Thermal Energy Consumption Research Articles

A novel integrated solar-driven system with Ag@SiO2 nanofluid filters for generating hydrogen using seawater: Parametric assessment and optimization

Both renewable energy and fresh water inputs are required to develop sustainable green hydrogen. However, there is still a lack of an integrated system generating hydrogen cleanly. Therefore, this study aims to develop a full spectrum solar energy-driven system to co-generate fresh water and hydrogen. The seawater desalination and proton exchange membrane (PEM) electrolysis are introduced into a Ag@SiO2 nanofluid-filtered photovoltaic/thermal (PV/T) system. The desalinated seawater can be directly used for the electrolysis, realizing the self-supply of water for the hydrogen production process. A comprehensive examination is performed via modelling the integrated system to assess the influences of mass flow rates and nanofluid parameters on system function. Results reveal that the system performance is more sensitive to the mass flow rate of nanofluid than that of coolant, and concentrated nanofluids can easily affect system performance by adjusting their depth. Furthermore, mass flow rates and nanofluid parameters are optimized using a genetic algorithm with multiple-objectives. It was determined that the direct contact membrane distillation (DCMD) unit is capable of producing sufficient water for the electrolysis process. The optimal system attains a hydrogen production rate of 1.95 × 10−5 kg/s, a specific thermal energy consumption of 310.18 kWh/m3, and a system efficiency of 22.39%.

Exergy efficiency improvement by compression heat recovery for an integrated natural gas liquefaction-CO2 capture-NGL recovery process

For liquefied natual gas production, cryogenic distillation offers lower thermal energy consumption and a more compact footprint for carbon capture unit than the widely used chemical absorption. However, the reduction in thermal energy consumption comes at the cost of increased power consumption. To reduce the power consumption of cryogenic distillation based natural gas lqiuefaction plants, an integrated process for liquefied natual gas production, cryogenic CO2 capture and natural gas liquids recovery is proposed, which is called the base process. This base process is further integrated with a heat recovery unit (Organic Rankine cycle or Kalina cycle) to investigate the optimal utilization of compression heat in the system. The proposed processes are modeled in Aspen HYSYS and optimized using a genetic algorithm installed in Matlab. The results show that specific power consumption of the base case is 0.385 kWh/Nm3 NG. Due to the lack of compression heat recovery, significant exergy loss occurs at the water coolers, accounting for approximately 37 % of the total system exergy destruction. Among the evaluated methods, the supercritical Organic Rankine cycle, using R1234ze as the working fluid, recovers approximately 60 % of the exergy from compression heat with an 8.7 % improvement in system exergy efficiency. The subcritical Organic Rankine cycle, using R600a as the working fluid, achieves a slightly lower exergy efficiency improvement of 7.1 %. The Kalina cycle, while less efficient, still improves the system’s exergy efficiency by 6.3 %. Economic analysis reveals that the total annualized cost of the base process is $8,441,416, with a levelized cost of $0.1411/kg. The subcritical Organic Rankine Cycle provides the most cost-effective solution, with the lowest total annualized cost of $8,305,154 and a levelized cost of $0.1402/kg. The Kalina cycle ranks second in cost-effectiveness, with a total annualized cost of $8,345,914 and a levelized cost of $0.1405/kg NG. Although the supercritical ORC requires the highest capital investment, it proves more cost-effective than the base process due to its reduced annual operating costs.

Towards cleaner desalination systems utilizing waste heat: a bibliometric analysis

Water scarcity is a global issue facing the coming generations. Desalination is a dependable, nonconventional freshwater method. However, desalination is an energy-intensive water treatment method. The primary energy source used to power various desalination processes for thermal and electrical energy consumption is fossil fuels, such as coal, oil, and gas. The widespread use of fossil fuels has been linked to climate change and global warming, leading to numerous demands to reduce their usage and energy utilization. Waste heat has an excellent potential for energy recovery that can reduce the consumption of fossil fuels. This research study has been conducted to evaluate related waste heat desalination literature with data analysis, bibliometric, and clustering methods. Based on articles published between 2013 and 2023, the current study analyzed existing trends, distribution of publication subjects, journals' performances, countries' collaborations, affiliations' performances, most cited publications, authors' contributions, keyword analysis, and future perspectives on waste heat desalination systems. The findings showed that the most active journal in this field is Desalination, with 133 publications and 6332 citations. China led in publications with 242, while the United States topped the list of citations with 3598. Also, King Abdullah University of Science and Technology in Saudi Arabia published 50 documents. The top 10 institutions in this field of research are in the Middle East and North Africa (MENA) region and Asia, particularly in Saudi Arabia, China, Iran, Egypt, and Singapore. Moreover, the most frequently used terms are analyzed and clustered into three main topics. The top 3 clusters are solar-powered desalination technologies, membrane-powered desalination technologies, and power cycles driving desalination technologies.

Urban heat islands’ effects on the thermo-energy performance of buildings according to their socio-economic factors

Urban areas experience the urban heat island (UHI) effect, which affects the thermal comfort and energy consumption of buildings. These consequences could vary depending on the socio-economic status of the neighbourhoods. Few studies have investigated how UHI affects socio-economically contrasting districts in thermal comfort and energy performance. Therefore, the primary goal of this research is to evaluate and compare the energy efficiency and thermal comfort conditions of residential buildings in the same city (Temuco, Chile) but located in socio-economically contrasting neighbourhoods. Urban weather files were first modelled in four urban zones using UWG software. Also, EnergyPlus building simulations were conducted to evaluate discomfort hours in adaptive comfort models and energy performance. The results showed annual average UHI intensities between 1.5 and 2.5 K. Urban–rural cooling energy load differences ranged between 12.47% and 38.92%, while heating energy load differences ranged between -20.47% and -81.95%. These distinctions depended on the urban zone, residence model analysed, or energy building standard applied. Similarly, urban-rural differences in thermal comfort times varied from 0.5% to 100%. Results illustrate that the risk of overheating could increase in socio-economically vulnerable areas. This issue could worsen if urban segregation continues to generate poor urban design in low-income districts.

Effects of vertical greening on the thermal environment and energy consumption in different street canyons

Vertical greening is vital for energy conservation and urban sustainability. However, previous studies have seldom considered the energy-saving effects of vertical greening within street canyons—an important representative urban model. This study employs ENVI-met and EnergyPlus to evaluate the energy savings of vertical greening in twelve typical street canyon scenarios with varying aspect ratios (H/W = 1, 2, 4) and orientations (North–South, East–West, Northeast–Southwest, Northwest–Southeast). We quantified the relative contributions of building surface temperature reduction (ΔTₛₑ) and air temperature reduction (ΔTₐ) to overall energy efficiency. Remarkably, our findings reveal that ΔTₛₑ accounts for over 97% of the total energy-saving contribution—a novel insight contrasting with previous studies that emphasized combined impacts. Additionally, the results indicate that stronger solar radiation in street canyons leads to greater reductions in building surface temperatures. To achieve maximum daily energy savings, the optimal combinations of street orientation and aspect ratio are: North–South orientation when H/W = 1, Southwest–Northeast when H/W = 2, and Northwest–Southeast when H/W = 4. This study is among the first to quantify the combined effects of different street canyon configurations and vertical greening on urban energy savings, providing effective methodologies and new insights for implementing sustainable urban vertical greening.

New insights into the functional group influence on CO2 absorption heat and CO2 equilibrium solubility by piperazine derivatives

Piperazine(PZ) derivatives which have been widely used in CO2 capture technology exhibit stable physicochemical properties, such as resistance to thermal degradation and low regeneration energy consumption. Both two parameters of CO2 absorbents, low CO2 absorption heat(ΔHabs) and large CO2 equilibrium solubility(αe), are important to CO2 capture performance. However, the influence of functional group types of PZ derivatives on their CO2 capture performance remained unclear. This research aimed to study the functional group influence on the ΔHabs and αe by PZ derivatives with two amines using experimental and quantum chemical methods. The results indicated that PZ derivatives with the ethyl side chain had larger ΔHabs and αe than those with the methyl side chain. The presence of the hydroxy group in PZ derivatives reduced the ΔHabs and the αe. The presence of cyclic methyl side chains on the N atom of PZ derivatives decreased the ΔHabs and increased αe at the same time. The findings show that PZ derivatives with cyclic methyl side chains, steric hindrance effect, and no hydroxy group are favorable for CO2 capture. Among the eight PZ derivatives, TEDA with lower ΔHabs(48.99 kJ/mol) and higher αe(0.917 mol CO2/mol amine) is an excellent absorbent. The results of this study are very important for screening efficient and low-energy consumption absorbents for CO2 capture.

Innovative solar-assisted direct contact membrane distillation system: Dynamic modeling and performance analysis

The study presents an innovative solar-assisted dual-tank direct contact membrane distillation (DCMD) system designed to enhance the operational stability and efficiency of solar-powered desalination. The proposed system integrates a dual thermal storage tank configuration, allowing for continuous operation by alternating between two tanks that store pre-heated water, thereby mitigating the impact of solar energy fluctuations. The dynamic modeling approach used in this study predicts the system's performance under varying solar conditions, focusing on key parameters such as permeate flux, evaporation efficiency, and specific thermal energy consumption. The simulation results show that the system achieves an average permeate flux of 14.4 L/h m² and a thermal efficiency of 53.3 % at a hot water temperature of 60 °C, with a corresponding average specific thermal energy consumption of 1567 kWh/m³. These findings highlight a substantial improvement in both thermal efficiency and water production compared to conventional single-tank systems.The dual-tank DCMD system is particularly suited for deployment in remote or arid regions where stable and efficient freshwater production is critical. This research provides a comprehensive analysis of a novel solar-assisted desalination technology, contributing to the advancement of sustainable water resources management by providing a reliable and scalable solution that can maintain high operational efficiency even in remote areas with variable solar conditions.

A Review on the Effective Utilization of Organic Phase Change Materials for Energy Efficiency in Buildings

Energy efficiency is critical for achieving building sustainability because it means that fewer resources are consumed. In this context, the advancement of phase-changing materials has attracted attention with regard to the integration and management of energy efficiency in construction projects. Buildings consume 40% of the global energy output annually, accounting for one-third of the global greenhouse gas emissions. For hot weather-prone construction, PCMs should have a melting temperature of 25–50 °C. For more than 30 years, researchers worldwide have experimented with PCMs at various temperatures, but few studies have been conducted in hot or harsh environments. According to recent studies, the amount of PCMs in construction materials has been limited to 20%, and exceeding this ratio was shown to significantly affect the compressive strength of concrete specimens. In this study, various phase-changing concrete materials were investigated to reduce the thermal energy consumption of buildings. This paper aims to provide an overview of the current state-of-the-art phase change materials for constructing thermal energy storage building materials. It also includes a brief review of the most recent developments in phase change technologies and their encapsulation techniques based on thermophysical properties. Implementing PCM technology in buildings will also maintain good indoor air quality. These materials are widely used in various real-time applications to significantly enhance thermal comfort in buildings.

Analysis of airtightness performance of residential areas in Mediterranean climate: Balıkesir houses

Airtightness is one of the crucial physical characteristics of building envelope that affect the building thermal performance and energy consumption. The airtightness of the building is influenced by the quality of workmanship and various design parameters such as window/wall ratio, type of joinery, size of the usage area, wall material, and thermal insulation on the external wall. In this study aiming to determine the airtightness performance of buildings in the Mediterranean climate of Balıkesir houses, airtightness conditions of 43 different houses were determined by blower door test measurement. The air exchange rate (n50) values of 43 houses/residences were obtained between 1.94 and 49.02 h−1 and compared with the current various standards. The effect level of the design parameters on the air tightness of the building envelope was obtained as a result of the analysis performed with analysis of variance and post hoc methods. According to the analysis, joinery type was the most effective design parameter in terms of airtightness, followed by usage area and transparency of facades. The result will help in deciding on the design parameters affecting the airtightness of the building envelope for energy efficiency in the Mediterranean climate.

Multi-scale retrofit pathways for improving building performance and energy equity across cities: A UBEM framework

Institutional inequality has created an environment in which our physical surroundings reflect racial and economic biases – causing inequitable thermal comfort and energy consumption across neighborhoods. Just as energy and thermal comfort challenges are unique to each climate and built environment, the solutions to address these issues should be optimized for their context. We introduce a novel integrated data-driven and building energy simulation method that incorporates urban context, satellite imagery, and socioeconomic data to analyze multi-scale retrofit scenarios across disparate communities. We apply this method to case studies in New York City and Los Angeles to analyze energy and thermal comfort inequities across distinct climate zones and urban morphologies. Through parametric analysis, we demonstrate the efficacy of multi-scale retrofits at improving building performance and reducing existing thermal inequities. Our research shows that retrofit effectiveness is influenced by the microclimatic changes induced by the urban context and existing infrastructural inequity. For example, instantaneous building cooling energy demand in a disadvantaged community of Los Angeles is reduced more due to window retrofits (around 30 kWh) than by a greenspace retrofit (around 3 kWh). Greenspace installation dissipates more heat overnight and in the early morning, whereas window retrofits reduce solar heat gain during the day, showing the different heat reduction pathways that retrofits can achieve. Although the window retrofits lead to an order of magnitude higher utility cost savings ($70 savings from windows vs $9 for greenspace and $12 for reduced cars), the district-scale retrofits show promising pathways for reducing the cost burden across all residents. We also analyze pathways for achieving city-specific CO2 reduction targets and find that building-level retrofits are most effective at meeting building performance standards (reducing CO2 by 40%), whereas district-level retrofits should be used to achieve city-scale climate goals because of the sequestered and abated emissions offered by these pathways. This generalizable modeling framework empowers policymakers, urban planners, and building owners around the world to analyze pathways for meeting their climate action plan goals by reducing extreme heat, reducing greenhouse emissions, and reducing energy cost burden while improving environmental justice in their cities.

An energy-environment coupled simulation framework for multi-scale and multi-facet evaluation of data center

This paper focuses on analyzing the thermal environment and optimizing energy consumption in data centers, which has largely omitted from previous studies. The thermal environmental of data centers is simulated and analyzed by utilizing the established “server-rack-room” multi-scale heat transfer numerical model. Based on this, the coupling simulation model of thermal environment and energy consumption in data centers is proposed to explore the relationship between them, and the corresponding optimization strategy is put forward. The energy consumption simulated by energy-environment coupled model and non-coupled model can reach a discrepancy of over 30 %, which indicates that the thermal environment impacts the power consumption of the data center significantly. Besides, the effect of several operational parameters of air conditioning system on the thermal environment and energy consumption of data center is analyzed. Through the particle swarm optimization algorithm, the optimal system parameters, which meet the requirements of thermal environment and lead to the lowest energy consumption, are found for typical cities in different climatic regions. The recommended settings include the supply air temperature of about 24 ∼ 26 ℃, the air supply volume of 8 m3/s, and the temperature difference of about 3.5 ℃ between the supply air temperature and the supply chilled water temperature. Under the optimized parameter setting, the highest temperature of server decreases to below 71 ℃, and the energy saving rate is more than 6 %.

Information Technologies for Calculating Anthropogenic Heat Flux in Urban Areas

Modern megalopolis face challenges in effectively managing energy resources and minimizing the impact of human activities on the environment. One of the significant aspects of anthropogenic impact is the heat flow generated by buildings, transport and industry. This article presents a set of programs for assessing anthropogenic heat flow (AHF) caused by heat loss from buildings during the heating season. The study is based on a spatial geometric model of the city constructed using OpenStreetMap data. The thermophysical properties of enclosing structures and specific characteristics of thermal energy consumption are obtained from building codes. The proposed method includes the stages of buildings modeling, filtering, supplementing information from Yandex Maps and State Information System of Housing and Communal Services, eliminating collisions, assigning specific characteristics and calculating AHF. The method is implemented through scripts for the Rhinoceros platform, known for its wide functionality and visual programming environment Grasshopper. The proposed approach allows us to effectively analyze and visualize anthropogenic heat flow in cities, which is a key step in developing strategies for sustainable energy management and reducing negative environmental impacts.

THE IMPACT OF SOLAR RADIATION ON THE TEMPERATURE REGIME OF A ROOM IN WINTER

The article is devoted to the computational studies of the air-thermal state of office premises taking into account the effect of solar radiation coming through window openings. The study was conducted for a room with two windows using two heating devices installed under them. The air-temperature regime of premises in winter, characterized by the highest thermal energy consumption for heat supply, is considered. The study is based on the solution of a three-dimensional nonlinear heat transfer problem described by a system of equations of turbulent momentum and energy transfer. The k-e turbulence model is used to close this system. The results of numarical modeling of the physical situation under study are presented. The research data on the features of the air-thermal state of the premises under solar radiation conditions are given. The results of a comparative analysis of the air-temperature conditions of office premises corresponding to the solution of the specified heat exchange problems in the presence and absence of solar radiation are presented and the effects of solar radiation on the structure of the air flow and the thermal state of the premises are established. It is shown that in the presence of solar radiation, the air flow picture and the character of the temperature fields in the premises change significantly. In particular, in these conditions, the increase in the average temperature of the premises for the studied period is 2.5 °С. The possibility of a certain reduction of the load on the heating system in the presence of solar radiation is noted. Bibl. 17, Fig. 5.

Optimizing solarized desalination unit through the implementation of 4-step MED method using energy, exergy, economic and environmental analysis

The consumption of thermal energy in thermal desalination plants leads to a higher price for the fresh water they produce compared to other methods. By utilizing optimization techniques, it is possible to lower both energy consumption and price. The focus of this paper is on optimizing a solarized desalination unit through the implementation of the 4-step MED method with a PTC collector. To achieve this objective, the NSGA II algorithm was implemented in MATLAB using a function for optimization. This algorithm is known for its cost-effectiveness and high energy efficiency. According to the results, there has been an improvement in the fresh water flow rate, desalination efficiency, and GOR, with values reaching 126.87, 53.6%, and 3.66 respectively, compared to the previous values of 116.5, 49.21%, and 3.32. In the ideal condition, the power generated is 6089 kW, priced at 3.28 cents per kilowatt, and the cost of producing fresh water is 8.49 dollars per cubic meter, which decreases as the process lifespan increases. Solar collectors and thermal tanks account for the largest portion (64%) of exergy destruction, as indicated by the exergy analysis. Optimization of the process has led to energy and exergy efficiencies of 59.8% and 58%, respectively, representing a notable enhancement of around 10% in the system's lifespan. The optimal mode also includes the completion of the sensitivity analysis. The process was subjected to LCA analysis, and the results indicated that the largest impact is on human health, with the collectors and thermal storage tanks being responsible for most of the pollution. As a result, the optimized process has delivered outstanding results while also being environmentally conscious.

Optimizing the performance parameters of vacuum evaporation technology for management of anaerobic digestate in a waste water treatment plant using fuzzy MCDM method

Evaporation technology in waste water treatment plants is used to treat excess liquid digestate, eventually reaping the essential nutrients from the process. In the present study, the input conditions have been optimized for implementing and achieving optimal performance of the digestate evaporation technology used in waste water treatment plants by employing fuzzy multi-criteria decision making method. Three input parameters, namely the Temperature, the Pressure, and the Mass Flow rate, each at three levels are considered. Experiments are conducted as per the Taguchi’s L9 standard orthogonal array. The performance of the evaporator is examined based on a few response characteristics, such as payback period, thermal energy consumption, power consumption and cost per unit of electricity. Temperature's impact on multi performance stands out significantly, contributing the most (70.52 %), followed by mass flow rate (18.95 %), and pressure (5.37 %). Result of the study reveals that within the investigated range of input parameters, temperature at 80 ℃, pressure at 0.3 bar and mass flow rate at 20 kg/h is the optimal combination. The results of the present study will help in enhancing the efficiency and effectiveness of the evaporation process, leading to improved digestate treatment that supports circular economy initiatives.

Development of an enhanced electrical injera baking pan (Ethiopian Traditional mitad) using steel powder additives and gypsum insulation

Electric Injera baking Pan are prevalent in Ethiopia but are highly inefficient, resulting in significant heat loss, high energy consumption, and increased energy bills. This research investigates improving these devices using steel powder as an additive and gypsum as an insulator. The study examines thermal conductivity, baking time, energy consumption, heat loss, and insulation effectiveness. The objectives of this research are to improve the thermal conductivity of the baking surface while ensuring even heat distribution, enhance the insulation properties of the pan to reduce heat loss, improve the safety of the user by reducing the risk of excessive heat exposure to the outer surfaces, and reduce the overall energy consumption of the Injera baking process. Temperatures were measured using an infrared thermometer, digital thermometer, and thermocouple. Four samples (A0, A1, A2, & A3) with different steel powder compositions (0 %, 15 %, 25 %, and 35 %) and a constant 75 % clay soil composition were tested. The analysis showed an average baking energy of 0.45 kWh per kg of injera (0.198 kWh per injera) and a thermal efficiency of 86.4 % when baking 4.395 kg of injera. The total heat energy loss was 1402.78 KJ (14.08 % of 10300 KJ input energy). The losses were distributed among the retained (92.17 %), the baking plate (3.95 %), the bottom enclosure (2.08 %), the side enclosure (1.04 %), and the cover lid (0.76 %).

OPTIMIZATION OF HEAT CONSUMPTION IN CENTRAL HEATING SYSTEMS AT COMMERCIAL FACILITIES

Rising energy prices and stricter environmental regulations are exacerbating the problem of inefficient heat consumption in the commercial sector. Central heating systems of office buildings, shopping malls, and industrial complexes are often characterized by excessive thermal energy consumption, which leads to significant economic losses and a negative impact on the natural environment. The purpose of the study is to study the directions and trends of optimization in the field under consideration (taking into account modern technological capabilities, and economic factors). There are disagreements in the professional community about the priority of measures to improve energy efficiency: some experts prefer improving the thermal insulation of buildings, others — the introduction of intelligent control systems, and others — the integration of renewable energy sources. The present study demonstrates that the greatest effect is achieved with a systematic approach combining various initiatives. The conclusion is formulated that in the current conditions and the future, a comprehensive application of modern thermal insulation materials, highly efficient heating equipment, intelligent management mechanisms, and alternative energy sources is required. The article is of interest to engineers-designers of heating systems, energy managers of commercial facilities, specialists in energy efficiency of buildings, and heads of companies interested in optimizing operating costs and improving the environmental friendliness of their real estate.

Predictive building energy management with user feedback in the loop

Retrofitting buildings with predictive control strategies can reduce their energy demand and improve thermal comfort by considering their thermal inertia and future weather conditions. A key challenge is minimizing additional infrastructure, such as sensors and actuators, while ensuring user comfort at all times. This study focuses on retrofitting with intelligent software, incorporating the users’ feedback directly into the control loop. We propose a predictive control strategy using an optimisation-based energy management system (EMS) to control thermal zones in an office building. It uses a physically motivated grey-box model to predict and adjust thermal demand, with individual zones modelled using an RC-approach and parameter estimation handled by an unscented Kalman filter (UKF). This reduces deployment effort as the parameters are learned from historical data. The objective function ensures user comfort, penalises undesirable behaviour and minimises heating and cooling costs. An internal comfort model, automatically calibrated with user feedback by another UKF, further improves system performance. The practical case study is an office building at the ”Innovation District Inffeld”. Operation of the system for one year yielded significant results compared to conventional control. Thermal comfort was improved by 12% and thermal energy consumption for heating and cooling was reduced by about 35%.

Enhancing adsorbent performance for direct air capture of CO2 by in-situ amine-grafting of layered double hydroxides

The development of efficient and cost-effective CO2 adsorbents is crucial for carbon capture from ultradilute conditions. Amine-grafted mesoporous materials prepared by silane chemical reactions are well-known CO2 adsorbents with high thermal stabilities, but their capacities for direct air capture (DAC) are usually restricted by low amine loadings and CO2 capture capacity. Herein, we present an in-situ amine grafting method that enables high amine loadings by in-situ grafting initial ultrathin LDHs nanosheets in an organic solvent. For in-situ triamine grafted Mg2Al-CO3 LDH (IN-TRI-LDH) amine loading is boosted to 5.91mmol N g−1 and ultimately achieving a remarkable adsorption capacity of 0.98 mmol g−1 at 25°C and 400 ppm CO2, nearly double that of the amine-LDHs grafted through a conventional two-step process. A further 22 % enhancement of the CO2 capacity is observed under 20 RH%. In addition, IN-TRI-LDH maintains a working capacity of 0.85 mmol g−1 at a low desorption temperature of 70 °C. A 50 adsorption–desorption cyclic test under simulated humid DAC conditions shows minimal performance degradation. Such a sufficient working capacity and low desorption temperature reduces the thermal energy consumption to 2.27 GJ t−1 at a desorption temperature of 40 °C.

РОЛЬ САСО3 У ФОРМУВАННІ МІЦНІСНИХ І ДЕКОРАТИВНИХ ВЛАСТИВОСТЕЙ ПОРОШКОВОГО ЛУЖНО-АКТИВОВАНОГО ШЛАКОПОРТЛАНДЦЕМЕНТНОГО БЕТОНУ

The article discusses approaches to the formation of compositions of alkali-activated decorative Portland slag cements containing Portland cement type CEM1 5...45% with high performance and decorative properties. The optimization of the compositions of decorative alkali-activated Portland slag cements was carried out using statistical methods for designing experiments. Finely dispersed TiO2 and CaCO3 additives with a whiteness of 90% were used as bleaching components. The alkaline component is sodium metasilicate in the form of a non-hygroscopic powder. The research carried out made it possible to obtain decorative Portland slag cements with a whiteness of 45...77%, which allows them to be used to produce colored cements with a wide range of colors from white to black. It has been established that alkali-active decorative Portland slag cements have an activity of 37...59 MPa at the age of 28 days. All compositions have good hardening dynamics and, based on the strength at the age of 2 days  22...36.6 MPa, they can be classified as fast-hardening. Based on them, it is possible to produce dry construction mixtures. All mortar compositions based on alkali-active decorative Portland slag cements demonstrate fairly high frost resistance  F200. This allows them to be used for the manufacture of products and solutions both for indoor use and when exposed to atmospheric influences without loss of design characteristics and decorative appeal. The inherent shrinkage strains of decorative alkali-activated Portland slag cements are 0.51...0.61 mm/m, which eliminates cracking and premature destruction of products. The use of the CaCO3 additive is especially effective for controlling the shrinkage deformations. Thus, the CaCO3 additive performs the functions of not only a decorative component, but also a structure-forming component. Concrete and mortar mixtures can be used to produce decorative products using the traditional method, extrusion, 3D printing on construction printers, etc. And not too long setting times and a rapid increase in strength make it possible to produce products without thermal treatment or with minimal consumption of thermal energy.