Investigation of the possibilities for energy economy in continuous dryers through reduction of the drying time

The possibility for a reduction of the time duration of an industrial drying of ceramic bricks are analysed based on numerical simulation of the transient coupled mass transfer and mechanical processes in the material. The differences between the local mechanical stresses and strength in the dried bodies are computed and used as a criterion for this possibility. Ways for reorganization of the existing process parameters in the dryers to achieve the corrected drying kinetic curve are discussed. The expected effects on the efficiency of the drying installation are evaluated via material and thermal balance

INFLUENCE OF THE COATINGS ON THE THERMAL PERFORMANCE OF INSULATING GLASS UNITS ВЛИЯНИЕ НА ПОКРИТИЯТА ВЪРХУ ТОПЛИННИТЕ ХАРАКТЕРИСТИКИ НА СТЪКЛОПАКЕТИ

Abstract: A mathematical model of 3D conjugated heat transfer at insulating glass units (IGU) is composed and applied for numerical calculations by computational fluid dynamic technique with ANSYS. Temperature field in glass panes and temperature, pressure and velocity fields in gas space are calculated for several variants of flat double glazed IGU: uncoated glass panes; low emissivity coating on inner pane and uncoated outer glass pane, and solar control coating on outer pane and uncoated inner glass pane. The numerical calculations are made for winter and spring conditions in order to validate the models and to analyze the coatings influence on thermal behaviour of IGU

Analysis of the efficiency of an embedded floor heating for snow melting and freeze protection

An algorithm for modelling and numerical simulation of the three dimensional conjugate heat transfer in slab-embedded snow melting and freeze protecting systems is developed. The influence of the climate conditions on the heat transfer in the constructions is modelled according to the correspondent design method of ASHRAE. The models are verified and solved numerically via finite volume method for a road embedded hydronic installation at different piping configurations. The fluid flow parameters and temperature fields in the construction are obtained at steady state climate conditions, hardest for 95 % of the wintertime for the region. An analysis of the efficiency of the modelled configurations is implemented based on the computed snow-free area ratio of the road surfaces

Modelling and numerical simulation of the transport phenomena in water thermal energy storage tanks

Mathematical model for numerical simulation of the transient heat transfer and fluid flows in water thermal energy storage tanks is developed. The model allows analysis of the thermal fields in the accumulators at different schemes and modes of charging and discharging. It was verified and validated based on experimentally obtained information about the temperature stratification at charging of a thermal accumulator at a laboratory solar system. The proposed approach for numerical study of the thermal energy storage is convenient for parametrical estimation and improvement of the efficiency of the thermal systems

Modelling and numerical simulation of fire in a coffee storage hall

An approach for modelling of fire in halls at solid materials burning, based on gas phase combustion models in ANSYS/CFX, is proposed. The models are suitable for quick prediction of the flue gases distribution and thermal loads on the building envelopes at a design stage. They was applied for numerical simulation of such processes in a coffee storage hall at different fire positions and forced anti-smoke ventilation. The thermal, fluid flow and concentration field were obtained at the modelled scenarios. Maximal thermal loads on the building envelopes are established at the case of fire near their non-streamlined parts

THERMAL LOADS AT TRANSPARENT STRUCTURES INTEGRATED IN TROMBE WALLS

This contribution presents thermal load stress analysis of insulating glass units (IGU) integrated in Trombe walls. It is based on modelling and numerical simulation of the heat transfer processes occuring in the construction. The boundary conditions are based on experimental data, obtained from an existing Trombe wall test module, situated at the Technical University of Sofia. The investigations are performed for different cases of IGU fixing in the Trombe wall. The temperature fields and the ensuing thermal stresses in the IGU at winter conditions, obtained from the simulations, are used to analyze the possibility of glass failure due to the internal pressure loads

Cost analysis at different energy sources for heating of an air-supported dome for indoor tennis

Numerical analyses of the energy supply for heating of air supported structure for indoor tennis in Sofia via district heating, gas and liquid fuels are performed. The computational procedures are implemented through thermal balances of the structures, calibrated on the base of in situ measurements of the indoor temperature and the amount of the fuel, consumed at heating of an air supported balloon for tennis in University of Chemical technology and Metallurgy. The profitability of the different heating variants is estimated using the price of the energy and the systems

Modelling and numerical simulation of the heat transfer and natural ventilation in storage halls

An algorithm for modelling of the heat transfer in storage halls at different combinations of open doors and smoke vents is developed. The models allow numerical simulations of velocity, pressure and temperature fields in the halls in cases of transient and steady state conditions, taking into account the indoor buoyancy, heat sources, heat transfer through the building envelopes and outdoor wind pressures. The models are solved numerically via finite volume method in order to estimate the necessity of additional heating at a design stage of a courier logistic storage hall, situated in the temperate climate zone, at the hardest winter conditions of the region. Recommendations about the organization of the heating and the cargo input are done based on the analyses of the fluid flow and thermal fields at the modelled scenarios