Assessment of energy efficiency in electric storage water heaters

Nowadays there are several ways of supplying hot water for showers in residential buildings. One of them is the use of electric storage water heaters (boilers). This equipment raises the water temperature in a reservoir (tank) using the heat generated by an electric resistance. The behavior of this equipment in Brazil is still a research object and there is not a standard in the country to regulate its efficiency. In this context, an experimental program was conducted aiming to collect power consumption data to evaluate its performance. The boilers underwent an operation cycle to simulate a usage condition aiming to collect parameters for calculating the efficiency. This 1-day cycle was composed of the following phases: hot water withdrawal, reheating and standby heat loss. The methods allowed the identification of different parameters concerning the boilers work, such as: standby heat loss in 24 h, hot water withdrawal rate, reheating time and energy efficiency. The average energy efficiency obtained was of 75%. The lowest efficiency was of 62% for boiler 2 and the highest was of 85% for boiler 9. (C) 2008 Elsevier B.V. All rights reserved.

Optimizing the embedded heaters position in the pultrusion process using finite element analysis

This study is based on a previous experimental work in which embedded cylindrical heaters were applied to a pultrusion machine die, and resultant energetic performance compared with that achieved with the former heating system based on planar resistances. The previous work allowed to conclude that the use of embedded resistances enhances significantly the energetic performance of pultrusion process, leading to 57% decrease of energy consumption. However, the aforementioned study was developed with basis on an existing pultrusion die, which only allowed a single relative position for the heaters. In the present work, new relative positions for the heaters were investigated in order to optimize heat distribution process and energy consumption. Finite Elements Analysis was applied as an efficient tool to identify the best relative position of the heaters into the die, taking into account the usual parameters involved in the process and the control system already tested in the previous study. The analysis was firstly developed with basis on eight cylindrical heaters located in four different location plans. In a second phase, in order to refine the results, a new approach was adopted using sixteen heaters with the same total power. Final results allow to conclude that the correct positioning of the heaters can contribute to about 10% of energy consumption reduction, decreasing the production costs and leading to a better eco-efficiency of pultrusion process.

Computer tools applied to analysis of solar water heaters

The simulation programs are important tools to analyze the different energetic alternatives, including the use of renewable energy. The objective of this study was to analyze comparatively the different computer tools available for modeling of solar water heaters. Among the main simulation software of solar thermal systems, there are: RETScreen International, EnergyPlus, TRNSYS, SolDesigner, SolarPro, e T*SOL. Among the tools mentioned, only EnergyPlus and RETScreen International are free, but they allow obtaining interesting results when applied together. The first one has a detailed module of energy analysis of solar water heaters, while the second one provides an detailed economic feasibility study and an assessment of emissions of greenhouse gases. RETScreen International and EnergyPlus programs are aimed at a diverse audience, including designers, researchers and energy planners.

Development of solar air heaters & thermal energy storage system for drying applications in food processing industries

In the present work, the author has designed and developed all types of solar air heaters called porous and nonporous collectors. The developed solar air heaters were subjected to different air mass flow rates in order to standardize the flow per unit area of the collector. Much attention was given to investigate the performance of the solar air heaters fitted with baffles. The output obtained from the experiments on pilot models, helped the installation of solar air heating system for industrial drying applications also. Apart from these, various types of solar dryers, for small and medium scale drying applications, were also built up. The feasibility of ‘latent heat thermal energy storage system’ based on Phase Change Material was also undertaken. The application of solar greenhouse for drying industrial effluent was analyzed in the present study and a solar greenhouse was developed. The effectiveness of Computational Fluid Dynamics (CFD) in the field of solar air heaters was also analyzed. The thesis is divided into eight chapters.

Performance improvement of arc heaters for aerodynamic wind tunnels

Mode of access: Internet.

Operator, organizational, and direct support maintenance manual including repair parts and special tools lists : heaters, space, radiant type, portable (type I, model M1941, solid fuel) FSN 4520-257-4877, (type II, model M1941, liquid fuel) FSN 4520-927-4214, (Yukon model M1950, solid or liquid fuel) FSN 4520-287-3353 : heaters, immersion, liquid fuel fired, for corrugated cans ....

"December 1969."

Gas-fired radiant heaters

This dissertation covers four areas of particular interest for the successful application of radiant heating in industrial environments. In it the author tackles the problem of how to predict the thermal comfort produced both by single heaters and also systems of heaters; proposes a method for modelling the mechanisms by which heaters interact with the buildings in which they are installed, in the static and dynamic cases; explores techniques for measuring the radiation produced by heaters; and presents experiments concerned with finding the temperatures and power balances prevailing during normal operation. It is contended that, whilst the generally accepted guides for sizing and operating space heating plant were a good first approximation, there are intrinsic subtleties arising from the fact that the primary mode of heat transfer in this instance is radiative. These nuances are concerned with how best to maximise the heat transfer from the heat source to the heated object; the placement of heaters within a system; and an assessment of the various techniques and strategies involved in controlling a radiant heating system. The conclusions reached are that: if sized and controlled correctly radiant heating systems offer considerable operational advantages over other types of space heating systems in certain applications, in terms of both economy and controllability. The efficacy of radiant heating systems is affected primarily by the control strategy implemented; secondarily, by the structure of the building into which it is installed; and only marginally by all other factors.

Brood production increases when artificial heating is provided to colonies of stingless bees

Although stingless bees are capable of maintaining their nest temperature within certain limits, brood production of several species declines or even completely stops during periods of low ambient temperature. In the present study, we investigated whether the brood production of the meliponine species Nannotrigona testaceicornis can be artificially increased through heating the colonies during the cold season. For this, we monitored the rate of brood cell production of seven hives in intervals of 24 hours under two different experimental conditions: 1. without; and 2. with heating. Each treatment (first with and subsequently without heating) lasted for nine consecutive days. The ambient temperature (TA) during both experimental periods was very similar (TA(WITH) = 16.1 degrees C; TA(WITHOUT) = 16.3 degrees C). On average, the colonies built 3.6 brood cells per day without and 15.8 brood cells per day with artificial heating (Wilcoxon Rank Sum test: T = 10, Z = 4, P < 0.001). In both treatments, the rate of brood cell production increased with increasing environmental temperature (Spearman Rank Correlation: R(WITH) = 0.71, P = 0.02; R(WITHOUT) = 0.66, P = 0.05). We concluded that artificial heating during cold periods increased the brood cell production in N. testaceicornis Our results indicate that the use of heaters for stingless bee hives during periods of low ambient temperature may be helpful for stingless beekeeping.

Desenvolvimento de sistema de teste de caixas de controlo electrónico

O objectivo desta Tese/Dissertação é conceber um sistema para a BOSCH Termotecnologia S.A., na qual exerço as funções de Engenheiro de Qualidade de Fornecedores de peças electrónicas, que permita testar funcionalmente dois tipos de PCBA (Printed Circuit Board Assembled) utilizados em dois modelos de esquentador estanque com denominação Celsius e Celsius Plus, produzidos nesta empresa para mercados de todo o Mundo. Os PCBA foram desenvolvidos internamente pelo departamento de ENG (Departamento de Desenvolvimento) e são actualmente peças de compra cujo fornecedor está localizado na China. Em primeiro lugar foi efectuado um estudo das necessidades da empresa relativamente aos projectos necessários para melhorar os processos de investigação de falhas e melhoria de Qualidade dos fornecedores de peças electrónicas, no contexto do departamento onde este projecto se insere. A conclusão chegada foi que existe uma grande necessidade de investigar avarias nas PCBA de compra do fornecedor asiático de forma rápida e precisa, de modo a que seja possível trabalhar mais activamente e rapidamente na melhoria de Qualidade do mesmo, melhorando, por exemplo, os seus processos produtivos. Em segundo lugar concebeu-se a solução a realizar. Optou-se por um conjunto hardware e software desenvolvido de raiz, que inclui um jig (gabarit anti-erro – Poke Yoke) dotado de agulhas para o teste FCT (Functional Circuit Test), um hardware de aquisição de dados analógicos e digitais adquirido para o projecto, um hardware de interface entre o PC (Personal Computer) e o hardware de aquisição de dados, e um software desenvolvido em LabVIEW versão 8.6 (Laboratory Virtual Instruments Engineering Workbench).

Comparative study about heating systems for pultrusion process

Different heating systems have been used in pultrusion, where the most widely used heaters are planar resistances. The primary objective of this study was to develop an improved heating system and compare its performance with that of a system with planar resistances. In this study, thermography was used to better understand the temperature profile along the die. Finite element analysis was performed to determine the amount of energy consumed by the heating systems. Improvements were made to the die to test the new heating system, and it was found that the new system reduced the setup time and energy consumption by approximately 57%.

Optimising the energy consumption on pultrusion process

This study is based on a previous experimental work in which embedded cylindrical heaters were applied to a pultrusion machine die, and resultant energetic performance compared with that achieved with the former heating system based on planar resistances. The previous work allowed to conclude that the use of embedded resistances enhances significantly the energetic performance of pultrusion process, leading to 57% decrease of energy consumption. However, the aforementioned study was developed with basis on an existing pultrusion die, which only allowed a single relative position for the heaters. In the present work, new relative positions for the heaters were investigated in order to optimise heat distribution process and energy consumption. Finite Elements Analysis was applied as an efficient tool to identify the best relative position of the heaters into the die, taking into account the usual parameters involved in the process and the control system already tested in the previous study. The analysis was firstly developed based on eight cylindrical heaters located in four different location plans. In a second phase, in order to refine the results, a new approach was adopted using sixteen heaters with the same total power. Final results allow to conclude that the correct positioning of the heaters can contribute to about 10% of energy consumption reduction, decreasing the production costs and leading to a better eco-efficiency of pultrusion process.

Saving energy in the GFRP pultrusion process

This study addresses to the optimization of pultrusion manufacturing process from the energy-consumption point of view. The die heating system of external platen heaters commonly used in the pultrusion machines is one of the components that contribute the most to the high consumption of energy of pultrusion process. Hence, instead of the conventional multi-planar heaters, a new internal die heating system that leads to minor heat losses is proposed. The effect of the number and relative position of the embedded heaters along the die is also analysed towards the setting up of the optimum arrangement that minimizes both the energy rate and consumption. Simulation and optimization processes were greatly supported by Finite Element Analysis (FEA) and calibrated with basis on the temperature profile computed through thermography imaging techniques. The main outputs of this study allow to conclude that the use of embedded cylindrical resistances instead of external planar heaters leads to drastic reductions of both the power consumption and the warm-up periods of the die heating system. For the analysed die tool and process, savings on energy consumption up to 60% and warm-up period stages less than an half hour were attained with the new internal heating system. The improvements achieved allow reducing the power requirements on pultrusion process, and thus minimize industrial costs and contribute to a more sustainable pultrusion manufacturing industry.

Avaliação e Otimização Energética das Fornalhas da Fábrica de Aromáticos

O consumo energético verificado nas refinarias petrolíferas é muito elevado, sendo as fornalhas os equipamentos que mais contribuem para esse consumo. Neste estudo foi efetuada uma avaliação e otimização energética às fornalhas da Fábrica de Aromáticos da Refinaria de Matosinhos. Numa primeira fase foi efetuado um levantamento exaustivo de dados de todas as correntes de entrada e saída dos equipamentos para posteriormente efetuar os balanços de massa e energia a cada uma das fornalhas. Os dados relativos ao levantamento compreenderam dois períodos de funcionamento distintos da unidade fabril, o período de funcionamento normal e o período relativo ao arranque. O período de funcionamento normal foi relativo ao ano de 2012 entre os meses de janeiro a setembro, por sua vez o período de arranque foi de dezembro de 2012 a março de 2013. Na segunda fase foram realizados os balanços de massa e energia quantificando todas as correntes de entrada e saída das fornalhas em termos mássicos e energéticos permitindo o cálculo do rendimento térmico das fornalhas para avaliar a sua performance. A avaliação energética permitiu concluir que existe um consumo maior de energia proveniente da combustão do Fuel Gás do que do Fuel Óleo, tanto no período de funcionamento normal como no arranque. As fornalhas H0101, H0301 e a H0471 possuem os consumos mais elevados, sendo responsáveis por mais de 70% do consumo da Fábrica de Aromáticos. Na terceira fase foram enunciadas duas medidas para a otimização energética das três fornalhas mais consumidoras de energia, a limpeza mensal e o uso exclusivo de Fuel Gás como combustível. As poupanças energéticas obtidas para uma limpeza mensal foram de 0,3% na fornalha H0101, 0,7% na fornalha H0301 e uma poupança de 0,9 % na fornalha H0471. Para o uso exclusivo de Fuel Gás obteve-se uma poupança de 0,9% na fornalha H0101 e uma poupança de 1,3% nas fornalhas H0301 e H0471. A análise económica efetuada à sugestão de alteração do combustível mostra que os custos de operação sofrerão um aumento anual de 621 679 €. Apesar do aumento dos custos, a redução na emissão de 24% de dióxido de carbono, poderá justificar este aumento na despesa.