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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Drying of fine coal using warm air in a dense medium fluidised bed / Martha Johanna van Rensburg

Van Rensburg, Martha Johanna January 2014 (has links)
Fluidised bed drying is currently receiving much attention as a dewatering option after the beneficiation of fine coal (defined in this study as between 1mm and 2mm particles). The aim of this study was to investigate the removal of moisture from fine coal by using air at relatively low temperatures of between 25°C and 60°C within a controlled environment by lowering of the relative humidity of air. The first part of the experimental work was completed in a controlled climate chamber with the coal samples in a static non-fluidised state. Drying in the second part was carried out using a fluidised bed with conditioned air as the fluidising medium. Introduction of airflow to the system led to a lower moisture content in the coal samples and it also proved to have the ability to increase the drying rate. It was determined that the airflow had the ability to remove more free moisture from the filter cake. In addition more inherent moisture could also be removed by using upward flowing air, resulting in a lower equilibrium moisture content. It was proven that the airflow rate and relative humidity of the drying air contributed to faster drying rates. The effect of temperature was not as significant as expected, but higher temperatures did increase the drying rate at higher airflow and lower humidity conditions. The larger surface areas of particles create surface and capillary forces that prevent the moisture from leaving the finer coal particles. It was found that the rate of drying is independent of the moisture content in the coal sample. Just in terms of the fastest drying time and drying rate in the fluidised bed, it was concluded that the most efficient conditions is airflow above minimum fluidisation point causing vigorous mixing and maximum contact with the drying air. In addition to the high airflow it was concluded that 30% relative humidity and 55°C resulted in the fastest drying time. All the drying processes at all the airflow rates, temperature and relative humidity conditions were energy efficient. This process was shown to be energy positive, resulting in an overall energy gain. The overall energy consumption for the fluidised bed is lower than for all the dryer systems compared to and it compared favourably with other thermal drying technologies. It was therefore shown that this is a viable technology for the dewatering of fine coal. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2014
2

Drying of fine coal using warm air in a dense medium fluidised bed / Martha Johanna van Rensburg

Van Rensburg, Martha Johanna January 2014 (has links)
Fluidised bed drying is currently receiving much attention as a dewatering option after the beneficiation of fine coal (defined in this study as between 1mm and 2mm particles). The aim of this study was to investigate the removal of moisture from fine coal by using air at relatively low temperatures of between 25°C and 60°C within a controlled environment by lowering of the relative humidity of air. The first part of the experimental work was completed in a controlled climate chamber with the coal samples in a static non-fluidised state. Drying in the second part was carried out using a fluidised bed with conditioned air as the fluidising medium. Introduction of airflow to the system led to a lower moisture content in the coal samples and it also proved to have the ability to increase the drying rate. It was determined that the airflow had the ability to remove more free moisture from the filter cake. In addition more inherent moisture could also be removed by using upward flowing air, resulting in a lower equilibrium moisture content. It was proven that the airflow rate and relative humidity of the drying air contributed to faster drying rates. The effect of temperature was not as significant as expected, but higher temperatures did increase the drying rate at higher airflow and lower humidity conditions. The larger surface areas of particles create surface and capillary forces that prevent the moisture from leaving the finer coal particles. It was found that the rate of drying is independent of the moisture content in the coal sample. Just in terms of the fastest drying time and drying rate in the fluidised bed, it was concluded that the most efficient conditions is airflow above minimum fluidisation point causing vigorous mixing and maximum contact with the drying air. In addition to the high airflow it was concluded that 30% relative humidity and 55°C resulted in the fastest drying time. All the drying processes at all the airflow rates, temperature and relative humidity conditions were energy efficient. This process was shown to be energy positive, resulting in an overall energy gain. The overall energy consumption for the fluidised bed is lower than for all the dryer systems compared to and it compared favourably with other thermal drying technologies. It was therefore shown that this is a viable technology for the dewatering of fine coal. / MIng (Chemical Engineering), North-West University, Potchefstroom Campus, 2014
3

Větrání a teplovzdušné vytápění autoservisu / Ventilation and warm air heating of service station

Bašta, Milan January 2009 (has links)
This diploma thesis is focused on the design project of ventilation and warm air heating of a service station. The thesis starts with the introduction into this issue and the layout of the service station is presented here. Afterwards, calculations of the heat penetration coefficient, heat losses and heat load, as well as the amount of fresh air are presented here. Furthermore, the amount of supply air is assigned in this part. Consequently, a design project of ventilation and air heating is set up based on these calculations. The design project also includes the choice, dimensioning of local exhausting, a slot diffuser and of air duct paths. Moreover, pressure losses are calculated and the choice of an ventilation and heating unit is made. A design documentation with material specifications is also part of this diploma thesis.
4

Posouzení tepelné pohody v nízkoenergetickém rodinném domku s teplovzdušným vytápěním / Assessment of thermal comfort in a low-energy family house with warm-air heating

Kos, Jan January 2008 (has links)
The task of this master´s thesis is an evaluation of warm-air heating system in a low energy family house from the viewpoint of thermal comfort during winter season. The CFD simulation using CCM+ code was used for this purpose. The environment parameters in the central living room were evaluated for two variants – with underfloor heating and without it. The thermal comfort was evaluated using indices according ČSN EN ISO 7730 standard.
5

Sálavé vytápění průmyslových hal / Radiant heating of industrial halls

Rybář, Jakub January 2012 (has links)
Indoor climate of industrial halls is now advantageously shaped radiant heating systems, which are more flexible and efficient than convection systems. The crucial component of indoor climate in these systems mean radiant temperature. The work focuses on theoretical and experimental research on the location and operation of radiant panels. For the theoretical part is used new computer software able to calculate the Institute TZB mean radiation temperature distribution in 2D space. The experimental part was carried out comprehensive measurements of indoor climate parameters specific industrial halls and subsequently compared. Work includes the design and comparison of three variants of heating in the indoor facility.
6

Teplovzdušné vytápění / Warm air heating

Rohlíková, Věra January 2013 (has links)
The subject of this master's thesis is warm air heating system. The task is to apply this heating method to a specified building and to design technical solutions. The degree of completion of the extended project is appropriate for the requirements of building permit documentation. Proposed solutions were evaluated in the viewpoint of inner environment, space requirements, operation economy and environmental impact. Warm air heating system made by Atrea is used for building heating. The text part of the thesis deals with building air permeability and the experimental part describes performance of blower door test in a family house and evaluation of experiment data
7

Větrání a vytápění průmyslové haly / Ventilation and heating of an industrial building

Švábenský, Jiří January 2008 (has links)
The goal of this diploma thesis is suggest solution of ventilation and heating of industrial building. The solution is primarily based on calculation of thermal losses and thermal gains of the building. The project deals with supply of air for individual parts of construction in summer and winter. The solution consist of proposal of ducting and calculation of air handling units and unit heaters. The system of ventilation and heating is process in drawing documentation.
8

Energetická simulace vlivu zemního výměníku tepla na provoz rekuperační jednotky teplovzdušného vytápění / Energy simulation of ground heat exchanger influence to operation of warm-air heating recuperation unit

Kolbábek, Antonín January 2009 (has links)
The thesis deals with energy simulation of a heat recovery system in coupling with a ground heat exchanger (GHE) in a low-energy family house with warm-air heating and ventilation. The effect of GHE on operation and effectiveness of a heat recovery unit was assessed from the results of the simulation. Next, energy and economic benefits of the heat recovery with and without GHE and consequent savings were evaluated as well. The profitability of the investment was assessed using comparison with the investment costs. Recommendations for the operation of the system were suggested.
9

Náhrada klasického zemního výměníku tepla solankovým u rodinného domu s teplovzdušným vytápěcím systémem / Substitution of a classic ground heat exchanger by a brine one in a family house with warm-air heating system

Sokola, Robert January 2010 (has links)
The thesis deals with an energy simulation of a ground heat exchanger (GHE) in classical and brine performance, which is used as an accessory of warm air heating system recovery in a low-energy family house. On basis of simulation results, the benefits of both heat exchangers were assessed. Furthermore, the energy and economics savings of heat recovery coupled with GHE were evaluated. Comparing the investment costs, the profitability of each investment were assessed and recommendations for the operation, implementation and appropriateness were outlined.
10

Teplovzdušný vytápěcí a větrací systém pro nízkoenergetický rodinný dům / Warm-air heating and ventilating system for low-energy family house

Musil, Zdeněk January 2012 (has links)
The diploma thesis deals with warm-air heating and ventilation system of energyefficient family house. The part of thesis is theoretical introduction to low-energy and passive houses, ventilation and heating. The proposal itself is based on the applicable standards and includes all progressive steps, including the calculation of the thermal performance and sizing individual parts of the system. The drawing project documentation is listed in appendixes.

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