Redução de consumo de energia eletrica a partir de reaproveitamento de energia termica com uso de ciclo rankine orgânico

This paper is proposed the usage of an Organic Rankine Cycle (ORC) along with waste heat recovery from an inconstant heat source. This method of waste heat recovery with intermittent heat source is part of a technical viability study. This paper also brings up the usage of thermal energy storage as heat source for the ORC. This paper is based on a heat treatment company study in which a natural gas furnace is explored. Data such as mass flow, temperature and specific waste gas heat from this furnace are used through calculations. Calculations are made also based on furnace cycles. This viability study considers a series of working fluids such as ammonia, benzene, R113 and R134a. Results point out that ORC with out thermal storage and using refrigerant fluid ammonia is the best alternative

Produção e aplicação de adubo orgânico, proveniente da compostagem de resíduos da FCT/UNESP

This work presents the objective of producing organic fertilizer from the waste generated at FCT/UNESP and its use in the growing sunflower. For this, there were collected wastes of pruning/weeding and organic waste from the canteen. It were made two types of treatments, one conventional and the other mechanized, using three mass ratios: ratio 1 (30% wastes of pruning/weeding (RP) + 70% organic waste (RC)), ratio 2 (50% RP + 50% RC) and ratio 3 (70% RP + 30% RC). The conventional system was done windrow with turning manual and the mechanized system was developed in reactors by injecting compressed air. The compounds produced were analyzed in terms of pH, organic matter, organic carbon, mineral residue, nitrogen, phosphorus and potassium, which could be compared to the values stipulated by the Instrução Normativa n° 25 de 23/07/2009 do Ministério da Agricultura, Pecuária e Abastecimento. The compounds produced were used on growing sunflowers in 14 different conditions for the systems manual and mechanized, totaling 26 treatments with the following proportions... (Complete abstract click electronic access below)

Projeto de uma rede de ar comprimido industrial

In this study was shown the historical uses of compressed air by humanity, the general scenario of its uses and the most important steps of a project to set up an industrial network of compressed air, from the selection of a suitable compressor to the design of a distribution network, discussing all the possibilities and their characteristics as well as the feasibility of them. A case study was conducted in a food company where was implemented an industrial compressed air network. Information was collected regarding the consumers points of compressed air, as well as the layout of the new facility, necessary for the development of the distribution system. Two methods were used, analytical and nomogram, which complemented each other to the definition of appropriated tubing, both financially and physically

Chaveamento de cargas intermitentes usando sensor de corrente

Due to concerns about rational use of energy, several alternative technologies of power generation appeared, including the conversion of solar energy into electrical energy by photovoltaic panels. In low-income households, the refrigerator represents considerable impact on the electric bill, since it requires constant power given its use in food preservation. It is possible to reduce this share, with the use of an alternative energy source. This work presents a timed switching electronic system, which allows commercial equipment that is not affected by short interruptions in the power supply to use a photovoltaic panel as a source of alternative energy, which usually do not provide energy continuously. Switching is made automatically in case of low incidence of sunlight, and without any form of energy storage. Between each switching, there is a dead time without power supply, therefore preventing the use of synchronizers circuits between the photovoltaic panel and the public power grid. A circuit containing a 80C31 microcontroller is used to control the system’s switching. The photovoltaic panel’s voltage inverter is in H bridge configuration, and is also controlled by the microcontroller through Pulse Width Modulation, which makes use of preprogrammed tables to generate the control signals of the power transistors. Through the use of software simulations, the proposed system was tested, which is capable of supplying intermittent single-phase loads. The simulations indicates that the project developed in this paper can be assembled into a prototype and be tested under real operating conditions, as long as the scaling of components, the characteristics of the photovoltaic panel to be used, and the project involved load are taken into account

Sistema de gerenciamento de energia para controle de carga/descarga entre baterias de lítio e ultracapacitores, envolvendo sistema de tração elétrica com frenagem regenerativa

Pós-graduação em Engenharia Elétrica - FEIS

Otimização de sistemas de distribuição de energia elétrica radiais usando programação cônica de segunda ordem inteira mista

Pós-graduação em Engenharia Elétrica - FEIS

Electropolymerization using binuclear nickel(II) Schiff base complexes bearing N4O4 donors as supramolecular building blocks

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise do comportamento da bateria utilizada em sistemas fotovoltáicos de pequeno porte

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Compensação ativa paralela baseada na teoria de potência conservativa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise numérica de um sistema integrado coletor solar/armazenador térmico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Analysis of the accumulated energy by thermal stratification of liquid inside storage tanks with porous layers

A mathematical model was developed in order to study the behavior of thermal stratification of liquid in a typical storage tank with porous medium. The model employs a transient stream function-vorticity formulation to predict the development of stream function and temperature fields in a charging process. Parameters analyzed include Biot, Darcy, Reynolds and Richardson numbers, position, and the thickness of the porous medium. The results show the influence of these physical parameters that should be considered for a good design of storage tanks with thermal stratification.

Chemical Composition, Rumen Fermentation Kinetics, Digestibility and Energy Value of Cassava Leaves Hay at Different Storage Times

Cassava leaves have been widely used as a protein source for ruminants in the tropics. However, these leaves contain high level of hydro-cyanic acid (HCN) and condensed tannins (CT). There are evidences that making hay can eliminate more than 90% of HCN and that long-term storage can reduce CT levels. A complete randomized design with four replicates was conducted to determine the effect of different storage times (0-control, 60, 90 and 120 days) on chemical composition, in vitro rumen fermentation kinetics, digestibility and energy value of cassava leaves hay. Treatments were compared by analyzing variables using the GLM procedure (SAS 9.1, SAS Institute, Inc., Cary, NC). Crude protein (CP) and ether extract (EE) of the cassava hay were not affected (P > 0.05) by storage time (17.7% and 3.0%, respectively). Neutral detergent fiber, acid detergent fiber, total carbohydrate and non-fiber carbohydrate were not affected either (P>0.05) by storage time (47.5, 32.6, 72.3 and 25.8% respectively). However, other parameters were influenced. CT was lower (P<0.05) in hay after 120 days of storage compared with control (1.75% versus 3.75%, respectively). Lignin and insoluble nitrogen in neutral detergent, analyzed without sodium sulfite, were higher (P<0.01) after 120 days of storage, compared with the control (11.22 versus 13.57 and 1.65 versus 3.81% respectively). This suggests that the CT has bound to the fiber or CP and became inactive. Consequently, the in vitro digestibility of organic matter (50.36%), total digestible nutrients (44.79%) and energy (1.61 Mcal/KgMS), obtained from gas production data at 72 h of incubation, has increased (P<0.05) with storage times (56.83%, 51.53% and 1.86 Mcal/KgMS, respectively). The chemical composition and fermentative characteristics of cassava hay suffered variations during the storage period. The best values were obtained after 90 days of storage. This is probably due to the reduction in condensed tannins.