Abstract: Energy generated by the force of water in hydropower
can provide a more sustainable, non-polluting alternative to fossil
fuels, along with other renewable sources of energy, such as wind,
solar and tidal power, bio energy and geothermal energy. Small scale
hydroelectricity in Iran is well suited for “off-grid" rural electricity
applications, while other renewable energy sources, such as wind,
solar and biomass, can be beneficially used as fuel for pumping
groundwater for drinking and small scale irrigation in remote rural
areas or small villages. Small Hydro Power plants in Iran have very
low operating and maintenance costs because they consume no fossil
or nuclear fuel and do not involve high temperature processes. The
equipment is relatively simple to operate and maintain. Hydropower
equipment can adjust rapidly to load changes. The extended
equipment life provides significant economic advantages. Some
hydroelectric plants installed 100 years ago still operate reliably. The
Polkolo river is located on Karun basin at southwest of Iran. Situation
and conditions of Polkolo river are evaluated for construction of
small hydropower in this article. The topographical conditions and
the existence of permanent water from springs provide the suitability
to install hydroelectric power plants on the river Polkolo. The
cascade plant consists of 9 power plants connected with each other
and is having the total head as 1100m and discharge about 2.5cubic
meter per second. The annual production of energy is 105.5 million
kwh.
Abstract: Although White LED lighting systems powered by solar cells have presented for many years, they are not widely used in today application because of their cost and low energy conversion efficiency. The proposed system use the dc power generated by fixed solar cells module to energize White LED light sources that are operated by directly connected White LED with current limitation resistors, resulting in much more power consumption. This paper presents the use of white LED as a general lighting application powered by tracking solar cells module and using pulse to apply the electrical power to the White LED. These systems resulted in high efficiency power conversion, low power consumption, and long light of the white LED.
Abstract: Tomato powder has good potential as substitute of tomato paste and other tomato products. In order to protect physicochemical properties and nutritional quality of tomato during dehydration process, investigation was carried out using different drying methods and pretreatments. Solar drier and continuous conveyor (tunnel) drier were used for dehydration where as calcium chloride (CaCl2), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl2 +KMS), and sodium chloride (NaCl) selected for treatment.. lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning in addition to moisture, sugar and titrable acidity were studied. Results show that pre-treatment with CaCl2 and NaCl increased water removal and moisture mobility in tomato slices during drying of tomatoes. Where CaCl2 used along with KMS the NEB was recorded the least compared to other treatments and the best results were obtained while using the two chemicals in combination form. Storage studies in LDPE polymeric and metalized polyesters films showed less changes in the products packed in metallized polyester pouches and even after 6 months lycopene content did not decrease more than 20% as compared to the control sample and provide extension of shelf life in acceptable condition for 6 months. In most of the quality characteristics tunnel drier samples presented better values in comparison to solar drier.
Abstract: Predict daily global solar radiation (GSR) based on meteorological variables, using Multi-layer perceptron (MLP) neural networks is the main objective of this study. Daily mean air temperature, relative humidity, sunshine hours, evaporation, wind speed, and soil temperature values between 2002 and 2006 for Dezful city in Iran (32° 16' N, 48° 25' E), are used in this study. The measured data between 2002 and 2005 are used to train the neural networks while the data for 214 days from 2006 are used as testing data.
Abstract: Laboratory experiments have been performed to investigate photocatalytic detoxification by using TiO2 photocatalyst for treating dairy effluent. Various operational parameters such as catalyst concentration, initial concentration, angle of tilt of solar flat plate reactor and flow rate were investigated. Results indicated that the photocatalytic detoxification process can efficiently treat dairy effluent. Experimental runs with dairy wastewater can be used to identify the optimum operational parameters to perform wastewater degradation on large scale for recycling purpose. Also effect of two different types of reactors on degradation process was analyzed.
Abstract: Where renewable energy sources, solar, hydro, wind are available the remote communities and businesses can be provided with the most reliable and affordable source of electrical energy. This paper presents a model of safari rest contains all the necessary services for the interested tourists who visit the safari Sinai desert. The PV energy system provides the rural energy needs of remote communities. A photovoltaic renewable energy system is designed to feed the global Ac and Dc electrical required load of this safari rest . The benefits of photovoltaic renewable energy at rural applications are its versatility and convenience. This model of safari rest must be taken in consideration by Egyptian Government as it will provide the tourism plane by new interested tourism field which put a big spot on Red sea area: El Ghordaka.
Abstract: The distillation process in the general sense is a
relatively simple technique from the standpoints of its principles.
When dedicating distillation to water treatment and specifically
producing fresh water from sea, ocean and/ briny waters it is
interesting to notice that distillation has no limitations or domains of
applicability regarding the nature or the type of the feedstock water.
This is not the case however for other techniques that are
technologically quite complex, necessitate bigger capital investments
and are limited in their usability. In a previous paper we have
explored some of the effects of temperature on yield. In this paper,
we continue building onto that knowledge base and focus on the
effects of several additional engineering and design variables on
productivity.
Abstract: The development incompatible with environment cannot be sustainable. Using renewable energy sources such as solar energy, geothermal energy and wind energy can make sustainable development in a region. Iran has a lot of renewable and nonrenewable energy resources. Since Iran has a special geographic position, it has lot of solar and wind energy resources. Both solar and wind energy are free, renewable and adaptable with environment. The study of 10 year wind data in Iranian South coastal and Islands synoptic stations shows that the production of wind power electricity and water pumping is possible in this region. In this research, we studied the local and temporal distribution of wind using three – hour statistics of windspeed in Iranian South coastal and Islands synoptic stations. This research shows that the production of wind power electricity is possible in this region all the year.
Abstract: A SnO2/CdS/CdTe heterojunction was fabricated by
thermal evaporation technique. The fabricated cells were annealed at
573K for periods of 60, 120 and 180 minutes. The structural
properties of the solar cells have been studied by using X-ray
diffraction. Capacitance- voltage measurements were studied for the
as-prepared and annealed cells at a frequency of 102 Hz. The
capacitance- voltage measurements indicated that these cells are
abrupt. The capacitance decreases with increasing annealing time.
The zero bias depletion region width and the carrier concentration
increased with increasing annealing time. The carrier transport
mechanism for the CdS/CdTe heterojunction in dark is tunneling
recombination. The ideality factor is 1.56 and the reverse bias
saturation current is 9.6×10-10A. The energy band lineup for the n-
CdS/p-CdTe heterojunction was investigated using current - voltage
and capacitance - voltage characteristics.
Abstract: As known that efficiency of photovoltaic cells is not
high as desired level. Efficiency of PVs could be improved by
selecting convenient locations that have high solar irradiation,
sunshine duration, mild temperature, low level air pollution and dust
concentration. Additionally, some environmental parameters called
derating factors effect to decrease PV efficiencies such as cloud, high
temperature, aerosol optical depth, high dust concentration, shadow,
snow, humidity etc. In this paper, all parameters that effect PV
efficiency are considered in detail under climatic conditions of
Istanbul. A 750 Wp PV system with measurement devices is
constructed in Maslak campus of Istanbul Technical University.
Abstract: This study was carried out experimentally and analytically about the performance of solar cell panel system for operating the pump coupled by dc-motor. The solar cell panel with total area 1.9848 m2 consists of three modules of 80 Wp each. The small centrifugal pump powered by dc-motor is operated to lift water from 1m to 7m heads in sequence and gives the amount of water pumped over the whole day from 08.00 to 16.00 h are 11988, 10851, 8874, 7695, 5760, 3600, 2340 L/d respectively. The hourly global solar radiation during the day is an average of 506 W/m2. This study also presents the I-V characteristics of the panel at global radiations 200, 400, 600, 800 and 1000 W/m2 matched with the operation of the pump at the above lifting heads. It proves that the only solar radiations 800 and 1000 W/m2 could provide lifting head from 1m to 7m. The analysis shows the best efficiency point of the performance of solar cell panel system occurs at the pumping head 2.89 m.
Abstract: This paper shows the potential system benefits of
simple tracking solar system using a stepper motor and light sensor.
This method is increasing power collection efficiency by developing
a device that tracks the sun to keep the panel at a right angle to its
rays. A solar tracking system is designed, implemented and
experimentally tested. The design details and the experimental results
are shown.
Abstract: Accumulation of dust from the outdoor environment
on the panels of solar photovoltaic (PV) system is natural. There
were studies that showed that the accumulated dust can reduce the
performance of solar panels, but the results were not clearly
quantified. The objective of this research was to study the effects of
dust accumulation on the performance of solar PV panels.
Experiments were conducted using dust particles on solar panels with
a constant-power light source, to determine the resulting electrical
power generated and efficiency. It was found from the study that the
accumulated dust on the surface of photovoltaic solar panel can
reduce the system-s efficiency by up to 50%.
Abstract: We design and discuss metal-dielectric antireflection coating on metallic substrates for Solar Selective Absorbers of Concentrating Solar Power Systems. The average reflectance is 8.5% at 400-3000nm and 84.4% at 3000nm-10000nm of the metal-dielectric structure.
Abstract: In this paper the Analytic Network Process (ANP) is
applied to the selection of photovoltaic (PV) solar power projects.
These projects follow a long management and execution process
from plant site selection to plant start-up. As a consequence, there are
many risks of time delays and even of project stoppage.
In the case study presented in this paper a top manager of an
important Spanish company that operates in the power market has to
decide on the best PV project (from four alternative projects) to
invest based on risk minimization. The manager identified 50 project
execution delay and/or stoppage risks.
The influences among elements of the network (groups of risks
and alternatives) were identified and analyzed using the ANP
multicriteria decision analysis method. After analyzing the results the
main conclusion is that the network model can manage all the
information of the real-world problem and thus it is a decision
analysis model recommended by the authors. The strengths and
weaknesses ANP as a multicriteria decision analysis tool are also
described in the paper.
Abstract: Optical properties of sputter-deposited ZnS thin films
were investigated as potential replacements for CBD(chemical bath
deposition) CdS buffer layers in the application of CIGS solar cells.
ZnS thin films were fabricated on glass substrates at RT, 150oC, 200oC,
and 250oC with 50 sccm Ar gas using an RF magnetron sputtering
system. The crystal structure of the thin film is found to be zinc blende
(cubic) structure. Lattice parameter of ZnS is slightly larger than CdS
on the plane and thus better matched with that of CIGS. Within a
400-800 nm wavelength region, the average transmittance was larger
than 75%. When the deposition temperature of the thin film was
increased, the blue shift phenomenon was enhanced. Band gap energy
of the ZnS thin film tended to increase as the deposition temperature
increased. ZnS thin film is a promising material system for the CIGS
buffer layer, in terms of ease of processing, low cost, environmental
friendliness, higher transparency, and electrical properties
Abstract: The objective from this paper is to design a solar
thermal engine for space vehicles orbital control and electricity
generation. A computational model is developed for the prediction of
the solar thermal engine performance for different design parameters and conditions in order to enhance the engine efficiency. The engine is divided into two main subsystems. First, the concentrator dish
which receives solar energy from the sun and reflects them to the
cavity receiver. The second one is the cavity receiver which receives
the heat flux reflected from the concentrator and transfers heat to the
fluid passing over. Other subsystems depend on the application required from the engine. For thrust application, a nozzle is
introduced to the system for the fluid to expand and produce thrust.
Hydrogen is preferred as a working fluid in the thruster application.
Results model developed is used to determine the thrust for a
concentrator dish 4 meters in diameter (provides 10 kW of energy),
focusing solar energy to a 10 cm aperture diameter cavity receiver.
The cavity receiver outer length is 50 cm and the internal cavity is 47
cm in length. The suggested design material of the internal cavity is
tungsten to withstand high temperature. The thermal model and
analysis shows that the hydrogen temperature at the plenum reaches
2000oK after about 250 seconds for hot start operation for a flow rate
of 0.1 g/sec.Using solar thermal engine as an electricity generation
device on earth is also discussed. In this case a compressor and
turbine are used to convert the heat gained by the working fluid (air)
into mechanical power. This mechanical power can be converted into
electrical power by using a generator.
Abstract: New lead-free ferroelectric relaxor ceramics were
prepared by conventional solid-state synthesis in the BaTiO3-Bi2O3-
Y2O3 systems. Some of these ceramics present a ferroelectric relaxor
with transition temperature close to room temperature. These new
materials are very interesting for applications and can replace leadbased
ceramic to prevent the toxic pollutions during the preparation
state. In the other hand, the energy band diagram shows the
potentiality of these compounds for the solar energy conversion.
Thus, some compositions have been tested successfully for H2
production upon visible light. The best activity occurs in alkaline
media with a rate evolution of about 0.15 mL g-1 mn-1 and a quantum
yield of 1% under polychromatic light.
Abstract: A convenient and physically sound mathematical model of the external or I - V characteristic of solar cells generators is presented in this paper. This model is compared with the traditional model of p-n junction. The direct analytical calculation of load regime leads to a quadratic equation, which is importantly to simplify the calculations in the real time.
Abstract: The feasibility of employing solar radiation for
enhanced Fenton process in degradation of combined chlorpyrifos,
cypermethrin and chlorothalonil pesticides was examined. The effect
of various operating conditions of the process on biodegradability
improvement and mineralization of the pesticides were also
evaluated. The optimum operating conditions for treatment of
aqueous solution containing 100, 50 and 250 mg L-1 chlorpyrifos
cypermethrin and chlorothalonil, respectively were observed to be
H2O2/COD molar ratio 2, H2O2/Fe2+ molar ratio 25 and pH 3. Under
the optimum operating conditions, complete degradation of the
pesticides occurred in 1 min. Biodegradability (BOD5/COD)
increased from zero to 0.36 in 60 min, and COD and TOC removal
were 74.19 and 58.32%, respectively in 60 min. Due to
mineralization of organic carbon, decrease in ammonia-nitrogen from
22 to 4.3 mg L-1 and increase in nitrate from 0.7 to 18.1 mg L-1 in
60 min were recorded. The study indicated that solar photo-Fenton
process can be used for pretreatment of chlorpyrifos, cypermethrin
and chlorothalonil pesticides in aqueous solution for further
biological treatment.