Vol 52, No 4 (2016)

It was analysed the thermal performance of V-trough solar air heater with the thermal storage for drying applications. An active V trough solar air heater having concentration ratio of 1.5 with the thermal energy storage is designed and fabricated by using the flat plate non-selective surface embedded by paraffin wax based thermal energy storage. The developed system is tested by thermal performance test at site having the latitude of 12.97° N and longitude of 77.57° E over the period of time with and without the thermal storage. It was found that the incorporation of thermal storage is gives 10% higher thermal performance than without the thermal storage and other existing flat plate air heater. The total cost of the system is INR.30834/- and it saves conventional fuels and saves environment. It was concluded that the proposed system will be more economical if it was hybridized with utilization of the renewable energy sources of heat or waste heat.

This paper presents the results of studies on the development of the technology for powdering agricultural products using solar energy. It is found that the evaporation of moisture from crushed products (pasty mass) is similar to the evaporation from the free water surface. It is much more intensive than the evaporation from noncrushed products and usually consists of one stage.

In the current paper presented short review of the state of the art of solar powered reverse osmosis (RO) desalination systems, basic parameters, energy demand of RO process and also exergy analysis. In order to identify the main energy losses in desalination processes, to improve their performances from a thermodynamic point of view, there is a need for exergy analysis. The exergy analysis or second law analysis involves a comparison of exergy input and exergy destruction along various desalination processes. Using the exergy analysis methodology, presented in the current paper, the specific exergy and exergy flow rates at various points of a RO system can be evaluated. Once exergy flow rates are available, exergy destroyed within any component can be determined from exergy balance.

It is analysed the possibilities of solar power augmentation of existing power plants in the UAE. The authors set out to analyse briefly the power sector in the UAE providing insights to peak capacities of existing power plants. The research utilizes several factors such as age of plant, capacity factor, gross available capacity peak, amount of land, topography of the land and solar efficiency using to rank each of the power plant in the UAE and are capable of solar augmentation. An analysis of each of the factor and the possibility of solar augmentation for each of the power plan considered for the study is presented. Challenges for solar augmentation and future research potential is discussed.

This article considers the technology of fabricating clusters of nickel atoms in a silicon crystalline lattice with controlled parameters. Silicon solar cells with clusters of nickel atoms have been fabricated and their parameters determined. It has been established that the content of nickel atoms in the lattice makes it possible to considerably expand the spectral sensitivity region of silicon photovoltaic cells to the IR range up to 4 μm.

Hyderabad is reeling under a severe power crisis aggravated due to the recent bifurcation of the state of Andhra Pradesh. Telangana state needs more power than residual Andhra Pradesh due to greater demand from its Industrial and Agricultural consumers. The installed capacity (established as well as under construction) of power plants under Telangana Power Generation Corporation (TSGENCO) includes 2282.5 MW of thermal coal based power, 2081.76 MW of hydro power and 1 MW solar power. As more than 50% of the power source is coal based, there exists a threat of fossil fuel depletion and enhanced Green House Gas (GHG) emissions. Solar electricity has the potential to offset these negative impacts. This paper concentrates on evaluating the roof top area required for solar power generation using Remote Sensing and GIS apart from developing an algorithm using analytical methods, to estimate the photo-voltaic system components required, for the total power requirement of Hyderabad city.

New solar modules intended for typical solar collectors containing semiparabolic trough concentrators and receivers that convert solar energy into thermal energy are considered. Mathematical modeling is carried out to develop an algorithm for estimating the structure of a heating module with the assigned energy parameters according to the laws of geometrical optics, as well as heat and mass transfer. When using such modules, which are based on a parabolic concentrator and a receiver with a system of coolant flow, cogeneration plants can be designed to produce electricity and heat. The mockups developed using this procedure are studied on the corresponding facilities and are tested under in-situ conditions. A solar module with an asymmetric parabolic trough concentrator and a linear wedge-like photoelectric receiver of concentrated radiation with a system of coolant flow provides the maximum power of 386 W at a temperature of 40°C and an efficiency of 60%, and 319 W at 60°C and 49%, respectively. Such modules are proposed for use to design solar collectors with the required performance.

The results of numerical studies aimed to evaluate the heat capacity of short-term phase change heat accumulators applied in passive solar heating systems (PSHS) with a three-layer energy active translucent enclosure (TE) are presented. An example is given of calculation of specific (per unit of TE surface area) weight of heat accumulator using dimethyl sulfoxide, (СН₃)₂SO, with melting temperature 18.6°C and latent heat of phase transition 173 kJ/kg, as the heat storage agent.

In the present work, sol–gel method is used to synthesize TiO₂ nanoparticle. The characterization of the prepared TiO₂ powder is done using Powder X-ray diffraction (powder XRD), Scanning Electron Microscope (SEM), Energy-Dispersive X-Ray Spectroscopy (EDS) and Ultraviolet-Visible Spectrophotometry (UV-Vis). The XRD pattern reveals formation of anatase phase TiO₂. The SEM images reveal agglomeration of nanoparticles. The absorbance spectrum of TiO₂ nanoparticles was observed with excitonic peaks at 327 nm and the band gap came out to be ~3.2 eV. This prepared TiO₂ was tested for photovoltaic performance by using it in the Dye sensitized solar cell (FTO/TiO₂/N719/KI-I₂/Pt). Conversion of solar light energy to electricity was successfully done using this TiO₂. The fabricated cell showed an open-circuit voltage (V_OC) of 587 mV and short-circuit current density (J_SC) of 5.06 mA/cm². Maximum power (P_max) generated was 1.912 mW/cm² with a fill factor (FF) of 0.644 and a conversion efficiency of 1.91%.

The effect of blade number on performance of drag type vertical axis wind turbine (VAWT) is studied by Ansys numerical simulation, it involves 3-blade, 5-blade and 6-blade VAWTs. The optimized width of blade for each VAWT at maximum power efficiency is obtained, and simulation for the wind turbine with different number of blade is conducted for the VAWTs with turbine radius of 2 m at the inlet wind speed 8 m/s. By simulations, it gets the evolution curve of torque with respect to time, and the cyclical characteristics for these wind turbines. The results show that the maximum power efficiency and the stability of the wind turbine increase with the number of blade of the wind turbine, however the optimal d/D decreases with the number of blade of the wind turbine. The maximum power efficiencies are 20.44, 24.30 and 26.82% for 3-blade, 5-blade and 6-blade wind turbines, and the correspondingly optimal d/D are 0.66, 0.40 and 0.35, respectively. While the optimal rotational rate of turbine decreases with blade number.