Solar Energy Conversion

Desalination plays critical role in filling the gap between fresh water demand and availability in water scarce Sultanate of Oman since 1976. Installed desalination capacity in the country has almost increased by 60 times that in 1976 with increasing fresh water demand. Even though desalination share in meeting the fresh water demand is increasing, 80-85% of fresh water demand today is still satisfied with ground water. This is leading to increased soil salinity in recent years affecting the crop production. All the planned and installed desalination plants in the country use conventional fuels for their operation. None of the plant is based on any form of renewable energy source. Consumption of fossil fuels for the operation of plants is increasing at an average rate of 3-5% affecting the net export for the country. Sultanate of Oman is considered to be one of the most suitable destinations for solar energy applications and can play a vital and sustainable role in meeting the gap b...

Many applications use dc to dc boost converter. For example, laptop chargers, dc Motor drives and any applications that require high dc voltages [1][5]. The benefit of using this circuit is to minimize from using large numbers of batteries. This circuit produces high output dc voltage. Almost this voltage is greater than or equal input voltage that depend on type of application. The aim of this paper is to make controllers for boost converter in S-domain and Z-Domain by using MATLAB SISTOOL. Also, comparison between two controllers are investigated in this paper. Keywords Boost Converter, MATLAB SISOTOOL, Controller in S-Domain and Z-Domain.

Hybrid nanocomposites of Cu 2 O−(R)TiO 2 , CuO−(R)TiO 2 , and Cu 3 TiO 4 −(R)TiO 2 (where R represents the rutile phase of TiO 2) nanopowders (NPs) were produced via solid state reaction followed by 20 h of ball milling; their photocatalytic activities were evaluated for methylene blue (MB) degradation under visible light intensity (∼65 mW/ cm 2) and compared to Degussa P25 under both ultraviolet (UV) and visible light irradiations. The highest MB degradation rate under the visible light irradiation was observed to be 0.271 ± 0.010 h −1 for Cu 2 O−(R)TiO 2 NPs, which was 2.5 times higher than that of P25, while under UV illumination both the Cu 2 O−(R)TiO 2 and Cu 3 TiO 4 − (R)TiO 2 NPs were slightly less active than that of the P25, and CuO−(R)TiO 2 was the least active among all. The solar energy conversion performance of the Cu x O−(R)TiO 2 NPs was observed to be controlled by the applied potentials. The highest stable cathodic photocurrent density (6.3 μA/cm 2) was observed for Cu 2 O−(R)TiO 2 NPs at a low negative bias voltage (−0.3 V vs Ag/AgCl, 3 M KCl) and under the solar simulator (AM 1.5G). This method to design multifunctional visible-light-active metal oxides is simple and scalable and has the potential to prepare other efficient photocatalysts for solar energy conversion.

Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions. © 2014 Nahidul Hoque Samrat et al.

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Desalination plays a critical role in filling the gap between freshwater demand and availability in water-scarce Sultanate of Oman since 1976. Installed desalination capacity in the country has almost increased by 60 times that in 1976 with increasing fresh water demand. Even though desalination share is increasing, 80-85% of freshwater demand today is still satisfied with groundwater and natural sources. This is leading to increased soil salinity in recent years affecting the crop production. All the planned and installed desalination plants in the country use conventional fuels for their operation. None of the plants are based on any form of renewable energy source. Consumption of fossil fuels for the operation of these plants is increasing at an average rate of 3-5% affecting the net export for the country. Sultanate of Oman is considered to be one of the most suitable destinations for solar energy applications and solar energy can play a vital and sustainable role in meeting the gap between the demand and supply of fresh water using solar thermal desalination. This paper emphasizes on addressing this aspect for the country. An overview of present desalination status and fresh water demand, fuel requirements, solar energy availability, thermal desalination technologies and solar thermal technologies has been presented in the paper. Conventional thermal desalination technologies and solar thermal technologies have been compared for same capacity on the scale of 1 to 5 for various factors in the context of Sultanate of Oman. Few of the challenges and barriers in the implementation of solar thermal desalination in the country are also discussed in the paper. Fixed focus type Scheffler dish reflectors (SDR) are suggested as one of the best suitable option to be coupled with multi-effect desalination technology for small to medium capacity decentralized type plants. Parabolic trough collectors (PTC) coupled with Combined Cycle Gas Turbine (CCGT) or Open Cycle Gas Turbine (OCGT) plants would be a feasible solution for higher capacity desalination plants.

The world requires inexpensive, reliable, and sustainable energy sources. Solar photovoltaic (PV) technology, which converts sunlight directly into electricity, is an enormously promising solution to our energy challenges. This promise increases as the efficiencies are improved. One straightforward method of increasing PV device efficiency is to utilize multi-junction cells, each of which is responsible for absorbing a different range of wavelengths in the solar spectrum. Indium gallium nitride (In x Ga1−x N) has a variable band gap from 0.7 to 3.4 eV that covers nearly the whole solar spectrum. In addition, In x Ga1−x N can be viewed as an ideal candidate PV material for both this potential band gap engineering and microstructural engineering in nanocolumns that offer optical enhancement. It is clear that In x Ga1−x N is an extremely versatile potential PV material that enables several known photovoltaic device configurations and multi-junctions with theoretic efficiencies over 50 pct. This potential is driving immense scientific interest in the material system. This paper reviews the solar PV technology field and the basic properties of In x Ga1−x N materials and PV devices. The challenges that remain in realizing a high-efficiency In x Ga1−x N PV device are summarized along with paths for future work. Finally, conclusions are drawn about the potential for In x Ga1−x N photovoltaic technology in the future.

The thermal stability of thin (50 nm) PEDOT:PSS films, was investigated by dc conductivity measurements, X-ray and UV photoelectron spectroscopies as a function of heating temperature and heating time. The mechanism of electrical conductivity as a function of temperature is consistent with a hopping type carrier transport. The electrical conductivity decreased, as a function of time, in agreement with a granular metal type structure, in which aging is due to the shrinking of the PEDOT conductive grains. XPS and UPS spectra indicate that conformational changes of the PEDOT:PSS film are responsible for this behaviour and a model for these modifications is proposed.

Using sun as the energy source, natural photosynthesis carries
out a number of useful reactions such as oxidation of water to
molecular oxygen and fixation of CO2 in the form of sugars.
These are achieved through a series of light-induced multielectron-
transfer reactions involving chlorophylls in a special
arrangement and several other species including specific
enzymes. Artificial photosynthesis attempts to reconstruct
these key processes in simpler model systems such that solar
energy and abundant natural resources can be used to
generate high energy fuels and restrict the amount of CO2 in the
atmosphere. Details of few model catalytic systems that lead to
clean oxidation of water to H2 and O2, photoelectrochemical
solar cells for the direct conversion of sunlight to electricity,
solar cells for total decomposition of water and catalytic
systems for fixation of CO2 to fuels such as methanol and
methane are reviewed here.

Solar photovoltaic (PV) systems are frequently installed in climates with significant snowfall. To better understand the effects of snowfall on the performance of PV systems, a multi-angle, multi-technology PV system was commissioned and monitored over two winters. A novel methodology was introduced and validated with this system, which allows for the determination of snowfall losses from time-series performance data with correlated meteorological observations down to a 5-min resolution. In addition, a new method for determining the probability distribution of snow deposition on a module from image data was developed. It was found that the losses due to snowfall are dependent on the angle and technology being considered and the effects of increased albedo in the surroundings of a PV system can increase expected yields, particularly in the case of high tilt angle systems. Existing methods for predicting losses due to snowfall were investigated, and were found to provide overly conservative estimates of snow losses. Overall the results show that the proper assessment of snow related losses can help improve system performance and maintenance. It is concluded that proper characterization of the snowfall effect on PV system performance can influence better systems optimization for climates experiencing snowfall.

Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vect...

The study assessed the potential and economic viability of solar PV standalone systems for embedded generation, taking into account its benefits to small off-grid rural communities in forty meteorological sites in Nigeria. A specific electric load profile was developed to suite the communities consisting 200 homes, a school and community health centre. Data (daily mean relative humidity, maximum and minimum temperatures, and daily global solar radiation for 24 years spanning 1987-2010) obtained from the Nigeria Meteorological Agency were used. It focused on the assessment of design that will optimally meet daily load demand for the rural communities with an LOLP of 0.01. The HOMER® software optimizing tool was engaged for the feasibility study and design. A 15 MW PV distributed generation system was utilized to economically compare the different sites in terms of life cycle cost as well as levelised cost
of producing energy. A profit for potential investors in the range of $ 0.01/kWh to $ 0.17/kWh was discovered for 29 of the 40 available meteorological sites, while the remaining sites were not profitable with the present tariff regime in Nigeria.

Correct modelling of solar photovoltaic (PV) system yields is necessary to optimize system design, improve reliability of projected outputs to ensure favourable project financing and to facilitate proper operations and maintenance. An improved methodology for fine resolution modelling of PV systems is presented using module short-circuit current (Isc) at 5-min time-scales, and clearly identifies pertinent error mechanisms that arise when working at this high resolution. This work used a modified version of the Sandia array performance model, and introduces new factors to the calculation of Isc to account for identified error mechanisms, including instrumentation alignment, spectral, and module power tolerance errors. A simple methodology was introduced and verified where specific module parameters can be derived solely from properly filtered performance time series data. In particular, this paper focused on methodologies for determining the predicted Isc for a variety of solar PV module types. These methods of regressive analysis significantly reduced the error of the predicted model, and demonstrate the need for this form of modelling when evaluating long term PV array performance. This methodology has applications for current systems operators, which will enable the extraction of useful module parameters from existing data in addition to more precise continuous monitoring of existing systems, and can also be used to more accurately model and optimize new systems.

—although in many parts of India certain crops can be produced at certain period of year, the major part of the produce such as cereals & other crops are seasonal. Food produced in one harvest period lasts only for few weeks. This which must be stored for gradual consumption until next harvest and seeds must be held for next season crops. Also the market value of any crop tends to rise during off season. Therefore it is important to minimize losses and prepare the food for long lasting storage. This paper consist of various requirement of storage of cereals as cereals covers larger part of diet, for proper storage includes needs study of various properties of grains of cereals. This study shows that proper drying is required for proper storage, the solar dryer development details are presented in the paper.

A way of exploiting the solar energy is to use cells photovoltaic which convert the energy conveyed by the incidental radiation in a continuous electric current. This conversation is based on the photovoltaic effect engendered by the absorption of photons. A part of the absorbed photons generates pairs electron-hole in which an electric field created in the zone of load of space of a junction p–n.Thus, the junction p-n, its characteristics, its components and its dimensions are the parameters responsible of the efficiency and the performances of a solar cell. To study this, we are going to use a very
known software in the mode of the simulation of solar cells, the PC1D, and we are going, at the end, to draw a conclusion around the ideal parameters that a good solar cell has to have.

This paper describes the environmental and health impacts of toxic emissions from
the energy uses for cooking along with application of simple physics with detailed experimental
studies on procedures of reducing “On-stove time” and cooking with minimum Energy (Heat)
using a new innovative energy efficient cooking techniques with a simple inexpensive insulation
box. The total minimum amount of heat, Qm, and on-stove time t1 required to cook 1 kg of dry
rice, 1 kg of dry beans, 1 kg of raw potato and 1 kg of goat meat using the new technique of
cooking with a stove of power 626 + 10 W are found as: 562+ 3 kJ, 708 + 4 kJ, 278 + 2 kJ, 716
+ 4 kJ. The barest minimum (sensible) heat, ht required to transform 1 kg of raw food into cooked
food of these items are: 440 + 3 kJ, 609 + 4 kJ, 212 + 2 kJ and 626 + 4 kJ. With computations
of the Global CDM potential of our new cooking method we have discussed the possible
contributions of the energy and economically efficient cooking method towards significant
reduction of emissions of CO2 and other toxic gases and protection of environment and health.
KEYWORDS: Sensible Heat Of Transformation, Energy Efficient Cooking, CDM Potential,
Heat Insulation Box, Environment and Health Protection, Toxic Emissions.

As a visible light active p-type semiconductor, CuBi 2 O 4 is of interest as a photocatalyst for the generation of hydrogen fuel from water. Here we present the first photovoltage and photocatalytic measurements on this material and DFT results on its band structure. Single crystalline CuBi 2 O 4 nanoparticles (25.7 AE 4.7 nm) were synthesized from bismuth and cupric nitrate in water under hydrothermal conditions. Powder X-ray diffraction (XRD) confirms the CuBi 2 O 4 structure type and UV-Vis spectroscopy shows a 1.75 eV optical band gap. Surface photovoltage (SPV) measurements on CuBi 2 O 4 nanoparticle films on fluorine doped tin oxide yield 0.225 V positive photovoltage at >1.75 eV photon energy confirming holes as majority carriers. The photovoltage is reversible and limited by light absorption. When dispersed in 0.075 M aqueous potassium iodide solution, the CuBi 2 O 4 particles support photochemical hydrogen evolution of up to 16 mmol h À1 under ultraviolet but not under visible light. Based on electrochemical scans, CuBi 2 O 4 is unstable toward reduction at À0.2 V, but a pH-dependent photocurrent of 6.45 mA cm À2 with an onset potential of +0.75 V vs. NHE can be obtained with 0.01 M Na 2 S 2 O 8 as a sacrificial electron acceptor. The photoelectrochemical properties of CuBi 2 O 4 can be explained on the basis of the band structure of the material. DFT calculations show that the valence and conduction band edges arise primarily from the combination of O 2p and Cu 3d orbitals, respectively, with additional contributions from Cu 3d and Bi 6s orbitals just below the Fermi level. Trapping of photoelectrons in the Cu 3d band is the cause for reductive photocorrosion of the material, while the p-type conductivity arises from copper vacancy states near the VB edge. These findings provide an improved understanding of the photophysical properties of p-CuBi 2 O 4 and its limitations as a proton reduction photocatalyst.

Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic-(PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions.

Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic-(PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions.

Climate change caused by continuous rising level of CO 2 and the depletion of fossil fuels reserves has made it highly desirable to electrochemically convert CO 2 into fuels and commodity chemicals. Implementing this approach will close the carbon cycle by recycling CO 2 providing a sustainable way to store energy in the chemical bonds of portable molecular fuels. In order to make the process commercially viable, the challenge of slow kinetics of CO 2 electroreduction and low energy efficiency of the process need to be addressed. To this end, this review summarizes the progress made in the past few years in the development of heterogeneous electrocatalysts with a focus on nanostructured material for CO 2 reduction to CO, HCOOH/HCOO − , CH 2 O, CH 4 , H 2 C 2 O 4 /HC 2 O − 4 , C 2 H 4 , CH 3 OH, CH 3 CH 2 OH, etc. The electrocatalysts presented here are classified into metals, metal alloys, metal oxides, metal chalcogenides and carbon based materials on the basis of their elemental composition , whose performance is discussed in light of catalyst activity, product selectivity, Faradaic efficiency (FE), catalytic durability and in selected cases mechanism of CO 2 electroreduction. The effect of particle size, morphology and solution-electrolyte type and composition on the catalyst property/activity is also discussed and finally some strategies are proposed for the development of CO 2 electroreduction catalysts. The aim of this article is to review the recent advances in the field of CO 2 electroreduction in order to further facilitate research and development in this area.

At present there are many applications which use hot water in the range of 45 0 C to 60 0 C like in medical labs, paper industries, fermentation industries, etc. Many conventional and non-conventional methods are used to achieve this. Now days these methods are becoming costlier. In the present paper a study has been carried out on use of building material (concrete) for providing hot water in the range of 45 0 C to 60 0 C during daytime. Trials were conducted on a MFRC (Metal Fiber Reinforced Collector) concrete collector of size 100cm X 200 cm X 1.8 cm with copper tubing (Meander type) for the summer season. The experimental results of these trials have been presented in this paper. The average temperature obtained is in the range of 52 0 C to 59 0 C for the season. This paper paves way for possible integration of MFRC collector with roof slab. Such integration will provide comfort temperature zone within the building. This knowledge can be used by the architects while designing the roof of the buildings which may serve the purpose of providing hot water for domestic purpose to the occupants of the building.

The paper proposes a simple model to evaluate the monthly average performance of a solar collector by taking into account the influence of cloud cover. Also, a combined graphical and tabular technique is developed. Useful simplifications are discussed. The dependence on cloud cover of some quantities such as the maximum useful operating time and maximum useful heat delivered by the collector is analyzed. The combined influence of cloud cover and collector tilt angle or thermal regime on the same quantities is presented.