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AbstractThis paper presents two different reactor concepts, an external and integrated reactor, for thermochemical energy stores which are operating in an open process using ambient air for the heat and mass transport. In the external reactor concept the material charging and discharging is performed in a reactor separated from the material store whereas in the integrated reactor concept the charging and discharging take place directly in the material store itself. For both reactor concepts, the heat and mass transfer inside the reactor or the material store respectively, have been analyzed in detail by means of numerical simulations. Based on the theoretical investigations a reactor design and an operation strategy have been developed. At laboratory scale an external test reactor (approx. 20 l of storage volume) has been built and experimentally tested. The experiments have proven the concept of the developed reactor design. A high thermal performance during the charging and discharging process of the thermochemical energy store has been obtained.

Abstract To improve food security a conceptual integration beyond the scope of production in the agricultural sector due to examination of critical supply chain system compartments and levels of services (“integrated food production and supply systems”) is proposed. For creating systematic results, a platform integrating various perspectives of experts has been established following the principle of triple helix stakeholdership (business practice, public management/policy and also science). During a series of workshops, the main actors, success factors, challenges and communication strategies have been identified for shaping sustainable food supply chains under use of systems thinking and the application of Participatory Systems mapping (PSM). In this line, the paper presents how “system maps” based on the method of PSM are used to gain insights into sustainable logistics services facilitating sustainable consumption patterns, enabling participatory considerations and the productive exchange of knowledge.

Abstract In this contribution we compare the results of a line-scanning camera and line-wise illumination based PL-imaging system (Line-PLI) to the results of a “classic” PL-imaging system featuring a matrix camera and a full area illumination of the wafer. We investigate the impact of the different injection conditions which result from the significantly higher irradiance user in the Line-PLI system. We derive a formula which can easily be used to predict how high the irradiance may be without causing the lifetime to be limited by intrinsic silicon recombination. We compare the image contrasts caused by regions of different recombination activity and we compare the robustness of the method, which calibrates the PL-images to local effective lifetime using photoconductance (QSSPC) measurements. As a result it can be said that contrasts between regions of high and low recombination activity are more pronounced using the investigated Line-PLI setup, which qualifies it excellently for the visualization of process inhomogeneities causing defects on solar cell precursor. We calculate that the irradiance of the investigated setup is still low enough to differentiate between regions of different Shockley-Read-Hall recombination if the effective sample lifetimes are roughly below 250 µs. Moreover we derive an uncertainty of 24 % on the absolute values of effective lifetime using the Area-PLI setup while we derive an uncertainty of only 8 % on the absolute values of effective lifetime using the Line-PLI setup for the investigated samples.

Abstract As a representation of smart and green city development, bike-sharing system is one of the hottest topic in the fields of transportation, public health, urban planning, and so on. With the development of Mobility as a Service (MaaS), emerging technologies such as mobile data mining give some new solutions for optimizing bike-sharing system and predicting the emission reduction. Here, we propose a bike-sharing layout optimization and emission reduction potential analysis structure under the concept of MaaS. A human travel mode detection method and a geometry-based probability model are proposed to support the particle swarm optimization process. We implement a comparison study to analyze the computational efficiency. Taking Setagaya ward, Tokyo as the study case with about 3 million GPS trajectories, the result shows that with the increase of station number from 30 to 90, the adoption of bike-sharing system can reduce about 3.1-3.8 thousand tonnes of CO2 emission.

Abstract Membrane contactors offer a promising alternative to conventional CO2 absorption processes using columns. In a membrane contactor the advantages of absorption technology and membrane technology are combined as direct contact of the solution and gas feed stream is avoided by membrane barrier. In this study, the possibility of employing the enzyme carbonic anhydrase (CA) for the acceleration of CO2 reaction in MDEA and MEA solution in combination with the use of a membrane contactor was investigated in a lab scale module. The membranes employed in this study were microporous and specifically chosen to have both hydrophobic (bulk) and hydrophilic (surface) properties in order to avoid wetting of solution and reduce fouling by the enzymes simultaneously. By adding the enzyme carbonic anhydrase (CA), a significant improvement of CO2 absorption rate was observed in MDEA solution while a negative effect was observed in MEA solution. Meanwhile the porous hydrophobic membranes were coated with a highly selective poly(ionic liquids) layer increasing the affinity of CO2 towards the interfacial area and hence also the driving force. The concept may initially appear counter intuitive, as the dense membrane layer introduces an added resistance, however the active membrane material gave promising results and was observed to accelerate CO2 transport in MDEA solution. The combination of both enzyme and PILs resulted in synergies, which significantly improved CO2 absorption in MDEA solution.

AbstractThis paper describes accelerated aging tests on parabolic trough receivers. Overheating of parabolic trough receivers about 80-100K over the nominal operating temperature is applied for accelerated aging of the absorber coating.A lifetime prediction based on the Arrhenius parameters requires extensive testing; A reduced test with heating receivers to 478°C for 1000hours is applied on receivers for oil fluid in order to compare heat loss and optical efficiency before and after such accelerated aging. In a further test set, such receivers are thermally cycled between 200°C and 478°C for 100 times. A bellow fatigue test has been developed for testing of the bellows stability for the compression and expansion. Receivers are subjected to 20,000 cycles and rested for a 24 hour waiting period. The receiver heat loss during the bellow fatigue test shall not increase more than 30%. Durability of the antireflex coating on the glass is tested with the Taber linear abrasor using the CS-10F rubber (¾”) and MIL 12397 Eraser (¼”). Both abrasive materials proved to be suited to obtain reproducible results, although the discussion is still ongoing on which material should be used. The larger diameter of the CS-10F rubber offers the advantage that transmittance measurement with the Lambda 950/1050 spectrophotometer can be performed without the necessity for multiple abrading stripes.

AbstractMinimizing the optical and electrical losses from cell to module is essential for highly efficient PV modules. We use metal wrap through (MWT) solar cells with passivated rear surface to integrate them into a PV-module and minimize the cell to module losses. For this purpose, we analyze the optical properties of different encapsulation materials with respect to this specific cell type, i.e. the absorption losses in the encapsulants and coupling gains from refractive index. The best performing encapsulant shows a cell-to-module power loss of 0% for a 16-cell MWT module. The fill factor loss is 1.4% absolute. We reach a module efficiency of 17.4% on the aperture area implying a CTM-loss in efficiency of only 0.5% absolute.

AbstractEurope, North America, Australia and other individual countries have certification and testing procedures for solar thermal equipment designed to support innovation and product development and to protect consumers from poor performance and unsafe designs. For the first time, as a result of the international coll aboration under the IEA-SHC Task 43 umbrella and the working groups of Solar Keymark Network, SRCC, ISO/TC180 and CEN/TC312, it has been possible to develop a common international standard draft for solar thermal collector testing. This paper describes in detail the new ISO/DIS 9806 standard and the relevant topics which clarify and refine existing test procedures or extend their scope: including solar air heating collector testing and tracking/concentrating collector testing. The new ISO/DIS 9806 standard opens the door to a global certification scheme for solar thermal collectors, thereby helping to overcome problems resulting from many different regional certification schemes.