01821 New helio-photocatalytic-photovoltaic hybrid system for simultaneous water decontamination and solar energy conversion

01821 New helio-photocatalytic-photovoltaic hybrid system for simultaneous water decontamination and solar energy conversion

13 Alternative energy supplies (solar energy) For the first time the simple solar parabolic cooker (SPC), of the cylindrical trough shape, is analysed...

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13 Alternative energy supplies (solar energy) For the first time the simple solar parabolic cooker (SPC), of the cylindrical trough shape, is analysed from the exergy viewpoint. The paper presents the methodology of detailed exergy analysis of the SPC, the distribution of the exergy losses, and, on the example of the cooker surfaces, explains the general problem of how the exergy loss on any radiating surface, should be determined, if the surface absorbs many radiation fluxes of different temperatures. An imagined surface was used in the considerations to close the system of the cooker surfaces. It was shown that optimization is needed, to increase the energy and exergy efficiencies of the cooker. Equations for heat transfer between the three surfaces: cooking pot, reflector and imagined surface making up the system, were derived. The model allowed for theoretical estimation of the energy and exergy losses: unabsorbed insolation, convective and radiative heat transfer to the ambient, and additionally, for the exergy losses: the radiative irreversibilities on the surfaces, and the irreversibility of the useful heat transferred to the water. The exergy efficiency of the SPC, was found to be relatively very low (1%), and to be about 10 times smaller than the respective energy efficiency which is in agreement with experimental data from the literature. The influence of the input parameters (geometrical configuration, emissivities of the surfaces, heat transfer coefficients and temperatures of water and ambience) was determined on the output parameters, the distribution of the energy and exergy losses and the respective efficiencies.

06/01818 Modeling and simulation on the thermal performance of shape-stabilized phase change material floor used in passive solar buildings Xu, X. et al. Energy and Buildings, 2005, 37, (10), 1084-1091. Shape-stabilized phase change material (PCM) is a kind of novel PCM. It has the following salient features: large apparent specific heat for phase change temperature region, suitable thermal conductivity, no container. In the present paper, a kind of shape-stabilized PCM floor is put forward which can absorb the solar radiation energy in the daytime and release the heat at night in winter. Therefore, in winter the indoor climate can be improved and the energy consumption for space heating may be greatly reduced. A model of analysing the thermal performance of this shape-stabilized PCM floor is developed. By using the modelling, the influence of various factors (thickness of PCM layer, melting temperature, heat of fusion, thermal conductivity of PCM, etc.) on the room thermal performance was analysed. The model was verified by the experimental results. The model and the analysis are helpful for the application of shape-stabilized PCM floor in solar buildings.

06•01819 Multi-junction III-V solar cells: current status and future potential Yamaguchi, M. et al. Solar Energy. 2005, 79, (l), 78-85. Recent R&D activities of III-V compound multi-junction (MJ) solar cells are presented. Conversion efficiency of InGaP/lnGaAs/Ge has been improved up to 31-32% (AM1.5) as a result of technologies development such as double hereto-wide band-gap tunnel junction, I n G a P - G e hetero-face structure bottom cell, and precise latticematching of InGaAs middle cell to Ge substrate by adding indium into the conventional GaAs layer, For concentrator applications, grid structure has been designed in order to reduce the energy loss due to series resistance, and world-record efficiency lnGaP/InGaAs/Ge 3junction concentrator solar cell with an efficiency of 37.4% (AM1.5G, 200-suns) has been fabricated. In addition, the study also demonstrated high-efficiency and large-area (7000 cm 2) concentrator InGaPlInGaAs/ Ge three-junction solar cell modules of an outdoor efficiency of 27% as a result of developing high-efficiency InGaP/InGaAs/Ge 3-junction cells, low optical loss Fresnel lens and homogenizers, and designing high thermal conductivity modules. Future prospects are also presented. The study proposes concentrator III-V compound MJ solar cells as the 3rd generation solar cells in addition to 1st generation crystalline Si solar cells and 2nd generation thin-film solar cells. Lowcost and high output power concentrator MJ solar cell modules with an output power of 400 W/m z for terrestrial applications are now being developed,

06/01820 Nanostructured materials for solar energy conversion Oelhafen, P. and Schiiler, A. Solar Energy, 2005, 79, (2), 110-121 . This review article deals with the motivation for using nanostructured materials in the field of solar energy conversion. Some recent fundamental observations on supported nanoclusters and optical properties of embedded metallic nanoclusters in a dielectric matrix are included. An overview on current research and existing applications in this field is also given. Nanocomposite thin films developed for the application as optically selective absorber coatings in thermal solar collectors are described in some more detail. These coatings are based on transition metal containing amorphous hydrogenated carbon films (a-C:H/TM) or on transition metal containing silicon-carbon films (a-Si:C:H/TM) produced by a combined PVD/PECVD process.

06/01821 New helio-photocatalytic-photovoltaic hybrid system for simultaneous water decontamination and solar energy conversion Sarria, V. et al. Solar Energy, 2005, 79, (4), 353-359. Test results for a designed and installed hybrid photocatalyticphotovoltaic system (HPPS) are presented in this paper. The HPPS consists of one device with dual functions: The photocatalytic system uses UV radiation to promote degradation of organic pollutants, and beside it absorbs the IR radiation, The photovoltaie (PV) system converts the visible radiation into electricity, which can either be used directly by the recirculation pump or stored in a battery for other purposes. The suggested design aims to achieve an autonomous, environmentally friendly method for the treatment of biorecalcitrant pollutants. Two prototypes were erected: HPPSr, using Plexiglas and HPPSG using commercial glass. Both were tested outdoors to determine their impact on photovoltaic power production. Test results showed that PV power diminished to 14% and 22% for HPPSG and HPPSp respectively, compared to a PV panel alone.

06/01822 Optimal operation of thermoelectric cooler driven by solar thermoelectric generator Khattab, N. M. and E1 Shenawy, E. T. Energy Conversion and Management, 2006, 47, (4), 407-426. The possibility of using a solar thermoelectric generator (TEG) to drive a small thermoelectric cooler (TEC) is studied in the present work. The study includes the theory of both the TEG and the TEC, giving special consideration to determination of the number of TEG modules required to power the TEC to achieve the best performance of the T E G - T E C system all year round. Commercially available thermoelectric modules (TE) are used in the system. The TEG contains 49 thermocouples and the TEC contains 127 thermocouples. A simple arrangement of plane reflectors that are designed to receive maximum solar energy during noon time is used to heat the TEG. Performance tests are conducted to determine both the physical properties and the performance curves of the available TE modules. Also, empirical relations describing the performance of the TEG and TEC modules have been established. These relations are used to develop a mathematical model simulating the T E G - T E C system to predict its performance all year round under the actual climatic conditions of Cairo, Egypt (30°N latitude). The model results are used to determine the number of TEG modules required to drive a single TEC module at maximum cooling capacity. The results show that five thermocouples of the TEG can drive one thermocouple of the TEC, which coincides with the previous theory of the TEG-TEC. This means that 10 of the used TEG modules are required to power the used TEC at optimum performance most times of the year.

06•01823 Optimizing the solar photo-Fenton process in the treatment of contaminated water. Determination of intrinsic kinetic constants for scale-up Rodr/guez, M. et al. Solar Energy, 2005, 79, (4), 360-368. The elimination of aromatic compounds present in surface water by photo-Fenton with sunlight as the source of radiation was studied. The concentrations of Fe 3+ and HzO: are key factors for this process. A solar simulator and a prototype parabolic collector were used as laboratory-scale reactors to find the parameters of those key factors to be used in the CPC (compound parabolic collector) pilot plant reactor. The initial mineralization rate constant (/Cobs) w a s determined and evaluated at different Fe 3+ and H202 concentrations to find the best values for maximum efficiency. In all the experiments the mineralization of an aqueous phenol solution was described by assuming a pseudo-first-order reaction. The intrinsic kinetic constants not dependent on the lighting conditions were also estimated for scale-up.

06/01824 Parametric studies for heating performance of an earth to air heat exchanger coupled with a greenhouse GhosalG, M. K. and Tiwari, N. hzternational Journal of Energy Research, 2005, 29, (11), 991-1005. A thermal model has been developed to investigate the potential of using the stored thermal energy of the ground for greenhouse heating with the help of an earth to air heat exchanger (EAHE) system integrated with the greenhouse located in the premises of IIT, Delhi, India. Experiments were conducted extensively during the winter period from November 2002 to March 2003, but the model developed was validated against the clear and sunny days. Parametric studies performed for E A H E coupled with the greenhouse illustrate the effects of buried pipe length, pipe diameter, mass flow rate of air, depth of ground and soil types on greenhouse air temperatures. Temperatures of greenhouse air with the experimental parameters of E A H E were found to be on an average 7-8°C more in the winter than the same greenhouse without EAHE. Greenhouse air temperatures increase in the winter with increasing pipe length, decreasing pipe diameter, decreasing mass flow rate of flowing air inside buried pipe and increasing depth of ground up to 4 m. Predicted and measured values

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