Wyniki wyszukiwania - BazTech

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A Two-dimensional Numerical Model of Heat Exchange in the Soil Massif During the Operation of a Shallow Horizontal Soil Heat Exchanger

Basok Boris, Pavlenko Anatoliy, Nedbailo Oleksandr, Bozhko Ihor, Moroz Maryna

Rocznik Ochrona Środowiska

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2023

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Tom 25

274--281

EN

The current article uses a two-dimensional numerical model to represent the results of theoretical studies of the heat exchange in the soil massif during the operation of a shallow horizontal soil heat exchanger. The analysis of literature sources showed that one of the important conditions for the effective operation of a shallow-soil heat exchange is its rational design parameters, such as the total length of the pipeline, the diameter of the pipe, the distance between the axis of the adjacent pipes, the depth of the heat exchanger placement, etc. A two-dimensional heat exchange model in the soil mass was developed, which made it possible to investigate the operation of a shallow horizontal soil heat exchanger. It was found that the step between the axis of the adjacent pipes of the multi-loop heat exchanger, which is 0.95 m, is optimal when creating a shallow horizontal soil heat exchanger in the soil conditions of Kyiv.

2

Analysis of the Energy Efficiency of the Earth-To-Air Heat Exchanger

Basok Boris, Pavlenko Anatoliy, Nedbailo Aleksandr, Bozhko Ihor, Novitska Maryna, Koshlak Hanna, Tkachenko Myroslav

Rocznik Ochrona Środowiska

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2022

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Tom 24

202--213

EN

This article represents the results of experimental studies of the temperature regime during the long-term operation of the earth-to-air heat exchanger. The average annual, total monthly and daily average specific amounts of heat extracted from the soil or released into the soil mass, respectively, depending on the cold or warm periods of the year, were determined. Analyzing the given data allowed a monthly assessment of the energy efficiency of using the earth-to-air heat exchanger. It is noted that the most significant thermal contribution occurs in the middle of the warm and cold periods of the year when the most significant difference in temperature of the outside air and the soil massif is observed. The use of earth-to-air heat exchangers is one of the necessary tools to lower the energy consumption for modern air-conditioning systems of buildings due to their energy efficiency.

3

Numerical Modeling and Experimental Studies of the Operational Parameters of the Earth-To-Air Heat Exchanger of the Geothermal Ventilation System

Basok Boris, Bozhko Ihor, Novitska Maryna, Nedbailo Aleksandr, Tkachenko Myroslav

Rocznik Ochrona Środowiska

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2021

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Tom 23

42--64

EN

This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.

4

The influence of geometric characteristics of the buildings facades on the heat transfer to the wind flow

Basok Boris, Davydenko Boris, Pavlenko Anatoliy, Novikov Vladimir, Novitska Marina

Journal of New Technologies in Environmental Science

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2021

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Vol. 5, nr 1

11--22

EN

This paper presents the results of a numerical study of heat transfer from the external surfaces of freestanding structures in the surface layer of the atmosphere. Numerical models of structures have the same heat transfer area, but different heights and lengths. Numerical modeling of heat transfer from structures in a wind flow in a three-dimensional formulation made it possible to establish some features of convective heat transfer from enclosing structures, depending on the height of the building and the speed of the wind flow. In particular, it is shown that the dependence of the surface-averaged values of the heat flux density on the height of the building has a local minimum, after which the average heat flux density increases insignificantly with an increase in the height of the building.

5

Generation of pressure oscillations in air flows in vertical channels with internal heat release

Basok Boris, Davydenko Boris, Pavlenko Anatoliy

Journal of New Technologies in Environmental Science

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2021

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Vol. 5, nr 3

106--116

EN

The characteristics of the air flow in a vertical channel, arising due to local internal heat release, are investigated by the method of numerical simulation. Heat is supplied to the flow from internal sources located in a limited volume closer to the inlet section of the channel. The problem of flow and heat transfer is described by a system of unsteady Navier-Stokes and energy equations for a compressible medium. The coefficients of viscosity and thermal conductivity are considered to be temperature dependent. From the numerical solution of this system, the velocity, pressure, and temperature fields in the channel are determined. Based on the results of the calculations, the regularities of the change in time of velocity and pressure in the channel are determined. From the analysis of the results it follows that from the moment the heat supply begins, a vertical air flow develops in the channel, which is accompanied by oscillations in velocity and pressure. Self-oscillations arising in a gas flow are a manifestation of instability of flow. It is shown that stable oscillations take place in the presence of additional local hydraulic resistance in the channel. The dependence of the amplitude and frequency of pressure oscillations and the air flow velocity on the power of the sources of internal heat release and the height of the channel has been investigated. It was determined that with an increase in the power of the source of internal heat supply and the height of the channel, the amplitudes of the velocity and pressure fluctuations increase.