Oliver Opel | Leuphana University (original) (raw)

Papers by Oliver Opel

Proceedings of the 14th International Renewable Energy Storage Conference 2020 (IRES 2020), 2021

Thermochemical solid/gas sorption systems are known for their environmental benefits. T hey c an ... more Thermochemical solid/gas sorption systems are known for their environmental benefits. T hey c an u se low-grade temperature sources for supplying cold storage and cooling of buildings. The thermochemical working pair calcium chloride/methanol is well suited for sorption refrigeration and storage due to low costs, high energy density and good cyclability. The energy storage capacity results from the reversible sorption of methanol by the salt. Heating up the salt (desorption) stores thermal energy. Refrigeration results from the endothermic methanol evaporation which is induced by the salt reabsorbing the methanol and thus lowering the methanol vapor pressure. This study presents results from a 2 kW technical scale demonstrator of a closed thermochemical process with calcium chloride/methanol. The demonstrator consists of two alternatingly working sorption reactors to enable continuous operation. The operation was done under atmospheric pressure using fans for the mass transport of m...

International Climate Protection

The Leuphana University of Lueneburg achieved the first climate-neutral energy balance for heat, ... more The Leuphana University of Lueneburg achieved the first climate-neutral energy balance for heat, electricity, cars and business trips in 2014. The chapter focuses on the energy concept as part of an integral approach towards sustainability. A simulation study was carried out to quantify the advantageous impact of a seasonal heat storage in an aquifer on the district level. With the integration of the heat storage, the share of renewable heat reaches 95% and leads to 2,400 t less CO2 emissions.

Renewable and Sustainable Energy Reviews

Energy, 2016

A lab-scale thermochemical heat storage reactor was developed in the European project “thermal ba... more A lab-scale thermochemical heat storage reactor was developed in the European project “thermal battery” to obtain information on the characteristics of a closed heat storage system, based on thermochemical reactions. The present type of storage is capable of re-using waste heat from cogeneration system to produce useful heat for space heating. The storage material used was SrBr2·6H2O. Due to agglomeration or gel-like problems, a structural element was introduced to enhance vapour and heat transfer. Honeycomb heat exchanger was designed and tested. 13 dehydration-hydration cycles were studied under low-temperature conditions (material temperatures < 100 °C) for storage. Discharging was realized at water vapour pressure of about 42 mbar. Temperature evolution inside the reactor at different times and positions, chemical conversion, thermal power and overall efficiency were analysed for the selected cycles. Experimental system thermal capacity and efficiency of 65 kWh and 0.77 are respectively obtained with about 1 kg of SrBr2·6H2O. Heat transfer fluid recovers heat at a short span of about 43 °C with an average of 22 °C during about 4 h, acceptable temperature for the human comfort (20 °C on day and 16 °C at night). System performances were obtained for a salt bed energy density of 213 kWh·m3. The overall heat transfer coefficient of the honeycomb heat exchanger has an average value of 147 W m−2 K−1. Though promising results have been obtained, ameliorations need to be made, in order to make the closed thermochemical heat storage system competitive for space heating.

ABSTRACT Sustainability implementation affects all parts of an institution. Research institutes t... more ABSTRACT Sustainability implementation affects all parts of an institution. Research institutes typically have high energy demands and traffic / mobility emissions, but buildings, paper, office supply, waste, the canteen and other segments are also of great importance. Energy savings and reduction of mobility emissions surely are key factors and need custom-tailored solutions. However, sustainability means more than reducing direct emissions. To reach all parts of an institution, high level decisions are needed, and a management and reporting scheme, best case with external auditing, is necessary to ensure long-term progress and sustained efforts to reach sustainability goals. Last but not least dedicated staff is needed to introduce sustainability guidelines and support. http://indico.cern.ch/conferenceOtherViews.py?view=standard&confId=245432

ABSTRACT The invention relates to a method for heating and cooling a working fluid using ≥1 therm... more ABSTRACT The invention relates to a method for heating and cooling a working fluid using ≥1 thermochem. heat storage medium, wherein the working fluid is conducted through ≥1 thermochem. heat storage comprising the heat storage medium, wherein the working fluid is conducted in a noncontact manner to the heat storage medium, wherein upon charging of the heat storage medium a heat flow is transferred from the working fluid to the heat storage medium and ≥1 substance is released from the heat storage medium and discharged from the heat storage, and wherein upon discharging of the heat storage medium the substance is fed with release of heat to the heat storage medium or at least to a reaction product of the heat storage mediums that was produced during charging of the heat storage mediums, and a heat flow is transferred to the working fluid. [on SciFinder(R)]

ABSTRACT Copyright (C) 2012 American Chemical Society (ACS). All Rights Reserved.

The design of smart buildings requests assistance systems, which grant the intuitive integration ... more The design of smart buildings requests assistance systems, which grant the intuitive integration of users and visitors into cooperative building arrangements. In this paper an adaptive assistance system is proposed with the ability of implicit man-environmentcommunication to react customized to specific user preferences distributed by mobile devices. Embedding methods of knowledge processing into distributed systems is a key factor for enabling the cooperation of a user's mobile device and a smart building. Using the semantic knowledge description language OWL and meta services, technical devices, house establishments and internet services can interact in order to support the user's preferences. With the example of a straightforward ontology it is shown how a presence control switch is semantically modeled in description logic and the integration of the whole ontology in modern building services management control can help saving energy using mobile devices. As a result the paper shows how a maximum of comfort can be combined with a maximum of energy efficiency in the use of a day to day office life.

Zusammenhänge zwischen gemessenen und aus Fe 2+-Konzentrationen errechneten Redoxpotentialen in d... more Zusammenhänge zwischen gemessenen und aus Fe 2+-Konzentrationen errechneten Redoxpotentialen in den Fluiden der thermischen Aquifer-Energiespeicher im Energiesystem der Parlamentsbauten am Spreebogen in Berlin Zusammenfassung Die Arbeit stellt ein Schlüsselergebnis der Entwicklung einer Methode zur Abschätzung von Verockerungspotentialen aus üblicherweise bestimmten Vor-Ort-Parametern dar. Hierzu wurden gemessene Redoxpotentiale mit aus der Fe 2+-Konzentration errechneten Potentialen verglichen und Abhängigkeiten identifiziert. Die Daten repräsentieren routinemäßige Messungen aus den Jahren 2000 bis 2008 in den Fluiden der Aquiferwärme-und Kältespeicheranlagen im Energiesystem der Berliner Parlamentsbauten. Weitere wasseranalytische Daten wurden ebenfalls im Rahmen des seit Inbetriebnahme der Anlage durch die Universität Lüneburg durchgeführten wasserchemischen Monitorings erhalten. Die Daten zeigen einen deutlichen Einfluss der Bildung von Eisen(II)hydroxocarbonat-Komplexen auf die Elektrodenaktivität des Fe 2+. Unter weiterer Berücksichtigung der Parameter pH-Wert, Temperatur, Sauerstoffgehalt und Leitfähigkeit konnten die gemessenen Redoxpotentiale mithilfe eines linearen Modells erklärt werden. Die gezeigten Ergebnisse legen den Schluss nahe, dass die Berechnung von Fe 2+-Aktivitäten aus den genannten Vor-Ort-Parametern möglich ist und als Basis für eine Abschätzung von Fe(OH) 3-Bildungsgeschwindigkeiten genutzt werden können.

ABSTRACT Occurring in wells, pipework, and in natural groundwaters, the oxidation of ferrous iron... more ABSTRACT Occurring in wells, pipework, and in natural groundwaters, the oxidation of ferrous iron is a partly abiotic-, partly biotic-induced process. One of the most frequent species of neutrophilic iron oxidising bacteria is Leptothrix discophora. It is known to be able to oxidise Fe(II) as well as Mn(II). The adverse effects of ferric iron depositions are well known, but how Leptothrix benefits from this feature is still not fully understood. The elimination of H2O2 by MnO2 [1] or the protective effect from high, inhibitory concentrations of Mn(II) and Fe(II) within the sheaths [2] have been discussed as possible advantages. We assume that the iron oxidation through Leptothrix discophora is a purely abiotic process: iron is oxidised by the simultaneous reduction of actively oxidised Mn(IV). Fe(II) can be oxidised by Mn(IV). Oxidation experiments have been carried out in artificial groundwater, comparing the iron oxidation rates of biotic and abtioic produced Mn(IV). As a reference, the influence of bacterial cells without Mn(IV) depositions on the iron oxidation has been measured. L. discophora SS1, a sheathless strain and L. discophora SP6, a sheathed strain have been grown in a complex and L. discophora SP6 only in a minimal medium with and without the addition of Mn(II). The cells have been harvested in stationary phase by centrifugation. The bacteria or abiotic MnO2 precipitates have been added to a buffered, artificial groundwater. Samples from the stirred experimental reactor have been taken regularly to determine Mn(II), Mn(IV) and Fe(II) concentrations by ICP-OES in filtered and unfiltered samples and ferrozine assay. Oxidation rates have been calculated for all sets of experiments. L. discophora cells grown without the addition of Mn(II) do not accelerate the Fe(II) oxidation rate, compared to oxidation rates in artificial groundwater without the addition of cells or Mn(IV). Comparing iron oxidation in artificial groundwater with Mn(IV) from all sources (L. discophora SP6 and SS1 in minimal and complex medium, abiotic MnO2) lead to very similar oxidation rates. Mn(IV) particles are hardly incorporated in sheaths or covered with EPS. All biotically produced Mn(IV) can serve as an oxidating agent for iron oxidation. Leptothrix can oxidise the freshly reduced Mn again and lead, therefore, to constant iron oxidation even in low Mn containing systems. [1] G. Dubinina, Mikrobiologiia 1978, 47, 783–789. [2] S. Rogers, J. Anderson, J Bacteriol 1976, 126, 264–271.

Bedanken möchte ich mich zuallererst bei Prof. Dr.-Ing. Wolfgang Ruck für das faszinierende Thema... more Bedanken möchte ich mich zuallererst bei Prof. Dr.-Ing. Wolfgang Ruck für das faszinierende Thema, die Betreuung meiner Arbeit, seinen Wissens-und Erfahrungsschatz, den er mit mir geteilt hat, das Vertrauen sowie die vielfältigen weiteren Möglichkeiten in der Welt der Forschung, Lehre und Wissenschaft im Rahmen meiner Tätigkeit am Institut für nachhaltige Chemie und Umweltchemie. Bedanken möchte ich mich zudem bei Tanja Eggerichs und Tobias Otte, die sich ebenfalls für das Themenfeld biotische und abiotische Eisenoxidation begeistern konnten. Mein Dank gilt weiterhin allen weiteren Mitgliedern der Arbeitsgruppe Umweltchemie für die spannende Zusammenarbeit, die geteilte Leidenschaft, die Unterstützung, die Geduld und das immer hervorragende Arbeitsklima sowie viele heitere Stunden während und nach der Arbeit. Hervorgehoben sei Dr. Wolf-Ulrich Palm, von dessen Wissen und Erfahrung ich ebenfalls stark profitiert habe. Besonders bedanken möchte ich mich bei meiner Familie, insbesondere meinen lieben Eltern, die meine experimentellen Erfahrungen schon im Grundschulalter glücklicherweise nicht verhindern konnten und mir einen frühen Zugang und eine entsprechende Ausbildung ermöglichten sowie ganz besonders bei meiner geliebten Frau Carola, die mir mit einem auch zu später Stunde offenen Ohr für wasserchemische und weitergehende Fragestellungen und mit viel Geduld und Zuneigung eine wesentliche Quelle von Inspiration und Kraft war und ist. Weiterhin gebührt mein Dank Prof. Dr. Ernst Huenges als Projektleiter des vom BMWi geförderten Vorhabens "Thermische Untergrundspeicher in Energiesystemen: Optimierung der Einbindung der Aquiferspeicher in die Wärme-und Kälteversorgung der Parlamentsbauten im Berliner Spreebogen" FKZ 0329809C/D, das meine Arbeit entscheidend prägte, sowie Prof. Dr.-Ing. Wolfgang Calmano für die Übernahme des Koreferats. Danken möchte ich auch den weiteren Projektpartnern, insbesondere

Proceedings of the 14th International Renewable Energy Storage Conference 2020 (IRES 2020), 2021

Thermochemical solid/gas sorption systems are known for their environmental benefits. T hey c an ... more Thermochemical solid/gas sorption systems are known for their environmental benefits. T hey c an u se low-grade temperature sources for supplying cold storage and cooling of buildings. The thermochemical working pair calcium chloride/methanol is well suited for sorption refrigeration and storage due to low costs, high energy density and good cyclability. The energy storage capacity results from the reversible sorption of methanol by the salt. Heating up the salt (desorption) stores thermal energy. Refrigeration results from the endothermic methanol evaporation which is induced by the salt reabsorbing the methanol and thus lowering the methanol vapor pressure. This study presents results from a 2 kW technical scale demonstrator of a closed thermochemical process with calcium chloride/methanol. The demonstrator consists of two alternatingly working sorption reactors to enable continuous operation. The operation was done under atmospheric pressure using fans for the mass transport of m...

International Climate Protection

The Leuphana University of Lueneburg achieved the first climate-neutral energy balance for heat, ... more The Leuphana University of Lueneburg achieved the first climate-neutral energy balance for heat, electricity, cars and business trips in 2014. The chapter focuses on the energy concept as part of an integral approach towards sustainability. A simulation study was carried out to quantify the advantageous impact of a seasonal heat storage in an aquifer on the district level. With the integration of the heat storage, the share of renewable heat reaches 95% and leads to 2,400 t less CO2 emissions.

Renewable and Sustainable Energy Reviews

Energy, 2016

A lab-scale thermochemical heat storage reactor was developed in the European project “thermal ba... more A lab-scale thermochemical heat storage reactor was developed in the European project “thermal battery” to obtain information on the characteristics of a closed heat storage system, based on thermochemical reactions. The present type of storage is capable of re-using waste heat from cogeneration system to produce useful heat for space heating. The storage material used was SrBr2·6H2O. Due to agglomeration or gel-like problems, a structural element was introduced to enhance vapour and heat transfer. Honeycomb heat exchanger was designed and tested. 13 dehydration-hydration cycles were studied under low-temperature conditions (material temperatures < 100 °C) for storage. Discharging was realized at water vapour pressure of about 42 mbar. Temperature evolution inside the reactor at different times and positions, chemical conversion, thermal power and overall efficiency were analysed for the selected cycles. Experimental system thermal capacity and efficiency of 65 kWh and 0.77 are respectively obtained with about 1 kg of SrBr2·6H2O. Heat transfer fluid recovers heat at a short span of about 43 °C with an average of 22 °C during about 4 h, acceptable temperature for the human comfort (20 °C on day and 16 °C at night). System performances were obtained for a salt bed energy density of 213 kWh·m3. The overall heat transfer coefficient of the honeycomb heat exchanger has an average value of 147 W m−2 K−1. Though promising results have been obtained, ameliorations need to be made, in order to make the closed thermochemical heat storage system competitive for space heating.

ABSTRACT Sustainability implementation affects all parts of an institution. Research institutes t... more ABSTRACT Sustainability implementation affects all parts of an institution. Research institutes typically have high energy demands and traffic / mobility emissions, but buildings, paper, office supply, waste, the canteen and other segments are also of great importance. Energy savings and reduction of mobility emissions surely are key factors and need custom-tailored solutions. However, sustainability means more than reducing direct emissions. To reach all parts of an institution, high level decisions are needed, and a management and reporting scheme, best case with external auditing, is necessary to ensure long-term progress and sustained efforts to reach sustainability goals. Last but not least dedicated staff is needed to introduce sustainability guidelines and support. http://indico.cern.ch/conferenceOtherViews.py?view=standard&confId=245432

ABSTRACT The invention relates to a method for heating and cooling a working fluid using ≥1 therm... more ABSTRACT The invention relates to a method for heating and cooling a working fluid using ≥1 thermochem. heat storage medium, wherein the working fluid is conducted through ≥1 thermochem. heat storage comprising the heat storage medium, wherein the working fluid is conducted in a noncontact manner to the heat storage medium, wherein upon charging of the heat storage medium a heat flow is transferred from the working fluid to the heat storage medium and ≥1 substance is released from the heat storage medium and discharged from the heat storage, and wherein upon discharging of the heat storage medium the substance is fed with release of heat to the heat storage medium or at least to a reaction product of the heat storage mediums that was produced during charging of the heat storage mediums, and a heat flow is transferred to the working fluid. [on SciFinder(R)]

ABSTRACT Copyright (C) 2012 American Chemical Society (ACS). All Rights Reserved.

The design of smart buildings requests assistance systems, which grant the intuitive integration ... more The design of smart buildings requests assistance systems, which grant the intuitive integration of users and visitors into cooperative building arrangements. In this paper an adaptive assistance system is proposed with the ability of implicit man-environmentcommunication to react customized to specific user preferences distributed by mobile devices. Embedding methods of knowledge processing into distributed systems is a key factor for enabling the cooperation of a user's mobile device and a smart building. Using the semantic knowledge description language OWL and meta services, technical devices, house establishments and internet services can interact in order to support the user's preferences. With the example of a straightforward ontology it is shown how a presence control switch is semantically modeled in description logic and the integration of the whole ontology in modern building services management control can help saving energy using mobile devices. As a result the paper shows how a maximum of comfort can be combined with a maximum of energy efficiency in the use of a day to day office life.

Zusammenhänge zwischen gemessenen und aus Fe 2+-Konzentrationen errechneten Redoxpotentialen in d... more Zusammenhänge zwischen gemessenen und aus Fe 2+-Konzentrationen errechneten Redoxpotentialen in den Fluiden der thermischen Aquifer-Energiespeicher im Energiesystem der Parlamentsbauten am Spreebogen in Berlin Zusammenfassung Die Arbeit stellt ein Schlüsselergebnis der Entwicklung einer Methode zur Abschätzung von Verockerungspotentialen aus üblicherweise bestimmten Vor-Ort-Parametern dar. Hierzu wurden gemessene Redoxpotentiale mit aus der Fe 2+-Konzentration errechneten Potentialen verglichen und Abhängigkeiten identifiziert. Die Daten repräsentieren routinemäßige Messungen aus den Jahren 2000 bis 2008 in den Fluiden der Aquiferwärme-und Kältespeicheranlagen im Energiesystem der Berliner Parlamentsbauten. Weitere wasseranalytische Daten wurden ebenfalls im Rahmen des seit Inbetriebnahme der Anlage durch die Universität Lüneburg durchgeführten wasserchemischen Monitorings erhalten. Die Daten zeigen einen deutlichen Einfluss der Bildung von Eisen(II)hydroxocarbonat-Komplexen auf die Elektrodenaktivität des Fe 2+. Unter weiterer Berücksichtigung der Parameter pH-Wert, Temperatur, Sauerstoffgehalt und Leitfähigkeit konnten die gemessenen Redoxpotentiale mithilfe eines linearen Modells erklärt werden. Die gezeigten Ergebnisse legen den Schluss nahe, dass die Berechnung von Fe 2+-Aktivitäten aus den genannten Vor-Ort-Parametern möglich ist und als Basis für eine Abschätzung von Fe(OH) 3-Bildungsgeschwindigkeiten genutzt werden können.

ABSTRACT Occurring in wells, pipework, and in natural groundwaters, the oxidation of ferrous iron... more ABSTRACT Occurring in wells, pipework, and in natural groundwaters, the oxidation of ferrous iron is a partly abiotic-, partly biotic-induced process. One of the most frequent species of neutrophilic iron oxidising bacteria is Leptothrix discophora. It is known to be able to oxidise Fe(II) as well as Mn(II). The adverse effects of ferric iron depositions are well known, but how Leptothrix benefits from this feature is still not fully understood. The elimination of H2O2 by MnO2 [1] or the protective effect from high, inhibitory concentrations of Mn(II) and Fe(II) within the sheaths [2] have been discussed as possible advantages. We assume that the iron oxidation through Leptothrix discophora is a purely abiotic process: iron is oxidised by the simultaneous reduction of actively oxidised Mn(IV). Fe(II) can be oxidised by Mn(IV). Oxidation experiments have been carried out in artificial groundwater, comparing the iron oxidation rates of biotic and abtioic produced Mn(IV). As a reference, the influence of bacterial cells without Mn(IV) depositions on the iron oxidation has been measured. L. discophora SS1, a sheathless strain and L. discophora SP6, a sheathed strain have been grown in a complex and L. discophora SP6 only in a minimal medium with and without the addition of Mn(II). The cells have been harvested in stationary phase by centrifugation. The bacteria or abiotic MnO2 precipitates have been added to a buffered, artificial groundwater. Samples from the stirred experimental reactor have been taken regularly to determine Mn(II), Mn(IV) and Fe(II) concentrations by ICP-OES in filtered and unfiltered samples and ferrozine assay. Oxidation rates have been calculated for all sets of experiments. L. discophora cells grown without the addition of Mn(II) do not accelerate the Fe(II) oxidation rate, compared to oxidation rates in artificial groundwater without the addition of cells or Mn(IV). Comparing iron oxidation in artificial groundwater with Mn(IV) from all sources (L. discophora SP6 and SS1 in minimal and complex medium, abiotic MnO2) lead to very similar oxidation rates. Mn(IV) particles are hardly incorporated in sheaths or covered with EPS. All biotically produced Mn(IV) can serve as an oxidating agent for iron oxidation. Leptothrix can oxidise the freshly reduced Mn again and lead, therefore, to constant iron oxidation even in low Mn containing systems. [1] G. Dubinina, Mikrobiologiia 1978, 47, 783–789. [2] S. Rogers, J. Anderson, J Bacteriol 1976, 126, 264–271.

Bedanken möchte ich mich zuallererst bei Prof. Dr.-Ing. Wolfgang Ruck für das faszinierende Thema... more Bedanken möchte ich mich zuallererst bei Prof. Dr.-Ing. Wolfgang Ruck für das faszinierende Thema, die Betreuung meiner Arbeit, seinen Wissens-und Erfahrungsschatz, den er mit mir geteilt hat, das Vertrauen sowie die vielfältigen weiteren Möglichkeiten in der Welt der Forschung, Lehre und Wissenschaft im Rahmen meiner Tätigkeit am Institut für nachhaltige Chemie und Umweltchemie. Bedanken möchte ich mich zudem bei Tanja Eggerichs und Tobias Otte, die sich ebenfalls für das Themenfeld biotische und abiotische Eisenoxidation begeistern konnten. Mein Dank gilt weiterhin allen weiteren Mitgliedern der Arbeitsgruppe Umweltchemie für die spannende Zusammenarbeit, die geteilte Leidenschaft, die Unterstützung, die Geduld und das immer hervorragende Arbeitsklima sowie viele heitere Stunden während und nach der Arbeit. Hervorgehoben sei Dr. Wolf-Ulrich Palm, von dessen Wissen und Erfahrung ich ebenfalls stark profitiert habe. Besonders bedanken möchte ich mich bei meiner Familie, insbesondere meinen lieben Eltern, die meine experimentellen Erfahrungen schon im Grundschulalter glücklicherweise nicht verhindern konnten und mir einen frühen Zugang und eine entsprechende Ausbildung ermöglichten sowie ganz besonders bei meiner geliebten Frau Carola, die mir mit einem auch zu später Stunde offenen Ohr für wasserchemische und weitergehende Fragestellungen und mit viel Geduld und Zuneigung eine wesentliche Quelle von Inspiration und Kraft war und ist. Weiterhin gebührt mein Dank Prof. Dr. Ernst Huenges als Projektleiter des vom BMWi geförderten Vorhabens "Thermische Untergrundspeicher in Energiesystemen: Optimierung der Einbindung der Aquiferspeicher in die Wärme-und Kälteversorgung der Parlamentsbauten im Berliner Spreebogen" FKZ 0329809C/D, das meine Arbeit entscheidend prägte, sowie Prof. Dr.-Ing. Wolfgang Calmano für die Übernahme des Koreferats. Danken möchte ich auch den weiteren Projektpartnern, insbesondere