Level Of Thermal Protection Research Articles

Acai Oil-Based Organogel Containing Hyaluronic Acid for Topical Cosmetic: In Vitro and Ex Vivo Assessment.

Organogels are semi-solid pharmaceutical forms whose dispersing phase is an organic liquid, for example, an oil, such as acai oil, immobilized by a three-dimensional network formed by the gelling agent. Organogels are being highlighted as innovative release systems for cosmetic active ingredients such as hyaluronic acid for topical applications. Acai oil was evaluated for its physicochemical parameters, fatty acid composition, lipid quality index, spectroscopic pattern (Attenuated total reflectance Fourier Transform Infrared Spectroscopy), thermal behavior, total phenolic, total flavonoids, and total carotenoids and β-carotene content. The effectiveness of the organogel incorporated with hyaluronic acid (OG + HA) was evaluated through ex vivo permeation and skin retention tests, in vitro tests by Attenuated total reflectance Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry. The physicochemical analyses highlighted that the acai oil exhibited quality standards in agreement with the regulatory bodies. Acai oil also showed high antioxidant capacity, which was correlated with the identified bioactive compounds. The cytotoxicity tests demonstrated that the formulation OG + HA does not release toxic substances into the biological environment that could impede cell growth, adhesion, and efficacy. In vitro and ex vivo analyses demonstrated that after 6 h of application, OG + HA presented a high level of hydration, thermal protection and release of HA. Thus, it can be concluded that the OG + HA formulation has the potential for physical-chemical applications, antioxidant quality, and potentially promising efficacy for application in the cosmetic areas.

Thermal Protection Performance Evaluation Based on Structural Composition Changes of the Intermediate-Layer Fabric in Thermal Protective Clothing

This study is a follow-up to ‘Research on the Development of Fabrics for Industrial and Firefighting Protective Clothing and Comparison of Flame Retardant Performance,’ focusing on the thermal protection performance of clothing designed to protect the human body from high temperatures and heat in industrial settings and fire scenarios. In this study, additional thermal protection performance tests were conducted to provide a more comprehensive analysis. Aside from the flame-retardant performance evaluation conducted according to ISO 15025 on 12 base fabrics with different yarn compositions, the following thermal performance studies were carried out: radiant heat protection (ISO 9151), convective heat protection (ISO 6942), and combined radiant and convective heat protection (ISO 17492). The heat-transfer index of the intermediate layer, which plays a crucial role in the thermal protection performance of thermal clothing, was also assessed. The results indicated that although most of the 12 base fabrics offered a certain level of thermal protection, some of them melted and failed to provide adequate thermal protection.

Use of paraboloid solar concentrators to reduce heat consumption of residential buildings in the climatic conditions of Uzbekistan

This work examines the possibility of reducing the specific heat consumption of residential buildings for the climate of Toshkent and Navoi using a solar paraboloid concentrator and a heated floor system. Mathematical models of a living space, a paraboloid concentrator and a heated floor system are integrated, and the calculations are performed in the MathCAD programming environment and Python programming languages. As the results show, when using a paraboloid concentrator and a heated floor system, the annual specific heat consumption can be reduced to 26%, and the payback period is 18-22.5 years, depending on the level of thermal protection.

Method of arrangement of internal thermal insulation of external protective structures of the room

This article aims to discuss the conditions of insulation and avoidance of moisture condensation in the enclosing structures of buildings whose facades cannot be insulated from the outside due to historical and cultural value. The paper presents a study of the energy-efficient design of the facade of a residential building, which uses insulating materials that are suitable for internal thermal insulation of historical buildings. The analysis of domestic and European literary sources regarding the improvement of the level of thermal protection of buildings shows that the improvement of energy efficiency is important for ensuring a sustainable, affordable and safe energy system. The paper presents the results of a study aimed at increasing energy efficiency in residential buildings, as well as an analysis of the humidity state and the possibility of condensation when using internal insulation. Numerical simulations were performed to confirm the results. The obtained results indicate that the use of mineral insulation "BETOL®" and aluminium foil as a vapour barrier, applied from the inside, contributes to the improvement of thermal insulation of the walls and reduces the risks of condensation. Computer simulations have shown that under the considered conditions, condensation does not occur. The relative humidity in the structure does not reach 90%. The same structure without the vapour barrier causes condensation because the relative humidity exceeds 100 % in whole thickness of the brickwork, which will cause destruction of the historical structure. This research makes an important contribution to the development of energy-efficient solutions for the construction industry, as it will ensure the minimum permissible value of the heat transfer resistance of the enclosing structures and extend the service life of them and buildings as a whole.

ANALYSIS OF DIRECTIONS TO INCREASE THE ENERGY EFFICIENCY OF OFFICE BUILDINGS IN UKRAINE TO THE NZEB LEVEL

The article is an analysis of the feasibility of replacing the energy source with heating an office building in Kyiv to the level of a building using energy produced by renewable sources (biomass). The authors assessed the potential of biomass in Ukraine, the logistics routes to ensure uninterrupted supply and the cost of renewable resources. Estimation of necessary investments of transition from energy source to heating, running on natural gas, to energy source, running on biomass (sunflower husk), is given by changing the integral cost of heating costs for three options for thermal protection of the building: non-insulated (existing) building; building, the level of thermal protection of which meets the requirements of Ukraine; a building whose thermal protection level satisfies the requirements of Sweden. In particular, the authors determined that the integral cost of heating when using a boiler on pellets from sunflower husks without improving the thermal insulation of the enclosing structures of the building is significantly lower than when using natural gas as an energy carrier for the production of thermal energy, and the initial cost of an insulated building meets the requirements of Ukraine and the requirements of Sweden when using a natural gas boiler is significantly higher than an uninsulated building with a biomass boiler. The results obtained indicate that there are prospects for scaling buildings with almost zero energy consumption in Ukraine, given the development potential of biomass and the significantly lower unit cost of biomass energy compared to natural gas.

The required level of thermal protection of enclosing structures of administrative buildings in the transport infrastructure in Russia and European countries

Comparison of various standard values and calculation methods adopted in Russia and European countries has always aroused quite a lot of interest, and many works are devoted to this topic. However, the last comparisons were carried out quite a long time ago, and the purpose of this study is to compare the required level of thermal protection of the building envelopes of administrative buildings in the transport infrastructure in Russia and European countries according to the current regulatory documents to determine the ratio of these values to each other. The normalized values of the level of thermal protection of external enclosing structures are related to the degree-days of the heating period. Moreover, the definition of this value in Russia and the EU countries differ from each other. And it is possible to compare the level of thermal protection of enclosing structures in different countries only according to the same characteristic, that is, with the same (or very close) value of the degree-day of the heating period. Also, the level of required resistance to heat transfer of external enclosing structures in Russia is set taking into account heat-conducting inclusions in the enclosing structure, and in European countries without taking into account. That is, it is impossible to compare these two quantities in the original form - you need to take into account the design of the outer shell of the building.

MODERN ARCHITECTURE AND ENERGY EFFICIENCY

The article analyzes the design solutions for the outer walls of residential buildings built in 2020-2022 in a city that belongs to the II temperature zone of Ukraine. The outer walls of the monolithic reinforced concrete frame of the building are made of hollow brick 250 mm thick with a façade system of heat-insulating and finishing class A. A verification thermotechnical calculation of the outer wall was carried out, taking into account heat-conducting inclusions, the reduced heat transfer resistance of an opaque enclosing structure (wall) does not correspond to the minimum allowable value of heat transfer resistance of the corresponding structure according to DBN V.2.6 – 31:2016 for the II temperature zone. When taking into account the effect of air permeability on reducing the overall level of thermal protection of the fence, it was determined that the calculated reduced value of the resistance to heat transfer of the outer wall will be even lower due to the fact that the structure consists of light cellular materials with a significant breathability. External enclosing structures and internal, dividing rooms with a temperature difference of 4 ° C or more, have insufficient insulation thickness. When developing insulation measures, the effect of air filtration through wall structures made of lightweight materials is not taken into account. The requirements for the insulation of complex structural units of enclosing structures to prevent the formation of "cold bridges", for example, a balcony slab, are not met. Translucent structures, which occupy more than 50% of the facades, are the cheapest, their heat transfer resistance is less than the minimum allowable value. Based on the results of the analysis, the main measures to improve the energy efficiency of residential multi-storey buildings were identified to enable the installation of large windows in residential and public buildings in the climatic conditions of Ukraine.

Recuperative Heat Exchanger-Utilizer Thermodynamic Modes in Low Capacity Supply-and-Exhaust Ventilation Unit

The increase in the thermal protection level of the existing buildings enclosing structures, due to the need to comply with the current norms of building heat engineering requirements, leads to increasing in the part of heat losses in the thermal balance of a building due to infiltration and exhaust ventilation operation. After exhaustion of the possibilities for the implementation of technical measures to reduce energy costs by changing in volumetric planning solutions and insulating building envelopes further decreasing heat consumption level should be associated with the use of the secondary and renewable resources potential. The paper presents the results of assessing the technical and economic feasibility of using the exhaust air thermal potential for heating the supply air in the forced supply-and-exhaust ventilation system of a building taking as a low-capacity unit as an example. For a counterflow air-to-air recuperative type heat utilizer finned with ribbed heat pipes in the form of a plurality of continuous sheets, the influence of changes in the physical properties of the exhaust air during the phase transition of the water vapor contained in it into a liquid state on the heat exchanger-utilizer performance and characteristics of its efficiency has been established. The conditions of heat exchange are determined (without condensate, with condensate in the part of the heat exchanger-utilizer, with condensate in the entire heat exchanger-utilizer and with the risk of icing) in the supply air temperature range from (–26) to (+8) °C for three variants of its operation with a balance of the nominal amount of exhaust and supply air and with two variants of imbalance. Variants with imbalances have been investigated in order to find possible combinations of supply and exhaust air temperatures, at which there would be no phase transition of water vapor in the exhaust air flow to the liquid state in the entire volume of the heat utilizer, which would eliminate the need for measures to collect and remove condensate and preventing it from freezing.

Experimental Study Of The Interaction Between A Turbulent Flame And A Cooling Air Film

The current experimental study is focused on the analysis of the interactions between a V-shaped lean turbulent premixed methane-air flame and a parietal cooling air film generated by means of a splash-cooling system. The flame structure, the reactive aerodynamics and the wall temperature are simultaneously studied by implementing planar laser-induced fluorescence of the OH radical (OH-PLIF), reactive particle image velocimetry (PIV) and surface intensity-ratio phosphor thermometry (PT). Results show that the mean flow field and the mean flame topology significantly differs according to the level of blowing ratio. Further joint correlations of experimental measurements highlight various FCAI regimes. For blowing ratios below unity, a common flame-wall interaction process occurs and the air film has a limited influence on the flame dynamics. Increasing the blowing ratio enables to establish a cooling air film at the wall. Though it effectively increases the level of thermal protection, it does not have much influence on the flame topology. Eventually, for larger blowing ratios, the flame dynamics is piloted by the shear layer dynamics, associated with strong flow strain. The flame is pushed away from the wall and is located in the outer region of the shear layer. The cooling effectiveness is not improved anymore and shows no more dependencies with the blowing ratio.

The Aero-Thermal Performance of Purge Flow and Discrete Holes Film Cooling of Rotor Blade Platform in Modern High Pressure Gas Turbines: A Review

Design of cooling systems for rotor platforms is critical due to the complex flow field and heat transfer phenomena related to the secondary flow structures originating at the blade leading edge. Horseshoe vortex and passage vortex are the fluid-dynamic features that largely influence the aerodynamic behaviour and the thermal protection level of the platform. The driving parameter is the coolant to mainstream momentum flux ratio, but several issues have to be considered in the design process of cooling technologies. As well acknowledged, an in-depth understanding of losses and heat transfer phenomena are deemed necessary to design effective cooling systems. In the present review, measurements and predictions on the behaviour of the HPT rotor cooled platform, obtained during the last two decades by several research groups, are gathered, described and analysed in terms of aerodynamic losses and heat transfer performance, and are compared with one another with respect to the effectiveness level that is ensured.

Effectiveness Assessment of Energy-Saving System of Organized Supply and Exhaust Ventilation for Multi-Storey Buildings with Low Level Thermal Protection

By usage of the technical and economic calculation method developed by the authors for installations with recuperative-type heat exchangers, the operational modes of the centralized supply and exhaust system of organized ventilation, in which the supplying air is heated by the solar radiation heat and the heat of the air removed from the premises, have been investigated in the paper. The paper presents results of the thermal and economic efficiency assessment of such ventilation system for multi-storey buildings. A comparison of the thermal energy consumption for the needs of heating and ventilation through the use of the proposed ventilation system has been made for two variants of buildings – with the thermal protection level of enclosing structures that meets modern regulatory requirements (buildings with heat consumption up to 130 kW×h/(m2×year)), and for a building similar in terms of planning structure, but with enclosing structures, the insulation level of which corresponds to buildings built before 1993 (buildings with heat consumption up to 260 kW×h/(m2×year)). The temperature conditions have been determined under which it becomes necessary to turn on the operation of devices for additional (peak) heating of the supply air, when the thermal potential of solar radiation and secondary energy resources is insufficient to provide the calculated temperature of the supply air. For the ventilation system under consideration, it has been established that the thermal resistance of the building envelope influences the indicators of the thermodynamic and economic efficiency of the proposed solution. The climatic conditions under which the utilization of the exhaust air heat in the proposed ventilation system is technically justified and economically expedient have been determined. The results of the research

Assessment of heat protection characteristics of building enclosing structures of the building of the men’s monastery

The article presents the results of a thermal imaging study and thermal engineering calculation of the building enclosing structures of the monastery hotel building in the village of Vinnovka, Stavropol district, Samara region. The survey was conducted in order to determine the causes of low temperatures in the hotel premises. According to SP 50.13330.2012 Thermal protection of buildings, energy saving standards in construction do not apply to religious buildings. The level of thermal protection of the above buildings is determined by the provision of modern sanitary and hygienic standards. Based on computer simulation of temperature fields in the outer walls, made in the form of well masonry with the use of polystyrene concrete as insulation, it was found that the value of the reduced resistance to heat transfer they meet regulatory requirements. The actual values of the reduced resistance to heat transfer of the exterior walls, obtained by the results of thermal imaging examination, in the lower part of the exterior walls in individual rooms were significantly lower than the standard ones, which leads to increased heat loss and, as a consequence, to cooling of the indoor air. The reasons for the lowered air temperatures in the hotel premises have been established and recommendations have been developed to eliminate the above-mentioned defects.

Assessing thermal properties of enclosing structures of construction facilities by analysis of thermograms

Objective. One of the most effective ways to assess thermal protection of construction facilities of various applications is thermal control. Methods. According to the national standard “Method for thermal imaging quality control of thermal insulation of enclosing structures” in force on the Russian Federation territory, the results of thermal imaging monitoring of capital and completed construction facilities are divided into qualitative and quantitative depending on set goals and objectives. Qualitative assessment involves computer processing and visual interpretation of thermograms using specialized software. Quantitative analysis of thermograms involves determining and numerically comparing parameters of reference areas and characteristics of defects detected in an object being under thermal control. Results. The paper describes particular characteristics and results of qualitative and quantitative analysis of thermograms (thermal images) obtained via thermography of fragments of external enclosing structures of a completed construction facility—an apartment building. The paper analyses existing methods of a quantitative assessment of thermograms described in regulatory documents and methodological recommendations, and presents specific examples of their application. Conclusion. Thermal imaging diagnostics makes it possible to qualitatively and quantitatively assess the level of thermal protection of the outer shell of an object under control by “decoding” thermograms and comparing calculated parameters with standard indicators.

Analysis of the effect of the estimated temperature difference on the cost of the heating system of an individual residential building

This paper assesses the impact of the temperature potential of the coolant on the expected cost-effectiveness of autonomous heating systems for an individual residential building. The analysis is based on a system of equations that characterize the dependence of the economic criterion - specific costs from the consumption of the heat carrier and the size of the equipment of the water heating system - pipes, heating devices, water boilers, circulating pumps, fittings for facilities located in different climatic zones, taking into account the existing regulatory recommendations on the level of thermal protection of buildings with different volume and planning indicators.

Effects of the positive pre-swirl purge flow on endwall aero-thermal performance of a gas turbine blade

The harsh thermal environments and the complicated near-endwall secondary flows pose great challenges to the thermal management of a blade endwall. To improve the endwall aero-thermal performance, a series of inclined guide fins are mounted inside the interface gap, generating a positive pre-swirl purge flow. The effects of the guide fins' inclined angle on aerodynamic losses, film cooling effectiveness and heat transfer performance of an endwall are investigated under three coolant-to-mainstream mass flow ratios (MFR). Results indicate that the guide fins’ inclined angle exerts significant impacts on the flow-thermal interplay between the secondary flow structures and the coolant ejection. A positive pre-swirl purge flow stimulates the boundary layer fluid to weaken the near-endwall cross flows and thereby significantly reduces the blade aerodynamic losses, especially for MFR >1.0%. More importantly, increasing the inclined angle improves both the effectiveness and coverage of endwall film cooling dramatically when MFR <1.0%, although the cooling performance downstream of the slot exit is lowered when MFR = 1.5%. Besides, increasing the inclined angle marginally enhances the endwall heat transfer level when MFR = 0.5%, but significantly decreases that when MFR >1.0%. Overall, a positive pre-swirl purge flow is beneficial to improve the endwall thermal protection level.

The influence of the climatic features of the construction area on the level of energy-efficient thermal protection of of the office buildings

The choice of the level of the building thermal protection should be based on economic indicators of these buildings, taking into account the cost of maintaining a given room thermal microclimate. However, an economic calculation can only be performed after evaluating the impact of the thermal protection level on the building energy performance. The specific energy consumption of a building is affected by the size of the building, since in the buildings of different lengths and number of storeys, the ratio of ordinary rooms on the intermediate and the upper floors is different, as is the number of ordinary and corner rooms. The purpose of the article is to identify the energy consumption for heating, free and machine cooling of the buildings of various sizes and number of storeys in the areas which differ by the heating period duration and the solar radiation intensity, i.e. in Moscow and in Astrakhan. Three options of the building thermal protection have been considered herewith, differing from each other in the resistance to heat transfer of the outer wall and the coating. The area of the windows made 55% of the facade area. The calculation has been performed for several values of the outdoor air temperature during the year in each city.

The influence of the climatic features of the construction area on the level of economical-efficient thermal protection of the office buildings

Now, the thermal protection of buildings is determined by the assessment of the heat consumption for heating and ventilation of buildings during the cold period, which should not exceed the energy consumption norms chosen by a volitional means. At the same time, the economic indicators of the operation of engineering systems serving the building are not taken into account, and energy costs for maintaining the thermal microclimate in the warm season are not considered. The economic assessment of the thermal protection of a building should take into account the year-round operating costs of maintaining a thermal microclimate in it and the capital costs of the systems themselves and their connection to power supply networks. These costs are in antiphase with the capital costs of building insulation, which increase with the strengthening of thermal protection. Since building insulation is a very expensive part of construction, it is important to determine its economically feasible level, taking into account the cost of all the listed costs in the conditions of the climate of the construction area and territorial economic indicators.

Heat Engineering Heterogeneity Of The Outer Walls Of Earthquake-Resistant Buildings

When assessing the level of energy efficiency of civilian buildings, a special place is given to establishing the level of thermal protection of their external enclosing structures. Significant discrepancies in the results of theoretical and experimental studies of heat fluxes through the outer walls of buildings erected in seismic areas are associated with the design features of fences - the presence of reinforced concrete elements in them: anti-seismic belts at the level of floors, cores at intersections of walls and along the edges of large window openings ... In addition, in recent years, external walls have become widespread, which are filling of bricks or aerated concrete blocks between the main structural elements of the frame - monolithic reinforced concrete columns and crossbars. The introduction of reinforced concrete elements into the structure of the external wall fencing provides strength, rigidity and stability of buildings, guarantees its seismic resistance. At the same time, reinforced concrete inclusions are significant “cold bridges” in warmer brick or aerated concrete masonry. Such heat engineering heterogeneity of earthquake-resistant outer walls significantly complicates the process of determining their heat-shielding properties. This, in turn, leads to errors in the design of heating systems, which inevitably affects the thermal comfort of the premises, the formation of condensation and mold zones in the cold zones of the inner surface of the fences. The article presents the results of theoretical and experimental studies to determine the heat-shielding properties of external heat-engineering heterogeneous walls of earthquake-resistant buildings. The most reliable method for calculating the reduced resistance to heat transfer of an inhomogeneous external structure and the coefficient of its thermal inhomogeneity have been established.

Thermally conductive cost of the heat-insulating materials

The article presents the results of theoretical research to achieve the maximum effect in determination of the economically feasible level of buildings thermal protection. It must be optimal both thermally and economically, an indicator of which there are the costs. Graphical and analytical dependences are given. The research results substantiate the maximum effect when different thermal insulating materials are used. The aim is to increase the efficiency of energy saving measures, reduce their cost by optimizing the cost of thermal energy and insulating materials, determining the optimization criteria and justification for choice the optimal insulating material and its thickness, and determining the optimal thermal resistance, identifying ways to improve energy efficiency and substantiation of the calculation method. One of the most common thermal renovation measures, namely insulation of external walls, is considered. An economic assessment has been conducted, which is an important factor in a certain energy-saving proposition. The solution of the problem is presented, which includes two stages. The result of the first stage is the selection of the optimal heat-insulating material. The second stage is a substantiation of economically expedient thickness of the heatinsulating material. The obtained results make it possible to increase the efficiency of energy saving in thermal renovation of buildings taking into account both energy and economic aspects. In this paper the results of mathematical provement of such factor importance as the thermally conductive cost of the heat-insulating material at their thickness optimization are presented. Determining for the establishment of the normative thermal resistance in the future is the ratio of the cost of thermal energy to the thermal conductivity of the insulating material.

Теплопровідна вартість теплоізоляційних матеріалів

The article presents the results of theoretical research to achieve the maximum effect in determination of the economically feasible level of buildings thermal protection. It must be optimal both thermally and economically, an indicator of which there are the costs. Graphical and analytical dependences are given. The research results substantiate the maximum effect when different thermal insulating materials are used. The aim is to increase the efficiency of energy saving measures, reduce their cost by optimizing the cost of thermal energy and insulating materials, determining the optimization criteria and justification for choice the optimal insulating material and its thickness, and determining the optimal thermal resistance, identifying ways to improve energy efficiency and substantiation of the calculation method. One of the most common thermal renovation measures, namely insulation of external walls, is considered. An economic assessment has been conducted, which is an important factor in a certain energy-saving proposition. The solution of the problem is presented, which includes two stages. The result of the first stage is the selection of the optimal heat-insulating material. The second stage is a substantiation of economically expedient thickness of the heat-insulating material. The obtained results make it possible to increase the efficiency of energy saving in thermal renovation of buildings taking into account both energy and economic aspects. In this paper the results of mathematical provement of such factor importance as the thermally conductive cost of the heat-insulating material at their thickness optimization are presented.