Use of partial load operating conditions for latent thermal energy storage management

A proper management of thermal energy storage (TES) charging and discharging processes allows the final users to optimize the performance of TES systems. In this paper, an experimental research is carried out to study how the percentage of charge in a latent heat TES system (partial load operating conditions) influences the discharge process. Several charging and discharging processes were performed at a constant heat transfer fluid (HTF) mass flow rate of 0.5 kg/s and temperature of 155 °C and 105 °C, respectively. High density polyethylene (HDPE) with a total mass of 99.5 kg was used as phase change material (PCM) in a 0.154m3 storage tank based on the shelland-tube heat exchanger concept. Five different percentages of charge have been studied: 58 %, 73 %, 83 %, 92 %, and 97 % (baseline test). Results showed that by modifying the percentage of charge, the time required for the charging process was reduced between 97.2% and 68.8% in comparison to the baseline case. However, the energy accumulated was only reduced a maximum of 35.1% and a minimum of 5.2%, while the heat transfer rates during the first 60 min of discharge were reduced a maximum of 45.8% and a minimum of 6%. Therefore, partially charging the TES system not lower than 85% of its maximum energy capacity becomes a good option if the final application accepts a maximum decrease of discharging heat transfer rates of 10% if compared to the fully charged system.The work was partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER), and ULLE10-4E-1305). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This project has received funding from the European Commission Seventh Framework Programme (FP/2007-2013) under Grant agreement No. PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 657466 (INPATH-TES). Jaume Gasia would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship (2017 FI_B1 00092). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Simone Arena would like to thank the Department of Mechanical, Chemical and Materials Engineering of the University of Cagliari for funding his research grant

Thermal energy storage implementation using phase change materials for solar cooling and refrigeration applications

The final goal of this study is to implement and to test a thermal energy storage (TES) system using different phase change materials (PCM) for solar cooling and refrigeration applications. A high temperature pilot plant able to test different types of TES systems and materials was designed and built at the University of Lleida (Spain). This pilot plant is composed mainly by three parts: heating system, cooling system, and different storage tanks. The pilot plant uses synthetic thermal oil as heat transfer fluid (HTF) and has a working temperature range from 100 ºC to 400 ºC. Two different PCM were selected after a deep study of the requirements of a real solar cooling plant and the available materials in the market, finally d-mannitol with phase change temperature of 167 ºC and hydroquinone which has a melting temperature of 172.2 ºC were used.The work is partially funded by the Spanish government (ENE2011-22722). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2009 SGR 534). Antoni Gil would like to thank the Col·legid’Enginyers Industrials de Catalunya for his research appointment. Eduard Oró would like to thank the University of Lleida for his research fellowship

Thermal performance evaluation of bischofite at pilot plant scale

The selection of the proper thermal energy storage (TES) material for an application is crucial. On the one hand, these materials should have suitable thermal properties for the operational temperatures range of the systems they are planned to work for, such as thermal stability, high latent heat and high heat capacity. On the other hand, they should be available on the market and at low price. Besides, researchers have to bear in mind the importance of testing TES materials not only at laboratory scale but also at higher scale, since it has been demonstrated that some thermal characteristics are volume-dependant. In the present study, bischofite, a by-product obtained from the non-metallic industry in the North of Chile with desired thermal properties for mid-temperature applications (around 100 C), has been studied. A first analysis was performed in terms of comparing the thermal properties and cost of bischofite with other material previously studied as TES materials in order to evaluate its potential in both latent and sensible phases. Afterwards, a second analysis was experimentally performed in terms of testing bischofite at large-scale (204 kg) in a pilot plant facility. The experimental procedure consisted on several charging processes within two different temperatures ranges: from 50 C to 80 C and from 80 C to 120 C in order to study the behavior of the material in the sensible solid phase and latent phase respectively. The temperature profiles, the power given by the HTF, the energy balance in the storage system and the accumulation energy rate of the bischofite were analyzed. Results of both analysis showed that bischofite has potential as TES material for mid-temperature applications.The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under Grant agreement n PIRSES-GA-2013-610692 (INNOSTORAGE). The work was partially funded by the Spanish government (Project ENE2011-22722). The authors would like to thank the Catalan Government for the quality accreditation given to their research group GREA (2014 SGR 123). The authors would like to acknowledge the collaboration of the company SALMAG. The authors acknowledge to FONDECYT (Grant No 1120422), CONICYT/FONDAP No 15110019, and the Education Ministry of Chile Grant PMI ANT 1201 for the financial support. Laia Miró would like to thank the Spanish Government for her research fellowship (BES-2012-051861). Andrea Gutierrez would like to thank to the Education Ministry of Chile her doctorate scholarship ANT 1106 and CONICYT/PAI NO 7813110010

Myliobatis freminvillii, bullnose eagle ray

The Bullnose Eagle Ray (Myliobatis freminvillii) is a medium-sized (to 106 cm disc width) demersal coastal eagle ray that occurs in the Northwest, Western Central, and Southwest Atlantic Oceans from Massachussetts, USA to the Texas coast of the Gulf of Mexico and from Venezuela to Buenos Aires, Argentina and inhabits continental shelves from the surface to a depth of 122 m. Its is captured by artisanal longlines, gillnets, beach seines and also in industrial shrimp trawls. In the Northwest Atlantic, population trend data are available from a deep-water trawl survey in the northern Gulf of Mexico that reveal steep increases in abundance over 2002-2013. There are no known threats in the Northwest and Western Central Atlantic, but in the Southwest Atlantic artisanal fisheries are intense. Further, there are largely unmanaged commercial trawl and longline fisheries in this area. This inshore eagle ray is exposed to intense and often unmanaged fishing pressure throughout the Southwest Atlantic portion of its range, and it has no refuge at depth. Due to the level of exploitation by widespread artisanal fisheries which lack adequate management, it is suspected that this species has undergone a population reduction of >80% over the past three generation lengths (44 years) in the Atlantic South American part of its range, but is stable in the Northwest and Western Central Atlantic. Overall, based on its range, with almost all threats found in the Southwest Atlantic, and the suspected low productivity of the species, the Bullnose Eagle Ray is suspected to have undergone a population reduction of 30-49% in the past three generation lengths (44 years) due to levels of exploitation, and it is assessed as Vulnerable A2bd.Fil: Carlson, J.. National Marine Fisheries Service; Estados UnidosFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Avalos, C.. Fundacion Mundo Azul; GuatemalaFil: Blanco Parra, M. P.. Universidad de Quintana Roo; MéxicoFil: Briones Bell lloch, A.. Direccion de Regulaciones Pesqueras y Ciencias; CubaFil: Cardeñosa, D.. Florida International University; Estados UnidosFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Derrick, D.. University Fraser Simon; CanadáFil: Espinoza, E.. Direccion Parque Nacional Galapagos; EcuadorFil: Mejía Falla, P. A.. Wildlife Conservation Society; Estados UnidosFil: Morales Saldaña, J. M.. Smithsonian Tropical Research Institute; PanamáFil: Motta, F.. Universidade Federal de Sao Paulo; BrasilFil: Naranjo Elizondo, B.. Universidad de Costa Rica; Costa RicaFil: Pacoureau, N.. University Fraser Simon; CanadáFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Perez Jiménez, J. C.. El Colegio de la Frontera del Sur; MéxicoFil: Rincon, G.. Universidade Federal Do Maranhao.; BrasilFil: Schneider, E. V. C.. Cape Eleuthera Institute; BahamasFil: Simpson, N. J.. Salvageblue; San Vicente y las GranadinasFil: Talwar, B. S.. Florida International University; Estados UnidosFil: Pollom, R.. University Fraser Simon; Canad