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In dieser Projektarbeit wird die Wärmeversorgung der Stadt Haßfurt über Solarthermieanlagen vorgestellt. Dabei werden vorerst zwei mögliche Herstellverfahren des Stülpmembranspeichers präsentiert. Mit Hilfe der Wärmeverbrauchsdaten der Stadtwerke Haßfurt werden Solarkollektoren ausgelegt. Das Ziel der Auswertung ist die benötigte Menge und Kosten der Solarthermieanlagen für ganz Haßfurt und für ein Neubaugebiet zu bestimmen.

Erstellt u. a. im Rahmen der Forschungs- und Entwicklungsprojekte: „Verbundvorhaben: Geosolare Nahwärmeversorgung für die Siedlung ‚Zum Feldlager‘“ (FKZ: 03ET1336C) im Rahmen des Förderkonzeptes „Energieeffiziente Stadt (EnEff:Stadt)" gefördert durch das Bundesministerium für Wirtschaft und Energie; „Verbundvorhaben: EnEff: Wärme – Smart Thermal Subgrid: Effiziente und erneuerbare Gestaltung von Subnetzen – Umsetzung eines systemischen Ansatzes am Beispiel des Konversionsgebiets Benjamin Franklin Village / Mannheim; Teilvorhaben: Anlagentechnische Integration Erneuerbarer Energien; Betriebsstrategien“ (FKZ: 03ET1580A-C) gefördert durch das Bundesministerium für Wirtschaft und Klimaschutz. Die Verantwortung für den Inhalt dieser Veröffentlichung liegt bei der Autorin.

Das Projekt "Chancen durch Solarw��rme und thermische Energiespeicher f��r das Energiesystem Schweiz 2050" beantwortet die Frage nach dem Potenzial von Solarw��rme in Kombination mit thermischen Energiespeichern in der Schweiz, identifiziert die bestm��glichen Einsatzgebiete, bewertet die Chancen und Risiken und erarbeitet schliesslich eine Roadmap zur F��rderung und zum Ausbauen dieser Technologien. Ziel ist dabei der gr��sstm��gliche Beitrag zur Energiestrategie 2050, wobei gerade auf einen realistischen Implementationsprozess Wert gelegt wird. In Work Package 2a wurden die wichtigsten Einsatzm��glichkeiten von Solarthermie und Energiespeichern und deren Bedeutung im Zeitverlauf bis 2050 bestimmt. Es wurden dabei 6 Systeme priorisiert. Anlagen zur Warmwasserbereitung sowie Kombi-Anlagen zur Heizungsunterst��tzung in Wohngeb��uden dominieren heute den Markt, werden aber an Bedeutung verlieren. Zunehmend wichtiger werden solche Anlagen in Kombination mit einem Saisonspeicher, aber auch Anlagen zur Erzeugung industrieller Prozessw��rme sowie l��ngerfristig Anwendungen in Kombination mit Klimatisierung. Mit dynamischen Systemsimulationen (TRNSYS) wurden verschiedene Systeme und Bedarfssituationen in der Schweiz untersucht. Erwartungsgem��ss erreichten Warmwassersysteme mit bis zu 80% den h��chsten solaren Deckungsgrad. Bei Kombisystemen, in denen Raumheizung enthalten ist, liegt der solare Anteil typischerweise im Bereich von 30-40 %. Bei den Investitionskosten zeigten die Simulationen eine grosse Bandbreite von rund 400 bis 4000 CHF/m2, je nach Gr��sse der Anlage. ��ber eine Laufzeit von 30 Jahren ergeben sich dabei die tiefsten W��rmegestehungskosten von 5 Rp./kWh bei W��rmeverb��nden in st��dtischen Gebieten, die h��chsten von ca. 30 Rp./kWh f��r Warmwasser in Einfamilienh��usern. In Work Package 2b wurde die Solarthermie im Energiesystemmodell Swiss Energyscope abgebildet, mit dem Ziel, die Rolle der verschiedenen Systeme in der zuk��nftigen Energieversorgung ermitteln zu k��nnen. Die wichtigste Erkenntnis lautet: Solarthermie kommt immer dann zum Einsatz, wenn eine begrenzte Ressource eingespart werden kann, z.B. Gas, Holz oder die Anergie in Erdsondenfeldern. Die Solarthermie steht allerdings in Konkurrenz zu anderen Technologien und Ressourcen, wie Tiefengeothermie oder W��rmepumpen. Betrachtet man jedoch Netto-Null Szenarien, in denen die Solarthermie ��berhaupt nicht eingesetzt wird, zeigt sich, dass die Gesamtkosten des Energiesystems um mehrere 100 Millionen CHF pro Jahr steigen. Gem��ss den Modellergebnissen kann die Solarthermie einen Beitrag von 5-10 TWh/a leisten, davon ca. 5 TWh/a in Ein- und Mehrfamilienh��usern f��r Warmwasser und Heizung. Im Work Package 3 wurden die heutigen Hemmnisse f��r die verschiedenen Anwendungsformen untersucht. Vertieft untersucht wurden dabei die Systeme "Regeneration von Erdw��rmesonden" und "Solarw��rme in W��rmeverbunden" bez��glich rechtlich/regulatorischer, wirtschaftlich/gesellschaftlicher und technischer Hemmnisse. Nebst Literaturrecherchen wurden zu diesem Zweck Experteninterviews sowie Workshops im Rahmen der Fachkommission Solarw��rme von Swissolar durchgef��hrt. Gegenstand des Work Package 4 war eine SWOT-Analyse der verschiedenen Systeme, aufgeteilt auf die Anwendungsbereiche Wohnbauten, Quartier (W��rmeverbunde) und Industrie. Bei den beiden letztgenannten, bisher in der Schweiz kaum anzutreffenden Anwendungen stehen tiefe Kosten und hohe Wirkungsgrade mangelndem Know-how und grossem Speicherbedarf gegen��ber. Aufgabe von Work Package 5 war die Erarbeitung von Massnahmen zum Abbau der Hemmnisse. Die Aufgaben der Branche liegen in der Standardisierung und Bewerbung von Kombi-Systemen (Solarw��rme mit Holz oder W��rmepumpen), der Verankerung von Systemen zum Einsatz im Bereich Prozessw��rme, in der Ausbildung von Fachkr��ften sowie im Bereich Digitalisierung. Im Bereich Forschung und Entwicklung m��ssen Solarw��rme und W��rmespeicher differenzierter in den Energiesystemmodellen abgebildet werden. Generell m��ssen W��rmespeicher weiterentwickelt, Eisspeicher optimiert und Speichernutzungen f��r die Prozessw��rme erforscht werden. Ebenso wird Forschungsbedarf bei der Erdsondenregeneration festgestellt, aber auch bei der Weiterentwicklung 4/100 von Kollektoren. Zudem braucht es Demonstrationsprojekte von grossen solarthermischen Anlagen f��r W��rmeverbunde. Bei den politischen Rahmenbedingungen werden Vorgaben f��r die Regeneration von Erdsonden, eine Pflicht f��r erneuerbare Energieproduktion statt Stromerzeugung auf Neubauten, ein nationales F��rderprogramm f��r grosse solarthermische Anlagen und eine nationale Nutzungsstrategie speicherbare Energien vorgeschlagen. Zudem soll der Bau von Solaranlagen ausserhalb der Bauzone in gewissen F��llen zugelassen werden., + ID der Publikation: hslu_86267 + Art des Beitrages: Bericht + Sprache: Deutsch + Letzte Aktualisierung: 2021-12-14 17:17:33

This is a report from SHC Task 64 / SolarPACES Task IV: Solar Process Heat and work performed in Subtask A: Integrateted Energy Systems. Dleverable Report D.A1, Gefördert vom deutschen Bundesministerium für Wirtschaft und Energie

Diese Arbeit untersucht die Eignung von flüssigem Blei-Bismut (Pb-Bi) als Wärmetransport-Medium in zentralen Rohr-Receivern von konzentrierenden solarthermischen Kraftwerken. Dazu werden zwei Ansätze verfolgt: a) auf theoretischer Ebene werden anhand existierender Literatur die Materialeigenschaften von Pb-Bi und existierende Auslegungswerkzeuge für Flüssigmetall-Anwendungen betrachtet und b) anhand eines Praxisbeispiels wird die Auslegung, der Bau, die Inbetriebnahme sowie erste Betriebserfahrung eines Pb-Bi-gekühlten Modellkreislaufs in einem eigens errichteten Solar-Ofen im Technikumsmaßstab erprobt. Der Pb-Bi-gekühlte Solarreceiver dieses Kreislaufs besitzt eine thermische Leistung von 10 kW. Pb-Bi besitzt einige hervorragende und einige ungünstige Stoffeigenschaften für seine Anwendung in Solarreceivern im kommerziellen Groß-Maßstab: eine hohe thermische Leitfähigkeit und eine geringe Viskosität stehen einer durchschnittlichen Wärmekapazität und einer sehr hohen Dichte gegenüber. Diese führen für Pb-Bi im Vergleich mit Alternativ-Wärmetransportmedien Solarsalz und Natrium beim Einsatz in Receiver-Rohren zu den höchsten Entropie-Erzeugungsraten. Pb-Bi ist darüber hinaus teuer. Im Pb-Bi muss eine definierte Sauerstoffkonzentration eingestellt werden, um die Korrosion der Edelstahl-Rohrwerkstoffe zu begrenzen. Dadurch wird allerdings der Bereich der Einsatztemperaturen eingeschränkt: Infolge dessen kann entweder der Vorteil einer geringen Schmelztemperatur von Pb-Bi nicht ausgenutzt werden, oder aber eine Betriebstemperatur oberhalb der Temperaturgrenze von Solarsalz kann nicht erreicht werden. Nach dem aktuellen Stand der Technik dient Solarsalz als Wärmetransportmedium. Die Literaturrecherche dieser Arbeit gibt deutliche Hinweise darauf, dass Fluide mit niedrigen Prandtl-Zahlen und insbesondere Pb-Bi empfindlicher als "konventionelle" Medien auf Randbedingungen mit inhomogener Wärmestromdichteverteilung reagieren. Tatsächlich werden die Rohrströmungen in konventionellen Solarreceivern nur einseitig beheizt. Unter dieser Randbedingung führen klassische Nusselt-Korrelationen, die für homogen beheizte, voll-turbulente Rohrströmung entwickelt wurden, bei Medien geringer Prandtl-Zahl zu einer deutlichen Unterschätzung der Wandtemperatur und damit einhergehend zu einer Unterschätzung der thermischen Spannungen in der Rohrwand. Daher werden alternative Auslegungsmethoden präsentiert. Erste Messungen am Pb-Bi-Kreislauf zeigen tatsächlich äußere Wandtemperaturen der Receiver-Rohre, die höher sind als von klassischen Nusselt-Korrelationen vorhergesagt. Trotz dieses Befundes hat Pb-Bi für seinen Einsatz in einem Modell-System seine Berechtigung, da es im Vergleich zu bspw. Natrium inhärent deutlich sicherer ist und kann für Receiver-Betrieb und die Untersuchung von Phänomenen, die spezifisch für Flüssigmetalle sind, verwendet werden. Diese Arbeit beschreibt die Auslegung der wichtigsten Teile des Pb-Bi-Kreislaufs und die ersten experimentellen Ergebnisse, darunter auch solche bei einer Wärmestromdichte von etwa 4 MW/m$^2$. Zur Messung derart hoher Wärmestromdichten wurde im Rahmen der Arbeit ein passiv-gekühlter Wärmestrom-Scanner entwickelt, dessen Funktion auf einem einzigen Heat-Flux-Mocro-Sensor basiert. Dieser Sensor bewegt sich während des Scannens auf einer Spiral-Bahn durch die Messebene. Dieses Messgerät wurde vor Messbeginn im Solarofen des DLR in Köln für den Betrieb kalibriert.

Die Wärme des Sommers im Winter zum Heizen nutzen – technisch ist dies mithilfe von thermischen Speichern möglich. Forschende der Hochschule Luzern arbeiten daran, diese klimaschonenden Lösungen für den Einsatz zu optimieren., + ID der Publikation: hslu_84148 + Art des Beitrages: Andere + Sprache: Deutsch + Letzte Aktualisierung: 2021-07-20 13:16:39

PVT collectors are an emerging technology which combines the generation of solar electricity and heat within a single component. Low heat losses and a high thermal efficiency are essential for the application in conventional solar thermal systems with fluid temperatures up to 90 °C. Glazed PVT collectors with low emissivity coatings offer highest energy yields. However, excessive stagnation temperatures require an adapted collector design to avoid material aging and collector failure. Two innovative PVT collectors with overheating protection are built and tested, and the effect on temperatures and performance is studied. Venting the PVT collector with ambient air reduces the maximum absorber temperatures from 148 °C to 102 °C. An innovative switchable film insulation renders an unprecedented switching range of thermal losses resulting in an uncritical maximum absorber temperature of 87 °C. Thus, conventional PV modules and inexpensive materials can be employed in collector and system, which might offset the additional costs for the overheating protection. Next to the improved reliability, also the electrical efficiency benefits from a lower temperature load.

Solar energy conversion requires permanent outdoor operation of essential components such as photovoltaic modules, solar collectors, or reflectors. They are exposed to weathering stresses. The stress levels depend on the local climates. Monitoring of climatic properties and sample properties in different climatic zones (alpine, arid, maritime, moderate, and tropical) during several years provided the base for categorization of these climates. The local climate does not differ very much from year to year in terms of frequency distributions, but big differences are found for different regions or climatic zones. Especially, the solar irradiation is very location‐dependent. The alpine location shows the highest UV irradiation. The UV fraction of the solar irradiation is varying between 2.2% (tropics) and 4.7% (alps). The temperature histograms can be modeled by Gaussian distribution functions. The maritime histogram is very slim and high, showing the cooling by the sea and the wind. Several approaches for a categorization of these local climates can be applied: Mean temperatures, effective temperatures, or the corresponding constant testing time for fictive degradation processes with arbitrary activation energy. The categorization of the relative humidity revealed humid climates in the alpine and the tropical test site, when considering the time of wetness (rh > 80%). Obviously, the humidity stress or the corrosivity would be very different at those sites. Therefore, a more holistic approach considering more stress factors simultaneously would be more appropriate for the categorization. The interaction between the samples and the climate creates the so‐called micro‐climate which is the real stress on the samples, such as surface temperature, daily temperature cycles, surface humidity, or temperature‐enhanced photo‐degradation. The conditions for accelerated life testing (ALT) modeled on the base of monitored climatic data and sample temperatures are different for the different locations. They offer another possibility for categorization of the climatic stresses and the option for designing climate‐adapted components.

A design of a box-type solar cooker was modeled and tested in the region of Sfax-Tunisia. This solar cooker was designed to allow reaching relatively high temperatures during days with low solar radiation owing to four outer reflectors. A mathematical model, which is based on thermal balances, was developed and implemented in a Matlab program to predict the thermal performances of the solar cooker. Several tests were effectuated in order to validate the robustness of the mathematical model and to determine the thermal performance of the solar cooker. The obtained results showed an acceptable matching between the experimental temperature values and the computed temperature values with a maximum error inferior to 4%. It was also proven that the use of four outer reflectors improved the optical efficiency of the solar cooker. Indeed, the first figure of merit passed from 0.07 to 0.14 and the maximum temperature of the absorber plate passed from 81.3 °C to 133.6 °C. The sensible loading test revealed that the calculated second figures of merit for different water loads were in the range of 0.34–0.39. Finally, two real cooking process were carried out where 72 min and 107 min were required to fully cook rice and beans respectively.

Based on an analysis of building processes to date, this paper proposes two ways to make Building Information Modelling (BIM) and with it complex building processes less expensive and more reliable. First, existing experience with building processes that include building-integrated solar systems is analysed, as they are one example for buildings with high energy-saving goals. Based on the analysis, the authors propose to include a new property set and functions in machine code in the next version of the Industry Foundation Classes (IFC). For the machine-code functions, several formats are proposed and the advantages and disadvantages of the proposed IFC extensions are discussed. For simple conventional building components, the existing IFC version 4 seems appropriate. Buildings with innovations that add complexity to the building process can profit most by the savings generated by exchanging machine-code functions. In building processes to date, much information is not shared because of proprietary matters. Functions in machine code can provide the necessary confidentiality so that more capabilities can be exchanged between the stakeholders. Models based on machine-code functions can be updated much faster than detailed models with many parameters. With machine-code functions, advantage can be taken of the greater accuracy of detailed models, as long as they are fast and easy to use. The modularity of the functions stimulates competition between alternative approaches, which makes simulation models less expensive. Finally, exchanging a closed, validated simulation model in machine code introduces a much lower risk of error than exporting and importing complex simulation models.

Solar building envelopes are attracting increasing interest. Building-integrated solar thermal (BIST) systems are one of the subgroups of solar building envelopes. This paper summarizes the most important contributions of recent years and extends them. First, BIST elements are defined and available BIST elements are presented. Then, the general functions which BIST systems can provide are presented and the conflict between the constant U and g values of simple planning software and the variable g and U values of BIST elements is discussed. Measurements to characterize BIST elements are presented as well as a design parameter space in which the current BIST elements are located and which can be used when developing innovative new components. Methods to evaluate and compare BIST technologies are presented. The substantial cost savings which were achieved in three building projects between 2002 and 2009 are discussed. Roles within the building process are presented, as well as the general methods and challenges for economic BIST calculations and one economic calculation as an example. Based on existing building processes, a vision for future BIST building process integration is presented. Simple BIST models, which need no programming, are provided with easy-to-use equations. The challenges of standards and regulations are outlined and future research topics are presented. This paper summarizes important recent contributions to BIST research as a basis for future progress in building-integrated solar thermal systems. Instead of aiming to cover all recent BIST developments, the focus is on BIST research findings which are relevant for cost reduction of BIST components and therefore necessary for the economic success of BIST technology. These are discussed, together with proposals for future research.

A photochromic (PC) device comprising an electrochromic film (WO 3 ) together with a photoactive film (usually, dye sensitized TiO 2 ) coated on glass and a redox electrolyte (e.g., iodide/triiodide together with lithium salt) reduces the optical transmission under solar illumination and bleaches, again, in dark or at low intensity of light. This work reports, for first time, on an application of sputter coated TiO 2 and WO 3 films for this type of PC devices. The applicability of TiO 2 and WO 3 films in PC device is individually investigated in dye solar cells and electrochromic cells, respectively. A dye solar cell with 180 nm TiO 2 was shown to be sufficient for the charge generation for electrochromic coloration of the WO 3 . The compatibility of WO 3 and redox electrolyte was studied in electrochromic devices by considering their redox potentials. The bleaching of the PC device has to be adjusted by the so called “loss current”. To address this, a thin catalytic layer of platinum (Pt) is deposited in between the photoactive and electrochromic layers. The optimized PC device exhibits a visual (solar) transmission modulation from 74 (63) down to 30% (20%) in 40 min under 1.5 A.M. illumination, and the bleaching is regained in 45 min in dark.

Die vorliegende Arbeit befasst sich hauptsächlich mit dem Thema Energie, dazu wurde eine Literaturrecherche durchgeführt. Es wurde ein Konzept erarbeitet, welches aus einem Zusammenschluss erneuerbarer Energien und verschiedenen Technologien besteht, aber auch der Natur ihren Platz zugesteht. Dieses Konzept wird mittels technischer Zeichnungen dargestellt, anschliessend wurden, durch Berechnungen und Simulationen, die dazugehörigen Werte der verschiedenen Systeme und Anlagen ermittelt. Das Konzept besteht aus zwei Gebäudekomplexen die Platz für zirka 12'000 Personen bieten, sie sind mit einer Fassaden- und Dachbegrünung ausgestattet und von einem Pumpspeicherkraftwerk, welches durch einen Wald kaschiert wird, umgeben. Es wurde darauf geachtet, dass verschiedene Anlageteile des Gesamtprojekts multifunktionell sind, das heisst Energie produzieren, Platz für die Natur lassen und den Bewohnern als Naherholungsgebiet dienen. Die Gebäudekomplexe besitzen verschiedene Photovoltaikanlagen, welche in den oberen Südfassaden integriert wurden, sich auf den Süddächern oder auf dem Pumpspeicherkraftwerk befinden. Die tagsüber durch die Photovoltaik erzeugte Energie, wird in den Gebäuden etagenweise mittels Akkus/Batterien gespeichert und für die Nacht verfügbar gemacht. Energieüberschüsse, welche mehrheitlich durch die Photovoltaikanlage des Pumpspeicherkraftwerkes erzeugt wurden, werden in diesem als potentielle Energie gespeichert. Das heisst am Tag wird Wasser mittels «Solarstrom» hochgepumpt und in der Nacht mittels Turbinen wieder in elektrische Energie umgewandelt. Die zwei Gebäudekomplexe A+B, sind jeweils in drei Häuser für rund 2'000 Personen gegliedert und besitzen ein eigenes, von den anderen Häusern unabhängiges, Heizungs-/Kühlungs-, Lüftungs- und Warmwasserbereitungssystem. Dieses System besteht aus Wärmepumpen und sorgt dafür, dass die Heizung/Kühlung, Kontrollierte Wohnungslüftung, sowie die Warmwasserbereitung pro Haus möglichst «klimaneutral» betrieben werden. Dazu wird das aufbereitete Hausabwasser, welches noch Restwärme besitzt, in einen grossen Brauchwassertank geleitet, wo ihm diese mittels Wärmepumpen entzogen und an den Hauptpufferspeicher des Warmwasserbereitungssystems abgegeben wird. Das nun kalte Brauchwasser wird in einen zweiten, extrem grossen unterirdischen Tank geleitet. Dort entzieht es im Winter der Umwelt Energie in Form von Wärme, respektive gibt diese im Sommer ab. Dieser Tank dient als Wärmequelle/senke für die Wärmepumpen des saisonalen Pufferspeichers, sowie als Wärmequelle für den Pufferspeicher der Warmwasserbereitung. Dadurch kann die benötigte Wärmeenergie für das Heizungs-/Kühlungs- und Lüftungssystem saisonal gespeichert und genutzt werden. Die beiden Pufferspeicher dienen dazu, da die Gebäudekomplexe relativ gross sind, die Wärme- und Kälteenergie zwischen zu speichern. Der Transport und die Verteilung der Energie wird mit Klimawärmepumpen bewerkstelligt, bei welchen der Kältekreis umgekehrt werden kann, dadurch kann die Energie, je nach Saison an das modular aufgebaute Heizungs-/Kühl-, Lüftungs- und Warmwasserbereitungssystem abgegeben, respektive aufgenommen werden. Die Warmwasserbereitung wird ganzjährig durch die Solarthermie und in der Wintersaison, durch ein Blockheizkraftwerk unterstützt. Das Blockheizkraftwerk wird mit Biogas, welches aus den biogenen Abfällen der Bewohner erzeugt wird, betrieben., The present paper deals primary with the topic of energy, for this was a literature research carried out. A concept was developed, which results form a combine of renewables energies and different technologies, but also lets nature take its place. This concept is presented by technical drawings, subsequently, the corresponding values of the various systems and facilities were determined through calculations and simulations. The concept consists of two building complexes, which have space for 12’000 people, they are covered with a green façade and roof and surrounded by a pumped storage power station, which is hided through forest. Care was taken, to ensure that different parts of the overall project are multifunctional. That means, that they produce energy, leave space for nature and serve the inhabitants as local recreation area. The building complexes have various photovoltaic systems, which are integrated in the upper south façade and are located on the south roofs, or on the pump storage power plant. The energy, which is produced by the photovoltaic systems during the day, is stored with accumulators/batteries and made it available for the night, that for the whole building floor by floor. Energy surpluses, which are mostly generated by the pump storage power plant, are stored in it as potential energy. This means, that during the day water is pumped up using «solar power», and at night it is converted back into electrical energy with turbines. The two building complexes A+B are divided into three houses, with space for 2’000 persons and each of them has their own heating/cooling, ventilation and hot water preparation system, independent of the other houses. This system consists of heat pumps and ensures, that the heating/cooling, controlled domestic ventilation and hot water preparation system is as climate neutral as possible. For this purpose, the treated domestic waste water, which still has residual heat, is fed into a large service water tank, where the residual heat is extracted by heat pumps and transferred to the main buffer tank of the hot water preparation system. The now cold process water is led into a second very large underground tank, there it extracts in the winter energy from the environment, in the form of heat, or releases it in summer. This tank serves as a heat source or a heat sink for the heat pumps of the seasonal buffer storage, and as a heat source for the buffer tank of the hot water preparation. This allows, the required thermal energy for the heating/cooling and ventilation system, to be stored and used seasonally. The fact that the building complexes are very large, the two buffer storage tanks are used, to store the heating and cooling energy temporarily. The transport and distribution of the energy is done with climate heat pumps, in which the cooling circuit can be reversed. This means that, depending on the season, the energy can be supplied to, or absorbed by the modular heating/cooling, ventilation and hot water preparation system. The hot water preparation system is supported around the year, by solar thermal energy. In the winter season, the hot water preparation system is supported by a cogeneration unit. The cogeneration unit is operated with biogas, which is produced from the biogenic waste of the residents.

Optical assessment of Central Receiver Solar Tower systems should be based on annual simulations due to the high variability of solar radiation throughout the year. The most basic approach is using a discretization of the temporal domain which requires a large number of computationally costly optical simulations. This study proposes an alternative approach based on a discretization of the sky which reduces the required number of simulations and therefore the computational effort significantly. For the subsequent annual performance assessment data three different interpolation methods are presented, compared and their respective advantages and drawbacks are discussed. The methodology is demonstrated by means of three representative heliostat field setups: the PS10 field, the Gemasolar field and a small, generic field. In this context, the dependency of the interpolation accuracy with respect to the resolution of the sky grid is investigated. For this purpose, annual optical efficiency weighted with direct normal irradiation is used as an integral figure of merit, while the Root-mean-square deviation is calculated as a benchmark value for single time step assessment. Eventually, it is shown that the proposed method decreases the required time for the annual optical assessment by several orders of magnitude while maintaining the original accuracy.

Polymeric collectors have been exposed on outdoor testing sites in three distinct climatic locations and the climatic loads and collector temperatures have been monitored by the minute. The obtained data was analyzed with focus on the frequency and extend of the thermal loads, which the different components of the collector were exposed to. As a result this data can be correlated to accelerated aging tests.

Enhanced heat transfer surfaces based on cylindrically shaped pin fins with wire diameters in the range of 100 µm were analyzed. The design is based on a high pin length to diameter ratio in the range of 20-100. Correlations for thermal and fluid dynamic characteristics of these fine wire structures are not available in literature. An in-line and staggered arrangement of pins were simulated for a variety of operational and geometrical conditions with a two-dimensional computational thermal and fluid dynamics model. Correlations for Nusselt number and friction factor with respect to Reynolds number and geometry were derived thereby. Reynolds numbers based on the wire diameter are in the range of 3-60. The correlations for the Nusselt number and friction factor can predict 93% and 97% of the simulated data within ±10%.

In der vorliegenden Masterarbeit werden die aktuellen und zukünftigen Vorgaben der OIB-Richtlinie 6 auf reale Bauvorhaben von Wohn- und Bürogebäuden analysiert, um die Realisierungsbereitschaft im Kontext der Perspektive der Gebäudeherstellenden und Gebäudenutzenden von Baukonzepten zu bewerten. Virtuell erstellte Modellgebäude mit kostenoptimalen Baukonzeptvariationen dienen als Grundlage. Um die Erderwärmung zu begrenzen, erlässt die Europäische Union kontinuierlich novellierte Regelwerke (EPBD Richtlinien) zur Verbesserung der Gesamtenergie-effizienz von Gebäuden im europäischen Raum. Ab dem Jahr 2021 müssen Gebäude als Niedrigstenergiegebäude unter der Berücksichtigung der Kostenoptimalität errichtet werden. In Österreich erfolgt die stufenweise Umsetzung als dualer Weg: Gebäude sind entweder an einem kostenoptimalen Niveau mit einer optimierten Gebäudehüllenqualität auszurichten oder eine etwaige Abweichung mit der Erwirtschaftung von lokalen Erträgen aus erneuerbaren Energien im Ausmaß zur Differenz zu kompensieren. Im Rahmen des Handlungsspielraums der dualen Anforderungsformulierung werden auf Basis von Modellgebäuden spezifische Baukonzepte mit den Mindestanforderungen erstellt und deren Bedarfswerte ermittelt. Die Quantifizierung der generierten Baukonzepte erfolgt nach dem Rationalprinzip des ökonomischen Handelns von Wirtschaftssubjekten. Dazu werden als Vergleichskriterien die Investitionskosten und deren zukünftigen wirtschaftlichen Auswirkungen auf Basis der Annuitätenmethode nach dem Zusatzkostenansatz ermittelt. Gemäß den aktuellen und zukünftigen Vorgaben der OIB-Richtlinie 6 werden aus aktueller Sicht bei Wohn- und Bürogebäuden unter dem Aspekt der Errichtungs- als auch Nutzungskosten vorrangig Baukonzepte mit einer thermisch optimierten Gebäudehülle umgesetzt. Der Einsatz von aktiven Energiesystemen wie Solarthermie und Photovoltaik zur Kompensierung einer Abweichung vom kostenoptimalen Niveau kann nur aus der Perspektive des Gebäudeherstellenden von Wohngebäuden mit den Anforderungen an die Zielvorgaben im Jahr 2021 einen Vorteil hinsichtlich der Investitionskosten bewirken. Der duale Weg als Impulsgeber trägt wesentlich zur Entwicklung neuer Baukonzepte bei. Neben dem zusätzlichen Wettbewerbsvorteil durch die Variantenvielfalt und der größeren Flexibilität bei der Gebäudeplanung werden etwaige regionale Eigenheiten wie solare Erträge und besondere Bebauungsmöglichkeiten berücksichtigt. In this Master's thesis, the current and future requirements of OIB Directive 6 are analysed for real residential and office building construction projects, with a view to evaluating readiness to implement in the context of the perspective of the building construction and occupants of building concepts. Virtually created model buildings with cost-optimised building concept variations serve as a basis. In order to limit global warming, the European Union is issuing continuously amended regulations (EPBD Directives) to improve the overall energy efficiency of buildings in Europe. From 2021, buildings will have to be constructed as lowest-energy buildings, taking into account cost-optimality. In Austria, phased implementation is a dual approach: buildings are either to be aligned at a cost-optimal level with an optimised building shell quality or to offset any deviation with the generation of local revenues from renewable energies to the degree of the difference. As part of the room for manoeuvre of the dual requirements formulation, specific building concepts with the minimum requirements are drawn up on the basis of model buildings and their demand values are determined. The quantification of the generated building concepts follows the rational principle of economic activity of economic entities. For this purpose, the investment costs and their future economic effects are determined on the basis of the annuity method in accordance with the additional cost approach as comparison criteria. In accordance with the current and future requirements of the OIB Directive 6, building concepts with a thermally optimised building shell are primarily implemented for residential and office buildings, taking construction and operating costs into consideration. The use of active energy systems such as solar thermal energy and photovoltaics to compensate for a deviation from cost-optimal levels can only provide investment advantages in terms of investment costs from the perspective of the builder of residential buildings with the target requirements in 2021. The dual approach as a driving force contributes significantly to the development of new building concepts. Alongside the additional competitive advantage, due to the variety of variants and greater flexibility in the planning of buildings, any regional characteristics such as solar yields and special construction possibilities are considered. vorgelegt von: Thomas Petto Wien, FH Campus Wien, Masterarb., 2019

Central Receiver Systems use thousands of heliostats distributed in a field to reflect the solar radiation to a receiver installed at a tower. The large distances between the heliostats and their aim point require a high precision of the heliostat control and drive system to efficiently concentrate the solar radiation and to allow for a safe and reliable plant operation. Precise calibration procedures are needed for the commissioning of open loop systems. Furthermore, the need for cost reduction in the heliostat field motivates for precise and fast calibration systems allowing for savings in the design of the individual heliostats. This work introduces a method for the measurement of true aim points of heliostats in operation. A proposed application is the plug-in system HelioControl, to be used for parallel in-situ calibration of multiple heliostats in operation. The approach aims at extracting the focal spot position of individual heliostats on the receiver domain using image analysis and signal modulation. A centralized remote vision system, installed far from the harsh conditions at the focal area, takes image sequences of the receiver domain. During the measurement, a signal is modulated on different heliostats which is then extracted for the retrieval of the true aim points. This paper describes the theoretical background of the methodology and demonstrates the functionality based on two simulated cases showing the practical advantages introduced with this approach.

Diese Projektarbeit beschäftigt sich mit der Realisierbarkeit der Energiewende durch den Einsatz von solarthermischen Kollektormodulen zur autarken Erzeugung von Wärmeenergie. Hauptaufgabe ist die Simulation und Auswertung einer solarthermischen Anlage und dem damit verbundenem CO2 Einsparpotential gegenüber einer Wärmeerzeugung aus Kraft- und Heizwerken. Zuerst werden die Grundlagen zu solarthermischen Kollektoren geklärt und die Wahl eines geeigneten Modules getroffen. Danach wird eine solare Strahlungsanalyse im Gebiet der Europäischen Metropolregion Nürnberg (EMN) durchgeführt. Anschließend wird ebenfalls für die Stadt Nürnberg eine Strahlungsanalyse erstellt und beide Ergebnisse miteinander verglichen. Dadurch soll festgestellt werden, ob benötigte Berechnungen anhand vorhandener Daten in der Region Nürnberg auch für die gesamte EMN sprechen. Als nächstes sind die vorhandenen Ergebnisse mit denen der im Jahr 2017 ausgekoppelten Wärme eines kommunalen Versorgers gegenüberzustellen. Jetzt wird eine solarthermische Analyse an einem gewählten Beispiel mithilfe einer anerkannten Simulation durchgeführt. Die vorhandenen Ergebnisse werden ausgewertet und in einer Vergleichsrechnung das CO2 Einsparpotential in Bezug auf die Fläche der eingesetzten Kollektoren aufgezeigt. Dadurch kristallisiert sich ein Ergebnis heraus, welches eine Aussage über die Rentabilität oder nicht Rentabilität in Bezug auf die Energiewende treffen kann.

Im Projekt wurde eine alternative Speicherkonstruktion im Bereich von 500 bis 6000 m3 für den Betrieb in Solar- und Fernwärmesystemen entwickelt. Ausgangspunkt bilden große Kaltwasserspeicher in Segmentbauweise. Die Bautechnologie bietet ein signifikantes Kostenreduktionspotenzial gegenüber geschweißten Flachbodentanks, konnte bisher aber nicht auf Wärmespeicher übertragen werden. Aufgrund der dünnwandigen Bauweise und der Projektziele musste eine Überarbeitung des Wandaufbaus, der Einbauten und der Peripherie erfolgen. Dieser Bericht liefert eine Beschreibung des Speicher-Systems und die Ergebnisse des Verbundvorhabens. Die Funktionsfähigkeit wurde mit einem dreistufigen Verfahren nachgewiesen. Das geplante Vorgehen mit Laborversuchen im kleinen Maßstab bis zum Test mit einem Demonstrator im Realmaßstab (100 m3) war notwendig und zielführend. Die Bearbeitung der Hauptaufgaben (z. B. Materialuntersuchungen, Konstruktion, Betrieb) erfolgte vernetzt durch die beteiligten Forschungsinstitutionen. Das grundlegende Potenzial für eine spätere Anwendung in solaren Nahwärmesystemen oder Sekundärnetzgebieten der klassischen Fernwärme sind gegeben. Vor allem im Bereich der Beladung und im Wandaufbau konnten große Verbesserungen erzielt werden. Weitere Optimierungen und die Umsetzung mit größeren Speichern stehen noch aus. In the project, an alternative construction for thermal energy stores in the range of 500 to 6000 m3 was developed for operation in solar and district heating systems. Large cold water storage tanks in segmental construction are the starting point. Their construction technology offers a significant potential for cost reduction compared to welded flat-bottom tanks, but could so far not be transferred to hot water storage tanks. Due to the new design and the project objectives, the wall structure, the internals and the periphery had to be completely revised. This report provides a description of the storage system and the results of the joint project. The functionality was proven with a three-stage procedure. The planned procedure with laboratory tests on a small scale up to the test with a demonstrator on a real scale (100 m3) was necessary and purposeful. The main tasks (e.g. material testing, design, operation) were carried out by the participating research institutions in a network. The basic potential for a later application in solar local heating systems or secondary network areas of conventional district heating is given. Significant improvements were realized, especially in regard of the charging system and the wall construction. However, further optimizations and the transfer to larger storage tanks is still pending.

Building-integrated solar thermal systems (BIST) outperform building-added solar thermal systems (BAST) due to smaller heat losses at the back of the collector. BIST offer economic advantages, too. The insulation behind the collector can be used to reduce the heating demand of the building as well as to increase the solar thermal yield. Therefore, less material and labour are needed. Of course, the energy flux to the building interior needs to be considered. This energy flux depends in general on the operation of the collector as well as on the irradiance. Several innovative solar thermal building skins have been modelled in detail to analyze this coupling between the active building skin and the building. However, planners need an easy approach to include BIST into their calculations. Often, there is not enough budget to measure and model the new facade. This paper presents several new and simple models which are more accurate than neglecting the coupling to the building and which are less complex than detailed physical models.

In the building sector there is a new tendency to integrate solar thermal technologies into buildings. These systems are known as Building-Integrated Solar Thermal (BIST) and offer several advantages in comparison with the Building-Added (BA) installations. The present study is a critical review on modelling of BIST systems and also covers other types of BI solar configurations such as Photovoltaic (PV) and Photovoltaic/Thermal (PVT) in order to provide a better view of the literature. For some instances where the model and/or the system are interesting, BA systems are also cited. The studies are presented into groups, depending on the type of modelling (energetic, thermal, optical, etc.) and based on the technical characteristics of each system (solar collector, skin facade, etc.). The present article is the first part of an investigation about BIST modelling and it gives emphasis on the studies which focus on the interaction between BIST and building (coupled building/system configuration). The study reveals that majority of the modelling are about BIPV and skin facades while there are very few studies on BIST systems. Thereby, more investigations on energetic, thermal, optical simulations for BIST installations particularly for active systems (e.g. active solar thermal collectors) are necessary. On the other hand, innovative ideas such as systems with phase change materials, nanofluids, concentrating solar thermal could also be examined as a future prospect for modelling/simulation. The study also shows that further development of environmental models on BIST systems is required.

As part of the Shagaya Renewable Energy Master Plan in Kuwait, the presented study describes the methodology developed and applied for the optimization of the technology mix for a 2̊GW, 1002km2 renewable energy park. Scenarios with different focuses for the technology mix were developed, selecting from 14 technology options (three wind, five PV and six CSP) and emphasizing either high peak load supply, high overall annual electricity production or low levelized cost of electricity. An optimization procedure that uses a general pattern search algorithm implemented in the software GenOpt was used to maximize a score calculated from eight criteria. These were determined in a social-techno-economic evaluation, which included performance simulations of every technology option for the allocated site in Kuwait. Besides the available land area, the capacity credit of the installed technology mix was included as an additional boundary condition. 2010 was selected as base year since it was the most recent year for which both high quality meteorological and electricity demand data was available. The results for all considered scenarios are presented in this paper, with the one that was chosen as final result of the master plan comprising 136̊MW wind power, 614̊MW of PV and 1250̊MW of CSP. Furthermore, the study showed that thermal storage is indispensable to serve peak demand hours and a diverse technology mix is important to achieve a high capacity credit.

Building-Integrated Solar Thermal (BIST) systems are a new tendency in the building sector and provide multiple advantages in comparison with the Building-Added (BA) installations. The present paper is a critical review about solar system modelling with emphasis on BIST configurations. The review includes also BI solar systems which produce electricity (Photovoltaic: PV) or both electrical/thermal energy (Photovoltaic/Thermal: PVT) in order to provide a more complete view of the current literature. For some cases where the system and/or the model are of great interest, BA configurations are also cited. The references are presented separated into groups, based on the model type (thermal, energetic simulation, etc.) and system characteristics (solar thermal collector, skin facade, etc.). The present review is the 2 nd part of an investigation about BIST modelling and it focuses on modelling studies about the solar system itself. The results reveal that most of the investigations about BI configurations refer to PVT, PV or skin facades while there are few studies about BIST systems. Thus, there is a need for more investigations about BIST installations, especially for active configurations which could provide thermal (or electrical/thermal) energy for building energy requirements. On the other hand, more optical simulations as well as more life-cycle analysis studies about BIST are also necessary. Taking into account the findings of the 1 st part of the present investigation, majority of the BIST modelling studies focus on the system itself; thereby, more investigations which examine the system in conjunction with the building are needed. Moreover, concepts such as BI concentrating solar systems could also be examined provided that the system is viable from technical/economic point of view.

In the process of improving the performance of concentrating solar collectors a variety of reflector materials are undergoing development. To allow comparable performance predictions, precise and replicable measuring methods are needed. In this paper we propose a measurement method and set-up (VLABS: very-low-angle beam spread) to determine the specular reflectance for variable angular acceptance. Our measurement set-up and method VLABS is advanced in measurement accuracy and speed, it gives as a result the specular reflectance for variable acceptance angles with an angular resolution of 0.03 mrad. We show exemplary results for a glass and an aluminum reflector and discuss the impact of acceptance angles up to 33 mrad on measured reflectance values at different wavelengths.

In the German national research and development project “HeizSolar” the building concept of Solar-Active-Housesis analyzed. The concept allows for a high fraction of solar thermal energyof more than 50% of the total heat supply. Within the project nine existing buildings have been monitored since the beginning of the heating period of 2011. The technology applied for this kind of supply concept has been introduced in [1,2]. Based on the data obtained from the in-situ monitoring, typical operation conditions have been identified and analyzed in [3]. The measured datawas also used to derive parameters to calibratea dynamic system simulation model for Solar-Active-Houses[4]. Theelaborated model focuses on the performance of the solar thermal collector as well as the solar circuit. What is more, the dynamic interaction between the solar thermal heat generator and the auxiliary heating systems as well as the heat distribution system are incorporated in detail. Finally the diffuse heat flux resulting of the integration of large hot water storage tanks into the building envelope is implemented to the model. This model is applied in the following to analyze the general thermal behavior of the supply concept and to derive optimization potentials. In detail the systems performance in regard to different types of heat transferal systems for space heating is demonstrated. Also the dimensioning in regard to the key parameters of collector area and the thermal capacity of the storage system consisting of a hot water storage tankare stated.

The main objectives of research on innovative materials (phase change materials, PCM, or thermochemical materials, TCM) for thermal storage are the development of low-loss and compact storage systems with high capacity (sensible water storages being the benchmark). If the storage is to be implemented in an application with the aim to increase its energy efficiency, beside the technical/thermal properties and cost factors, also the environmental impact of the storage production and operation need to be considered during development. Yet up to now, a holistic development approach that considers the primary energy used for the manufacturing, operation and disposal in relationship to the potential energy savings does not exist for innovative storage concepts. Therefore, we are presenting data on the environmental impact of PCM and TCM on material and component level developed within the German project ""Speicher LCA"" (engl. ""Storage Life Cycle Assessment""). The evaluation shows that PCM can be environmentally beneficial compared to water, if they are used in an application with a small useful temperature difference (e.g. cooling). Storing solar thermal heat with solid sorption materials in a closed system does not seem environmentally beneficial. Additional scenarios assuming the possible reuse of undegraded material, configurations with open sorption storage and/or other material classes (such as salt hydrates and liquid sorption) will be studied in the future.

In order to assess the solar radiation on the complex geometry of Solar Tower receivers, usually detailed maps of the flux distribution are generated using optical simulations based on ray tracing techniques. Transient modeling including a large set of such simulations implies very high computational effort. A new methodology is presented which allows for transient assessment of the flux distribution based on a comparatively small set of optical simulations and subsequent interpolations. For this purpose, two different discretization grids are used: a set of uniformly distributed solar vector nodes on the sky hemisphere and a set of different heliostat field fractions being on focus. For the interpolation in the sky discretization, three different techniques are introduced and compared in terms of accuracy. Partly defocused heliostat fields as well as complex aiming strategies can be readily taken into account by the presented approach. The methodology is validated by means of two exemplary test setups (PS10 and Gemasolar). The accuracy of the different interpolation techniques depending on the refinement of the discretization grids is assessed with appropriate error measures. Depending on the temporal resolution of the transient application, the computational effort can be reduced by several orders of magnitude compared to a direct simulation of the flux distribution for every time step. In addition to the quantitative validation, the use of the developed methodology in conjunction with a thermo-hydraulic simulation is demonstrated by means of the PS10 setup.

d -Mannitol is a potential phase change material to store thermal energy for process heat applications between 120 °C and 200 °C. This study presents thermal cycling stability tests of d -mannitol and its effect on melting enthalpy. Short-term cycling tests were carried out in differential scanning calorimeter in combination with air and nitrogen/vacuum as atmosphere. Results show that melting enthalpy decreases in contact with oxygen, decreases less in vacuum and stays almost constant in nitrogen atmosphere over the performed cycles. Afterwards, a long-term cycling test in nitrogen atmosphere was performed. Here melting enthalpy decreases about 9% during 500 cycles. If this effect cannot be overcome, the material is unsuitable for most applications. Fourier-transform infrared spectroscopy was carried out to evaluate chemical stability after the cycling tests. A possible hypothesis for a degradation mechanism of d -mannitol is presented. It assumes that degradation products might be produced during thermal treatment. By additional oxidation the production of further degradation products might be triggered. It is likely that more degradation products were produced in the long-term cycling test than in the short-term cycling test in nitrogen leading to a decrease of melting enthalpy.

Ästhetisch ansprechend, ökologisch sinnvoll und kostengüstig - diese Ziele verfolgt das Fraunhofer-Institut für Solare Energiesysteme ISE zusammen mit Industriepartnern im Projekt Arkol - "Entwicklung von architektonisch hoch integrierten Fassadenkollektoren mit Heat-Pipes".

For the further development and dissemination of solar thermal technology, a continuous demonstration of its reliability is required. For this purpose, meaningful performance and acceptance testing is indispensable. The reliable determination of optical and thermal collector performance parameters involves a suitable testing and evaluation procedure. It additionally requires a dependable quality assessment of the test results. Sophisticated statistical inference calculations, however, are not commonly available in solar thermal collector testing. If applied at all, mostly standardly implemented (linear) confidence interval computations are used. The present publication proposes an advanced approach of confidence level computation, the so-called bootstrapping technique. It represents a common method in the area of economics and is suited to cope with the complexity of confidence calculations within the context of dynamic performance testing. The basic methodology and specific implementation of the bootstrapping approach are introduced in detail. Since this approach is new in performance evaluation procedures, it is validated with confidence results obtained from an extensive evaluation of a large measurement data basis of a linear Fresnel process heat collector. However, the procedure is equally suited for other collector types as parabolic trough, flat plate, and others. The validation with measurement data reveals the valuable capabilities of the bootstrap procedure. It moreover proves the standard confidence methods to fail, because these provide unrealistically narrow confidence intervals. Comparative results between the different methods are thoroughly discussed. They demonstrate the introduced bootstrapping approach to be a powerful tool, generating considerably more representative and therefore reliable confidence intervals than the customary methods. Consequently, bootstrapping is considered a key feature of an enhanced performance evaluation method, since it may provide improved information concerning parameter distribution, confidence levels, and hence the validity of corresponding test results. Meaningful performance testing represents an essential aspect to further increase the viability and reliability of the solar thermal technology in order to facilitate its easier commissioning and wide acceptance.