence of the difference in thermal conductivity on the moisture content of aerated concrete blocks is presented. When analyzing the effect of moisture on the thermal conductivity of aerated concrete, was used the characteristic deviation ± Δλ of thermal conductivity of aerated concrete in a wet state from the thermal conductivity of concrete in a dry state was used. Based on the results of the experiment carried out at OSACEA, the main conclusions and recommendations for determining the coefficient of thermal conductivity of aerated concrete in dry and wet conditions are given. Some aspects of energy saving in construction practice are presented, based on materials prepared by Doctor of Technical Sciences, prof. Gagarin V.G. The need to improve specific energy-saving measures is shown, which should be economically viable and not reduce the durability of construction objects. Generalized conclusions and recommendations are given.

High-technology energy-efficient composite material made from waste of thermal power plants

Polysulfide composite materials made from high tonnage waste of oil and gas and thermal power sectors were developed and studied. The composition of these materials was optimized. It was shown that the components interacted with each other, and a compact homogeneous structure was formed when pyrite was added.

Sarooj mortar: From a traditional building material to an engineered pozzolan -mechanical and thermal properties study

Abstract Developing new energy efficient building materials to reduce the carbon footprint is now the core of sustainability in construction and an essential factor of life cycle assessment (LCA). The extensive and increasing usage of conventional concrete, mortar, plasters and various cement-based materials is only one of the many factors contributing towards urban thermal discomfort caused by urban heat island phenomena and the poor thermal insulation of ordinary cement mortar. Not only this, the wide use of concrete and mortar in construction increases the consumption of their primary components mainly -Portland cement-requiring a large consumption of energy and causing a significant rise in CO2 emissions. Embedding natural and artificial cementitious/pozzolana materials in today's cement-based building materials has become a common practice. Cementitious and Pozzolanic materials are known to provide an added value to mortar/concrete not only in terms of mechanical and durability properties but also in energy efficiency and enhancing sustainability. Sarooj is a local term describing an artificial cementitious and pozzolana material obtained by traditional calcining of the raw clayey soil. Although its usage is nowadays very limited, Sarooj has been used in Oman and other neighboring countries for centuries, in various buildings and defense structures. The main objective of this research is to transform the traditionally produced Sarooj into an engineered binding material and hence investigating its physico-mechanical and thermal properties. The raw soil used to produce the traditional Sarooj was employed to engineer a modern “Sarooj” under controlled energy processing (grinding and calcination) conditions. The raw clay minded from specific location was ground first to a fine powdered material and then subjected to full characterization. The physical and chemical characterization indicated that the raw soil is suitable for producing a cementitious/pozzolanic calcined clay. The thermogravimetric and differential thermal analysis of the clay used reveal that only a moderate temperature of around 800 °C is required for its calcination which preserves energy and reduces CO2 emissions compared to 1600 °C to produce clinker cement. The strength development showed a slow early-age reactivity but an appreciable enhancement in long-term which demonstrates a remarkable latent hydraulic potential of the clay used. It was also found that adding an optimum amount of the calcined clay enhances the thermal properties. The annual energy performance of a typical housing in the hot climate of Muscat, Oman, was evaluated using DesignBuilder software, a whole-building simulation tool. The simulation results showed insignificant savings in annual energy consumption when the developed mixes are used as plastering materials. The clay alkali-activated with NaOH has, however, showed great potential to enhance the mortar's long-term strength. Using locally engineered cementitious material in a partial replacement of Portland cement can further enhance durability and sustainability by reducing the manufacturing energy of the produced building material such as mortars and plasters.

Study of thermal and mechanical traits of organic waste incorporated fired clay porous material

This study investigates thermophysical and mechanical traits of organic waste incorporated fired clay as an energy efficient material. Sawdust, tea waste, and wheat husk were added in clay to prepare composite blocks at different sintering temperatures. Physical and hydric properties of waste incorporated material revealed a linear relationship with waste percentage for water absorption, loss-on-ignition and porosity. Linear shrinkage analysis showed contraction or expansion of the bricks, depending on sintering temperature and combustible nature of organic waste. High loss-on-ignition values were correlated with a decrease in water absorption and porosity with a rise in temperature. The specific heat capacity, thermal conductivity and thermal diffusivity exhibited a decreasing trend with a rise in sintering temperature. Conversely, compressive strength increased with sintering temperature. The use of 2–6% of tea waste, 2–8% of sawdust and 1–2% of wheat husk is suggested for production of energy efficient blocks.

3D face-centered-cubic cement-based hybrid composites reinforced by tension-resistant polymeric truss network

Abstract After 30 years of development, 3D printing technology (3DPT) is becoming increasingly popular in civil engineering field. However, weak interlayer performance and lack of reinforcement significantly limit its application. Nowadays, structural-functional integrated energy-efficient building materials, theoretically requiring a balance of mechanical properties and thermal resistance, are an emerging interdisciplinary research area in civil engineering field. This work proposed a novel digital cement-based manufacture technology by integrating 3D printing technology with casting technology. By incorporating tension-resistant polymeric truss network (PTN), a category of 3D face-centered cubic-inspired cement-based hybrid composites (FCHCs) is proposed. Results show the printed PTN can effectively improve the tension-resistant capacity of cement mortar. The FCHCs not only exhibit a multiple cracking damage characteristic but also a low thermal conductivity compared to traditional cement-based materials. A building energy simulation program was performed to evaluate the effectiveness of FCHCs on the energy savings. It is found that 34% heating energy could be saved for FCHCs building.