Identification of basic thermal technical characteristics of building materials

summary:Modelling of building heat transfer needs two basic material characteristics: heat conduction factor and thermal capacity. Under some simplifications these two factors can be determined from a rather simple equipment, generating heat from one of two aluminium plates into the material sample and recording temperature on the contacts between the sample and the plates. However, the numerical evaluation of both characteristics leads to a non-trivial optimization problem. This article suggests an efficient numerical algorithm for its solution, based on the weak formulation of certain initial and boundary problem for the heat transfer equation, on the classical Fourier analysis and on the Newton iterative method, and demonstrates its practical application

The Physical Properties Of Cementitious Composites For Applications In A High-Temperature Energy Storage Device

The article was focused on experimental verification of the identification of thermal characteristics of high-performance cementitious composites at elevated temperatures. The purpose of the research was to verify the properties, and consequently the suitability of these special cement composites for the production of a heat storage device for the long-term accumulation of thermal energy. The theoretical prerequisites for the identification of thermal characteristics and the practical procedure of experimental verification of the characteristics were presented. A modified procedure for the determination of temperature conductivity by the hot wire method was suggested. Subsequently, the experimental verification and the results of the measured thermal characteristics were listed – and the temperature conductivity , the thermal conductivity [w/m.K], the volumetric heat capacity and the specific heat capacity c [J/kg.K] by the modified method were determined

Effect of Microwave Radiation on the Compressive Strength of Solid Ceramic Brick

Microwave radiation is widely utilized in construction practice, especially for drying building materials, remediating damp masonry, or sterilization of biotic pests that have infested building structures. The available scientific and technical literature reports that certain materials exposed to microwave radiation do not change their physical and mechanical properties, although this has not yet been adequately verified. This paper builds on many years of research in the area, adding to and refining existing information, providing new insights into the mechanical and physical properties of commonly available building materials that have been exposed to controlled microwave radiation, and comparing them with reference values. The experimental research on a set of clay brick samples is carried out using tests according to European standards, and it focuses on the effect of microwave radiation on compressive strength and water absorption. The experimental samples were compared to reference samples that had not been subjected to prolonged exposure to moisture and were subsequently treated with microwave radiation for dehumidification

Tepelné toky ve vybraném objektu zemědělskopotravinářského komplexu

The thesis is focused on the energy demands of storage objects with low controlled indoor operating temperature maintained at a constant value with year-round operation. Heat processes in freezer and refrigerator buildings are performed irregularly, heat losses by heat dissipation through the surrounding envelope, air exchange, lighting, service personnel, transportation technology, latent heat from the air, The simulation program SIM_Stabil is used for modeling of non-stationary heat flows and it can be used for evaluation of the building object in the annual energy consumption parameter needed to ensure the internal low controlled temperature, covering heat losses through all envelope structures in sunlight, lighting, handling, ventilation, etc. It serves as a benchmark for comparison with real energy consumption in an object

Identification of basic thermal technical characteristics of building materials

summary:Modelling of building heat transfer needs two basic material characteristics: heat conduction factor and thermal capacity. Under some simplifications these two factors can be determined from a rather simple equipment, generating heat from one of two aluminium plates into the material sample and recording temperature on the contacts between the sample and the plates. However, the numerical evaluation of both characteristics leads to a non-trivial optimization problem. This article suggests an efficient numerical algorithm for its solution, based on the weak formulation of certain initial and boundary problem for the heat transfer equation, on the classical Fourier analysis and on the Newton iterative method, and demonstrates its practical application

Possibilities of Using Microwave Radiation to Accelerate the Solidification of Mixtures Consisting of a Polymer Matrix Binder and a Waste Thermal Insulation Filler

The presented work deals with the possibility of using the action of microwave energy on fresh mixtures consisting of a filler from waste thermal insulation expanded polystyrene and a binder from a polymer mixture to accelerate the time required for the mixture to solidify. The influence of microwave exposure time on thermal engineering material properties of mixtures was experimentally tested

The Effect of a Green Roof vs. a Conventional Flat Roof on Thermal Stability of a Building

The presented work deals with assessing the influence of a green roof on the temperature course in individual rooms of a timber structure by the so-called dynamic numerical modelling method, which is based on the principle of non-stationary differential Schmidt method. Climatic data from the meteorological station at Brno Tuřany airport were used as boundary conditions for the calculation

Effect of Microwave Radiation on the Compressive Strength of Solid Ceramic Brick

Microwave radiation is widely utilized in construction practice, especially for drying building materials, remediating damp masonry, or sterilization of biotic pests that have infested building structures. The available scientific and technical literature reports that certain materials exposed to microwave radiation do not change their physical and mechanical properties, although this has not yet been adequately verified. This paper builds on many years of research in the area, adding to and refining existing information, providing new insights into the mechanical and physical properties of commonly available building materials that have been exposed to controlled microwave radiation, and comparing them with reference values. The experimental research on a set of clay brick samples is carried out using tests according to European standards, and it focuses on the effect of microwave radiation on compressive strength and water absorption. The experimental samples were compared to reference samples that had not been subjected to prolonged exposure to moisture and were subsequently treated with microwave radiation for dehumidification