56,095 research outputs found
Beitrag zur modellbasierten Ueberwachung und Optimierung des Betriebes heiz-und raumlufttechnischer Anlagen
No full textThe present paper reports on the operation control and detection of operating errors of heating and air-conditioning plants. It presents simulation models which serve to design model-based operation monitoring systems. The paper is divided into the following sections: Overview of the literature; simulation models; concept for model-based operation monitoring and control; simulation example. (HW)Die Arbeit berichtet ueber die Betriebsfuehrung und das Erkennen von Betriebsfehlern bei Heiz- und Raum-Lufttechnischen Anlagen. Es werden Simulationsmodelle aufgestellt, die eine modellbasierte Betriebsueberwachung gestaltet. Aufteilung der Arbeit: - Literaturuebersicht - Simulationsmodelle -Konzept zur modelbasierten Betriebsbegleitung - Simulationsbeispiel. (HW)SIGLEAvailable from TIB Hannover: RR 6940(1) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Kinderleicht sind Siemens-Gaskoch-, Brat-, Back-, Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien, IX.
No full textKINDERLEICHT SIND SIEMENS-GASKOCH-, BRAT-, BACK-, HEIZ- U. BADEAPPARATE ZU BEDIENEN, FRIEDR. SIEMENS, WIEN, IX.
Kinderleicht sind Siemens-Gaskoch-, Brat-, Back-, Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien, IX. ( -
Kinderleicht sind Siemens- Gaskoch-, Brat-, Back- Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien IX.
No full textKINDERLEICHT SIND SIEMENS- GASKOCH-, BRAT-, BACK- HEIZ- U. BADEAPPARATE ZU BEDIENEN, FRIEDR. SIEMENS, WIEN IX.
Kinderleicht sind Siemens- Gaskoch-, Brat-, Back- Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien IX. ( -
Kinderleicht sind Siemens Gaskoch-, Brat-, Back-, Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien IX
No full textKINDERLEICHT SIND SIEMENS GASKOCH-, BRAT-, BACK-, HEIZ- U. BADEAPPARATE ZU BEDIENEN, FRIEDR. SIEMENS, WIEN IX
Kinderleicht sind Siemens Gaskoch-, Brat-, Back-, Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien IX ( -
Kinderleicht sind Siemens Gaskoch-, Brat-, Back- Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien IX/2
No full textKINDERLEICHT SIND SIEMENS GASKOCH-, BRAT-, BACK- HEIZ- U. BADEAPPARATE ZU BEDIENEN, FRIEDR. SIEMENS, WIEN IX/2
Kinderleicht sind Siemens Gaskoch-, Brat-, Back- Heiz- u. Badeapparate zu bedienen, Friedr. Siemens, Wien IX/2 ( -
Entwicklung einer allgemeinen Bewertungsmethode fuer Heiz- und Trinkwassererwaermungssysteme am Beispiel einer Wohnung in einem Mehrfamilienhaus
No full textBuilding energy efficient houses results in new boundary conditions for heating systems. Therefore new heating systems need to be developed especially for flats and residential buildings where small heating systems are used. In publications on energy efficient housing experiments there are no criteria to be found which lead to the decision on the installation of specific heating systems. There exists also no recognizable optimally suitable system. This thesis introduces a procedure not only for energy evaluation but also for multiple evaluation, conception and selection of heating systems. The procedure enables to select the most suitable heating system in followable decision steps and by setting up values of utility. The procedure is applied to find a heating system for a flat in a multi-family house with an energy demand corresponding to the German 'Waermeschutzverordnung 1995' and for one which corresponds to the energy efficient building insulation standard. During the first evaluation step a number of possible heating systems are excluded as they do not reach the required aims; for the second evaluation step a hot air heating system, a hot water radiator heating system, a floor heating system, an electric storage heater and an electric blow heater remain. The highest value of utility is reached by the hot water radiator heating system for which several concepts are developed. These concepts are mathematically simulated using newly created computer simulation models. Not only the unsteady state behaviour of the building is simulated, but also the complete heating system and its interaction with the building. In order to optimize the heating system the influence of the controlling values, of the power of the heater including hot water heating, of various sizes and modes of operation of the hot water storage tank and the heating water storage tank as well as the pump and the pipes is examined. In the last evaluation step the best system is assessed. It is the heating system with the heater, which is dimensioned to serve up to twice the nominal heating load without a heating water storage tank and with a hot water storage tank which is loaded in the morning before heating starts. (orig.)Available from TIB Hannover: RR 6940(2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
A Dynamic Subfilter-scale Stress Model for Large Eddy Simulations Based on Physical Flow Scales
No full textWe propose a new definition of the length scale in an eddy-viscosity model for large-eddy simulations (LES). This formulation extends and generalizes a previous proposal [Piomelli, Rouhi and Geurts, Proc. ETMM10, 2014], in which the LES length scale was expressed in terms of the integral length-scale of turbulence determined by the flow characteristics and explicitly decoupled from the simulation grid; this approach was named Integral Length-Scale Approximation (ILSA). As in the original ILSA, the model coefficient was determined by the user, and required to maintain a desired contribution of the unresolved, subfilter scales (SFS) to the global transport. We propose a local formulation (local ILSA) in which the model coefficient is local in space, allowing a precise control over SFS activity as a function of location. This new formulation preserves the properties of the global model; application to channel flow and backward-facing step verifies its features and accuracy
NaxAu and CsxAu bimetal clusters: Finite size analogs of sodium-gold and cesium-gold compounds
No full textLarge-eddy simulation of a separated flow with a sub-filter scale model based on the integral length-scale
No full textA new sub-filter scale model for large-eddy simulations, which uses a length-scale proportional to the integral scale of the turbulence instead of the grid resolution to parametrize the modelled stresses, will be assessed in the prediction of the flow of a boundary-layer over a rough surface, which includes separation and reattachment
Near Wall PIV-Measurements on the Windward Slope of a Hill
No full textThe turbulent flow over periodic hills was measured near to the wall, using planar Particle-Image-Velocimetry (PIV) at high spatial resolution. Our focus is on the near wall turbulence structure on the windward slope of the hill. For large-eddy simulation (LES) we suspect that, if this was not predicted accurately, it affects the prediction of the velocity profiles over the hill crest which in turn will affect the recirculation length downstream of the hill. Regarding the time averaged velocities, we were able to resolve the linear viscous region of the boundary layer. The velocity distribution and also the Reynolds stress does not comply with the law of the wall as it is valid for a turbulent boundary layer at equilibrium
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