227 research outputs found
High-Temperature Thermal Storage System for Solar Tower Power Plants with Open-Volumetric Air Receiver Simulation and Energy Balancing of a Discretized Model
This paper describes the modeling of a high-temperature storage system for an existing solar tower power plant with open volumetric receiver technology, which uses air as heat transfer medium (HTF). The storage system model has been developed in the simulation environment Matlab/Simulink®. The storage type under investigation is a packed bed thermal energy storage system which has the characteristics of a regenerator. Thermal energy can be stored and discharged as required via the HTF air.
The air mass flow distribution is controlled by valves, and the mass flow by two blowers. The thermal storage operation strategy has a direct and significant impact on the energetic and economic efficiency of the solar tower power plants
High-Temperature Thermal Storage System for Solar Tower Power Plants with Open-Volumetric Air Receiver Simulation and Energy Balancing of a Discretized Model
This paper describes the modeling of a high-temperature storage system for an existing solar tower power plant with open volumetric receiver technology, which uses air as heat transfer medium (HTF). The storage system model has been developed in the simulation environment Matlab/Simulink®. The storage type under investigation is a packed bed thermal energy storage system which has the characteristics of a regenerator. Thermal energy can be stored and discharged as required via the HTF air.
The air mass flow distribution is controlled by valves, and the mass flow by two blowers. The thermal storage operation strategy has a direct and significant impact on the energetic and economic efficiency of the solar tower power plants
DLR Institut für Solarforschung am Standort Jülich -Rückblick 2016 und Ausblick 2017
Der Vortrag gibt einen Überblick über die Aktivitäten des DLR am Standort Jülich rückblickend für das Jahr 2016 und vorausschauend für das Jahr 2017. Dabei stehen die Baumaßnahmen und Großforschungsanlagen im Vordergrun
Effiziente Wärmesysteme für Wohngebäude
Die Entwicklung effizienter Wärmesysteme für Wohngebäude ist eine zentrale Aufgabe der Energieforschung. Der Wohngebäudesektor hat seit Jahren
einen – witterungsbedingt leicht schwankenden –
Anteil von 25 – 30 % am Endenergieverbrauch in
Deutschland. Dabei werden über 80 % der im Sektor
Haushalte verbrauchten Energie zur Bereitstellung
von Wärme verwendet, im Jahr 2013 z. B. 585 TWh
oder mehr als ein Fünftel des gesamtdeutschen Endenergieverbrauchs. Da die Wärmeversorgung hauptsächlich noch über die fossilen Energieträger Erdgas und Heizöl betrieben wird, bieten Wärmesysteme für Wohngebäude ein erhebliches Potenzial für CO2-Einsparungen. Die Energiewende im Heizungskeller beruht dabei – genau wie in anderen Sektoren auch – auf den
beiden Säulen erneuerbare Energieversorgung und
Effizienz. Durch verschärfte Regelungen für Neubauten und
energetische Sanierungen von Bestandsimmobilien
wurde in den vergangenen Jahren ein leichter Rückgang
des durchschnittlichen flächenspezifischen Heizenergiebedarfs in Wohngebäuden erreicht. Diesem Trend stand jedoch ein steigender Wohnflächenverbrauch
pro Person entgegen, so dass der gesamte Heizenergieverbrauch langsamer sinkt als
der spezifische Heizenergiebedarf in den Gebäuden.
Die jährliche Totalsanierungsquote im Wohnbereich
liegt zudem weit unterhalb der als für die Erreichung
der Effizienzziele 2050 nötigen postulierten 2,7 %.
Ein verstärkter Ausbau des Einsatzes erneuerbarer
Energien im Heizungskeller bietet einen zusätzlichen
Freiheitsgrad, der zur Erreichung der angestrebten
CO2-Minderung beitragen kann
Integration of Heat Flow through Borders between Adjacent Zones in AixLib's Reduced-Order Model
For dynamically simulating the thermal behavior of a building, the reduced-order model (ROM) implemented in the Modelica IBPSA and AixLib libraries provides a time-efficient calculation method based on the standard VDI 6007-1. Additionally, the Python package TEASER features a possilibity to fill the model parameters with automatically generated typical and/or enriched building data. So far, both have not been capable of modelling heat flow through borders between thermal zones. In this contribution, we present the integration of this feature into the open-source software combination. Additional new features include non-constant soil temperatures and a new approach to estimate interior building elements in cases without proper knowledge. Calculation results are presented for an exemplary application and show satisfactory agreement with measured values. The respective code (including the example presented here) is in the process of being published as part of the AixLib and TEASER open-source repositiories
Ausbau des DLR-Standorts Jülich: Aktionsraum für CSP-Versuchsanlagen im Pilotmaßstab
Posterbeitrag zum aktuellen Stand des Ausbaus des DLR-Standorts Jülich. Es werden das Ausbaukonzept und einige konkrete Maßnahmen beschrieben
Detection of Air Leakage in Building Envelopes using Microphone Arrays
Unintended airflow through building envelopes leads to an increased demand in heating and cooling energy. The most common way to measure air leakage of buildings is the blower door test, which quantifies the overall leakage rate of one room or a building. To reduce air leakage and associated energy loss in new and existing buildings, it is necessary to identify leak locations and prioritize sealing of more substantial leaks. However, detection and quantification of individual leaks with smoke tracers or infrared thermography are challenging, time-consuming, and depend on the operator’s experience.
Acoustic methods have been identified to have the potential to localize and quantify individual leaks without the need for pressure or temperature differences. In this work, the acoustic beamforming method is proposed using a microphone array to detect leak locations and visualize them (acoustic camera). The objective of this investigation is to identify the potential of this technique for application to building envelopes. A pair of omnidirectional speakers is placed as a sound generator inside a room, and the microphone ring array with 48 microphones outside. As an experimental setup, cable ties are wedged in a window frame to simulate a damaged window gasket and to create reproducible leaks of different sizes at the same place. Overlay of an optical picture with the acoustic image obtained from beamforming enables the visualization of leaks of sound through the building envelope. All experiments were conducted using white noise with an analyzed frequency range of 1-25 kHz. The sound sources are evaluated at multiple third-octave bands within this frequency range, enabling a distinction between these leaks at different frequencies
Automated Generation of an Energy Simulation Model for an Existing Building from UAV Imagery
An approach to automatically generate a dynamic energy simulation model in Modelica for a single existing building is presented. It aims at collecting data about the status quo in the preparation of energy retrofits with low effort and costs. The proposed method starts from a polygon model of the outer building envelope obtained from photogrammetrically generated point clouds. The open-source tools TEASER and AixLib are used for data enrichment and model generation. A case study was conducted on a single-family house. The resulting model can accurately reproduce the internal air temperatures during synthetical heating up and cooling down. Modelled and measured whole building heat transfer coefficients (HTC) agree within a 12% range. A sensitivity analysis emphasises the importance of accurate window characterisations and justifies the use of a very simplified interior geometry. Uncertainties arising from the use of archetype U-values are estimated by comparing different typologies, with best- and worst-case estimates showing differences in pre-retrofit heat demand of about ±20% to the average; however, as the assumptions made are permitted by some national standards, the method is already close to practical applicability and opens up a path to quickly estimate possible financial and energy savings after refurbishment
- …