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The design of the latent heat thermal storage system (LHTESS) was developed with a thermal capacity of about 100 kW h as a part of small solar plant based on the organic Rankine cycle (ORC). The phase change material (PCM) used is solar salt with the melting/solidification temperature of about 220 °C. Thermophysical properties of the PCM were measured, including its phase transition temperature, heat of fusion, specific heat, and thermal conductivity. The design of the thermal storage was finalized by means of the 3D computational fluid dynamics analysis. The thermal storage system is modular, and the thermal energy is delivered with the use of thermal oil, heated by Fresnel mirrors. The heat is transferred into and from the PCM in the casing using bidirectional heat pipes, filled with water. A set of metallic screens are installed in the box with the pitch of 8–10 mm to enhance the heat transfer from heat pipes to the PCM and vice-versa during the charging and discharging processes, which take about 4 h. This work presents a numerical study on the use of metallic fins without thermal bonding as a heat transfer enhancement method for the solar salt LHTESS. The results show that the absence of the thermal bonding between fins and heat pipes (there was a gap of 0.5 mm between them) did not result in a significant reduction of charging or discharging periods. As expected, aluminum fins provide better performance in comparison with steel ones due to the difference in the material conductivity. The main advantage observed for the case of using aluminum fins was the lower temperature gradient across the LHTESS.

© 2019 MDPI AG. All rights reserved. Cooling the surface of large format batteries with solid conductive plates, or fins, has an inherent advantage of reducing the number of liquid seals relative to some mini-channel cold plate designs, as liquid is not passed through the numerous individual plates directly. This may reduce the overall pack leakage risk which is of utmost importance due to safety concerns associated with the possibility of a cell short circuit and thermal runaway event. However, fin cooling comes at a cost of an increased thermal resistance which can lead to higher cell temperatures and a poorer temperature uniformity under aggressive heat generation conditions. In this paper, a novel graphite-based fin material with an in-plane thermal conductivity 5 times greater than aluminium with the same weight is presented for advanced battery cooling. The thermal performance of the fin is benchmarked against conventional copper and aluminium fins in an experimental programme cycling real 53 Ah pouch cells. The results from the extensive experimental testing indicate that the new fin can reduce both the peak measured temperature and surface temperature gradient by up to 8 °C and 5 °C respectively, when compared to aluminium fins under an aggressive electric vehicle duty-cycle.

The small solar thermal power plant is being developed with funding from EU Horizon 2020 Program. The plant is configured around a 2-kWel Organic Rankine Cycle turbine and solar field, made of Fresnel mirrors. The solar field is used to heat thermal oil to the temperature of about 240 oC. This thermal energy is used to run the Organic Rankine Cycle turbine and the heat rejected in its condenser (about 18-kWth) is utilized for hot water production and living space heating. The plant is equipped with a latent heat thermal storage to extend its operation by about 4 hours during the evening building occupancy period. The phase change material used is Solar salt with the melting/solidification point at about 220 oC. The total mass of the PCM is about 3,800 kg and the thermal storage capacity is about 100 kWh. The operation of the plant is monitored by a central controller unit. The main components of the plant are being manufactured and laboratory tested with the aim to assemble the plant at the demonstration site, located in Catalonia, Spain. At the first stage of investigations the ORC turbine will be directly integrated with the solar filed to evaluate their joint performance. During the second stage of tests, the Latent Heat Thermal Storage will be incorporated into the plant and its performance during the charging and discharging processes will be investigated. It is planned that the continuous filed tests of the whole plant will be performed during the 2018- 2019 period. This study was funded by European Union’s Horizon 2020 Research and Innovation Program under Project Grant Agreement 723596 (Innova MicroSolar).

The design of the Latent Heat Thermal Storage System (LHTESS) was developed with thermal capacity of about 100 kWh as a part of small solar plant, based on the Organic Rankine Cycle (ORC). The phase change material (PCM) used is Solar salt with the melting/solidification temperature of about 220°C. Thermo-physical properties of the PCM were measured, including its phase transition temperature, heat of fusion, specific heat and thermal conductivity. The design of the thermal storage was finalized by means of the 3-D CFD analysis. The thermal storage system is made of six rectangular boxes with dimensions of 1 m (width) × 0.66 m (height) × 0.47 m (depth). The thermal energy is delivered to each of the thermal storage boxes with the use of thermal oil, heated by Fresnel mirrors. The heat is transferred into and from the PCM in the box using 40 bi-directional heat pipes with the external diameter of about 12 mm. The length of the heat pipe in the PCM box is 430 mm and it is placed in the cylindrical metallic protection cartridge, installed in the thermal storage vessel. The working fluid in the heat pipe is water. A set of metallic screens are installed in the box with the pitch of 8–10 mm to enhance the heat transfer from heat pipes to the PCM and vice-versa during the charging and discharging processes, which take about 4 hours. The one unit of the described thermal storage system is undergoing the laboratory tests. Preliminary results demonstrate that the performance of the thermal storage is in a good agreement with numerical predictions. After completion of final design modifications, all units will be assembled at the plant’s demonstration site and tested with the ORC turbine.

This paper presents black box models to represent a LHTESS (Latent Heat Thermal Energy Storage System) coupled with heat pipes, aimed at increasing the storage performance and at decreasing the time of charging/discharging. The presented storage system is part of a micro solar CHP plant and the developed model is intended to be used in the simulation tool of the overall system, thus it has to be accurate but also fast computing. Black box data driven models are considered, trained by means of numerical data obtained from a white box detailed model of the LHTESS and heat pipes system. A year round simulation of the system during its normal operation within the micro solar CHP plant is used as dataset. Then the black box models are trained and finally validated on these data. Results show the need for a black box model that can take into account the different seasonal performance of the LHTESS. In this analysis the best fit was achieved by means of Random Forest models with an accuracy higher than 90%. This study is a part of the Innova MicroSolar Project, funded in the framework of the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement No 723596). Prof. Cabeza would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. Dr. Alvaro de Gracia has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 712949.

Conductively cooling the surface of lithium-ion pouch cells may simplify the external cooling mechanism, as heat transfer mediums are not routed across the cell surface. In this paper, the thermal performance of cooling cells with metallic fins is analysed using a developed test rig and thermal model. Results indicate that single edge fin cooling with aluminum sheets is effective in limiting surface temperature gradients to below circa 5℃ for cells subject to realistic EV and mild PHEV duty cycles. For aggressive track racing EV cycles, double edge fin cooling is required to limit surface temperature gradients to below 12℃.\ud

The articles in this special issue focus on solar power generation, including new technologies, services, and applications.

Aims The aim of this study was to evaluate the safety, technical feasibility and performance of a new trans-catheter tricuspid repair system. Methods and results Thirty-one adult swine underwent implantation of a transcatheter tricuspid remodelling system under general anaesthesia. The steerable transcatheter device was introduced through a 24 Fr femoral sheath into the right femoral vein and delivered to the tricuspid annulus on the beating heart. A fixation element was implanted into the tricuspid annulus. Following implantation, a second delivery system was used to couple the fixation element with a self-expanding nitinol stent. The device was tensioned to reshape the tricuspid valve and increase the coaptation length of the valve leaflets under echo guidance. Finally, the stent was deployed in the inferior vena cava (IVC) to maintain the tension applied. The transcatheter device was successfully implanted in all animals (n=31). Doppler echocardiography prior to sacrifice showed that tricuspid valve function was stable and normal tricuspid leaflet motion was observed. Cinching of the tricuspid annulus resulted in an increase of leaflet coaptation length of 70% (4.5±0.7 mm to 7.78±1.3 mm), an increase in trans-tricuspid peak velocity of 79% (0.38±0.1 m/s to 0.68±0.1 m/s), and a reduction in septolateral tricuspid valve dimension of 30% (35.2±5 mm to 24.8±5 mm). At necropsy, the fixation element was firmly attached to the annulus within a fibrotic tissue, with no coronary lesions observed and no abnormality visible. The stent was fully deployed in the IVC, without displacement or change in the stent shape. Conclusions Percutaneous beating heart remodelling of the tricuspid annulus with a cinching device is safe and feasible.

Although higher education understands the need to develop critical thinkers, it has not lived up to the task consistently. Students are graduating deficient in these skills, unprepared to think critically once in the workforce. Limited development of cognitive processing skills leads to less effective leaders. Various definitions of critical thinking are examined to develop a general construct to guide the discussion as critical thinking is linked to constructivism, leadership, and education. Most pedagogy is content‐based built on deep knowledge. Successful critical thinking pedagogy is moving away from this paradigm, teaching students to think complexly. Some of the challenges faced by higher education moving to a critical thinking curricula are discussed, and recommendations are offered for improving outcomes.

This article examines how wind and solar integration studies have evolved, what analysis techniques work, what common mistakes are still made, and what and why calculating integration costs is such a difficult problem that should be undertaken carefully, if at all. Examples of integration costs for other generation technologies are examined to help illuminate underlying cost causation principles.

The last two years have seen a tremendous increase in the number of installed solar energy systems. In 2010, annual grid-connected photovoltaic (PV) installations in the United States and worldwide were expected to be about 0.8 GW and 16–18 GW, respectively. At the end of 2010, the cumulative installed base of grid-connected PVs in the United States and worldwide was about 2 GW and about 40 GW, respectively. One of the areas that has been receiving much attention recently is large utility-scale solar systems.

Future decision makers in natural resource fields will be required to make judgments on issues that lack clear solutions and with information complicated by ethical challenges. Therefore, natural resource, environmental, and agricultural professionals must possess the ability to think critically about the consequences of policy, economic systems, and individual human behaviors on the environment. To ensure that future professionals can examine competing claims, university students must develop critical thinking skills that allow them to examine ethical issues surrounding the environment. We review literature on critical thinking specifically in regard to necessary components to creating critical thinking opportunities in the classroom. We then discuss special considerations for teaching critical thinking in the context of natural resource and agriculture ethics education.

Freshwater marshes cover 4000 square kilometers of the Louisiana coastal zone and are the most abundant marsh habitat type. Many of these marshes actually float as organic mats on underlying water. Some estimates suggest as much as 70% of Louisiana's coastal freshwater marsh are of the floating variety. The slow flow of water characteristic of these environments generally transports very little sediment. As a result, the marsh substrate is composed of primarily live and dead organic matter (peat formation) rather than mineral sediments. Since floating marshes are structurally different than intertidal marsh habitats, many traditional oil spill response options are ineffective or inappropriate. Access to the marsh is often limited since there is no open water ingress and the marsh structure cannot support the weight of equipment. Oil spill response options are further complicated when the source of the oil is a pipeline leak located below the floating marsh mat; spilled oil is free to travel at the interface of the underlying water and mat. Protection booming is impossible. Oil impacts often result in the death of all the living plants that are integral to the formation and sustainability of the habitat. This paper reports on two oil spills in a floating marsh near Paradis, Louisiana that occurred eight years apart. Both spills were spatially close to each other, which provided an excellent comparison for assessing potential long-term impact from oil spills in floating marshes. During both oil spill responses, unique response techniques were developed to recover spilled oil and enhance marsh recovery. An effective technique was to rake away and remove the dead oil-contaminated surface plant debris from the site and employ sorbent recovery. Lessons learned from these responses were used to develop mitigation guidance for future responses.

Minority leaders face workplace issues not experienced by white leaders including lack of support, discrimination, racism, and stereotyping. The purpose of this study was to explore how racial/ethnic minority leaders encountered and overcame barriers as leaders of cultural community centers. Three racial/ethnic minority executive directors of cultural community centers located in a Midwestern city were interviewed and their responses were hand-coded to develop themes. Six themes emerged from this process: finding "inspiration", "developing thick skin", "stereotypes", "damage from within", "take your path", and "hope". Their stories help us understand the complexities of inter-racial relations in the workplace.

Healthcare organizations suffer from a disparate distribution of racial and ethnic minority employees in professional positions. Although the percentage of racial and ethnic minorities in the workforce continues to grow, the percentage of racial and ethnic minorities who compose the professional ranks, nursing and managerial positions, lags far behind the percentage of White individuals in similar positions. This gap has implications for organizational performance as research indicates organizations with more diverse workforces enjoy better outcomes. A more diverse workforce also has broader societal consequences directly tied to healthcare such as positively impacting health disparities. The authors posit that recruitment is critical to developing a diverse workforce.

A novel process consisting of two-selenizations of magnetron sputtered metallic precursors using Se vapor and a method for Ga incorporation using a single Cu Ga(22 at.%) alloy target without deleterious indium-gallium interaction have been developed for preparation of well-adherent, large, compact, well-faceted-polyhedral-grain CuIn 1− x Ga x Se 2 thin films having optimum composition of Cu:In:Ga:Se in atomic percent of 24.25:22.21:4.40:49.14. Higher indium proportion in the first precursor resulted in elimination of pits in the CuIn 1− x Ga x Se 2 films, which made them more suitable for preparation of solar cells with thin US heterojunction partner layers. Optimized selenization parameters with the maximum temperature of 550–560°C and a Se vapor incidence rate of 50–75As −1 resulted in improved morphology and enhanced gallium content of completed CuIn 1− x Ga x Se 2 thin films. The best solar cell had an open-circuit voltage V oc of 451.8 mV, a short-circuit current density J sc of 34.5 mA, a fill factor of 57.87%, a total-area efficiency of 9.02%, and a fairly constant spectral response over the entire spectral range.

The SunShot Vision Study defines a scenario for solar energy technologies to significantly contribute to meeting U.S. electricity demand. To achieve this, work is in progress to identify, quantify, and address the impacts of high levels of distributed PV generation on electric distribution systems. The Department of Energy (DOE) Solar Energy Technologies Program (SETP) initiated a project to gain experience and to identify and quantify these potential impacts, develop and verify models of these systems, evaluate methods for mitigating any impacts, and develop potential solutions. This paper summarizes the current progress of the six competitively selected projects.