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Heschl, Christian
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Official Name
Heschl, Christian
Alternative Name
Heschl, C
Main Affiliation
Akademische Titel
Prof.(FH) Dipl.-Ing. (FH) Dr.
Email
christian.heschl@fh-burgenland.at
Scopus Author ID
50161591800
Status
staff
Research Outputs
Now showing 1 - 10 of 13
- PublicationImproving predictions of heat transfer in indoor environments with eddy viscosity turbulence modelsHeat 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 points, entrainment, and velocity and time scales. A modified v 2–f model was made to correct the entrainment behaviour in the near wall and at the stagnation point. This new model was evaluated on six cases involving free and forced convection and room airflow scenarios and compared with the standard k–ε, and k–ω–SST models. The results showed that the modification to the v 2–f model provided better predictions of the buoyant heat transfer flows while the standard k–ε failed to reproduce and underestimate the convective heat transfer. The k–ω–SST model was able to predict the flow field well only for a 2D square cavity room, and 3D partitioned room case, while it was poor for the other four cases.
156 1Scopus© Citations 2 - PublicationMeasurement data from real operation of a hybrid photovoltaic-thermal solar collectors, used for the development of a data-driven model(2023)
; ; ; 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 temperatures) and electrical (raw current and voltage, Hampel filtered power). Further information on the collector are the PV cell temperature and the back surface temperature (in three points). It provides detailed weather information: ambient temperature, solar resource (direct normal, global and diffuse horizontal, global tilted in the collector plane), equivalent radiative sky temperature (calculated from a pyrgeometer), wind speed and direction both horizontal and in the tilted collector plane. The calculated sun position with Duffie and Beckmann method is also given (elevation and azimuth) . The dataset covers 58 summer days from 11th July to 6th September, with a 5 second time step. The data is available as .mat file (MATLAB) and .csv file. A selection of variables from this dataset has already been used in the development of a data-driven model (see related article) [1]. The extended data presented in this article offers mode detailed weather information, opening further investigations opportunities. Further options for data-driven modelling of PVT collectors could be investigated. The correlation of wind related losses to horizontal wind measurements could be compared to a model with wind measurements in the collector plane. The dataset could support the validation of solar models, with direct and diffuse shares on the horizontal or in the tilted plane. [Duck Duck Go](https://duckduckgo.com)67 611 - Publication
20 2Scopus© Citations 1 - PublicationModeling of solar radiation transmission through triple glazing based only on on-site measurements(2020)
; A model is developed which can calculate the irradiance behind a glazed façade, based on measured incident solar radiation. Data from a real office building is used to establish and test the model. Onsite irradiance measurements on both sides of the facades are exploited to calibrate the model. The main parameters are the average diffuse transmittance and a correlation for the direct transmittance, as a function of the incidence angle. Correction of the measurements, including the frame reflection, are taken into account. Hence, the model contributes to the solar heat flux identification, in the perspective of model predictive control application.25 148 - Publication
223 29911Scopus© Citations 8 - PublicationMonitoring data from an office room in a real operating building, suitable for state-space energy modelling(2024)
; ; ; 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 measurements. The incoming solar irradiance is calculated with two façade models –simple and enhanced–, using measurements (solar irradiance, movable shading settings) and building characteristics (geometry, glazing and shading properties). One year and four months of data is provided with a fine one-minute time step and a coarser fifteen-minute time step. The dataset can be used to test and validate data-driven models, for example for predictive control applications.14 179 - PublicationMicron particle deposition in the nasal cavity using the v2–f modelCommercial CFD codes are commonly used to simulate models that involve complicated geometries such as the human nasal cavity. This means that the user has to work within the limitations of the available models of the CFD code. One such issue is the turbulent dispersion of particles in the Lagrangian reference, namely the Discrete Random Walk (DRW) model which overpredicts the deposition of smaller inertial particles, due to its inherent isotropic treatment of the normal to the wall fluctuation, v′ , in the near wall region. DNS data for channel flows has been used to create a function that reduces the turbulent kinetic energy (TKE) to match the v′ profile which has delivered improved particle deposition efficiency results. This paper presents an alternative approach to reduce the TKE to match v′ , by directly taking the profile from the v2–f turbulence model. The approach is validated against experimental pipe flow for a 90° bend and then applied to particle dispersion in a human nasal cavity using Ansys-Fluent which showed improved results compared to no modification.
137 1Scopus© Citations 34 - PublicationTowards distributed enthalpy measurement in large-scale air conditioning systems(IEEE, 2015)
; 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 appropriate equipment. This paper introduces a distributed data acquisition system for large-scale AC systems based on low-cost flow sensors implemented by means of standard printed circuit board technology and interconnected via a wireless sensor network. A critical issue for the system installation is the placement of the sensors in the air ducts to obtain representative measurements of the air flow. To this end, extensive aerodynamical simulations are carried out to analyze the flow distributions in typical building blocks for air ducts, particularly with respect to turbulences. The simulation results are compared with experimental data from the literature and are shown to be reliable.145 1Scopus© Citations 7 - Publication
42 1252Scopus© Citations 2