Ferenc Szodrai

• PhD
• associate professor at University of Debrecen

Nowadays computational fluid dynamics now assists ventilation system designers and architects in understanding the induced flow behaviour in the indoor environment. The use of large-eddy simulation is a novel methodology for these types of assessments. The method requires that the computational domain be adequately discretized in order to resolve t...

Buses are large vehicles with the primary goal of carrying as many passengers as possible while maintaining a comfortable interior and an economical driving cycle. With various adjustments, small changes can add up to significant energy savings. This study investigates the issue of whether there is a scenario in which the enormous power demand need...

Almost every scale in thermal engineering requires performance optimization to lessen energy demand. The possibility of using pulsating flow for water cooling was investigated both experimentally and numerically. The experiments were conducted below a 60 mL∙min⁻¹ flow rate and frequencies of 3.3, 4, 5, 6.6, and 10 Hz. The flow rate and temperatures...

Appropriate ventilation may help in the mitigation of airborne transmission of viruses in buildings. Before the COVID-19 pandemic, the ventilation rate was determined depending on the number of occupants, net floor area, and building pollution category. Increasing the ventilation rate, the risk of cross infections may be reduced substantially. Vent...

The drag coefficient is usually considered to be a constant value, which allows us to calculate the aerodynamic losses. However, at lower speeds and wind, this value could be distorted. This also applies to buses in urban environments where due to traffic, the speed is relatively low. Since the schedule of the buses is fixed, based on the driving c...

As a result of COVID-19, many office buildings around the world have downsized their employees, but the comfort parameters in the building had to be kept. The facilities operation rearranged the workstations to keep physical distance and placed plexiglass sheets on the desks for physical protection. A series of measurements have been carried out wi...

In this paper different mechanical ventilation methods were analysed in a test room, having similar dimensions with a small office room. A series of measurements were performed with mixing, displacement and personalized isothermal ventilation having one or two occupants in the room. The main goal of this research was to investigate the air cleaning...

The paper presents 231 thermal transmittance values of a wall structure in function of different meteorological parameters while the indoor surface temperature was kept constant. In the calculations a 2D wall of a nearly zero energy building was examined at the external air temperature, wind speed and solar radiation, in accordance with the Hungari...

In fluid mechanics, drag related problems aim to reduce fuel consumption. This paper is intended to provide guidance for drag reduction applications on cars. The review covers papers from the beginning of 2000 to April 2020 related to drag reduction research for ground vehicles. Research papers were collected from the library of Science Direct, Web...

Vehicle-energetic-models are used to analyze the performances and when a comprehensive structure is established even optimization could be done. For these kinds of models, the losses of the vehicles have to be known. These losses could significantly effect of the vehicle fuel consumption. From these losses the rolling resistance, drive elements and...

A jármű üzemanyag fogyasztását jelentős mértékben befolyásolják a különböző veszteségek, ilyenek a gépjárműben keletkező veszteség (pl. csapágy veszteségek, a hajtásban, hajtóműben keletkező veszteségek stb.), a légellenállás vagy a gumiabroncsok gördülési ellenállása. Fontos tény, hogy üzemanyag-megtakarítást csak az üzem közben létrejövő vesztesé...

Localized air cooling can be used for various purposes, e.g.: electronic equipment cooling, and air conditioning. The paper emphasizes that the connection between the air-flow and cooling has to fulfill a contradictory requirement (low pressure loss and effective cooling). The cooling and the pressure loss are dependent on the moisture content of t...

In heat transfer calculations, transmittance values are often used as a constant in practice. With the spread of dynamic simulations, it opens an opportunity to study the sensitivity of the external effects (e.g., wind speed) on buildings. With the proper amount of result, adequate simplifications can be made to reduce the duration of the simulatio...

Energy saving is one of the most important research directions in the building sector. Personalized ventilation systems are energy conscious solutions providing fresh air for the occupants. As a side effect, cooling energy can be saved due to higher convective heat removal. Using the data gathered from previous experiments performed with the develo...

Traditional power plants still the dominating power source for all the major industries and power demanding facilities, the most crucial facility for the whole plant operations is the industrial boiler which generates steam, heating energy or electrical power. Boilers generate energy by combustion. The improvement of combustion efficiency could gre...

Nowadays the importance of renewable energy is growing, and the utilization of the low wind energy potential is getting crucial. There are turbines with low and high tip speed ratio. Turbines with low tip speed ratio such as the Savonius wind turbine can generate adequate amount of torque at low wind velocities. These types of turbines are also cal...

The laboratory investigations of the heat transfer properties of wall structures are very significant from the point of view of designing the buildings. In this article measurements and calculations will be presented in order to manifest the effect of the forced and un-forced convection of air at the cold surface of the wall. A steady-state method...

Cikkünkben a kis sebességű szélcsatornával foglalkoztunk. Célunk az volt, hogy létrehozzunk egy olyan nyitott rendszerű szívott légcsatornát, melynek segítségével a későbbiekben méréseket végezhessünk. Ehhez szükséges volt a szélcsatorna prototípusának megalkotása és kalibrációs mérések elvégzése, hogy a mérőtérben uralkodó áramlásviszonyokat felté...

Buildings in Europe, account for about 20–40% of total final energy consumption. Therefore reduction of energy demand is crucial. It has become one of the most important issues to achieve energy saving at installations and refurbishments of buildings. Humidity in the wall structure of buildings produced by precipitate and other circumstances could...

During the thermal assessment of buildings, proper understanding and knowledge of the thermal behavior of the materials is required. Certain indoor and outdoor conditions can cause moisture transfer and could change the thermal properties of buildings (e.g. thermal conductivity, resistance, thermal diffusivity, specific heat capacity, etc.). In thi...

Nowadays, energy saving as well as energy-conscious design and refurbishments of buildings became the most important actions to be achieved worldwide. The energy performance of a building can be considerably affected by climate. The significance of a ‘design with climate’ approach is highlighted in this paper. The article investigates the impact of...

Napjainkban egyre nagyobb figyelmet kell fordítanunk a megújuló energiaforrásokkal történő villamos energiatermelésre. A napelemes rendszer számos előnnyel rendelkezik. Viszont a rendszerek teljesítménye külső hatásra drasztikusan lecsökkenhet. Ezek elkerülése végett egy konkrét épület segítségével bemutatjuk a TIGO teljesítmény optimalizáló rendsz...

Vizsgálatunk célja olyan szélerőmű rendszer kidolgozása volt, mely képes városi környezetben is működni, olyan kevésbé kedvező szélrajzzal rendelkező területeken is, mint az alföldi városok. A javasolt rendszer a csőben áramló közegek tulajdonságait használja ki, miáltal képes jelentős teljesítménytöbbletet elérni kis szélsebesség esetén is a hagyo...

Ebben a cikkben be szeretnénk mutatni, hogy Magyarország és vele két szomszédos ország (Románia és Horvátország) fővárosainak éghajlati adatai mennyire befolyásolják ugyan-azon épület fűtési energiaszükségletét, amellett, hogy a külső homlokzatát még nedvesség (magas párataralom, csapóeső) is terheli. A vizsgálatainkat egy hipotetikus, szokványos p...

Recently, it has become extremely important to reduce the heating energy demand and the CO2 emission of buildings. This reduction can easily be achieved by insulating the shell of buildings. By thermal insulation not only the heating energy demand can be reduced but also higher thermal efficiency can be reached. Therefore, measurements, calculation...

Currently, thermal insulation of buildings is required from both an energy savings perspective and a money savings perspective. Insulation is primarily installed on the outer surface of the buildings. Weather and other circumstances can produce humidity that can act on the building structure, e.g., by changing its heat capacity, the heat transfer c...

Currently thermal insulating of the buildings is sorely needed from the point of view of energy as well as money savings. Isolations are mostly installed on the outer surface of the buildings. Weather and other circumstances can produce humidity that can affect the building structure by changing its heat capacity and heat transfer value and other f...