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A prototype air cycle cooling system, designed for forced cooling of HPOF pipe-type cable, was built under an EPRI contract. Its main components are a turbine and compressor operated on a single high speed shaft and a compact cable. oil to air heat exchanger. Air cooling is supplemented by a spray water system. Tests were conducted on the prototype unit at the EPRI Waltz Mill Cable Test Facility to evaluate its performance and operating characteristics. This paper briefly describes this equipment and presents the results of the test program.

Abstract. The impact of multiphase reactions involving nitrogen dioxide (NO2) and aromatic compounds was simulated in this study. A mechanism (CAPRAM 2.4, MODAC Mechanism) was applied for the aqueous phase reactions, whereas RACM was applied for the gas phase chemistry. Liquid droplets were considered as monodispersed with a mean radius of 0.1 µm and a liquid content (LC) of 50 µg m-3. The multiphase mechanism has been further extended to the chemistry of aromatics, i.e. reactions involving benzene, toluene, xylene, phenol and cresol have been added. In addition, reaction of NO2 with dissociated hydroxyl substituted aromatic compounds has also been implemented. These reactions proceed through charge exchange leading to nitrite ions and therefore to nitrous acid formation. The strength of this source was explored under urban polluted conditions. It was shown that it may increase gas phase HONO levels under some conditions and that the extent of this effect is strongly pH dependent. Especially under moderate acidic conditions (i.e. pH above 4) this source may represent more than 75% of the total HONO/NO2 - production rate, but this contribution drops down close to zero in acidic droplets (as those often encountered in urban environments).

This paper proposes a novel consensus-based distributed control algorithm for solving the economic dispatch problem of distributed generators. A legacy central controller can be eliminated in order to avoid a single point of failure, relieve computational burden, maintain data privacy, and support plug-and-play functionalities. The optimal economic dispatch is achieved by allowing the iterative coordination of local agents (consumers and distributed generators). As coordination information, the local estimation of power mismatch is shared among distributed generators through communication networks and does not contain any private information, ultimately contributing to a fair electricity market. Additionally, the proposed distributed algorithm is particularly designed for easy implementation and configuration of a large number of agents in which the distributed decision making can be implemented in a simple proportional-integral (PI) or integral (I) controller. In MATLAB/Simulink simulation, the accuracy of the proposed distributed algorithm is demonstrated in a 29-node system in comparison with the centralized algorithm. Scalability and a fast convergence rate are also demonstrated in a 1400-node case study. Further, the experimental test demonstrates the practical performance of the proposed distributed algorithm using the VOLTTRON platform and a cluster of low-cost credit-card-size single-board PCs. Comment: 16 Pages, 13 figures Figures order and references are corrected!

AbstractSolar fuels offer a promising approach to provide sustainable fuels by harnessing sunlight1,2. Following a decade of advancement, Cu2O photocathodes are capable of delivering a performance comparable to that of photoelectrodes with established photovoltaic materials3–5. However, considerable bulk charge carrier recombination that is poorly understood still limits further advances in performance6. Here we demonstrate performance of Cu2O photocathodes beyond the state-of-the-art by exploiting a new conceptual understanding of carrier recombination and transport in single-crystal Cu2O thin films. Using ambient liquid-phase epitaxy, we present a new method to grow single-crystal Cu2O samples with three crystal orientations. Broadband femtosecond transient reflection spectroscopy measurements were used to quantify anisotropic optoelectronic properties, through which the carrier mobility along the [111] direction was found to be an order of magnitude higher than those along other orientations. Driven by these findings, we developed a polycrystalline Cu2O photocathode with an extraordinarily pure (111) orientation and (111) terminating facets using a simple and low-cost method, which delivers 7 mA cm−2 current density (more than 70% improvement compared to that of state-of-the-art electrodeposited devices) at 0.5 V versus a reversible hydrogen electrode under air mass 1.5 G illumination, and stable operation over at least 120 h.

This research examines the economic implications of different designs for a national low carbon fuel standard (NLCFS) for the road transportation sector. A NLCFS based on the average Carbon Intensity (CI) of all fuels sold generates an incentive for fuel suppliers to reduce the measured CI of their fuels. The economic impacts are determined by the availability of low carbon fuels, estimates of which can vary widely. Also important are the compliance path, reference level CI, and the design of the credit system, particularly the opportunities for trading and banking. To quantitatively examine the implications of a NLCFS, we created the Transportation Regulation and Credit Trading (TRACT) Model. With TRACT, we model a NLCFS credit trading system among profit maximizing fuel suppliers for light- and heavy-duty vehicle fuel use for the United States from 2012 to 2030. We find that credit trading across gasoline and diesel fuel markets can lower the average costs of carbon reductions by an insignificant amount to 98% depending on forecasts of biofuel supplies and carbon intensities. Adding banking of credits on top of trading can further lower the average cost of carbon reductions by 5%–9% and greatly reduce year-to-year fluctuations in credit prices.

Pyroelectric energy harvesting has the ability to transform wasted heat into useful energy and as such has a potential to create “green” energy from freely available sources such as ambient temperature changes, and contribute to the fight against climate change. Current pyroelectrics applications are limited to low-power electronics, portable systems or tasks needing only very low range of power (μW–mW). Developing further this highly promising technology should ultimately lead to the creation of more powerful, autonomous and self-powered electronic devices that could one day use to recycle currently “lost” thermal energy to power electronic devices in both domestic and industrial settings. To the best of our knowledge, hexagonal phase ZnS (wurtzite ZnS) has not been studied as a possible energy harvesting pyroelectric material despite w-ZnS being isostructural to the well-exploited and widely praised hexagonal ZnO [1]. In addition, the Tc temperature (1020 ˚C for bulk material) is high enough for ZnS that it has the ability to operate at higher temperature that are good match with the working temperature of power plants and automobiles, and hence w-ZnS ceramics should have a potential to be used in pyroelectric harvesters of waste heat coming from those activities [2]. Here we report on the pyroelectric output registered for a wurtzite phase ZnS ceramic fabricated as part of our project. To probe the pyroelectric output for a w-ZnS ceramic a simple device (a “pyro-cell”) was created by evaporating gold electrods on both sides of a ceramic sample, which was mounted on a Cu-metalized rectangular insulating base (vetronite) using silver paint. This device is stable from room temperature up to approximately 180°C. Two different heating and cooling testing set-ups were established: Set-up n°1 used an industrial scale laser, providing a source with fast temperature change, and Set-up n°2 had a standard lab hot plate heating element, providing a much slower temperature change. The characterization required an accurate measurement of the currents of the order of 10-9 A. In addition, using the Pyroelectric Test System (PK‐SPIV17T, State College, PA, USA) with a Keithley 6517 B Picoammeter, we were able to measure the pyroelectric coefficient and monitor its change at different frequencies as a function of temperature from 20 °C up to 150° C, with a heating rate of between 2 and 10 °C/min. Figure 1: Pyroelectric current measurements on an ZnS ceramic sample, using testing set-up n°1. The horizontal axis shows the time (seconds). References [1] Y. Yang, W. Guo, K.C. Pradel, G. Zhu, Y. Zhou, Y. Zhang, Y. Hu, L. Lin, Z. Lin Wang, “Pyroelectric Nanogenerators for Harvesting Thermoelectric Energy”, Nano Lett, 12 (6), 2012, 2833–2838 [2] L.A. Chavez, F.O. Zayas Jimenez, B.R. Wilburn, L.C. Delfin, H. Kim, N. Love, Y. Lin, “Characterization of Thermal Energy Harvesting Using Pyroelectric Ceramics at Elevated Temperatures”, Energy Harvesting and Systems, 5(1-2), 2018, 3–10 This project was also partially supported by the Piano triennale di realizzazione 2019-2021 della ricerca di sistema elettrico nazionale – Progetto 1.3 Materiali di frontiera per usi energetici (C.U.P. code: I34I19005780001).