967 resultados para Drying energy saving


Relevância:

40.00% 40.00%

Publicador:

Resumo:

This guide describes things you can do around your home to reduce your utility bills and save you money. It offers some easy, practical steps that you can take to save energy and reduce the cost of heating and cooling your home. There are also tips on ways to reduce your electric and water usage. In addition, energy related health and safety information is also included. So, take a few minutes to read this guide and save it so you can refer to it in the future.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Abstract The present study aimed at investigating the influences of drying air temperature and flow rate on energy parameters and dehydration behaviour of apple slices. For this purpose, apple slices were dried in a convective dryer at air temperatures of 50, 60 and 70 °C, and air velocities of 1, 1.5 and 2 m s–1. Dehydration rate increased as the air temperature and flow rate increased from 50 to 70 °C and 1 to 2 m s–1, respectively. The effective moisture diffusivity was determined to be in the range of 6.75×10–10-1.28×10–9 m2 s–1. Results of data analysis showed that the maximum energy consumption (23.94 kW h) belonged to 50 °C and 2 m s–1 and the minimum (13.89 kW h) belonged to 70 °C and 1 m s–1 treatment. Energy efficiency values were in the range of 2.87-9.11%. Moreover, the results indicated that any increment in the air temperature increases thermal and drying efficiencies while any increment in the air flow rate decreases both of them.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

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.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

The main instrument of the Government's renewable energy policy is to promote wind power through regulation and subsidy. This gives rise to anomalies in rural planning when turbines are erected in sensitve areas in which other forms of development are strictly controlled. The situation is reviewed in the context of economic viability and considered also against the alternative of growing fuel crops. The latter are currently hampered by lack of Government support but could fulfil a useful secondary role of sustaining the agricultural sector and with it the management of lowland landscapes.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Includes bibliographies and indexes.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The spray drying method was used to prepare luminescent microspheres. These microspheres were prepared by spraying an aqueous solution of dextrin and an europium(III) complex with subsequent drying in a hot medium. The spray dried powder was characterized by scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL). Particle size distribution was estimated from SEM images. The ultrasonic spray drying technique was successfully applied to yield a microparticulated and red luminescent powder composed by the [Eu(dpa)(3)](3-) stop (dpa = dipicolinic acid) complex incorporated in dextrin microspheres.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Three different particular geometrical shapes of parallelepiped, cylinder and sphere were taken from cut green beans (length:diameter = 1:1, 2:1 and 3:1) and potatoes (aspect ratio = 1:1, 2:1 and 3:1) and peas, respectively. Their drying behaviour in a fluidised bed was studied at three different drying temperatures of 30, 40 and 50 degreesC (RH = 15%). Drying curves were constructed using non-dimensional moisture ratio (MR) and time and their behaviour was modelled using exponential (MR = exp(-kt)) and Page (MR = exp(-kt(n))) models. The effective diffusion coefficient of moisture transfer was determined by Fickian method using uni- and three-dimensional moisture movements. The diffusion coefficient was least affected by the size when the moisture movement was considered three-dimensional, whereas the drying temperature had a significative effect on diffusivity as expected. The drying constant and diffusivity coefficients were on the descending order for potato, beans and peas. The Arrhenius activation energy for the peas was also highest, indicating a strong barrier to moisture movement in peas as compared to beans and skinless cut potato pieces. (C) 2003 Elsevier Science Ltd. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Avança dados das perspetivas de diferentes gerações sobre questões ambientais e consumo energético.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Este trabalho surgiu no âmbito da Tese de Mestrado em Engenharia Química - Ramo Optimização Energética na Indústria Química, aliando a necessidade da Empresa Monteiro Ribas – Indústrias, S.A. em resolver alguns problemas relacionados com as estufas da unidade J da fábrica de revestimentos. Outro dos objectivos era propor melhorias de eficiência energética neste sector da empresa. Para tal, foi necessário fazer um levantamento energético de toda a unidade, o que permitiu verificar que as estufas de secagem (Recobrimento 1 e 2) seriam o principal objecto de estudo. O levantamento energético da empresa permitiu conhecer o seu consumo anual de energia de 697,9 tep, o que a classifica, segundo o Decreto-lei nº 71 de 15 de Abril de 2008, como Consumidora Intensiva de Energia (CIE). Além disso, as situações que devem ser alvo de melhoria são: a rede de termofluido, que apresenta válvulas sem isolamento, o sistema de iluminação, que não é o mais eficiente e a rede de distribuição de ar comprimido, que não tem a estrutura mais adequada. Desta forma sugere-se que a rede de distribuição de termofluido passe a ter válvulas isoladas com lã de rocha, o investimento total é de 2.481,56 €, mas a poupança pode ser de 21.145,14 €/ano, com o período de retorno de 0,12 anos. No sistema de iluminação propõe-se a substituição dos balastros normais por electrónicos, o investimento total é de 13.873,74 €, mas a poupança é de 2.620,26 €/ano, com período de retorno de 5 anos. No processo de secagem das linhas de recobrimento mediram-se temperaturas de todos os seus componentes, velocidades de ar o que permitiu conhecer a distribuição do calor fornecido pelo termofluido. No Recobrimento 1, o ar recebe entre 39 a 51% do calor total, a tela recebe cerca de 25% e na terceira estufa este é apenas de 6%. Nesta linha as perdas de calor por radiação oscilam entre 6 e 11% enquanto as perdas por convecção representam cerca de 17 a 44%. Como o calor que a tela recebe é muito inferior ao calor recebido pelo ar no Recobrimento 1, propõe-se uma redução do caudal de ar que entra na estufa, o que conduzirá certamente à poupança de energia térmica. No Recobrimento 2 o calor fornecido ao ar representa cerca de 51 a 77% do calor total e o cedido à tela oscila entre 2 e 3%. As perdas de calor por convecção oscilam entre 12 e 26%, enquanto que as perdas por radiação têm valores entre 4 e 8%. No que diz respeito ao calor necessário para evaporar os solventes este oscila entre os 4 e 13%. Os balanços de massa e energia realizados ao processo de secagem permitiram ainda determinar o rendimento das 3 estufas do Recobrimento 1, com 36, 47 e 24% paras as estufa 1, 2 e 3, respectivamente. No Recobrimento 2 os valores de rendimento foram superiores, tendo-se obtido valores próximos dos 41, 81 e 88%, para as estufas 1, 2 e 3, respectivamente. Face aos resultados obtidos propõem-se a reengenharia do processo introduzindo permutadores compactos para aquecer o ar antes de este entrar nas estufas. O estudo desta alteração foi apenas realizado para a estufa 1 do Recobrimento 1, tendo-se obtido uma área de transferência de calor de 6,80 m2, um investimento associado de 8.867,81 €. e uma poupança de 708,88 €/ano, com um período de retorno do investimento de 13 anos. Outra sugestão consiste na recirculação de parte do ar de saída (5%), que conduz à poupança de 158,02 €/ano. Estes valores, pouco significativos, não estimulam a adopção das referidas sugestões.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This paper presents a case study of heat exchanger network (HEN) retrofit with the objective to reduce the utilities consumption in a biodiesel production process. Pinch analysis studies allow determining the minimum duty utilities as well the maximum of heat recovery. The existence of heat exchangers for heat recovery already running in the process causes a serious restriction for the implementation of grassroot HEN design based on pinch studies. Maintaining the existing HEN, a set of alternatives with additional heat exchangers was created and analysed using some industrial advice and selection criteria. The final proposed solution allows to increase the actual 18 % of recovery heat of the all heating needs of the process to 23 %, with an estimated annual saving in hot utility of 35 k(sic)/y.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Dissertation presented to Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa for obtaining the master degree in Membrane Engineering

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This paper assesses the feasibility of impregnation/encasement of phase change materials (PCMs) in lightweight aggregates (LWAs). An impregnation process was adopted to carry out the encasement study of two different PCMs in four different LWAs. The leakage of the impregnated/encased PCMs was studied when they were submitted to freeze/thawing and oven drying tests, separately. The results confirmed that, the impregnation/encasement method is effective with respect to the large thermal energy storage density, and can be suitable for applications were PCMs cannot be incorporated directly such as asphalt road pavements.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The relevance of the building sector in the global energy use as well as in the global carbon emissions, both in the developed and developing countries, makes the improvement of the overall energy performance of existing buildings an important part of the actions to mitigate climate changes. Regardless of this potential for energy and emissions saving, large scale building renovation has been found hard to trigger, mainly because present standards are mainly focused on new buildings, not responding effectively to the numerous technical, functional and economic constraints of the existing ones. One of the common problems in the assessment of building renovation scenarios is that only energy savings and costs are normally considered, despite the fact that it has been long recognized that investment on energy efficiency and low carbon technologies yield several benefits beyond the value of saved energy which can be as important as the energy cost savings process. Based on the analysis of significant literature and several case studies, the relevance of co-benefits achieved in the renovation process is highlighted. These benefits can be felt at the building level by the owner or user (like increased user comfort, fewer problems with building physics, improved aesthetics) and should therefore be considered in the definition of the renovation measures, but also at the level of the society as a whole (like health effects, job creation, energy security, impact on climate change), and from this perspective, policy makers must be aware of the possible crossed impacts among different areas of the society for the development of public policies.