Predictive model of the dependence of the cost of insulation on thermal characteristics

In the market of building materials today there is a large selection of various thermal insulation materials, differing in cost, thermal conductivity and other characteristics. This article describes the predictive model of the cost of insulation from thermal characteristics, such as: thickness, thermal conductivity, (average) density, water absorption and combustibility group. The coefficient of determination was used to assess the quality of the obtained economic-mathematical model. The described predictive model can be effectively used to solve problems associated with determining the optimal characteristics of insulation by the criterion of minimizing cost

Energy audit and energy efficiency of modular military towns

The Ministry of Defense of the Russian Federation continues to actively modernize military towns: the bet is placed on prefabricated modular buildings. Such buildings comply with the basic requirement for military installations - mobility. The article presents examples of existing modular military towns, as well as the results of a thermal survey of fencing structures of a modular building to accommodate military personnel

Thermal Properties of Conventional and High-strength Concrete

Important characteristics for the Nordic countries: a freeze-thaw resistance and an ability of a material to keep heat inside the building. This paper aims to define the thermophysical properties of a high-strength concrete, compare the discovered performance with the conventional concrete properties. With this object in mind two experiments in cold chamber “CHALLENGE 250” have been conducted and followed by analysis. In these experiments, the insulation of facades is beyond the framework of the investigation. Only the thermophysical properties of concrete are taken into account. The samples were affected by temperature fluctuations. Results from the experiments show that strength characteristics of a material are in indirect ratio to accumulation properties of a structure. This conclusion is directly related to porosity of material and additives. During 70 minutes, with outside temperature being below zero, the temperature inside the concrete dropped to an average. As the outside temperature increases significantly to more than zero, the temperature inside the concrete has become below average (continued to decline) in 70 minutes. The more strength of material, the better thermophysical properties. High-strength concrete is less susceptible to temperature fluctuations, therefore more heat-resistant. As mentioned in the paper below, the material has one disadvantage: this is a large cost per cubic meter

Feasibility study of the insulation of the enclosing walls of high-rise buildings

On the example of a typical residential multi-apartment building, a feasibility study was carried out on the choice of energy-saving measures for the thermal insulation of facades. The decision to increase the energy efficiency of the building was made on the basis of calculating the loss of thermal energy through the external walls. Based on the parameters of the heating period, capital costs for additional thermal insulation of facades and calculated values of operating costs for heating, the optimum thickness of the additional layer of insulation is determined, in which the payback period assumes a minimum value

Thermal Properties of Conventional and High-strength Concrete

Important characteristics for the Nordic countries: a freeze-thaw resistance and an ability of a material to keep heat inside the building. This paper aims to define the thermophysical properties of a high-strength concrete, compare the discovered performance with the conventional concrete properties. With this object in mind two experiments in cold chamber “CHALLENGE 250” have been conducted and followed by analysis. In these experiments, the insulation of facades is beyond the framework of the investigation. Only the thermophysical properties of concrete are taken into account. The samples were affected by temperature fluctuations. Results from the experiments show that strength characteristics of a material are in indirect ratio to accumulation properties of a structure. This conclusion is directly related to porosity of material and additives. During 70 minutes, with outside temperature being below zero, the temperature inside the concrete dropped to an average. As the outside temperature increases significantly to more than zero, the temperature inside the concrete has become below average (continued to decline) in 70 minutes. The more strength of material, the better thermophysical properties. High-strength concrete is less susceptible to temperature fluctuations, therefore more heat-resistant. As mentioned in the paper below, the material has one disadvantage: this is a large cost per cubic meter

Feasibility study of the insulation of the enclosing walls of high-rise buildings

On the example of a typical residential multi-apartment building, a feasibility study was carried out on the choice of energy-saving measures for the thermal insulation of facades. The decision to increase the energy efficiency of the building was made on the basis of calculating the loss of thermal energy through the external walls. Based on the parameters of the heating period, capital costs for additional thermal insulation of facades and calculated values of operating costs for heating, the optimum thickness of the additional layer of insulation is determined, in which the payback period assumes a minimum value

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

SUBSTANTIATION OF DESIGN MEASURES TO INCREASE ENERGY EFFICIENCY OF EXTERIOR WALLS

Subject: multi-layer building envelope is the subject of the paper. Recently, in the context of energy conservation policies, the heat engineering requirements for enveloping structures of buildings and structures have significantly increased. At the same time, their moisture condition has a significant impact on the operational properties of materials of structures and on microclimate of rooms constrained by these structures. Research objectives: emphasize importance of the task of predicting the temperature and moisture condition of the walling at the stage of design and construction of building envelopes. In this paper, the temperature distributions in layered walls are analyzed. Materials and methods: to achieve the objectives, computational and experimental studies are conducted. By alternating (rearranging) layers and preserving the thermal resistance of the wall on the whole, we find the optimal alternation of layers that minimizes deviation of the maximum wall temperature from the average temperature. Results: for the optimal location of layers in the wall’s structure, the moisture penetration into the wall is minimal or absent altogether. This is possible if the heat-insulating layer is mounted on the outer surface of the structure. Conclusions: the obtained results of computational and experimental studies allow us to verify appropriateness of accounting for alternation of layers in multilayer structures. These calculations proved that the higher the average temperature level, the more energy-efficient the structure will be

Тепловой режим ограждающих конструкций высотных зданий

Предмет исследования: основные потери тепла происходят через оболочку здания. Исследуются ограждающие конструкции с различной теплопроводностью. Проблема накопления влаги в стене достаточно актуальна. Одна из главных проблем в строительстве это экономия на строительных материалах и неправильное проектирование ограждающих конструкций, что в свою очередь приводит к нарушению тепловлажностного режима в стене. Представлен один из методов решения данного вопроса. Цели: описание тепловлажностного режима в стеновом ограждении высотных зданий, анализ зависимости между теплофизическими характеристиками. Материалы и методы: распределение температуры в слоях анализируется на основе структуры, состоящей из 10 слоев; толщина слоя - 0,05 м. Использовались материалы с различной теплопроводностью. Каждый последующий слой отличался по теплопроводности от предыдущего на 0,01. Далее данные слои перестанавливались. Расчет влажностного режима включает нахождение распределения температуры по толщине ограждения при заданной температуре наружного воздуха. Фактором качества распределения температуры является максимальная средняя температура. Данные исследования проводятся в области энергоэффективности. Результаты: чем выше средняя температура стены, тем ниже температура воздуха, она отличается от температуры стенки. Кроме того, чем выше средняя температура стены, тем суше поверхность внутри стены. Однако влага накапливается на поверхности внутри помещения. Работоспособность многослойных ограждающих конструкций определяется температурным распределением и распределением влаги в слоях. Выводы: перемещение влаги через ограждение происходит за счет разности парциальных давлений водяного пара, содержащегося во внутреннем и наружном воздухе. Слой с минимальной теплопроводимостью должен располагаться на внешней поверхности стены в многоэтажном здании. Максимальное изменение амплитуды колебаний температуры наблюдается в слое, прилегающем к поверхности со стороны периодического теплового воздействия. Также учитывается, что процесс теплоусвоения оказывает большое влияние на изменение температур в толще стенового ограждения в наибольшей мере в пределах слоя резких колебаний (наружный слой). Центральная часть стены (несущий слой) будет наиболее сухой. Данным расчетам удовлетворяет конструкция навесного вентилируемого фасада

Numerical study of the low-Reynolds flows in the vertical heated caverns

The object of research is the critical geometry of a three-dimensional air flow in a cavern between two vertical heated plates. In this rate the convection's contribution to heat transfer will be limited due to thermal conductivity at a fixture temperature drop. A three-dimensional RANS approach closed by the k-w SST turbulence model in conjunction with the energy equation. The model validated and verified by comparison with the experimental results. The results of the work applied in developing of ventilated façades