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Rixrath D.,Forschung Burgenland GmbH | Wartha C.,Burgenland University of Applied Sciences
Integrated Environmental Assessment and Management | Year: 2016

The Renewable Energy and Efficiency Action (REACT) project is a European Union–funded cross-border cooperative venture featuring the participation of companies and researchers from the Austrian state of Burgenland and western Slovakia that is developing zero-energy concepts for newly built single-family homes. A variety of building structures are defined for family houses, and the different impacts they have on the environment are evaluated over the entire life cycle. This paper aims to compare the environmental impacts of different building shells during both the construction and the demolition phases. However, the operation phase of the building is not evaluated. One of the findings of the project thus far is that the demolition and disposal of building materials should be included in any such evaluation. For some environmental impact assessment categories, both demolition and disposal are important. The environmental impacts of various end-of-life scenarios can differ greatly based on the disposal method (e.g., landfill, incineration, recycling) chosen and on the proportion of recycled content. Furthermore, the results show that manufacturing building materials from renewable resources can have strong environmental impacts, particularly when substantial amounts of fossil fuel are required in their production. Integr Environ Assess Manag 2016;12:437–444. © 2016 SETAC. © 2016 SETAC

Heschl C.,Burgenland University of Applied Sciences | Inthavong K.,RMIT University | Sanz W.,University of Graz | Tu J.,RMIT University
Indoor Air | Year: 2014

Indoor airflow pattern is strongly influenced by turbulent shear and turbulent normal stresses that are responsible for entrainment effects and turbulence-driven secondary motion. Therefore, an accurate prediction of room airflows requires reliable modeling of these turbulent quantities. The most widely used turbulence models include RANS-based models that provide quick solutions but are known to fail in turbulent free shear and wall-affected flows. In order to cope with this deficiency, this study presents a nonlinear k-ε turbulence model and evaluates it along with linear k-ε models for an indoor isothermal linear diffuser jet flow measured in two model rooms using PIV. The results show that the flow contains a free jet near the inlet region and a wall-affected region downstream where the jet is pushed toward the ceiling by entrainment through the well-known Coanda effect. The CFD results show that an accurate prediction of the entrainment process is very important and that the nonlinear eddy viscosity model is able to predict the turbulence-driven secondary motions. Furthermore, turbulence models that are calibrated for high Reynolds free shear layer flows were not able to reproduce the measured velocity distributions, and it is suggested that the model constants of turbulence models should be adjusted before they are used for room airflow simulations. © 2013 John Wiley & Sons A/S.

Puchegger M.,Burgenland University of Applied Sciences
Energy and Buildings | Year: 2015

Due to the rising use of fluctuating renewable energy production, electricity production curve in the future will not be able to follow the demand curve anymore. Therefore, time-critical, variable charges are likely to be introduced. Whereas large consumers of electricity already have to pay attention to this issue - the peak demand is measured and cost effective for customers with a consumption higher than 100,000. kW. h or connection power more than 50. kW [1] - the topic will become relevant for other customers in the future. Due to the roll-out of smart metres, it is very likely that time-relevant tariffs will become standard for all kinds of users, which means that the moment of electricity consumption will be cost-relevant. This paper deals with the electric load behaviour of office buildings and their potential to use demand side management (DSM) to optimise load behaviour. Because of use during the day, when prices are usually higher than during the night, office buildings mainly demand electrical energy during periods of high prices. By identification and utilisation of DSM potential, considerable sections of the demand can be shifted to hours with lower prices. Concerning integration of photovoltaic systems, two aspects has to be taken into account. When PV is an additional option to reduce electrical energy demand during high prices, on-site produced electricity should be also used on-site and therefore it has to be assured, that demand does not fall below PV-production. Another possibility to shift loads is to use thermal or electrochemical storage systems. © 2015 Elsevier B.V.

Inthavong K.,RMIT University | Tu J.,RMIT University | Heschl C.,Burgenland University of Applied Sciences
Computers and Fluids | Year: 2011

Commercial 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. © 2011.

Heschl C.,Burgenland University of Applied Sciences | Inthavong K.,RMIT University | Sanz W.,University of Graz | Tu J.,RMIT University
Computers and Fluids | Year: 2013

Flow patterns produced by linear diffusers are highly dependent on the turbulent momentum exchange process. Hence a realistic computation of indoor room airflows that are produced from plane wall and free jets requires an accurate prediction of the anisotropic turbulent stresses. This is particularly the case in regions near the wall and entrainment effects which are caused by the turbulent shear stresses. For this reason a non-linear eddy viscosity assumption is presented which can be adjusted to account for the turbulent mixing process in the free shear flow region, and to reproduce the redistribution of the turbulent normal stresses near the wall. Based on several test cases such as a free and plane wall jet, IEA (International Energy Agency) Annex 20 room airflow, and a 3D room with a partition, the essential characteristics of the linear and non-linear k-ε, k-ω and ν2-f turbulence models are analysed. Thereby it is shown that the proposed non-linear assumption can improve the prediction of linear diffuser airflows. © 2012 Elsevier Ltd.

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