The paper illustrates the basic methodology and principal problems of CFD (Computational Fluid Dynamics) approach in designing a proper cooling system (capacity of cooling, determination of optimal position, number and size of openings for cooling, etc.) in special purpose objects. Taking as an example the design of the cooling for electrical equipment placed in a container of crane MK-46-"GOSA FOM", the problem of the selection of proper cooling system was demonstrated. It has been shown that the numerical fluid dynamics represents a superior approach to the design of these systems., with its ability to, provide precise three-dimensional images of velocity and temperature field in the fluid even before the construction of the facility, as well as to predict the changes of those fields that would appear with modification of geometry, boundary and spatial conditions (opening for injection and exhausting of air, position of the walls and obstacles).

A large number of producers offer a wide choice of various types of industrial cooling towers. Usually, a proper choice of pre-fabricated cooling tower satisfies end-user needs. However, if there are specific end-user requirements, it is necessary to design cooling tower according to those requirements. For the adhesive factory located in southern region of Serbia, 350 kW mechanical draught wet cooling tower was designed and built. Dimensioning of the cooling tower was done according to parameters of the ambient air, higher than the standard recommendations given in the literature. In this paper, the reasons for deviation from recommendations are given. The analysis of the cooling tower operation based on real meteorological parameters for 2015 is also shown in this paper. According to this analysis, cooling tower provides required water temperature in any season, and gives opportunity for energy savings in winter, with opportunity for heat capacity enlargement if production capacity is raised as it is planned in the factory.

The purpose of thermal comfort is to specify the combinations of indoor space environment and personal factors that will produce thermal environment conditions acceptable to 80% or more of the occupants within a space. Naturally ventilated indoors has a very complex air movement, which depends on numerous variables such as: outdoor interaction, intensity of infiltration, the number of openings, the thermal inertia of walls, occupant behaviors, etc. The most important mechanism for naturally ventilated indoors is the intensity of infiltration and thermal buoyancy mechanism. In this study the objective was to determine indicators of thermal comfort for children, by the CFD model based on experimental measurements with modification on turbulent and radiant heat transfer mathematical model. The case study was selected on school children of 8 and 9 years in "France Presern" primary school in Belgrade. The purpose was to evaluate the relationships between the indoor environment and the subjective responses. Also there was analysis of infiltration and stack effect based on meteorological data on site. The main parameters that were investigated are: operative temperature, radiant temperature, concentration of CO 2 , and air velocity. The new correction of turbulence and radiative heat transfer models has been validated by comparison with experimental data using additional statistical indicators. It was found that both turbulence model correct and the new radiative model of nontransparent media have a significant influence on CFD data set accuracy.

This paper presents experimental verification of the accuracy and acceptability ofFaxen-Rydberg-Huber analytical expression for determining thermal characteristics of the heating panels. The verification of accuracy of the Faxen-Rydberg--Huber expression, which describes the 2-D temperature field in the wall with series of embedded heated pipes having uniform temperature, was performed by comparing the temperatures on the surface of three types of heating wall panels, differing in structure and geometric characteristics. The analysis of results has shown high accuracy of Faxen-Rydberg-Huber expression in describing the temperature field. Also, it was noted that small changes in heating fluid temperature, occurring along the pipe in the heated panel, have a negligible influence on the accuracy of prediction by the expression. This confirmed that the Faxen-Rydberg-Huber expression can be used to describe the temperature field in the wall heating panels. At the same time, this expression has proven to be extremely sensitive primarily to thermophysical characteristics of the panel layers, as well as to the geometric parameters of the panels.

Optimal design of a borehole heat exchanger, as the outer part of a ground source heat pump heating system, requires information on the thermal properties of the soil. Those data, the effective thermal conductivity of the soil λeff and the average temperature of the soil T0, enable us to determine the necessary number and depth of boreholes. The determination of thermal conductivity of the soil in laboratory experiments does not usually coincide with the data under in-situ conditions. Therefore, an in-situ method of experimental determination of these parameters, the so-called thermal response test, is presented in this paper. In addition to the description of the experimental procedure and installation overview, the paper describes methods based on theory and presents their basic limitations, through the presentation of experimental data. [Acknowledgment. This paper is made in a scope of the project TR 33047 “Intelligent climate control systems to achieve energy efficient regime in the complex conditions of exploitation” funded by the Ministry of Education and Science of the Republic of Serbia.