• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 438
  • 312
  • 61
  • 44
  • 41
  • 28
  • 18
  • 13
  • 11
  • 11
  • 11
  • 11
  • 11
  • 11
  • 8
  • Tagged with
  • 1233
  • 1233
  • 310
  • 263
  • 171
  • 168
  • 145
  • 136
  • 116
  • 101
  • 90
  • 88
  • 81
  • 80
  • 79
  • 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.
121

Design, manufacture and performance of solar-powered floating fountain

Gomez, Eduardo J. Owusu, Yaw A. January 2006 (has links)
Thesis (M.S.)--Florida State University, 2006. / Advisor: Yaw A. Owusu, Florida State University, FAMU-FSU College of Engineering, Dept. of Manufacturing and Industrial Engineering. Title and description from dissertation home page (viewed June 14, 2006). Document formatted into pages; contains ix, 78 pages. Includes bibliographical references.
122

Energy conservation at the Purnell School

Jones, William J William J., Meyer, James Wagner 02 1900 (has links)
No description available.
123

Capture solar energy and reduce heat-island effect from asphalt pavement

Chen, Bao-Liang. January 2008 (has links)
Dissertation (Ph.D.)--Worcester Polytechnic Institute. / Keywords: Temperature; Asphalt Pavement; Thermal Conductivity; Heat Transfer. Includes bibliographical references (leaves 156-159).
124

Research and development of CuInSe₂-based photovoltaic solar cells

Delsol, Thomas January 2001 (has links)
The work reported in this thesis includes the growth and characterisation of CuInSe[2]-based materials as well as the assessment and development of CuInSe[2]-based solar cells by the technique of electrodeposition. Cu(InGa)(SeS)[2] layers grown on glass/molybdenum by the two-stage method at Showa Shell have been used for comparison. Electrodeposition of window materials (ZnSe and CdS) on glass/TCO substrates following the conditions prior-established at Sheffield Hallam University has been achieved. CuInSe[2] films have been successfully grown on glass/TCO by electrodeposition. The semi-conducting layers were characterised to investigate their crystallinity, morphology, composition, optical and electrical properties. The structure of the films was characterised by XRD and Raman spectroscopy. The morphology was studied by SEM and AFM. The elemental bulk analysis was performed using XRF and ICPMS. The elemental surface analysis was performed using XPS and the depth profile analysis was studied by GDOES. The optical properties were characterised by optical absorption and the conductivity type was determined by PEC measurements. The conditions of electrodeposition and post deposition treatments were found to influence strongly the properties of the electrodeposited films. Near-stoichiometric films grown by electrodeposition are polycrystalline with a (112) preferential orientation of the chalcopyrite structure. CIS films appear dense with a good mechanical adhesion to the conducting oxide substrates and show crack-free surfaces with spherical grains electrically well connected to each other with a size up to 1 um. Cu, In and Se atoms are not uniformly distributed within the CIS films and In-rich phases, such as CuIn3Se5, cover the surface of the films. Testing of electrical conductivity shows that the films are generally p-type. I-V and C-V measurements were used to characterise the solar cells based on electrodeposited CuInSe[2]. Early stage CuInSe[2]-based solar cells showed encouraging results with efficiencies up to 15.9 % for the best devices. The maximum values of the V[oc], J[sc] and FF observed for the glass/FTO/ZnSe/CuInSe[2]/Au devices were 0.3 V, 105.0 mA/cm[2], and 50 %, respectively.
125

A unified numerical model for optics and heat transfer within line-axis concentrating solar energy collectors : development, validation and parametric analysis

Eames, Philip C. January 1990 (has links)
No description available.
126

Measurement of some radiative properties of solar absorber materials

De Silva, A. A. January 1986 (has links)
This work describes, (i) the designing and building of two sets of apparatus, namely a Liquid Nitrogen Cooled Ditectional Emissometer and a Laser-source Spectral Bidirectional Reflectometer (ii) measurements using the above apparatus on Solar selective absorber (Maxorb, Cusorb, Skysorb, Solarcoat- 100), non-selective absorber (Nextel, Solarcoat-50) and metal (Al, Cu and brass) samples. The emissometer incorporates liquid nitrogen cooling of the sample chamber thus reducing the error due to emission from the surroundings and extending the working range of sample temperature down to about 273 K. This instrument also uses a beam chopper with a phase sensitive detection system, and a Golay-cell detector. The overall error in the emittance values measured is estimated to be ± 5%. Using the emissometer all the samples in (ii) above were studied. The directional emittance behaviour of the metals and the non-selective absorbers agree well with theoretical predictions and with measurements made by other workers. In the case of the solar selective absorbers however, a peak in the directional emittance at 20°-30° reported by Hutchins (1979) is not seen in any of the present measurements. It is suggested that the ∈/∈'(0°) vs. ∈'(0°) plot can be used in comparing the emittance properties of solar selective absorbers with their substrate metals. The bidirectional reflectometer incorporates a novel device for mounting, positioning and orienting both the sample and the detector (Sample and Detector Assembly - SDA). The relatively small dimensions of this device compared with that of other bidirertional reflectometers reported makes it convenient to use and also allows it to be housed within a light-tight enclosure that minimizes problems with stray light. Extensive measurements have been made using laser sources at λ - 633 nm and λ - 1152 nm on the same set of samples of solar absorbers (selective and non-selective) studied with the emissometer. Comparison of the bidirectional reflectance characteristics of the solar selective absorbers shows marked differences between the materials. However certain features common to 'specularly' reflecting materials and others common to 'diffusely' reflecting materials have been identified. Materials like Cusorb and Solarcoat-lOO show a combination of these. Some of these features are discussed in terms of the surface microstructure data obtained using a scanning electron microscope and a conventional stylus type instrument.
127

The efficient collection and long term storage of solar energy in the UK, using air as the working fluid

Oreszczyn, T. January 1985 (has links)
This thesis describes the results of four years work on the design, construction, testing and evaluation of a high performance air heating collector designed to supply heat to a communal interseasonal store, which could heat many houses all the year round in the U.K. Interseasonal storage utilizing a pebble bed was investigated but shown to be costly both in terms of money and energy. The performance of medium to high temperature storage is shown to improve with high performance collectors. The level of insulation specified in the 1978 Building Regulations is found to be inadequate for solar heating with long and short term storage, because it is more economic to add more insulation than to install solar heating. While investigating the interseasonal storage of solar energy in pebble beds, data on the design and operation of air heating solar collectors was found lacking. Therefore the development and testing of both a high and low performance solar air heater was undertaken. The standard methods of testing collectors and in particular high performance collectors are shown not to provide an adequate method of comparing the daily efficiency of various types of collectors. Methods of testing air collectors are presented under transient conditions more representative of collector operation in the U.K. The parameters affecting high performance collectors are examined, in particular the reduction of heat loss between cover and absorber, and the effect on performance of diffuse and transient radiation. Results are also presented for testing a low cost plastic collector.
128

Computer simulation and optimisation of solar heating systems for Cyprus

Michaelides, Ioannis M. January 1993 (has links)
This thesis reports the results of research into the modelling and simulation of solar water and space heating for Cyprus, and the investigation of the factors concerning the optimisation of such systems. Further a number of design criteria, which can be used by consultants and designers of solar heating systems, have been established. Five solar heating system configurations have been modelled using the component models of the TRNSYS programme. They concern thermosyphon solar water heating systems, active solar water heating systems, solar space heating systems, combined solar water and space heating systems and solar assisted heat pump systems for space and water heating. These models are used to simulate the thermal performance of the systems and investigate their cost effectiveness under the weather and socioeconomic conditions of Cyprus. The results of the simulations have been used to identify the optimum design criteria for such systems in the Cyprus environment. The design criteria that have been established are concerned mainly with the solar collector and the storage tank and they are key design factors for a solar heating system. The design factors include the collector orientation and tilt angle, the collector to load factor which relates the collector surface area to the annual thermal load, the storage factor which relates the capacity of the storage tank to the collector size, the collector water flow flux, which relates the water flow rate through the collector with the collector area, and other criteria, which concern the auxiliary heat supply and the heat exchangers. For space heating systems, in addition to the above factors, a new design criterion is introduced, the collector to floor area factor, which relates the collector area to the building floor area, while for domestic hot water systems, the collector to consumer factor is used to specify the collector surface area needed for each hot water consumer in the building. This work has resulted in the publication of four papers in refereed International Journals and the presentation of three other papers at International Conferences. A list of publications is included in the Appendices.
129

The application of solar energy to the design of school buildings, and the development of a model of solar irradiance

Grindley, Peter Columbia January 1994 (has links)
ABSTRACT : THESIS PART ONE. The thermal performances of two schools with central atria, and a typical primary school class- base, were assessed using the SERI-RES computer model. ABSTRACT : THESIS PART TWO. To improve the modelling of sunlight and daylight, measured values of solar radiation, recorded at one minute intervals, were used to examine the relationship attributed to Lui A Jordan(1960), between the fraction of the solar radiation which is received on a horizontal surface, and the equivalent diffuse fraction,
130

Passive solar space and water heating systems

Lo, S. N. G. January 1990 (has links)
The performance of three types of passive solar feature has been studied; fifteen Roof-Space Collectors on an estate of low energy houses at the Milton Keynes Energy Park, 101m2 of Thermosyphoning Air Panels at a county primary school in Nazeing, Essex, and three Thermosyphon Solar Water Heaters installed on a group of three terraced cottages at Cranfield, Bedfordshire. Each of these passive solar features was monitored intensively for at least one heating season using dedicated data-acquisition systems. The maximum specific annual solar contributions to the auxiliary space/water heating systems were 128 kWh/M2 , 78 kWh/M2' and 104 kWh/M2 respectively. The corresponding payback periods were 25,37 & 21 years respectively, on replication.

Page generated in 0.0665 seconds