Christian Heschl

• University of Applied Sciences Burgenland

In the realm of building performance optimization, understanding occupancy dynamics is pivotal for enhancing both energy efficiency and occupant comfort. Occupancy forecasts, serving as critical inputs for data-driven predictive control technologies, play a significant role in this domain. To address this need, we propose a novel model that directl...

The dataset provides all necessary variables for data-driven energy modelling of an office room. The measurement data have been obtained from an office building operating as living lab in a temperate climate of Central Europe. The temperatures and the ventilation air flowrate are raw measurements, while the heat flows are calculated from measuremen...

This article presents a measurement dataset from real operation of a hybrid photovoltaic-thermal solar collector. The data is from a summer period, when the collector works at its higher temperature limit, with low thermal efficiency. The dataset characterizes the output of the collector: thermal (heat transfer fluid flowrate, inlet and outlet temp...

Downstream electrostatic precipitators (ESP) represent the state of the art separation technology in medium and large biomass combustion plants. However, these technologies are often difficult to implement in smaller furnaces due to economic aspects and space constraints. This study deals with the integration of ESP systems into the heat exchanger...

Biomassefeuerungsanlagen stehen immer wieder in der Kritik hinsichtlich des Ausstoßes von gas- und partikelförmigen Emissionen. Die Kesselproduzenten haben in den vergangenen Jahren durch konsequente Forschungs- und Entwicklungstätigkeiten die freigesetzten Emissionen bereits deutlich reduzieren können, was u.a. auch durch zertifizierte Abnahmemess...

Standard heat pump (HP) systems with horizontal ground heat exchangers (HGHE) are commonly designed based on empirical knowledge gained over time. Therefore, under-sizing of the HGHE could result, especially if the thermal properties of the ground soil are not carefully considered. In such situations, the HP efficiency decline and remediation measu...

Standard heat pump (HP) systems with horizontal ground heat exchangers (HGHE) are commonly designed based on arbitrary knowledge gained over time and the use of the rule of thumb. Where an undersizing of the HGHE occurs, the HP efficiencies are lowered. Undersizing could result as a consequence of underestimating the soils thermal conductivity. The...

Computational Fluid Dynamics (CFD) is a commonly accepted tool for studying the wind flow over complex terrain and buildings. But an accurate prediction of the flow field implies a cor-rect reproduction of the turbulent quantities and consequently the right choice of the turbu-lence model. Due to the highly dissipative behavior of the RANS based tu...

Heat transfer modelling in indoor environments requires an accurate prediction of the convective heat transfer phenomenon. Because of the lower computational cost and numerical stability, eddy viscosity turbulence models are often used. These models allow modification to turbulent Prandtl number, and near wall correction which influences stagnation...

Air conditioning systems are among the major energy consumers in buildings. Energy-efficient operation of AC systems is an important step towards better energy management in building automation, but requires efficient monitoring of the energy or enthalpy flows within the AC installation, which is currently still difficult because of the lack of app...

For development of ventilation, and surface heating & cooling systems a precise knowledge of room airflow distribution is necessary. This requires an accurate method to describe the fluid dynamics in indoor airflows. In principle Computational Fluid Dynamics (CFD) can be used to solve complex three dimensional flows and heat transport phenomena, ho...

To investigate the relative humidity in indoor environments of residential buildings, an unsteady hybrid simulation model (combination of a finite volume transport model with a node model) was developed. With this model the influence of the moisture storage capacity of different building materials, different air exchange rates and the user behaviou...

Indoor airflow pattern are strongly influenced by turbulent shear and turbulent normal stresses which are responsible for entrainment effects and turbulence-driven secondary motion. Therefore an accurate prediction of room airflows requires reliable modelling of these turbulent quantities. The most basic turbulence models include RANS-based models...

A discussion covers the description of the hydrodynamics of column sieve plates as developed at the computational fluid dynamics "CFD Center" course of study at the Fachhochschule Burgenland GmbH in Austria. Discussion topics include introduction; model description; validation using a rectangular sieve plate; validation using a round sieve plate; a...

Computational Fluid Dynamics (CFD) is a commonly accepted tool for studying the wind flow over complex terrain and buildings. But an accurate prediction of the flow field implies a correct reproduction of the turbulent quantities and consequently the right choice of the turbulence model. Due to the highly dissipative behavior of the RANS based turb...

In buildings very exact thermal conditions are often needed to ensure a high quality production process or comfortable indoor environment. To fulfil these require-ments the accurate prediction of room airflows plays an important part in the design process of ventilation systems. Computational Fluid Dynamics (CFD) is a promising tool in this context...

It is well known that the turbulence anisotropy has a remarkable influence on the flow of three dimensional wall jets. So the accurate simulation of room airflows with air supplies mounted just below the ceiling requires a highlevel turbulence closure. Therefore in this paper the potential for the improvement of room airflow prediction by using dif...

In the past various experimental investigations about room airflows were published. But most investigations are limited regarding measurement positions (restricted flow pattern) and the availability of turbulent quantities (Reynolds-Stresses, entrainment, macroscopic instabilities etc.). Based on the available experimental data a targeted improveme...

It is well-known that the turbulence anisotropy has a remarkable influence on the flow distribution of three dimensional wall jets. So it can be expected that accurate simulations of room airflows with air supplies mounted just below the ceiling demands a higher level turbulence closure. In this paper detailed three dimensional PIV measurement resu...

This paper discusses the capability of different turbulence closure models to predict the remarkable lateral spreading rate of three dimensional wall jets. Based on the equation for the mean streamwise vorticity it can be shown, that the strong lateral spreading rate clearly depends on the anisotropy of the turbulent normal stresses. Therefore it c...

Previous investigations of free jet propagation are usually limited to axialsymmetrical and qasi two-dimensional jets. Multiple jets in the form of nozzle arrays or slot inlets have hardly been subject of systematic investigation. In this article the turbulent mixing processes occuring in this case are discussed with the aid of Computational Fluid...