ventilation

The paper investigates the dynamics of air flows in the cabin of a low-entry city bus to improve passenger comfort and energy efficiency. The modeling was performed by CFD analysis in Ansys Fluent using the Mercedes-Benz Citaro Hybrid cabin model. Under winter conditions (flow inlet temperature - 27°C, bus body walls - 0°C), the maximum flow velocity reached 3.69 m/s in the doorway area, while insufficient ventilation was found in the front and rear parts of the cabin (velocity <0.8 m/s).

The article is devoted to solving the urgent problem of increasing the efficiency of linking sections in the hydraulic calculation of pipeline systems to reduce the material and energy consumption of the system as a whole. The aim of the work is to create an effective method of hydraulic linking of sections of pipelines of microclimate support systems, namely the "two-diameter method" and the establishment of analytical calculations, provided that a meager percentage of the inconsistency of parallel sections.

The article presents the results of theoretical and experimental developments regarding the marking of scans and patterns of fittings of the ventilation system, provided that the unification of installation and procurement work.

The issue of the normative air exchange ensuring in the premises of the boiler houses is extremely important. The article presents the results of theoretical and experimental studies of air velocity determination in the distribution of air by round and compact jets in the boiler room. Graphical and analytical dependences are given. The research results substantiate the higher accuracy of the average air flow velocity determination in small boiler rooms.

In this article the results of return flow at air distribution by flat laying jets experimental investigations are presented. The chart is composed, analytic equations are also obtained. By these results high efficiency of proposed air distribution scheme using in technological small-sized rooms is shown.

At present, the problem of energy efficiency remains extremely important. Modern building technologies allow you to create houses with the minimum power consumption, using energy efficient external protections, including plastic windows. This leads to a reduction in the heat loss of the room, but there is a danger of reducing the required air exchange.

In low-energy and passive houses, about 80 % of the total energy is consumed for fresh air heating or cooling, the reason being the improved thermal insulation and air tightness of such a building. In fact, actual trend of building construction is to keep the windows closed. A similar situation is already encountered in some means of transportation, i. e. air-conditioned trains. Ventilation of the passenger space is assured mainly by a mechanical ventilation and, when the train stops, by a natural ventilation through door opening.

Replacement of old wooden windows in a new plastic windows, in the old buildings, we achieve the massive reducing heat loss of the building. New windows are characterized by better tightness. The question is, how much more are reduce the uncontrolled ventilation. In the article is presented the experimental measurement indoor air quality in the room in two phases. In the first phase is in the room installed 55 year old wood window. In the second phase is in the same room installed new plastic window.

A purpose of this submission is a dynamic analysis of indoor environment on the suitably chosen classrooms, which are situated in the loft spaces of Civil Engineering Faculty in Kosice. The evaluation was doing by using energy simulation tool and is oriented on evaluation of heat load during summer period. The subject of analysis is to consider influence of selected mode of natural and mechanical ventilation on a modification of operative temperature in classrooms.

The aim of the article is to establish the necessary air exchange rate in the room at the principal production carbon dioxide calculation and experiment. In order to determine the necessary volume the air flow was made more experimental measurements in selected rooms. From the measured data of concentration CO2 by combination of graphic method and mathematical formulas we can determinate the required air flow which meets the hygiene requirements. The entire computation we can see on the example.