@article{HagenkampBlankeDoering2021,
  author    = {Hagenkamp, Markus and Blanke, Tobias and D{\"o}ring, Bernd},
  title     = {Thermoelectric building temperature control: a potential assessment},
  series = {International Journal of Energy and Environmental Engineering},
  volume    = {13},
  journal   = {International Journal of Energy and Environmental Engineering},
  publisher = {Springer},
  address   = {Berlin},
  doi       = {10.1007/s40095-021-00424-x},
  pages     = {241 -- 254},
  year      = {2021},
  abstract  = {This study focuses on thermoelectric elements (TEE) as an alternative for room temperature control. TEE are semi-conductor devices that can provide heating and cooling via a heat pump effect without direct noise emissions and no refrigerant use. An efficiency evaluation of the optimal operating mode is carried out for different numbers of TEE, ambient temperatures, and heating loads. The influence of an additional heat recovery unit on system efficiency and an unevenly distributed heating demand are examined. The results show that TEE can provide heat at a coefficient of performance (COP) greater than one especially for small heating demands and high ambient temperatures. The efficiency increases with the number of elements in the system and is subject to economies of scale. The best COP exceeds six at optimal operating conditions. An additional heat recovery unit proves beneficial for low ambient temperatures and systems with few TEE. It makes COPs above one possible at ambient temperatures below 0 ∘C. The effect increases efficiency by maximal 0.81 (from 1.90 to 2.71) at ambient temperature 5 K below room temperature and heating demand Q˙h=100W but is subject to diseconomies of scale. Thermoelectric technology is a valuable option for electricity-based heat supply and can provide cooling and ventilation functions. A careful system design as well as an additional heat recovery unit significantly benefits the performance. This makes TEE superior to direct current heating systems and competitive to heat pumps for small scale applications with focus on avoiding noise and harmful refrigerants.},
  language  = {en}
}
@article{BlankeRegerDoeringetal.2021,
  author    = {Blanke, Tobias and Reger, Vitali and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Kuhnhenne, Markus},
  title     = {Koaxiale Stahlenergiepf{\"a}hle},
  series = {Stahlbau},
  volume    = {90. 2021},
  journal   = {Stahlbau},
  number    = {6},
  publisher = {Wiley},
  address   = {Weinheim},
  pages     = {417 -- 424},
  year      = {2021},
  abstract  = {Ein entscheidender Teil der Energiewende ist die W{\"a}rmewende im Geb{\"a}udesektor. Ein Schl{\"u}sselelement sind hier W{\"a}rmepumpen. Diese ben{\"o}tigen eine W{\"a}rmequelle, der sie Energie entziehen k{\"o}nnen, um sie auf ein h{\"o}heres Temperaturniveau zu transformieren. Diese W{\"a}rmequelle kann bspw. das Erdreich sein, dessen W{\"a}rme durch Erdsonden erschlossen werden kann. In diesem Beitrag werden in Stahlpf{\"a}hle integrierte Koaxialsonden mit dem Stand der Technik von Erdsonden gleichen Durchmessers bez{\"u}glich ihrer thermischen Leistungsmerkmale verglichen. Die Stahlenergiepf{\"a}hle bieten neben der W{\"a}rmegewinnung weitere Vorteile, da sie auch eine statische Funktion {\"u}bernehmen und r{\"u}ckstandsfrei zur{\"u}ckgebaut werden k{\"o}nnen. Es werden analytische und numerische Berechnungen vorgestellt, um die thermischen Potenziale beider Systeme zu vergleichen. Außerdem wird ein Testaufbau gezeigt, bei dem Stahlenergiepf{\"a}hle in zwei verschiedenen L{\"a}ngen mit vorhandenen g{\"a}ngigen Erdsonden verglichen werden k{\"o}nnen. Die Berechnungen zeigen einen deutlichen thermischen Mehrertrag zwischen 26 \% und 148 \% der Stahlenergiepf{\"a}hle gegen{\"u}ber dem Stand der Technik abh{\"a}ngig vom Erdreich. Die Messergebnisse zeigen einen thermischen Mehrertrag von {\"u}ber 100 \%. Es l{\"a}sst sich also signifikante Erdsondenl{\"a}nge einsparen. Dabei ist zu beachten, dass sich damit der thermisch genutzte Bereich des Erdreichs reduziert, wodurch die thermische Regeneration und/oder das Langzeitverhalten des Erdreichs an Bedeutung gewinnt.},
  language  = {de}
}
@incollection{HoffschmidtAlexopoulosRauetal.2021,
  author    = {Hoffschmidt, Bernhard and Alexopoulos, Spiros and Rau, Christoph and Sattler, Johannes, Christoph and Anthrakidis, Anette and Teixeira Boura, Cristiano Jos{\´e} and O'Connor, B. and Caminos, R.A. Chico and Rend{\´o}n, C. and Hilger, P.},
  title     = {Concentrating Solar Power},
  series = {Earth systems and environmental sciences},
  booktitle = {Earth systems and environmental sciences},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {978-0-12-409548-9},
  doi       = {10.1016/B978-0-12-819727-1.00089-3},
  year      = {2021},
  abstract  = {The focus of this chapter is the production of power and the use of the heat produced from concentrated solar thermal power (CSP) systems. The chapter starts with the general theoretical principles of concentrating systems including the description of the concentration ratio, the energy and mass balance. The power conversion systems is the main part where solar-only operation and the increase in operational hours. Solar-only operation include the use of steam turbines, gas turbines, organic Rankine cycles and solar dishes. The operational hours can be increased with hybridization and with storage. Another important topic is the cogeneration where solar cooling, desalination and of heat usage is described. Many examples of commercial CSP power plants as well as research facilities from the past as well as current installed and in operation are described in detail. The chapter closes with economic and environmental aspects and with the future potential of the development of CSP around the world.},
  language  = {en}
}
@article{HerrmannSchwarzenbartDittmannGabrieletal.2019,
  author    = {Herrmann, Ulf and Schwarzenbart, Marc and Dittmann-Gabriel, S{\"o}ren and May, Martin},
  title     = {Hochtemperatur-W{\"a}rmespeicher f{\"u}r die Strom- und W{\"a}rmewende},
  series = {Solarzeitalter : Politik, Kultur und {\"O}konomie erneuerbarer Energien},
  volume    = {31},
  journal   = {Solarzeitalter : Politik, Kultur und {\"O}konomie erneuerbarer Energien},
  number    = {2},
  issn      = {0937-3802},
  pages     = {18 -- 23},
  year      = {2019},
  language  = {de}
}
@inproceedings{SattlerChicoCaminosAttietal.2020,
  author    = {Sattler, Johannes Christoph and Chico Caminos, Ricardo Alexander and Atti, Vikrama Nagababu and {\"U}rlings, Nicolas and Dutta, Siddharth and Ruiz, Victor and Kalogirou, Soteris and Ktistis, Panayiotis and Agathokleous, Rafaela and Alexopoulos, Spiros and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf},
  title     = {Dynamic simulation tool for a performance evaluation and sensitivity study of a parabolic trough collector system with concrete thermal energy storage},
  series = {AIP Conference Proceedings 2303},
  booktitle = {AIP Conference Proceedings 2303},
  publisher = {American Institute of Physics},
  address   = {Melville, NY},
  issn      = {0094-243X},
  doi       = {10.1063/5.0029277},
  pages     = {160004},
  year      = {2020},
  language  = {de}
}
@article{MeyerHaenelBeehetal.2020,
  author    = {Meyer, S. and H{\"a}nel, Matthias and Beeh, B. and Dittmann-Gabriel, S{\"o}ren and Dluhosch, R. and May, Martin and Herrmann, Ulf},
  title     = {Multifunktionaler thermischer Stromspeicher f{\"u}r die Strom- und W{\"a}rmeversorgung der Industrie von morgen},
  series = {ETG Journal / Energietechnische Gesellschaft im VDE (ETG)},
  volume    = {2020},
  journal   = {ETG Journal / Energietechnische Gesellschaft im VDE (ETG)},
  number    = {1},
  issn      = {2625-9907},
  pages     = {6 -- 9},
  year      = {2020},
  language  = {de}
}
@article{BlankeHagenkampDoeringetal.2021,
  author    = {Blanke, Tobias and Hagenkamp, Markus and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Reger, Vitali and Kuhnhenne, Markus},
  title     = {Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates},
  series = {Geothermal Energy},
  volume    = {9},
  journal   = {Geothermal Energy},
  number    = {Article number: 19},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {2195-9706},
  doi       = {10.1186/s40517-021-00201-3},
  pages     = {23 Seiten},
  year      = {2021},
  abstract  = {Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellstr{\"o}m's borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54\% of the outer pipe radius for laminar fow and 60\% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth's thermal properties and the fow type. Conclusively, coaxial geothermal probes' design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.},
  language  = {en}
}
@inproceedings{ElMoussaouiKassmiAlexopoulosetal.2021,
  author    = {El Moussaoui, Noureddine and Kassmi, Khalil and Alexopoulos, Spiros and Schwarzer, Klemens and Chayeb, Hamid and Bachiri, Najib},
  title     = {Simulation studies on a new innovative design of a hybrid solar distiller MSDH alimented with a thermal and photovoltaic energy},
  series = {Materialstoday: Proceedings},
  volume    = {45},
  booktitle = {Materialstoday: Proceedings},
  number    = {8},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {2214-7853},
  doi       = {10.1016/j.matpr.2021.03.115},
  pages     = {7653 -- 7660},
  year      = {2021},
  abstract  = {In this paper, we present the structure, the simulation the operation of a multi-stage, hybrid solar desalination system (MSDH), powered by thermal and photovoltaic (PV) (MSDH) energy. The MSDH system consists of a lower basin, eight horizontal stages, a field of four flat thermal collectors with a total area of 8.4 m2, 3 Kw PV panels and solar batteries. During the day the system is heated by thermal energy, and at night by heating resistors, powered by solar batteries. These batteries are charged by the photovoltaic panels during the day. More specifically, during the day and at night, we analyse the temperature of the stages and the production of distilled water according to the solar irradiation intensity and the electric heating power, supplied by the solar batteries. The simulations were carried out in the meteorological conditions of the winter month (February 2020), presenting intensities of irradiance and ambient temperature reaching 824 W/m2 and 23 °C respectively. The results obtained show that during the day the system is heated by the thermal collectors, the temperature of the stages and the quantity of water produced reach 80 °C and 30 Kg respectively. At night, from 6p.m. the system is heated by the electric energy stored in the batteries, the temperature of the stages and the quantity of water produced reach respectively 90 °C and 104 Kg for an electric heating power of 2 Kw. Moreover, when the electric power varies from 1 Kw to 3 Kw the quantity of water produced varies from 92 Kg to 134 Kg. The analysis of these results and their comparison with conventional solar thermal desalination systems shows a clear improvement both in the heating of the stages, by 10\%, and in the quantity of water produced by a factor of 3.},
  language  = {en}
}
@inproceedings{DuemmlerOetringerGoettsche2020,
  author    = {D{\"u}mmler, Andreas and Oetringer, Kerstin and G{\"o}ttsche, Joachim},
  title     = {Auslegungstool zur energieeffizienten K{\"u}hlung von Geb{\"a}uden},
  series = {DKV-Tagung 2020, AA IV},
  booktitle = {DKV-Tagung 2020, AA IV},
  pages     = {1109},
  year      = {2020},
  abstract  = {Thematisch widmet sich das Projekt Coolplan- AIR der Fortentwicklung und Feldvalidierung eines Berechnungs- und Auslegungstools zur energieeffizienten K{\"u}hlung von Geb{\"a}uden mit luftgest{\"u}tzten Systemen. Neben dem Aufbau und der Weiterentwicklung von Simulationsmodellen erfolgen Vermessungen der Gesamtsysteme anhand von Praxisanlagen im Feld. Der Schwerpunkt des Projekts liegt auf der Vermessung, Simulation und Integration rein luftgest{\"u}tzter K{\"u}hltechnologien. Im Bereich der K{\"a}lteerzeugung wurden Luft- Luft- W{\"a}rmepumpen, Anlagen zur adiabaten K{\"u}hlung bzw. offene K{\"u}hlt{\"u}rme und VRF- Multisplit- Systeme (Variable Refrigerant Flow) im Feld bzw. auf dem Teststand der HSD vermessen. Die Komponentenmodelle werden in die Matlab/Simulink- Toolbox CARNOT integriert und anschließend auf Basis der zuvor erhaltenen Messdaten validiert. Einerseits erlauben die Messungen das Betriebsverhalten von Anlagenkomponenten zu analysieren. Andererseits soll mit der Vermessung im Feld gepr{\"u}ft werden, inwieweit die Simulationsmodelle, welche im Vorg{\"a}ngerprojekt aus Pr{\"u}fstandmessungen entwickelt wurden, auch f{\"u}r gr{\"o}ßere Ger{\"a}teleistungen G{\"u}ltigkeit besitzen. Die entwickelten und implementierten Systeme, bestehend aus verschiedensten Anlagenmodellen und Regelungskomponenten, werden gepr{\"u}ft und dahingehend qualifiziert, dass sie in Standard- Auslegungstools zuverl{\"a}ssig verwendet werden k{\"o}nnen. Zus{\"a}tzlich wird ein energetisches Monitoring eines H{\"o}rsaalgeb{\"a}udes am Campus J{\"u}lich durchgef{\"u}hrt, das u. a. zur Validierung der K{\"u}hllastberechnungen in g{\"a}ngigen Simulationsmodelle genutzt werden kann.},
  language  = {de}
}
@inproceedings{OetringerDuemmlerGoettsche2020,
  author    = {Oetringer, Kerstin and D{\"u}mmler, Andreas and G{\"o}ttsche, Joachim},
  title     = {Neues Modell zur 1D-Simulation der indirekten Verdunstungsk{\"u}hlung},
  series = {DKV-Tagung 2020, AA II.1},
  booktitle = {DKV-Tagung 2020, AA II.1},
  pages     = {250 -- 262},
  year      = {2020},
  abstract  = {Im Projekt Coolplan- AIR geht es um die Fortentwicklung und Feld- Validierung eines Berechnungs- und Auslegungstools zur energieeffizienten K{\"u}hlung von Geb{\"a}uden mit luftgest{\"u}tzten Systemen. Neben dem Aufbau und der Weiterentwicklung von Simulationsmodellen erfolgen Vermessungen der Gesamtsysteme anhand von Praxisanlagen im Feld. Eine der betrachteten Anlagen arbeitet mit indirekter Verdunstung. Diese Ver{\"o}ffentlichung zeigt den Entwicklungsprozess und den Aufbau des Simulationsmodells zur Verdunstungsk{\"u}hlung in der Simulationsumgebung Matlab- Simulink mit der CARNOT- Toolbox. Das besondere Augenmerk liegt dabei auf dem physikalischen Modell des W{\"a}rme{\"u}bertragers, in dem die Verdunstung implementiert ist. Dem neuen Modellansatz liegt die Annahme einer aus der Enthalpie- Betrachtung hergeleiteten effektiven W{\"a}rmekapazit{\"a}t zugrunde. Des Weiteren wird der Befeuchtungsgrad als konstant angesehen und eine standardisierte Zunahme der W{\"a}rme{\"u}bertragung des feuchten gegen{\"u}ber dem trockenen W{\"a}rme{\"u}bertrager angenommen. Die Validierung des Modells erfolgte anhand von Literaturdaten. F{\"u}r den trockenen W{\"a}rmetauscher ist der maximale absolute Fehler der berechneten Austrittstemperatur (Zuluft) kleiner als ±0.1 K und f{\"u}r den nassen W{\"a}rmetauscher (K{\"u}hlfall) unter der Annahme eines konstanten Verdunstungsgrades kleiner als ±0.4 K.},
  language  = {de}
}