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

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

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

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

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

Data-driven classification of Urban Energy Units for district-level heating and electricity demand analysis

The building sector is a significant contributor to global energy consumption and accounts for approximately one-third of total greenhouse gas emissions. While building energy analysis has traditionally focused on individual buildings, analyzing larger settlements, such as districts or neighbors, offers additional opportunities. The objective of this study is to define and classify typical urban areas for energy analysis, referred to in this paper as Urban Energy Units (UEUs), which represent geographical regions within a city with specific building characteristics, settlement patterns and energy demand. Sixteen different UEUs were classified using literature and open data. The proposed methodology leverages open-source data and uses a random forest model to enhance missing building properties of the building stock such as building age and construction type. It further subdivides the study area into geographically defined sections, and deploys a decision tree model to classify these sections into the sixteen different UEUs. These UEUs enable the creation of energy districts in a modular manner and flexible for its use in any given area. This study demonstrates the practical implications related to the 2023 german municipality heating plan. The methodology was applied in Oldenburg, a mid-sized German city. The city was subdivided into a total of 8249 UEUs, with the detailed results for energy demand presented in this report

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