Level Of Thermal Protection Research Articles

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

The choice of the level of thermal protection of administrative agricultural buildings should be based on the economic indicators of these buildings, taking into account the costs of maintaining a given thermal microclimate of the premises. It is concluded that first it is necessary to determine the energy costs for heating, free and machine cooling of buildings of various sizes and number of storeys in areas with different duration of the heating period and the intensity of solar radiation.

Thermal properties of thermal insulation chambers

The paper presents the investigation of thermal properties of thermal insulation chambers as an actuator in intelligent clothing, having the property of automatically adjusting the thermal protection level. The chambers are designed to vary their thickness based on the pressure of the inflated air in them. The pressure value measured in the thermal insulation chamber gives the microcomputer information on the thickness of the chamber. The paper presents the investigation of the functional dependencies of changes in the thickness of the chambers on the air pressure in them and the thermal resistance depending on the thickness of the thermal insulation chamber. Experimental thermal insulation chambers were made and integrated into an intelligent article of clothing and filled with air of 0–50 mbar, whereby chamber thicknesses of 0–25 mm were measured. Next, thermal resistance of 0.1876–0.5022 m2 k/W was measured on the thermal manikin. It was found that the ratio of thermal insulation of non-activated to maximally activated chambers was 1:2.7. Research has shown good results for the area where intelligent clothing can automatically adjust its thermal insulation properties. The technical systems described represent a suitable basis for experiments and scientific research during the introduction of intelligent clothing with active thermal protection into human life. The third-generation prototype shows very good properties from the aspect of automatic control of thermal protection in intelligent clothing. This forms the basis for further research. Cold protection has always been carried out by wearing garments with higher or lower thermal protection as well as wearing multiple layers of clothing. The conceptual starting point of the development of intelligent clothing is the development of an adaptive insulation layer with changeable thickness in the form of thermal insulation chambers filled with air. In this way, layered clothing as well as the use of several clothing layers can be avoided. Thus, one intelligent article of clothing regulating its thermal insulation properties can be used in a wide range of cold weather in the environment of the wearer.

Primary energy consumption for insulating

In this article a mathematical model for thermal protection level analysis is developed. It is based on the consumption rate of primary energy. It allows to calculate the relevant thickness of the selected insulation material under any climatic and economic conditions with any constant layers of building envelope taken from structural considerations. The key factors influencing the model are also evaluated. The main factors to influence the energy model are the region degree-days and the energy consumption rate for the production, transportation and installation of the insulation material. The following results were reached: this approach requires the data, which sometimes has no public access, provides us with an objective assessment criteria when comparing the level of building thermal protection in different countries.

ТЕРМОМОДЕРНІЗАЦІЯ ОГОРОДЖУВАЛЬНИХ КОНСТРУКЦІЙ БУДІВЕЛЬ І СПОРУД

Urgency of the research. It is well known that most of the building envelopes are occupied by external walls, so their influence on the loss of heat by the building is the main one. Therefore, when using facade insulation systems, not only a high rate of thermal conductivity is ensured, but also a normal moisture-resistant mode of structures during operation, and hence comfortable conditions for people to live. As a rule, heat-insulating materials are used for thermal insulation of exterior walling, and in multilayer walling, heat-insulating materials are used as a heat-insulating layer. Target setting. When carrying out construction work, it should be borne in mind that the thermal modernization of buildings is a whole range of works aimed at rationalizing the heat engineering indicators of building envelopes, indicators of energy consumption by engineering systems and ensuring the energy efficiency of buildings at a level not lower than that established by the minimum requirements for energy efficiency. Actualscientific researches and issues analysis. The work reviewed the latest publications on this topic, which are presented in the public domain, including existing regulatory documents. Uninvestigated parts of general matters defining. A significant proportion of the currently existing buildings is characterized by an extremely low level of thermal protection and unacceptably high heat costs to maintain the necessary microclimate parameters. Among the main reasons for the low energy efficiency of buildings, there is a low level of thermal resistance of the main building structures. Therefore, in this scientific work, the task is to provide for a device of heat-reflecting thermal insulation between the heating devices and the outer wall and also the choice of heat-insulating material for building envelopes. The research objective. The purpose of this scientific work is to formulate measures for the modernization of building envelopes of buildings and structures based on a comprehensive analysis of space-planning, structural and engineering solutions, as well as for planning, organizing and conducting energy audits of existing buildings with the development of recommendations for improving the energy efficiency of relevant facilities. The statement of basic materials. The thermal insulation layer can be performed by various methods, depending on the type and density of the thermal insulation products. The geometrical parameters of the 22 building of the CNUT for energy protection of the building were determined, and on their basis the thermal engineering parameters of the building were calculated with the subsequent experimental determination of thermal imaging diagrams and their processing in the software package.

Influence of Solar Radiation Heat Input into Room on Level of Economically-efficient Thermal Protection of Building

Techniques for choosing an energy and economically feasible thermal protection of buildings in the climatic conditions of Moscow are discussed earlier. An important basis of these techniques is that it was possible to identify the thermal parameters on the basis of which the generalization of the basic energy and economic indicators of the building, depending on its thermal protection, was carried out. The methods were tested for buildings whose working day lasts from 9 am to 6 pm with various internal heat generation. In this case, it was believed that solar radiation is completely obscured. From consideration of the effect of heat gains on energy-efficient thermal protection, it was found that with increasing heat gains, the load on heating systems decreases regardless of the level of heat protection, and the load on the room cooling systems increases more with higher thermal protection than with low thermal protection. However, there are buildings of a number of functional purposes in which solar radiation is partially obscured or not obscured at all. These include some commercial, residential and other buildings. Accounting for heat gains from solar radiation, with variable intensity throughout the year, makes significant adjustments to the choice of the level of thermal protection. This is due to the fact that often cooling of the room is required during periods when the outside air temperature is below the maximum allowable temperature of the room. During these periods, enhanced thermal protection is an obstacle to the natural outflow of heat from the premises. Calculations showed that the higher the heat gain from solar radiation, the smaller the proportion of buildings it is energetically feasible to warm according to the basic standards stipulated in SP 50.13330.2012. And although it is not energetically feasible to carry out thermal insulation for sanitary and hygienic requirements, the conclusions about the benefits of building insulation with reduced heat transfer to the walls and coatings of a building are economically significant. It is also important that when identifying an economically feasible thermal protection of a building, it is necessary to take into account all the components of financial expenses that are affected by the thermal protection of a building. The calculations also showed that an increase in the cost of heat and electricity over time changes the thermal performance of buildings for which this or that thermal protection is economically feasible.

The influence of the solar radiation heat input into the room on the level of energy-efficient thermal protection of the building

The task of increasing the energy efficiency of external enclosing structures is often considered as the need to increase their heat transfer resistance. At the same time, the main indicator of this efficiency is the heat consumption reduction for heating of the buildings having high thermal protection. Despite the fact that Russia is a rather cold country with a long heating period in most of its territory, the lack of accounting the cold consumption in warm period of the year leads to wrong understanding by the specialists of the energy expediency of the building thermal protection level. In today’s world, more and more buildings, which have been built, house the civil technologies with high heat emissions, i.e. administrative and office, entertainment, training, shopping and other buildings. These buildings require high energy consumption for cooling, which is often necessary even during the heating period. Taking into account the heat input from the solar radiation with variable intensity throughout the year, the thermal protection level is subject to significant corrections. This is due to the fact that often the cooling of the room is required during the periods when the outdoor temperature is below the maximum allowable room temperature. During these periods, the enhanced thermal protection is an obstacle to the natural heat outflow from the premises. The calculations showed that the higher is the solar radiation heat input, the smaller is the part of energetically feasible buildings according to the basic norms prescribed by the SP 50.13330.2012. And although the sanitary and hygienic requirements show no reasons of the building heat insulation from the energy point of view, the conclusions about the profitability of the building insulation with a reduced basic resistance to heat transfer of walls and coatings of the building are economically significant.

ВЛИЯНИЕ ПРИЧИН ФОРМИРОВАНИЯ ДИНАМИКИ РАСПРОСТРАНЕНИЯ ВЫСОЛОВ ПРИ ВЗАИМОДЕЙСТВИИ ИНФИЛЬТРАЦИОННЫХ И ЭКСФИЛЬТРАЦИОННЫХ ПОТОКОВ НА ТЕПЛОЭФФЕКТИВНОСТЬ ЗДАНИЙ

The article discusses options for technical solutions to increase the level of thermal protection of buildings and reduce the cost of their operation when interacting infiltration and exfiltration flows of moisture in enclosing structures. An analysis of the dynamics of efflorescences in the winter period indicates an increase in chemical processes at the contact of the facing verst and the insulation layer, in which slag accounts for 60-65%. These water soluble salts migrate to the freezing front. However, the reason for the accelerated migration in the winter is the exfiltration of warm moist air through the unsealed joints of the stoned panels during the installation of the stairwell. Also in the parapet, the largest efflorescence is due to the penetration of vaporous moisture through a monolithic reinforced concrete ceiling into the insulation layer, and from there into the brickwork of the parapet. Studies of heat and mass transfer, moisture transfer in various designs have shown that the combination of the interaction of infiltration and exfiltration leads to large heat losses and a deterioration in the thermal regime and indoor microclimate. Thus, the survey results showed that efflorescence is an important indicator of additional heat loss of buildings and structures, and the use of effective heat-insulating materials is not always enough. Errors and defects in the design and construction of structures and natural ventilation systems have a direct effect on reducing the thermal efficiency of exterior fencing.

The increase in energy efficiency of residential buildings of military towns

Most of the residential multi-apartment buildings in use in our country do not meet modern regulatory requirements for the level of thermal protection of external enclosing structures. Such buildings require renovation. The objects of the research are residential buildings of KPD-4570 series, which are a typical series of buildings for military towns. The options for improving the energy efficiency of residential construction with the help of selection of heaters that meet the requirements for thermal protection of buildings are proposed. The method of calculating the discounted payback period for insulation costs is presented.

Energy Efficiency of Buildings for Various Purposes

The construction industry is the largest consumer of material and energy resources. Resource saving makes a great contribution to energy, environmental security and improving the quality of life of the population – the constituent elements of national security. An important part of resource saving is improving the energy efficiency of buildings. The problem of energy efficiency has been relevant for more than fifty years. Energy-efficient buildings must meet the requirements of minimum energy consumption not only at the design stage, but in general throughout the life cycle, which includes the processes of design, construction and installation works, construction control, operation and disposal. Improving of the energy efficiency of buildings is the process of bringing the design of the total reduced costs of external walling and heating of the building to the minimum possible value. The main elements of the operating costs for heating the building are fuel costs. Therefore, the optimization of the level of thermal protection of buildings will not only increase the level of energy efficiency and comfort of civil buildings, but also provide a significant economic effect, the value of which will continuously increase in accordance with the life of the building. The method of optimizing the level of energy efficiency, including thermal protection of buildings for various purposes, should help to improve the balance of wall materials and structures, so that the production of the most cost-effective products continuously increases and, accordingly, the share in the balance of less economical products decreases. As a result of this restructuring of the building materials industry can get a significant economic effect. Thus, there is a link between the level of thermal comfort of civil and industrial buildings and the increase in productivity, the reduction in the number of diseases of workers, the reduction of the corresponding costs of production and health care and, ultimately, the growth of national income.

Thermal Modernization of the Panel Buildings External Walls

The thermal protection level of the first mass series panel buildings (series 111-94) is the lowest among residential buildings in Poltava. The problems of these buildings’ thermal modernization, is consideration of heat-conducting inclusions effect on the reduced resistance to heat transfer. In the studies such heat-conducting inclusions as the panel joints’ design, the window slope and the external wall geometry (the external corner) were taken into account. Studies were performed for the four pattern sections of the outer wall. Panels of two thickness variants with two joint designs were under consideration.To analyze the thermal protection level, the results of the two-dimensional temperature fields’ calculations were used. The analysis of the wall panels’ thermal protection level before the thermal modernization was performed. The magnitude of the heat conducting inclusions effect on reduced resistance of the walling to the heat transfer before and after the thermal modernization is determined. Possible ways of improving the wall panels’ heat-protective properties to the level of the standards in Ukraine are considered. The optimal variant of insulation for each pattern was chosen.

Influence of metal frame on heat protection properties of a polystyrene concrete wall

The use of novel thermal-efficient building materials and technologies that allow increasing the level of thermal protection of external envelope structures and reducing the time for construction are of practical interest and represent a relevant task in the conditions of rapidly changing and increasing requirements to energy efficiency of buildings. This research aims at simulating the process of spatial heat transfer in a multilayer non-uniform structure of an external cast-in-place framed wall produced from polystyrene concrete with a stay-in-place formwork. Based on the physico-mathematical model developed with the use of ANSYS and COMSOL software complexes, parametric analysis of the impact of various factors on thermal behavior of the external wall was performed with the account of heat-stressed frame elements. The nature of temperature fields distribution in a polystyrene concrete structure was defined, and its thermal protection properties were investigated. The impact of a metal frame on thermal protection properties of a wall was found to be insignificant.

Influence of metal frame on heat protection properties of a polystyrene concrete wall

The use of novel thermal-efficient building materials and technologies that allow increasing the level of thermal protection of external envelope structures and reducing the time for construction are of practical interest and represent a relevant task in the conditions of rapidly changing and increasing requirements to energy efficiency of buildings. This research aims at simulating the process of spatial heat transfer in a multilayer non-uniform structure of an external cast-in-place framed wall produced from polystyrene concrete with a stay-in-place formwork. Based on the physico-mathematical model developed with the use of ANSYS and COMSOL software complexes, parametric analysis of the impact of various factors on thermal behavior of the external wall was performed with the account of heat-stressed frame elements. The nature of temperature fields distribution in a polystyrene concrete structure was defined, and its thermal protection properties were investigated. The impact of a metal frame on thermal protection properties of a wall was found to be insignificant.

Economic justification of the choice of the thermal protection of buildings

A large number of factors influence the economically feasible heat transfer resistance of the building enclosing structures. First of all, it is the cost of insulation and heat for the building heating in the cold season. As shown by studies, it is not enough for air-conditioned buildings. The result depends on the mode of the building operation in time and the heat load on the heating and cooling systems. Therefore, in addition to these significant factors of economic feasibility of the thermal protection level, there are the cost of electricity for the production of cold for cooling the building, the cost of the building heating and cooling systems and the cost of connection to power supply networks. The got result is important to convey to the professional community in a clear and compact form. In the present work the buildings of administrative and office purpose are considered, the working day of which lasts from 9-00 to 18-00 hours with different specific heat supply from 0 to 80 W/m2 on the estimated area during working hours. Generalization of the research results is made on the basis of specific heat protection characteristics of the building, which is a product of the overall heat transfer coefficient of the building and the compactness coefficient. The total heat transfer coefficient of the building characterizes the heat losses and the heat inflows to the building through the enclosing structures, and the compactness coefficient can serve as an indicator of the surface area of the building, which is covered with insulation. For these buildings provision has been made for identification of the areas of the total discounted cost combination for all of the above components and the specific heat protection characteristics of the building relating to the feasibility of the specified level of the thermal protection.

Determining temperature ratings for children's sleeping bags

Manufacturers label their sleeping bags with a temperature rating to assist consumers in selecting a bag that will provide them with an acceptable level of thermal protection under the expected conditions of use. These temperature ratings are typically based on thermal manikin testing and whole-body heat loss models. Due to physical and physiological differences between children and adults, existing adult sleeping bag temperature rating models cannot be applied to children's bags. Therefore, a model for determining the temperature ratings of children's sleeping bags is proposed. Issues related to measuring the thermal insulation of children's sleeping bags are also discussed. The results of the model indicate that an older child has a higher temperature rating than a younger child for the same level of insulation. This is due to the higher sleeping metabolic rate of younger children.

EFFECTS OF SOCIAL FACTORS ON A DESIRED LEVEL OF THERMAL PROTECTION OF OUTER WALLS OF RESIDENTIAL BUILDINGS

The requirements to a desired level of thermal protection of outer walls of buildings have been analysed. The relation between such requirements and social factors of a country was shown. Comparison data regarding heat releasing surface area of outer walls and windows and heat losses per person have been received for variable residential density of apartments. The authors have shown international practices and the needs for transition to construction of buildings with a higher level of thermal protection of outer walls. Since cold generation is 3-5 times as expensive as heat generation for many buildings, the transition was made from ventilation of the naturally driven type to controlled and mechanical one providing heat recovery of exhaust air. It was suggested that problem of energy-saving in the sector of construction and housing and communal services could be solved providing a desired life of outer walls and costs of current and major repairs required for projected lifetime of a building.

Study of heat shielding qualities of brick wall angle with additional insulation located on the outside fences

The results of theoretical studies of heat-shielding properties of the angle of external wall a residential building are presented. The brick wall thickness of 510 mm was considered. The studies were performed for the I-st temperature zone of Ukraine. Heat insulation was located on the external side of enclosure. Thermal protection problems of the angle are consideration of the impact of heat-conductive inclusion on adjusted heat transfer resistance of enclosure. Conductive inclusion on the external angle area is its configuration. An additional layer of insulation in the angle area is necessary to use for bringing the level of thermal protection of angle area to the standards. The results of calculations of two-dimensional temperature fields were used for the analysis of thermal protection. Two options for additional insulation were studied. The first option: continuous strip insulation covering the external wall angle. Another one provides division of additional insulation layer into two parts and displacement them from the angle within the design scheme. Studies were performed for different thickness of additional insulation. There was additionally taking into account the value of insulation displacement from the angle for the second option. The optimal location and size of additional insulation were determined. The minimum amount of additional insulation under which the thermal protection requirements are performed was accepted like optimality criterion.

Thermophysical aspects of reconstruction of cold roof spaces

The results of theoretical studies of thermal modernization of cold roof floor. The designs of overlap of long-life roofs of public buildings were considered. Overlap of these buildings are made by wooden or concrete beams and made of concrete slabs with upward edges. The problems of thermal modernization of these designs are consideration of the impact of heat-conducting inclusions on the resistance to heat. The heat-conducting inclusions of constructions are beams and vertical edges of the slabs. The results of calculations of the temperature fields were used for the analysis. The research was carried for the two temperature zones which Ukraine’s territory is divided into. The analysis of thermal protection level of structures overlap was made. The magnitude of the impact of heat-conducting inclusions on resistance to heat after thermal modernization of cold roof floor was observed. The analysis showed that the thermal protection properties of structures less than standard, therefore the insulation of areas with heat-conducting inclusions is required. The options of insulation of these areas were considered. The optimal insulation options with the least amount of additional insulation over the heat conductive areas were selected.

Thermal protection retention of fire protective clothing after repeated flash fire exposure

Fire protective clothing worn by the emergency responders may be exposed to intensive heat condition time and time again during a firefighting work. In this research, the level of thermal protection retained by the fire protective clothing after repeated exposures to flash fire was investigated from bench-scale test to full-scale test. A thermal protective performance tester and an instrumented manikin with a transverse motion system device which was capable of simulating the action of running across the flame were used for the exposure test. Physical properties (mass, thickness, thermal shrinkage, tear strength) and thermal protective property of the test specimens were examined after each exposure. The results showed that repeated heat exposures resulted in continuous decrease of mechanical performance of the fabrics. The thermal protective performance of fabrics with good thermal dimensional stability such as polybenzimidazole/Kevlar and flame resistant cotton decreased after exposure. For the fabrics with severe thermal shrinkage such as Nomex IIIA and polysulfonamide, the thermal protective performance was improved due to the increase of fabric thickness induced by thermal shrinkage. However, this positive effect of thermal shrinkage diminished in the manikin test as it decreased the air gap size between the garment and flame manikin. The thermal protective property of Nomex IIIA garment exhibited continuous decrease after repeated exposures. This study was expected to provide new sights for the performance evaluation and application of fire protective clothing.

Thermal Rehabilitation Technology and the Nearly Zero-Energy Buildings. Romanian Representative Education Buildings-Case Study

Improving energy efficiency of the existing buildings is essential, not only for the achievement of the national objectives of energy efficiency in the medium term, but also to meet long-term objectives of the strategy on climate change and the transition to a competitive economy based on low carbon dioxide emission by 2050. Recognizing the diversity of traditions and current practices in the building sector, the climatic conditions and different methodologies of approach across the EU, EPBD [1] does not establish an uniform methodology for implementing nearly zero energy buildings (nZEB), determining each EU Member State to develop its own definition of nZEB. In addition to the new buildings construction, nZEBs and important energy savings in building sector also can be obtained by retrofitting the existing building stock. Until now, the thermal rehabilitation activity was particularly aimed at collective housing sector for which there are appropriate regulations and technologies. Public buildings, in general, are characterized by certain constructive and functional diversity, requiring a specific approach for each case.The aim of the paper is to study the potential of existing education buildings to become nZEBs, by applying current technologies based on improving the general level of thermal protection.

Ventilation systems with local recirculation diffusers

Improving indoor air quality while simultaneously minimizing the consumption of ventilation and air conditioning systems has received increased attention in recent years (Joo et al. (2012) [1], Le Dreau et al. (2013) [2], Rackes and Waring (2014) [3], Han et al. (2014) [4], Van den Bulck et al. (2013) [5], Ngoc Quang et al. (2013) [6], Naumov and Kapko (2013) [7], Naumov et al. (2013) [8]). The standard thermal protection level of outdoor enclosure structures has increased significantly (Rulebook of the Russian Federation 50.13330.2012 Thermal protection of buildings [9]). In addition, office buildings are characterized by considerable heat emissions during their operation. Using traditional solutions for heating and ventilation in the heating period results in wasted energy: outdoor air is heated to the desired temperature in the air heater of the supply ventilator unit (usually equal to the temperature of the room air); also, the air conditioning system consumes energy to produce cold air to address the internal heat emissions. The heat consumption in ventilation systems can be reduced by recirculation. This article presents a discussion of the advantages and disadvantages of different ventilation systems, including the ventilation scheme with local recirculation diffusers developed by the authors for rooms with considerable heat emissions. Based on the analysis of the life cycle cost, the article presents an assessment of the marginal cost of one local recirculation diffuser for these systems.