Thermal Technical Requirements for Wall Materials and Analysis of Thermal Stability of Enclosing Structures under Non-Stationary Heat Flow

Abstract

The article is devoted to the problem of reducing energy consumption in the production of building materials and the operation of buildings by replacing the traditional wall material with more efficient material such as lightweight concrete based on the porous filler of glass granulate (foamed glass granulate concrete) and mineral wool mats, as well as the analysis of the thermal stability of enclosing structures with non-stationary heat flow. Much attention is paid not only to the energy efficiency of systems providing microclimate but also to the efficiency of capital construction, since the development of market relations in the economy has led to a significant increase in the prices for all types of energy carriers. The right shape tuff has been applied in Armenia for the wall material, obtained by sawing mechanically from a rock mass, which in modern construction becomes ineffective, as the thermal technical requirements for building envelopes have become tougher. During the mining of the rock, huge amount of wastes have been accumulated that have valuable properties and can serve as raw materials for obtaining building materials according to energy-saving schemes because of their activity. The issue of disposal of these wastes, which are of great importance both from an economic and environmental point of view, is considered. Given that building materials, products and structures account for 50÷60% of construction costs, the choice of energy-efficient, environmentally friendly building materials will significantly reduce construction costs and lower operating costs. Clinker-free binders have been developed on the basis of cement-free concrete of cellular and conjoint structure using the inherent activity of the rock and by means of energy-saving technologies. In these article thermal technical requirements for enclosing construction in some developed countries and the classification of buildings in terms of energy saving are considered. The ways to improve the energy efficiency of buildings in Armenia are considered taking into account the duration of the heating season with the thermal resistance required ranges from 1.8 to 4.6 (m2oC) /W. In the view of the peculiarities of climatic conditions in Armenia it is not possible to limit only by indicators of thermal resistance, it is necessary to take into account the heat absorption, thermal stability and thermal inertia of materials. Based on the calculations found that in the structure of construction the lowest fluctuation in temperature takes place with mineral wool mat Aτ=0.167°C, and the largest - concrete on foam glass granulate Aτ=0.381 °C, in addition, a change in the temperature of the outside air does not immediately affect the change in temperature on the inner surface of the structures, since there is a time deviation between a concrete on foam-glass granulate which is 7.16 hours and mats on mineral wool - 8.44 hours.