International Journal of Advanced Renewable Energy Research
Volume:1 Issue: 8, 2012

Flat plate collector is commonly used in solar collector because of its uniqueness to operate within low temperature. However, the heat transfer fluid used inside flat plate collector is of great concern lately due to degradation of this fluid over certain period of time. In this work, ethylene glycol water solution was analyzed in the ICPMS spectrometry and chromatography laboratory. It was established that degradation of ethylene glycol water occurs as function of time due to impurities. This degradation process will ultimately lead to corrosion of solar collector system.

Cu2ZnSnS4 (CZTS) thin film is a potential candidate for absorber layer in thin film heterojunction solar cell, which has been successfully deposited by solution growth technique on glass substrates. CuCl2.H2O, ZnCl2.H2O, SnCl2.H2O and Thiourea were used as the starting materials, ethanol and water as the solvent. The coated solution was dried at room temperature. The morphology of the film was analyzed by scanning electron microscopy, structural and optical property of the as deposited film was determined by a combination of X-ray diffraction, Raman scattering and UVVis spectroscopy. In this work we suggest novel CZTS thin film fabrication process that involves solution growth technique and also capable of producing large-area thin films.

Energy is the lifeline for economic growth, with consequences for quality of life of people and environment. Global energy demand is continuing to grow unabated. All eyes are on China and India, where energy demand is growing at 2 to 3 times that of global annual average of about 1.7%1. Indian economic growth is likely to lead to a huge increase of energy use in buildings but so far, policies to address this issue are lacking. Standard building energy use concerning glazing, air conditioning and lighting in different climatic zones across India leads to energy use per m2 which is 3-4 times of the German average. We assess the potential to improve building energy efficiency and how measures in the building sector could be framed as projects under the Clean Development Mechanism (CDM). CDM case studies for large buildings in the Indian public and private sector are presented. They achieve annual greenhouse gas reductions of 500 to 10,000 ton, which may not be sufficient to overcome the CDM transaction cost barrier. Despite short payback periods, the high initial investment and lack of integrated building management makes these projects additional. Large-scale appliance dissemination programs for Water heating system, air-conditioners, LEDs etc may offer interesting opportunities if the monitoring challenge can be overcome.

We presented in this study an experimental and theoretical study of a solar water heater (SWH), tested at the hot region of Adrar (Algeria). The SWH was composed essentially with a solar collector and a water storage tank. The experimental work allowed following the variation of the temperatures of the most important components of the SWH, which are the glass and the absorber. The results have shown that 80째C are reached with around 2 hours of inertia. The theoretical study focused on the effect of withdrawal. The efficiency of the system was: 32.89%.

The major application of the stand-alone power system is in remote areas where utility lines are uneconomical to install due to terrain, the right-of way difficulties or the environmental concerns. Villages that are not yet connected to utility lines are the largest potential market of the hybrid stand-alone systems using diesel generator with wind or PV for meeting their energy needs. The stand-alone hybrid system is technically more challenging and expensive to design than the grid-connected system that simply augments the existing utility system. This paper presents a regulated AC/DC/AC supply to convert wind energy to stand alone system. Multilevel inverter technology has emerged recently as a very important alternative in the area of high-power medium-voltage energy control. The topology of the diodeclamped inverter is presented with the relevant control and modulation method developed for this converter, which is: multilevel selective harmonic elimination, where additional notches are introduced in the multi-level output voltage. These notches eliminate harmonics at the low order/frequency and hence the filter size is reduced without increasing the switching losses and cost of the system. The proposed modulation method is verified through simulation using a five-level Diode-clamped inverter prototype. The harmonic of the supply generator current affect the electromechanical torque which has an impact on the vibration of the wind turbine. A multiphase transformer is designed to eliminate lower order harmonics of the generator current. The system consists of a wind-driven permanent magnet synchronous generator whose output is stepped down via a multiphase transformer, whose secondary voltages are rectified through an uncontrolled AC/DC converters to provide different input DC voltage levels to the diode clamp quazi phase multilevel inverter where the pulse widths are adjusted to eliminate low order harmonics of the output voltage whose magnitude is kept constant with different loading condition by controlling the inverter switching and maintaining low total harmonic distortion THD.

Cu2O thin films have been deposited using reactive dc magnetron sputtering technique using an Edward Auto 306 Magnetron Sputtering System. Transmittance and reflectance data in the range 300 nm-2500 nm were obtained using UV-VIS NIR Spectrophotometer Solid State 3700 DUV for all the thin films samples that were prepared. Transmittance values of above 70% were observed. The optical measurements were simulated using SCOUT 98 software to determine optical constants and optical bad gap of the thin. The optical properties in these films were varied by varying oxygen flow rate at constant power of 200 W. Optical studies show a direct allowed transition and a shift in the optical absorption edge as the oxygen flow rate varies at constant argon flow rate and other deposition parameters. These results show that single phase Cu2O thin films can be synthesized at a relatively low substrate temperature using the reactive dc magnetron sputtering technique. Band gap values of 1.62 eV-2.54 eV is observed. The surface sheet resistivities at room temperature of 298 K were found to vary with the deposition parameters and film thickness. Urbach energy varied between 0.6at10^-4 to 1.92at10^4.

Multilevel inverter technology has emerged recently as a very important alternative in the area of highpower medium-voltage energy control. This paper presents selective harmonic elimination method for cascade multilevel converters to eliminate the specified harmonics in the output voltage. The principle of the converter is analyzed. Then the switching angles are computed to eliminate the low order harmonics in theory, and the gating signals for the converter are given. The Selective Harmonic Elimination, SHE modulation method is presented where additional notches are introduced in the multi-level output voltage. These notches eliminate harmonics at the low order/frequency and shifts it a higher order/frequency and hence the filter size is reduced without increasing the switching losses and cost of the system. Static power converters are used for many applications, such as general power supplies. This paper analyzes the performance of single phase AC-DC-AC converter, where the converter consists of two parts, an AC to DC controlled rectifier cascaded with a DC to AC multilevel inverter, so as to increase the number of voltage levels of the inverter to reduce the filter size of the output voltage of the DC-AC converter. The experimental results show that the method can effectively eliminate the specific harmonics as expected.