The use of solar energy for water desalination becomes vital for sustainable water supply.
This paper aims to analyze the experimental behavior of double slope solar theoretically still
(DSSS). In this work, we proposed a theoretical model that can predict the DSSS performance. The
theoretical results of temperatures and the impact of wind speed on water production are in good
agreement with experimental findings. It is found that the temperature augments with augmenting the wind speed until a critical value, where the temperature starts to drop. In addition, water
production increases with increasing speed. In this way, we determined the optimum wind speed
to have maximum water production with minimum energy consumption simultaneously. The validation of the theoretical model allows us to predict the DSSS production under different climatic
conditions and to scale DSSS dimensions according to the need of water. The salinity of the water
is not a determining factor in its production. The production at 4.2 kWh/m2 daily insolation was
0.58 L/d. The volume of distilled water reaches a maximum value (62.3% efficiency) when glass
and environment temperatures are similar. This phenomenon occurs at 5.5 m/s wind speed
Historically, medicinal plants have always had an important place in medicine. Medicinal plants processing represents a great challenge, due to their compounds sensitive to the environmental conditions that surround and degrade them. Mostly of these plants require to be dry to preserve its safety and medicinal properties; therefore, for proper drying, it is necessary to use sustainable devices that protect the desirable characteristics of plants from direct radiation. In this work, the kinetics of dehydration of three medicinal plants are presented in an indirect solar dryer. In addition, the experimental results were adjusted to nine mostly used models, to estimate the drying conditions required to achieve a desired final moisture content. Modified Page and Page were the models with better fit to experimental results. Furthermore, a computational simulation of temperature evolution and distribution inside the dryer is presented. These results agree with those obtained experimentally.
EXPERIMENTAL INVESTIGATION OF THERMAL PERFORMANCE OF CURTAIN-WALL-INTEGRATED ...ijiert bestjournal
A wall-integrated solar heating system refers to an archite ctural design approach that combines hot water generation with the building's construction sys tem. This combination allows this system to feature a hot water generation function and b ecome part of the building fa�ade. Environmental control devices and/or designs in buildings that are capable of harvesting solar thermal energy can effectively capture and st ore this solar energy and provide energy through the use of,for instance,a hot water system or a low-power thermoelectric material. Thermal energy storage (TES) is the key component f or such solar energy use,and it is one of the most promising and sustainable methods for energy stora ge in buildings. The TES systems used in buildings can be easily divided into three type s:sensible,latent,and thermo chemical energy storage (TCES).Because of its numerous advantages,such as its wide range of storage temperatures,high thermal capacity,non toxic ity,low cost,and easy obtain ability,water is often used as the storage medium in a sol ar water heating (SWH) system for domestic solar utilization.
Historically, medicinal plants have always had an important place in medicine. Medicinal plants processing represents a great challenge, due to their compounds sensitive to the environmental conditions that surround and degrade them. Mostly of these plants require to be dry to preserve its safety and medicinal properties; therefore, for proper drying, it is necessary to use sustainable devices that protect the desirable characteristics of plants from direct radiation. In this work, the kinetics of dehydration of three medicinal plants are presented in an indirect solar dryer. In addition, the experimental results were adjusted to nine mostly used models, to estimate the drying conditions required to achieve a desired final moisture content. Modified Page and Page were the models with better fit to experimental results. Furthermore, a computational simulation of temperature evolution and distribution inside the dryer is presented. These results agree with those obtained experimentally.
EXPERIMENTAL INVESTIGATION OF THERMAL PERFORMANCE OF CURTAIN-WALL-INTEGRATED ...ijiert bestjournal
A wall-integrated solar heating system refers to an archite ctural design approach that combines hot water generation with the building's construction sys tem. This combination allows this system to feature a hot water generation function and b ecome part of the building fa�ade. Environmental control devices and/or designs in buildings that are capable of harvesting solar thermal energy can effectively capture and st ore this solar energy and provide energy through the use of,for instance,a hot water system or a low-power thermoelectric material. Thermal energy storage (TES) is the key component f or such solar energy use,and it is one of the most promising and sustainable methods for energy stora ge in buildings. The TES systems used in buildings can be easily divided into three type s:sensible,latent,and thermo chemical energy storage (TCES).Because of its numerous advantages,such as its wide range of storage temperatures,high thermal capacity,non toxic ity,low cost,and easy obtain ability,water is often used as the storage medium in a sol ar water heating (SWH) system for domestic solar utilization.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Collectors innovation to increase performance solar water heatereSAT Journals
Abstract There have been many studies to improve the performance of the solar water heater. The long term goal of research is to obtain scientific information, teaching materials and as the foundation of scientific development of energy conversion. The specific objective of this study is to find or develop new models and models that can improve the efficiency of the solar water heater. Research methods; research conducted using the experimental method, which is to test the amount of cover glass, flow rate and preheat a working fluid that can improve the efficiency of solar water heater. Research output: 1) The efficiency of the best solar water heater is the sum of three layers of glass cover compared to the cover glass number two layers and one layer, 2) The greater the water flow rate, the efficiency of the solar water heater increases, 3) initial heating on water entry, exit and cause the water temperature absorber plate temperature is relatively the same, so the efficiency of the solar water heater close to zero. Keywords: number of glass cover, flow rate, initial heating, solar water heater
effect of environmental variables on photovoltaic performance based on experi...IJCMESJOURNAL
This paper investigated the effect of environment variables on Photovoltaic PV performance. It is surely understood that local climate can dramatically affect the power generation from a PV system. The most obvious components are the solar radiation hitting the panels, air temperature, humidity and wind speed. The local climatic conditions and precipitation influence the extent to which the panels get to be dusty or polluted, which affects the electrical power generation. The high air temperature caused a reduction in the PV panel output power rated from 1.85 to 20.22%, as well as, increased relative humidity where the largest decline recorded was 32.24%. The wind has a cooling effect on the PV panel that limits the power reduction due to increased solar radiation or panel back temperature. Besides, the wind blows away the accumulated dust that enhances the resulted PV panel power.
Experimental Investigation of Solar Water Heater Integrated with a Nanocompos...ijtsrd
This present work contributes to the improvement in thermal energy storage capacity of an all glass evacuated tube solar water heater by integrating it with a phase change material PCM and with a nanocomposite phase change material NCPCM .. Paraffin wax as PCM and a nanocomposite of paraffin wax with 1.0 mass GeO2 nanoparticles as NCPCM had been used during the experiments. Three different cases, namely, without PCM, with PCM, and with NCPCM, were considered. The testing procedure involved the observation of total temperature variation in the tank water from 6.00 a.m. to 6.00 a.m. of next morning.OBJECTIVEThe main objective of my project is to increase the performance of solar water heater integrated storage tank with PCM and NCPCM which would serve the varying demands. Shashi Kumar | Prof. Ranjeet Arya "Experimental Investigation of Solar Water Heater Integrated with a Nanocomposite Phase Change Material" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd35820.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/35820/experimental-investigation-of-solar-water-heater-integrated-with-a-nanocomposite-phase-change-material/shashi-kumar
SIMULATION OF VAPOR AND HEAT FLUXES OVER WET AND DRY REGIME IN PADDY FIELD EN...IAEME Publication
Alternating dry-wet paddy field management such as System of Rice Intensification
(SRI) had become an interesting subject in research and development in paddy
cultivation which also been subject for trial for its implementation. The field’s
environment’s variation of biophysical parameters related to production had also
become important to be studied. This study aims to simulate the variation of
evaporation and thermal condition over a wet and dry regime of paddy field. The
simulation model used in this study was a combination of numerical surface energy
balance and soil water flow model consisting two layered resistance energy balance
model for non-ponded field, one-dimensional atmospheric boundary layer model of
wind, temperature and vapor changes, and soil heat transfer and soil water flow
models. Meteorological parameters at the site were measured and utilized as input for
the simulation. The simulation shows the fluctuating latent, sensible and ground heat
flux and also the variation of temperature, and soil condition for wet and dry regime
of paddy field.
Comparative studies on heat transfer and fluid flow in cored brick and pebble...eSAT Journals
Abstract
The article reports on comparison of transient heat transfer and fluid flow in two different sensible heat storage devices using Computational Fluid Dynamics. The candidate heat storage devices considered were cored brick and pebble bed and air was taken to be the working fluid. Same geometrical, material, porosity and boundary conditions, have been used for both the cored brick and pebble bed heaters, to compare the axial temperature history and pressure drop. The heat storage system comprises alumina, either in form of pebbles of diameter 6.5 mm, packed to a length of 0.455m in a 43mm diameter pipe, or cored brick of 43mm diameter and same length with through holes to have the same porosity (0.48) as that of the former. The conditions at inlet, outlet and lateral surface too have been taken to be same for both the systems. The fluid flow was considered to be incompressible with k-epsilon model to predict turbulence, and the thermo-physical properties of fluid and solid were assumed to remain constant. Simulations carried out for an inlet temperature of 465 K for velocities ranging from 2m/s to 5 m/s revealed that pressure drop in pebble bed to be considerably higher than those in cored brick, while the temperature history exhibited mixed trends.
Keywords: Cored Brick, Pebble Bed and Porosity
In this paper, the natural convection heat transfer in a cubic enclosure provided with
inclined baffles attached to the two adiabatic sides, heated from the bottom is studied
experimentally and numerically to assess the effect of the baffles on the heat transfer
process inside the enclosure. Two different configurations have been considered. The first
configuration corresponds to the heated from the bottom with uniform heat flux using two
baffles attached to the left and right walls, while the second configuration corresponding
that the enclosure’s floor has parallel bands that are heated to a constant, high
temperature and the bands are separated by gaps that are kept at a lower temperature
that is also constant and single baffle attached to the left wall. In both cases, the top wall
is kept at a lower temperature than the bottom wall and the inclined baffles are well
covered with an insulating material. The inclination angles of the baffles range as (0o ≤
and ≥ 150o). The governing parameter, Rayleigh number, is fixed within 2.6x1011. In
numerical solution, a commercial software package has been used for a 2-D computation,
and the effect of turbulence is modelled by using (k-ε) model. Depending on its
orientation, the partial baffle has been found to change significantly the flow field which
in turn causes a reduction to the heat exchange inside the enclosure due to the damping
caused to the flow field. For all cases, the insulated baffle with any inclination angle
caused a reduction to the heat exchange inside the enclosure due to the damping caused
to the flow field. Also, a good agreement has been obtained between experimental
measurements and numerical results
A theoretical evaluation of a double slope solar still using the Energy2D computer program is presented in this document. The heat absorbing plate is 0.25 m2 square, 5 cm high and constructed of stainless steel. The water film is 3 cm high. Conduction heat losses of three commercial thermal insulation were studied: (i) polyurethane (PU), (ii) glass wool (GW), and (iii) expanded polystyrene (EPS). The insulation thickness is 15 cm and the glass cover is tilted at an angle of 30°. For the simulation, thermal conductivity, specific heat, mass density, and optical properties such as emittance, absorptance, reflectance, and transmittance coefficients were considered. After five hours of simulation, the left, central and right zones of insulator indicates 29.7°C; 45.2°C; 25.2°C, while the left, central and right zones indicates 75.7°C; 75.0°C; 75.5°C. The heat flux insulator, water and glass cover in its central zones are: 16.4, 301 and 72.9 W.m–2, correspondingly. The lower heat loss was observed when PU is used as thermal insulation, while the greater loss when EPS is used. The three materials PU, EPS, and GW registered a temperature of 45°C, at a simulation time of 3 h, 1.5 h, and 45 min, respectively.
CFD Analysis of Single Basin Double Slope Solar Stilljournal ijrtem
Abstract : This paper deals with thethermal and CFD analysis of single basin double slope solar still. The modeling of still is done in solid works software and CFD analysis in ANSYS. CFD analysis for different months of solar irradiance was carried out. Maximum production rate and temperature distribution in the still was analyzed. Keywords: Double slope solar still, CFD analysis, solar irradiance, desalination system.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Collectors innovation to increase performance solar water heatereSAT Journals
Abstract There have been many studies to improve the performance of the solar water heater. The long term goal of research is to obtain scientific information, teaching materials and as the foundation of scientific development of energy conversion. The specific objective of this study is to find or develop new models and models that can improve the efficiency of the solar water heater. Research methods; research conducted using the experimental method, which is to test the amount of cover glass, flow rate and preheat a working fluid that can improve the efficiency of solar water heater. Research output: 1) The efficiency of the best solar water heater is the sum of three layers of glass cover compared to the cover glass number two layers and one layer, 2) The greater the water flow rate, the efficiency of the solar water heater increases, 3) initial heating on water entry, exit and cause the water temperature absorber plate temperature is relatively the same, so the efficiency of the solar water heater close to zero. Keywords: number of glass cover, flow rate, initial heating, solar water heater
effect of environmental variables on photovoltaic performance based on experi...IJCMESJOURNAL
This paper investigated the effect of environment variables on Photovoltaic PV performance. It is surely understood that local climate can dramatically affect the power generation from a PV system. The most obvious components are the solar radiation hitting the panels, air temperature, humidity and wind speed. The local climatic conditions and precipitation influence the extent to which the panels get to be dusty or polluted, which affects the electrical power generation. The high air temperature caused a reduction in the PV panel output power rated from 1.85 to 20.22%, as well as, increased relative humidity where the largest decline recorded was 32.24%. The wind has a cooling effect on the PV panel that limits the power reduction due to increased solar radiation or panel back temperature. Besides, the wind blows away the accumulated dust that enhances the resulted PV panel power.
Experimental Investigation of Solar Water Heater Integrated with a Nanocompos...ijtsrd
This present work contributes to the improvement in thermal energy storage capacity of an all glass evacuated tube solar water heater by integrating it with a phase change material PCM and with a nanocomposite phase change material NCPCM .. Paraffin wax as PCM and a nanocomposite of paraffin wax with 1.0 mass GeO2 nanoparticles as NCPCM had been used during the experiments. Three different cases, namely, without PCM, with PCM, and with NCPCM, were considered. The testing procedure involved the observation of total temperature variation in the tank water from 6.00 a.m. to 6.00 a.m. of next morning.OBJECTIVEThe main objective of my project is to increase the performance of solar water heater integrated storage tank with PCM and NCPCM which would serve the varying demands. Shashi Kumar | Prof. Ranjeet Arya "Experimental Investigation of Solar Water Heater Integrated with a Nanocomposite Phase Change Material" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd35820.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/35820/experimental-investigation-of-solar-water-heater-integrated-with-a-nanocomposite-phase-change-material/shashi-kumar
SIMULATION OF VAPOR AND HEAT FLUXES OVER WET AND DRY REGIME IN PADDY FIELD EN...IAEME Publication
Alternating dry-wet paddy field management such as System of Rice Intensification
(SRI) had become an interesting subject in research and development in paddy
cultivation which also been subject for trial for its implementation. The field’s
environment’s variation of biophysical parameters related to production had also
become important to be studied. This study aims to simulate the variation of
evaporation and thermal condition over a wet and dry regime of paddy field. The
simulation model used in this study was a combination of numerical surface energy
balance and soil water flow model consisting two layered resistance energy balance
model for non-ponded field, one-dimensional atmospheric boundary layer model of
wind, temperature and vapor changes, and soil heat transfer and soil water flow
models. Meteorological parameters at the site were measured and utilized as input for
the simulation. The simulation shows the fluctuating latent, sensible and ground heat
flux and also the variation of temperature, and soil condition for wet and dry regime
of paddy field.
Comparative studies on heat transfer and fluid flow in cored brick and pebble...eSAT Journals
Abstract
The article reports on comparison of transient heat transfer and fluid flow in two different sensible heat storage devices using Computational Fluid Dynamics. The candidate heat storage devices considered were cored brick and pebble bed and air was taken to be the working fluid. Same geometrical, material, porosity and boundary conditions, have been used for both the cored brick and pebble bed heaters, to compare the axial temperature history and pressure drop. The heat storage system comprises alumina, either in form of pebbles of diameter 6.5 mm, packed to a length of 0.455m in a 43mm diameter pipe, or cored brick of 43mm diameter and same length with through holes to have the same porosity (0.48) as that of the former. The conditions at inlet, outlet and lateral surface too have been taken to be same for both the systems. The fluid flow was considered to be incompressible with k-epsilon model to predict turbulence, and the thermo-physical properties of fluid and solid were assumed to remain constant. Simulations carried out for an inlet temperature of 465 K for velocities ranging from 2m/s to 5 m/s revealed that pressure drop in pebble bed to be considerably higher than those in cored brick, while the temperature history exhibited mixed trends.
Keywords: Cored Brick, Pebble Bed and Porosity
In this paper, the natural convection heat transfer in a cubic enclosure provided with
inclined baffles attached to the two adiabatic sides, heated from the bottom is studied
experimentally and numerically to assess the effect of the baffles on the heat transfer
process inside the enclosure. Two different configurations have been considered. The first
configuration corresponds to the heated from the bottom with uniform heat flux using two
baffles attached to the left and right walls, while the second configuration corresponding
that the enclosure’s floor has parallel bands that are heated to a constant, high
temperature and the bands are separated by gaps that are kept at a lower temperature
that is also constant and single baffle attached to the left wall. In both cases, the top wall
is kept at a lower temperature than the bottom wall and the inclined baffles are well
covered with an insulating material. The inclination angles of the baffles range as (0o ≤
and ≥ 150o). The governing parameter, Rayleigh number, is fixed within 2.6x1011. In
numerical solution, a commercial software package has been used for a 2-D computation,
and the effect of turbulence is modelled by using (k-ε) model. Depending on its
orientation, the partial baffle has been found to change significantly the flow field which
in turn causes a reduction to the heat exchange inside the enclosure due to the damping
caused to the flow field. For all cases, the insulated baffle with any inclination angle
caused a reduction to the heat exchange inside the enclosure due to the damping caused
to the flow field. Also, a good agreement has been obtained between experimental
measurements and numerical results
A theoretical evaluation of a double slope solar still using the Energy2D computer program is presented in this document. The heat absorbing plate is 0.25 m2 square, 5 cm high and constructed of stainless steel. The water film is 3 cm high. Conduction heat losses of three commercial thermal insulation were studied: (i) polyurethane (PU), (ii) glass wool (GW), and (iii) expanded polystyrene (EPS). The insulation thickness is 15 cm and the glass cover is tilted at an angle of 30°. For the simulation, thermal conductivity, specific heat, mass density, and optical properties such as emittance, absorptance, reflectance, and transmittance coefficients were considered. After five hours of simulation, the left, central and right zones of insulator indicates 29.7°C; 45.2°C; 25.2°C, while the left, central and right zones indicates 75.7°C; 75.0°C; 75.5°C. The heat flux insulator, water and glass cover in its central zones are: 16.4, 301 and 72.9 W.m–2, correspondingly. The lower heat loss was observed when PU is used as thermal insulation, while the greater loss when EPS is used. The three materials PU, EPS, and GW registered a temperature of 45°C, at a simulation time of 3 h, 1.5 h, and 45 min, respectively.
CFD Analysis of Single Basin Double Slope Solar Stilljournal ijrtem
Abstract : This paper deals with thethermal and CFD analysis of single basin double slope solar still. The modeling of still is done in solid works software and CFD analysis in ANSYS. CFD analysis for different months of solar irradiance was carried out. Maximum production rate and temperature distribution in the still was analyzed. Keywords: Double slope solar still, CFD analysis, solar irradiance, desalination system.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Experimental analysis of a flat plate solar collector with integrated latent heat thermal storage
*Mauricio, Carmona1, Mario Palacio2, ArnoldMartínez3
1 Mechanical Engineering Department, Universidad del Norte, Colombia
2 Faculty of Mechanical and Industrial Engineering, Universidad PontificiaBolivariana, Colombia
3 Mechanical Engineering Department, Universidad de Córdoba, Colombia
1E mail: mycarmona@uninorte.edu.co,2E mail: mario.palaciov@upb.edu.co
A B S T R A C T
In the present paper, an experimental analysis of a solar water heating collector with an integrated latent heat storage unit is presented. With the purpose to determine the performance of a device on a lab scale, but with commercial features, a flat plate solar collector with phase change material (PCM) containers under the absorber plate was constructed and tested. PCM used was a commercial semi-refined light paraffin with a melting point of 60°C. Tests were carried out in outdoor conditions from October 2016 to March 2017 starting at 7:00 AM until the collector does not transfer heat to the water after sunset. Performance variables as water inlet temperature, outlet temperature, mass flow and solar radiation were measured in order to determine a useful heat and the collector efficiency. Furthermore, operating temperatures of the glass cover, air gap, absorber plate, and PCM containers are presented. Other external variables as ambient temperature, humidity and wind speed were measured with a weather station located next to the collector. The developed prototype reached an average thermal efficiency of 24.11% and a maximum outlet temperature of 50°C. Results indicate that the absorber plate reached the PCM melting point in few cases, this suggests that the use of a PCM with a lower melting point could be a potential strategy to increase thermal storage. A thermal analysis and conclusions of the device performance are discussed.
A B S T R A C T
In the present paper, an experimental analysis of a solar water heating collector with an integrated latent heat storage unit is presented. With the purpose to determine the performance of a device on a lab scale, but with commercial features, a flat plate solar collector with phase change material (PCM) containers under the absorber plate was constructed and tested. PCM used was a commercial semi-refined light paraffin with a melting point of 60°C. Tests were carried out in outdoor conditions from October 2016 to March 2017 starting at 7:00 AM until the collector does not transfer heat to the water after sunset. Performance variables as water inlet temperature, outlet temperature, mass flow and solar radiation were measured in order to determine a useful heat and the collector efficiency. Furthermore, operating temperatures of the glass cover, air gap, absorber plate, and PCM containers are presented. Other external variables as ambient temperature, humidity and wind speed were measured with a weather station located next to the collector. The developed prototype reached an average thermal efficiency of 24.11% and a maximum outlet temperature of 50°C. Results indicate that the absorber plate reached the PCM melting point in few cases, this suggests that the use of a PCM with a lower melting point could be a potential strategy to increase thermal storage. A thermal analysis and conclusions of the device performance are discussed.
CONTEMPORARY URBAN AFFAIRS (2017) 1(3), 7-12. Doi: 10.25034/ijcua.2018.3672
www.ijcua.com
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The aim of this research is to utilize the new control algorithm of the sun tracker and the developed computer capabilities to improve the efficiency of tracking. The new tracking method installed on new innovative approach of water distillation taking advantage of high possible concentration of parabolic trough collector to reach a new level of daily harvest per square meter. Water distillation yield is predicted to score high percentage output of distillate due to the high temperature average about 40 degrees as maximum and 30 degrees as minimum. Also the high sunny hours about 9-12 hours per day. Mechanical system will be designed and tested for high ability to withstand the extra loading also some imperfections are forecasted. The present study may found more reliable and trusting techniques in tracking and water distillation. Saline water distillation as predicted will score a noticeable level because of the use of parabolic collector and promoted the efficiency. Keeping good temperature difference between vapor and condensation surface will increase the output and reduce the capacity of temperature. The mechanical design must be convenient to Sultanate Oman climate conditions and have to running, smoothly and safe.
Enhancing Photoelectric Conversion Efficiency of Solar Panel by Water CoolingIJAPEJOURNAL
Photovoltaic solar cell generates electricity by receiving solar irradiance. The electrical efficiency of photovoltaic (PV) cell is adversely affected by the significant increase of cell operating temperature during absorption of solar radiation. This undesirable effect can be partially avoided by cooling the back side of the photovoltaic panel using water absorption sponge which was fixed on of PV panel and maintain wet condition by circulation of drop by drop water. The objective of the present work is to reduce the temperature of the solar cell in order to increase its electrical efficiency. Experiments were performed with and without water cooling. A linear trend between the efficiency and temperature was found. Without cooling, the temperature of the panel was high and solar cells were achieved an efficiency of 8–9%. However, when the panel was operated under water cooling condition, the temperature dropped maximally by 40C leading to an increase in efficiency of solar cells by 12%.
EXPERIMENTAL STUDY ON SOLAR HEATING BY NATURAL HEAT CONVECTION AND RADIATIONADEIJ Journal
Heat storage is a good energy saving option these days. Heat storage makes it possible to use thermal
energy at the required time. Solar water heaters for construction purposes and industrial purposes are the
best source to maintain traditional energy sources and thus can maintain high quality energy and liquid or
steel fuel due to the highest rise in their prices. In recent years, using solar energy has become remarkably
cheap and especially noteworthy. The efficiency of natural solar water heater system depends on collector
and reservoir setting, design and environmental factors such as solar intensity, ambient temperature and
wind conditions. Also, the relative height of the tank and collector separation mainly affects the volume of
the Siphon thermal flow rates, including both forward and reverse flow at night. In this pilot investigation,
two parallel rectangular glass plates were connected to the hot water storage tank. The effect of the
separation space between the plates (collectors) (D) was investigated and reported. The results reported
that outlet temperature in case D= 15 cm for two plates decreased approximately 24% and 23% for two
plates. Also, the heat radiated to the room decreased as the inner space between the two plates increased,
and decreased to approximately 25% as compared to stack plates.
In this communication, an attempt has been made to find out the heat transfer coefficients such as internal and external heat transfer modes and thermophysical properties such as dynamic viscosity, density, thermal conductivity, latent heat of evaporation and saturated vapor pressure for active solar distillation system. It is observed that water temperature plays a vital role in the distillate output (the yield) since it increases significantly with the rise of basin water temperature. Double slope step type solar still of area 1 m2 is constructed using a glass pieces. Top Glass cover with 10° slope ensures a very good transmission of solar radiation inside the still. The distillate water productivity is in the range of 2.758 litres to 2.805 liters per day for still performance study. Similarly the instantaneous efficiency for still performance study is in the range of 17.84% to18.25%. Dimensionless numbers such as the Nusselt number (Nu), the Grashof number (Gr), the Reynolds number (Re) and the Prandtl number (Pr) were also estimated. Heat transfer coefficient were estimated for the present system since the system overall efficiency depend on heat transfer modes. Internal (convection, evaporation and radiation) and external (convection, conduction and radiation) heat transfer modes were calculated for the present system and it is found that because of rise in water temperature, evaporative heat transfer coefficient value rises significantly.
Solar photovoltaic/thermal air collector with mirrors for optimal tiltsIJECEIAES
This work is the result of a study of a photovoltaic/thermal air collector that concentrates solar radiation using two mobile mirrors to enhance electrical and thermal energy. The study is made for the site of Tetouan (Morocco) (longitude=-5°, latitude=35.25°) for a daily variation during typical days in May, June, September, and December, days considered as clear sky. To prove the effectiveness of the mirrors on the production of both electrical and thermal energy by the collector, we compared their electrical and thermal efficiency in two cases, without and with mirrors at the optimal positions. We validate the obtained simulation results by comparing them to the results from experimental studies published in the literature, for which a strong agreement was obtained. The model estimates the solar energy received by the hybrid collector during the day, to optimize the performance of the fixed collector, we have searched for the values of the optimal daily tilt angles of the two mirrors which allowed us to enhance the quantity of incoming solar radiation on the collector. The tilt angles depend on the sun’s elevation angle, the azimuth angle for typical days of the year.
EXPERIMENTAL INVESTIGATION OF A SOLAR STILL USING LAURIC ACID AS A ENERGY S...IAEME Publication
The solar still is a simple device used for obtaining fresh water for small scale demand. Due to intermittent nature of solar energy, solar still s are not continuous in nature. To make them operative for non-sunshine hours energy storage
mediums are used. In the present work an attempt has been made to utilize the energy storage capacity of Lauric acid to enhance the performance of solar still. Experiments were carried out on single basin double slope solar still in the premises of SHIATS, Allahabad in the month of February. It is observed that the nocturnal distillate output is increased by more than 17% when Lauricacid is used as energy storage medium.
Time-dependent hydraulic conductivity during secondary consolidation of clayinventionjournals
Secondary consolidation occurs when excess pore pressure has dissipated in saturated compressible clay soils subjected to increased effective stress by the application of external loads. This paper provides time-dependent formulas for the hydraulic conductivity and the porosity during secondary consolidation. The formulas express the hydraulic conductivity and the porosity in terms of the void ratio during secondary consolidation. The intervening functional coefficients are obtainable from 1-D consolidation testing. An example illustrates the application of this paper’s results.
Characterization of a flat plate solar water heating system using different n...Barhm Mohamad
Flat-plate solar collectors (FPSCs) are the most effective and environmentally friendly heating systems available. They are frequently used to convert solar radiation into usable heat for a variety of thermal applications. Because of their superior thermo-physical features, the use of Nano-fluids in FPSCs is a useful technique to improve FPSC performance. Nano-fluids are advanced colloidal suspensions containing Nano-sized particles that have been researched over the last two decades and identified a fluid composed of strong nanoparticles with a diameter of smaller than (100 nm). These micro-particles aid in improving the thermal conductivity and convective heat transfer of liquids when mixed with the base fluid. The current study provides an in-depth review of the scientific advances in the field of Nano-fluids on flat-plate solar collectors. Previous research on the usage of Nano-fluids in FPSCs shows that Nano-fluids can be used successfully to improve the efficiency of flat-plate collectors. Though several Nano-fluids have been reviewed as solar collector operatin fluids. Nano-fluids have greater pressure drops than liquids, and their pressure drops andhence pumping power rise as the volume flow rate increases. Additionally, the article discusses the concept of Nano-fluids, the different forms of nanoparticles, the methods for preparing Nano-fluids, and their thermos-physical properties. The article concludes with a few observations and suggestions on the usage of Nano-fluids in flat-plate solar collectors. This article summarizes the numerous research studies conducted in this region, which may prove useful for future experimental studies.
Similar to Theoretical validation model of a double slope still with forced convection (20)
A nivel global, la contaminación de ríos y embalses constituye un desafío ambiental de gran magnitud, englobando la descarga indiscriminada de aguas residuales sin tratamiento previo y la contaminación originada por actividades agrícolas e industriales que contribuyen de manera substancial a la degradación de la calidad del agua. La problemática repercute en la pérdida de biodiversidad acuática, generando una amenaza palpable para la salud humana. En respuesta a esta situación, diversos países como China, han implementado programas de recuperación orientados a la mitigación de la contaminación, la restauración de hábitats acuáticos y la mejora general de la calidad del agua en ríos y cuencas afectadas.
Las membranas poliméricas, actualmente son unos de los materiales más versátiles para la separación de contaminantes en aguas residuales, son económicas, fáciles de elaborar y amigables con el ambiente. Se define como una barrera selectiva cuya función es restringir el paso de ciertas sustancias no deseadas. En otras palabras, una membrana polimérica funciona de manera similar a un colador de cocina, en donde al cocinar pasta se puede separar la parte sólida de su salmuera de cocción (líquido), empleando un colador (membrana). Las sustancias no deseadas presentes en el agua que provocan daños ambientales y a la salud humana, son consideradas contaminantes.
Los plásticos han sido utilizados por más de 100 años, y a menudo son objeto de controversia debido a su impacto en el ambiente. Sin embargo, el afirmar que todos los plásticos son malos o que todos los bioplásticos son ecológicamente superiores, es un error. Se estima que desde 1950 hasta el año 2017, se produjeron más de ocho mil trescientos millones de toneladas de plásticos, siendo reciclado tan solo el 9% mientras que cerca del 80% aún está en vertederos de basura y el resto se ha incinerado. Los plásticos han sido parte de la revolución tecnológica y han mejorado nuestro estilo de vida.
El litio es un elemento alcalino, altamente reactivo y por lo tanto no se encuentra libre en la naturaleza. Usualmente se encuentra unido a otros elementos como aluminio, potasio, silicio, oxígeno y flúor formando minerales como espodumena, lepidolita, ambligonita, petalita, entre otros. Actualmente, se reconocen cuatro tipos de yacimientos o fuentes de litio a nivel global: pegmatitas (rocas magmáticas), salmueras (lagos salados, geotérmicas y campos petrolíferos), arcillas litíferas y el agua de mar. En México, los principales recursos de litio están distribuidos en los estados de Baja California, Sonora, San Luis Potosí, Zacatecas, Durango y Puebla; donde se encuentran principalmente en forma de pegmatitas y salmueras conteniendo minerales con concentraciones variables de litio.
Los hot dogs, “jochos” o perritos calientes como comúnmente se les conoce en México, son los alimentos callejeros más populares a nivel mundial. El componente estrella de este alimento son las salchichas, que se colocan en un pan alargado y se aderezan con mayonesa, salsa de tomate y mostaza. Las salchichas están elaboradas con carne molida que puede ser de res, cerdo o pollo; además contienen grasa, sodio, nitritos, agua y otros condimentos (ajo, pimienta, clavo, canela y comino).
Los nanomateriales son partículas pequeñas entre 1 y 100 nanómetros (unidad de medida que equivale a una mil-millonésimas de metro), que a simple vista no se pueden ver. Estos nanomateriales pueden ser metálicos, como el hierro, cobre y zinc, también pueden ser no metálicos, como los nanomateriales de carbono y nanopartículas a base de quitosán. Lo interesante de estos materiales es que a estas dimensiones tienen propiedades distintas a la forma en que comúnmente se han aplicado, y al ser de tamaño reducido se aumenta el área superficial y esta característica le otorga mayor espacio para interactuar con otros átomos y moléculas.
Desde tiempos remotos, las flores han sido empleadas en su mayoría como elementos de decoración en alimentos, ya que aportan colores y sabores atractivos al consumidor. Sin embargo, contienen macronutrientes que tienen un impacto positivo en la salud. El uso de algunas flores como parte de la alimentación se remonta a las antiguas civilizaciones. Por ejemplo, los romanos usaban flores como las violetas, rosas y lavanda como ingredientes en salsas; algunos de los nativos americanos consumían de manera habitual las flores de calabaza, e incluso durante la Edad Media en Europa se elaboraban bebidas con diente de león. Resulta interesante el uso de las flores como parte de los tratamientos que se utilizaban en la medicina tradicional, a base de infusiones para aliviar enfermedades que eran recurrentes en la población.
La producción de alimentos suele desarrollarse en sitios que fueron deforestados. Es decir, que se eliminó su capa forestal y, por consiguiente, se perdieron los servicios ecosistémicos como producción de oxígeno, captura de agua y carbono, el paisaje escénico, entre otros. Ante estos cambios nos preguntamos, ¿los cultivos que se establecen, nos proporcionan también los servicios ecosistémicos que se pierden, tales como la captura de carbono?, la respuesta es sí. El ciclo del carbono en la biósfera es complejo e involucra factores abióticos así como componentes bióticos. Una de las formas en que se halla el carbono en la naturaleza, es como dióxido de carbono (CO2).
El término probiótico fue empleado por primera vez por Lilly y Stillwell en 1965, refiriéndose a cualquier sustancia u organismos que pudiese beneficiar y mantener el equilibrio intestinal en un animal. Actualmente, la Organización Mundial de la Salud (OMS), define a los probióticos como microorganismos vivos que, en cantidad suficiente, aportan un beneficio a la salud del cuerpo humano. Algunos probióticos son parte de la microbiota intestinal, la cual se define como el conjunto de microorganismos que viven en nuestro sistema digestivo (boca, estómago, intestinos), sin embargo, es importante mencionar que en otros sitios como la piel también habitan microorganismos benéficos.
Los microorganismos han impactado de diversas formas en la sociedad: se han usado para la preservación del ambiente y en diferentes industrias, como la alimentaria y la farmacéutica. Un ejemplo de ello es la penicilina, un antibiótico originalmente aislado a partir de hongos del género Penicillium. Desafortunadamente, el uso excesivo y desinformado de los antibióticos, en combinación con la gran capacidad de adaptación de los microorganismos, han propiciado la aparición de diversos mecanismos de resistencia. En este fenómeno, las bacterias son protagonistas ya que hoy en día, los fármacos pierden su efectividad rápidamente frente a ellas; por lo anterior, los investigadores buscan alternativas a los antibióticos tradicionales, con el fin de disminuir el tiempo empleado para la generación de nuevos fármacos antibacterianos, ya que las bacterias desarrollan resistencia en un tiempo menor que el empleado para el desarrollo de nuevos fármacos
La gestión eficiente del agua se vuelve fundamental ante el aumento de la demanda y la disminución de los recursos disponibles. La contaminación del agua proveniente de diversas fuentes, plantea un desafío adicional que demanda soluciones innovadoras y sostenibles. En este escenario, los Procesos de Oxidación Avanzada (POA) emergen como verdaderos héroes ambientales al desempeñar un papel crucial en el tratamiento y la reutilización sostenible del agua. Los POA son métodos en los que se producen especies altamente oxidantes, como los radicales hidroxilos, el peróxido de hidrógeno y el ozono.
A pesar de los avances tecnológicos que han reducido las muertes por enfermedades infecciosas, en comparación con épocas anteriores (como en el siglo XVIII) cuando las tasas de mortalidad eran significativamente más altas, aún enfrentamos nuevos desafíos en esta lucha. Uno de estos desafíos es la creciente resistencia desarrollada por las bacterias contra los antibióticos convencionales. Además, nos encontramos con la presencia de patógenos emergentes, es decir organismos que han surgido recientemente o que han experimentado un aumento repentino en su incidencia o capacidad de causar enfermedades.
En películas, quizás hemos escuchado la palabra nanotecnología, y la mayoría de las veces, la relacionan con un enorme riesgo para la humanidad, p.ej. películas G.I. JOE 2009, Transformers 2014, etc. En la vida real, cuando utilizamos el término nanotecnología, nos referimos a la manipulación de la materia a una escala tan pequeña que no puede ser observada a simple vista, es decir, la escala nanométrica la cual nos permite medir, conocer y estudiar el mundo invisible y, que tiene como unidad de medida el nanómetro (nm).
En el ámbito de la investigación científica, a menudo las soluciones más innovadoras surgen de los lugares más inesperados. En este caso, nos adentramos en un territorio fascinante y diminuto: los sistemas organ-on-a-chip (órganos en un chip). ¿Qué son exactamente y por qué están causando tanto impacto en la comunidad médica y científica? Los organ-on-a-chip son plataformas microfluídicas que manipulan pequeñas cantidades de fluidos en canales que van desde uno hasta 100 micrómetros (menor al grosor de un cabello humano).
Los átomos son aquellas partículas “indivisibles” que forman la materia, tienen un tamaño lo suficientemente pequeño que se podrían juntar en línea unos diez mil millones de ellos para formar un metro de largo. Esto nos lleva a pensar que el análisis de su comportamiento y características se vuelve muy complejo. Tan sólo el estudio de un trozo de materia a escalas tan diminutas requiere, en muchas ocasiones, de un tiempo considerable y de grandes recursos económicos, así como infraestructura sofisticada para efectuarlo a nivel laboratorio de manera adecuada.
La lista de espera actual para trasplantes de órganos ha crecido de manera constante en las últimas décadas hasta llegar a más de 120 mil candidatos a la espera de recibir un órgano. Solo en los Estados Unidos de América, cada día mueren en promedio 18 personas esperando un trasplante de órgano debido a la escasez de donadores. En México la situación no es diferente; el órgano humano más demandado para trasplante es el riñón, debido en gran medida al aumento en la prevalencia de diabetes mellitus y de hipertensión arterial. De 15 702 personas que están en espera de un riñón en México, solo 2 700 personas lograrán recibirlo. Es decir, alrededor del 83% de las personas que actualmente necesitan un riñón, se quedarán sin recibirlo.
Entender el patrimonio como un ideal social permite enfocar su gestión a modo de mecanismo mediador entre el patrimonio y la sociedad. Si bien los saberes tradicionales y el reconocimiento de la riqueza cultural coadyuvan a la unión social fomentando un sentido de pertenencia e identidad, esta condición no puede ser aprendida y transmitida por todos los integrantes de un lugar.
México es uno de los países que tiene múltiples problemas educativos y en donde gran parte de la población enfrenta los efectos de la desigualdad educativa; por lo que es importante realizar una búsqueda conjunta de nuevas alternativas para crear entornos educativos aptos y acordes a las demandas educativas de un entorno social globalizado. Las actuales condiciones sociales obligan a las instituciones educativas a fortalecer los procesos educativos y elevar la calidad de la educación que ofrecen, sin embargo, en las escuelas públicas que ofrecen servicio de educación básica (desde preescolar hasta secundaria) en los contextos marginados, aún no se ha logrado incorporar suficientes recursos innovadores o tecnológicos; hecho que resulta preocupante y a la vez, requiere de atención especial por parte del gobierno y demás actores involucrados a fin de lograr que, en un futuro no lejano, el servicio educativo de esos contextos se vea beneficiado con el uso creativo de nuevas herramientas tecnológicas y estrategias innovadoras.
La transformación digital de las universidades es un proceso complejo que implica una serie de cambios organizacionales, culturales y tecnológicos. Tecnologías como las plataformas de aprendizaje online abren las puertas a un repositorio de recursos educativos disponibles las 24 horas del día, los 7 días de la semana desde cualquier lugar. Esto significa que pueden estudiar en la hora que deseen y desde donde se encuentren, además de las posibilidades de colaboración y comunicación con sus compañeros y docentes.
En las últimas décadas han ocurrido una serie de sucesos en el mundo, los cuales nos llevan a replantear algunas condiciones que pudieran ser distintas en el proceso de globalización y el papel que el ser humano juega dentro de éste. De tal modo que algunos autores hablan de un cambio en la civilización, es decir, un cambio en la orientación del pensar y el actuar. Si bien es cierto que se han presenciado progresos en algunos campos como la ciencia y la tecnología, no deja de resultar inquietante el ejercicio del poder público, la brecha de desigualdad, la distribución de la riqueza, entre otros ramos. La educación humanista es uno de los aspectos fundamentales en el proceso de formación en las Instituciones de Educación Superior (IES) para lograr una sociedad más justa; por ello, al trabajar con el estudiantado se requiere aplicar métodos educativos que enseñen al educando a tener un determinado código de conducta con él mismo y los demás.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
2. J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
34
external condenser. Somwanshi and Tiwari enhanced the
performance of a single basin solar with water flow from an
air cooler on the cover [6].
In [7], the authors studied a system that uses solar
energy as a pressure source for reverse osmosis (RO)
water desalination. Mashaly et al. [8] investigated the per-
formance of a solar desalination system using three differ-
ent types of feed water to reach near-zero liquid discharge
(ZLD) under the hyper-arid environment.
Many researchers aim to develop mathematical models
that represent the thermodynamic phenomena to optimize
the distillation process, especially to predict the volume of
distilled water. Johnson et al. [9] proposed a thermal model
for predicting the performance of a solar still with Fresnel
lens. They found that the Fresnel lens can help improve the
overall efficiency of the solar still. Thermal modeling of a
double slope active solar still has been carried out based
on the energy balance of east and west glass covers, water
mass, and basin liner under natural circulation mode [10].
Kalbasi et al. [11] formulated a mathematical model to pre-
dict the performance of single and double effect solar still
by using modified heat transfer correlations. Two similar
experimental desalination units (single and double effect)
were designed to validate the mathematical model. Wind
speed is an essential parameter for distillation since it con-
tributes significantly to the condensation process; thus,
the increase of efficiency [12].
Recently, a thermal analysis of double slope solar still
by using free software called Energy2D is reported [13].
In this work, a theoretical validation of previous experi-
mental studies [2] and analysis of forced convection effects
in double slope solar still is performed.
The paper is organized as follows: in section 2, we define
used materials and methods. In section 3, the results are
discussed, and some findings are reported. Finally, section 4
is dedicated to the conclusions.
2. Experimental study
Two identical double solar stills were designed and
manufactured, with a square tray-type solar collector. Their
bottom has a side of 0.5 m (0.25 m2
collection area), con-
structed using the 16-gauge copper sheet (1.61 mm thick).
This bottom was coated with matte black paint resistant to
high temperatures to increase solar radiation absorption.
The tray was thermally insulated by 0.10 m thickness poly-
urethane foam to ensure thermal insulation. Finally, this
foam was covered with metal to enhance the mechanical
structure.
The still’s cover is formed by 3 mm thick glass placed
at an inclination of 23°. Two aluminum channels with a
slight slope and a 0.635 cm perforation, transport, and col-
lect the condensed water. At the center of the DSSS, a con-
tainer distributes the water to the stills, maintaining a con-
stant level of brackish water to be treated using a 0.635 cm
hose. Each still has an independent condensate collector.
The brine is eliminated by a hole located at the base of the
tray, and the distilled water is continuously recorded (Fig. 1).
To analyze the influence of the wind speed on the evap-
oration–condensation process of water, a closed wind tunnel
constructed of plastic was designed and placed at the roof
of one still to control and stabilize the airflow at a differ-
ent speed. The wind speed is produced inside the tunnel
using three fans powered electrically with a variable voltage
source. The process of switching on and off is performed
automatically during the 8:00–20:00 h period.
The principal objective of this paper is the validation
of the experimental results with a theoretical model and
simulation that analyzes the influence of wind speed and
saline concentration on double slope solar still productiv-
ity. In our knowledge, this work has not been treated in
the literature.
2.1. Materials and methods
In one still, the air is injected over the glass cover, using
a 3 mm thick plate for its speed distribution and control. Air
follows the outer contour, forming a tunnel. The effect of
placing this double cover was considered in the efficiency
still analysis. Three fans (119 mm × 119 mm × 38 mm and
a 390 g of weight), with a 0.94 A supply and a variable
voltage from 0 to 60 V DC, helped to obtain the desired
wind. A digital display shows the voltage and the electri-
cal current consumed by the fans. Fig. 2 shows the detail of
the parallel interconnection.
The salted water is supplied during the night to each
basin for distillation during the day. The water depth is
constant (2 cm). The following variables are collected in
real-time: solar radiation, temperatures: ambient, inside of
the still, basin water, and wind speed. The distilled water
is measured by recording the weight in a precision bal-
ance. The measurement cycles are taken at 20:00 h each
day. In the beginning, the average wind speed is fixed.
To achieve the required speed, three fans of dimensions
(119 mm × 119 mm × 38 mm) were used. To measure the
mass of distilled water, we used a Tor-Rey electronic scale,
L-EQ 5/10 series, with an accuracy of 0.001 kg. A computer
records the information every 10 min.
We used two sensors for the recording of wind speed.
One integrated into a Skywatch Owners model Geos 11
portable weather station, (±4% accuracy) and a Cole Palmer
thermo-anemometer, model EW-10323-11 with a resolution
Fig. 1. General view of the experimental device.
3. 35
J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
of 0.1 m/s. One was used to measure the speed at the surface
of the glass cover, and others to measure the speed across
the wind tunnel. A picture and schematic diagram of the
location of the fans placed in the wind tunnel are shown
in Fig. 3.
2.2. Experimental procedure
For the preparation of seawater at the laboratory, we
used the salt concentration values reported by Werlinger
et al. [14].
The brackish water distribution vessel supplies over-
night for daytime operation, keeping the level in each of
the constant at 2 cm using the constant level burette. The
DSSS is exposed to solar radiation, and the variations in
temperatures inside and outside the still, brackish water,
the environment, solar radiation, and the selected speed
inside the wind tunnel are recorded. The amount of distilled
water is measured by recording its weight on the precision
balance. The measurement cycles are recorded at 20:00 h
of each day. In the beginning, average wind speed is set,
and the variations of the different parameters are recorded
through an automatic data acquisition system (DAS).
2.3. Instrumentation
The stills were instrumented using K-type thermo-
couples placed inside and outside the device to measure
the temperature; using these thermocouples and a DAS
Brand Campbell CR10 model, these temperatures were
measured daily; installed program extracts data every 10 min
through the serial interface that connects to a computer.
Moreover, daily climatological data was acquired:
solar irradiance, ambient temperature, wind speed, wind
direction, and relative humidity, which are continuously
recorded at the Institute of Renewable Energies in Temixco,
Morelos, México. Table 1 shows the accuracy and descrip-
tion values given by the manufacturers of the different
sensors used in this solarimetric station.
2.4. Experimental and theoretical analysis
The experimental study was carried out at the Institute
of Renewable Energies of the National Autonomous Uni
versity of Mexico, in Temixco, Morelos, México, located at
18°51’NL and 99°14’WL. The experimental device consists of
one DSSS with a copper tray coated with black paint (high
temperature resistant), 0.25 m2
of the solar collection area, and
12.5 ± 0.2 L of capacity. The cover is made of standard glass
(3 mm thickness) with an inclination of 23° and south-
oriented,
resulting in an optimal transmittance according to the local
latitude. The walls and the bottom were thermally insulated
with polyurethane foam (10 mm of thickness), which was
covered with a metallic protective shield. The cover and the
enclosure was sealed to prevent any vapor and condensate
loss. The water depth was 2 cm, which corresponds to a 5.0 L
capacity. Asecond still with the same characteristics with nat-
ural convection kept operating at the same time to compare
the performance of both. Moreover, the exterior air does not
influence the interior wind speed. Fig. 1 shows a general view
of the experimental equipment. The purpose of this paper is
to validate the experimental results with a theoretical model
analyzing the influence of wind speed on DSSS productivity.
2.5. Transient model
The solar irradiance (G) passing through a transparent
cover with a transmittance (t) that depends on the material
and its thickness (τg
G). Aportion of this radiation is absorbed
(αg
G) or reflected (ρg
G). The portion of G that reaches the
water surface (τg
G) again undergoes a decomposition due
to the optical characteristics of the water; reflected (ρw
τg
G),
absorbed (αw
τg
G) and transmitted (τw
τg
G). The most radia-
tion amount transmitted to the base of the tray is absorbed
(αb
τw
τg
G), and a small portion is reflected (ρb
τw
τg
G) because
Fig. 2. Detail view of the parallel interconnection of the fans.
Fig. 3. (a) Schematic diagram and (b) photograph of the location of the fans in the wind tunnel. (1) Fans, (2) glass cover, and (3) wind
tunnel.
4. J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
36
the black color of the tray base has a high absorptance and
low reflectance. The energy absorption in the base of the
tray is the necessary energy to heat the water of the tray or
absorber. A portion is transmitted to the exterior by conduc-
tion through the tray thickness (Qk
). Another part is trans-
ferred to the water by convection (Qcw
), this heat gained
by water, reaches the glass cover from its surface by three
heat transfer phenomena: the first part is due to convection
through the internal air (Qc
), the second part constitutes the
latent heat which transports the vapor molecules that will
condense on the inner part of the glass cover (Qu
) which
represents precisely the amount of heat necessary to evap-
orate the water placed in the tray. The third phenomenon
is the radiative heat (Qr
) between the water surface and the
glass cover. This radiation produces the greenhouse effect.
The heat given to the glass is transferred to the exterior
due to the convection (Qca
). The overall optical and thermal
phenomena that occur in a solar still are illustrated in Fig. 4.
To calculate the still thermal efficiency (η) we used
the following equation:
η =
⋅
⋅ ⋅
V h
P H
fg
av
3 600
,
(1)
where V: distillate volume measured (L); hfg
: latent heat of
vaporization (J/kg). Its value was obtained considering
the maximum temperature obtained in the water to distill;
P: potency of the incidence of solar radiation on the absorber
surface (given by the product of the average irradiance
I of the day (W/m2
) by the surface S (m2
); H: total exposure
time or sun hours (h).
The product P·H·3,600 is the solar energy captured
by the absorber (J) [15,16]. The energy balance of the still
requires that solar radiation absorbed must be equal to the
transferred energy from the roof to the air plus the losses of
the bottom/walls and the stored energy in the system [17].
The corresponding equations are the following:
Eq. (2) gives the differential equation for the slope:
m
dT
dt
I I q q q q q
g g
g
g b g d r w g c g g r g c g
Cp ev air a
= +
( )+ + +
( )− +
− − − −
α α , , , , i
ir
(2)
The heat transferred by evaporation between the water
and the cover (qev
) is based on [10]:
q h P P
c w g
ev
= −
( )
16 28
. (3)
And pw
y pg
:
P e
w
Tw
=
−
( )
25 317 5 144
. , /
(4)
P e
g
Tw
=
−
( )
25 317 5 144
. , /
(5)
hc
represents the heat transfer coefficient by convection
and is calculated by the following equation:
h T T
P P T
P
c w g
w g w
w
= −
( )+
−
( )
−
( )
( )
0 884
268 900
2
.
,
/
W m K (6)
The heat transfer from the water to the cover by radia-
tion is given by Stefan–Boltzmann Law, considering that
the emittance of the glass cover is 0.9:
q T T
r w g w g
,
.
−
= −
( )
0 9 4 4
σ (7)
This heat is due to the radiant exchange between the
water surface and the glass cover.
The heat transferred by convection between the
absorber and the glass cover consists of the convection of
Table 1
Characteristics and description of the measuring instruments used in this work
Parameter Description Model Calibration Maximum error
Global irradiation Pyranometer Eppley PSP Annual (IGF-UNAM)
(K = 7.68 Sensor Campbell)
±0.5 W/m2
Ambient temperature and
relative humidity
Sensor Campbell, CS500 1,000 ΩPRT,
DIN 43760B
Biannual ±0.4°C
±3%
Wind speed and direction Air Sentry mod 03002-5
R.M. Young Company
03002–5 Biannual ±0.3 m/s
±3°
Fig. 4. Phenomena involved in the performance of the solar still.
5. 37
J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
the air enclosed between the evaporating and condensing
surface and is called internal convection. The amount of
heat transferred by this phenomenon can be calculated by
the following expression, which is modeled by Newton’s
cooling Law:
q h T T
c w g c w g
, −
= −
( ) (8)
The heat lost by the cover towards the atmosphere by
radiation is calculated with the following expression:
q T T
r g g
,
.
−
= −
( )
air sky
0 9 4 4
σ (9)
The exterior temperature depends on the amount of
water vapor and dust in the atmosphere, which will be
manifested in an increase in the heat reflectance of the soil.
The used Eq. (10) to find this value is [18]:
T T T
sky air dp
= + ( )
0 74 0 006
0 25
. .
.
(10)
where Tdp
is the dew point temperature of the ambient air
and can be calculated by [19]:
T
K
T
T K
T
dp
amb
amb
am
=
∅ +
+
− ∅ +
237 3
17 27
237 3
17 27
17 27
. ln
.
.
. ln
. b
b
amb
T K
+
237 3
.
(11)
The heat transfer by convection between the glass cover
and the ambient air is given by:
q h T T
c g g g
, −
= −
( )
air air (12)
The following Eq. (13) calculates the coefficient of heat
transfer by convection between the booth and the air:
h k L
g L f g g
= +
( )
Nu Nu
1 3
/
/ (13)
The energy balance Eq. (14) for the absorber is
calculated by:
m
dT
dt
q q q q
b b
b
r b c w b k x
Cp = − − +
( )
−
, ,
(14)
The heat transfer coefficient for the equation that mod-
els this convection is calculated according to the following
equation:
q h T T
c w b b w b
, −
= −
( ) (15)
The heat transfer coefficient between the water and the
absorber (qc, w–b
), is calculated using the following Eq. (16) [20]:
h
k
L
b
w
b
= Nu (16)
The last term in the Eq. (17) represents the heat losses by
conduction of the base and sides of the absorber into ambient
air and is modeled by Fourier’s law:
q q
k T T
L
k x
b b
b
+
( ) =
−
( )
amb
(17)
The energy balance Eq. (18) for the insulation of the
absorber is:
m
dT
dt
q q q
k x
in in
in
loss
Cp = +
( )− (18)
The heat loss by the insulator can be written:
q U T T
loss in in air
= −
( ) (19)
The total heat transfer coefficient of the insulator Uin
is
calculated by:
U
L
k h
in
in
in in
= +
−
1
1
(20)
In the same way as in the previous two Eqs. (19) and
(20), the convection coefficient (hin
) is calculated by the
Dunkle [15]:
h
k
L
in in
air
in
Nu
= (21)
The energy balance Eq. (22) of water is calculated by:
m
dT
dt
I q q q q
L
w w
w
w g c w b r w g c w g
w w w
Cp
Cp
ev
=
+
( )− + +
( )
− − −
α τ
ρ
, , ,
(22)
kw
is the water thermal conductivity and Lb
is the charac-
teristic length of the copper plate, evaluating both the base
and the height of the basin.
2.5.1. Numerical solution and computational model
The theoretical study presented is based on the experi-
mental results carried out in a DSSS. An acrylic sheet 3 mm
thickness was adapted on the glass cover with an opti-
cal transmission in the visible interval of 80.7% to create a
“wind tunnel” and the greenhouse effect. Three fans were
placed symmetrically to ensure a uniform air flux through-
out the inner surface of the roof (forced convection). This
airstream over the hot sheet enhances the heat convection
phenomenon. The parameters that affect the equations
of gain and loss of the energy in the solar still depends on
the climatic conditions during the day, Fig. 5. To evaluate
these equations, different heat values that depend on the
temperatures must be determined. The modeling process
begins with a proposed value for each temperature of the
glass cover Tg,t
, absorber Tb,t
insulator Tin,t
and water Tw,t
. The
ambient temperature is considered as a starting point for
6. J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
38
all equations. To solve these equations, we used the finite
difference method [21]. Eqs. (6)–(9) were discretized and
Access software was used as a computational tool to imple-
ment the solution. The simulation was performed using 1 h
between two successive iterations ∆t = 1 h.
T
t
S G q q q
q
g t t
g g
t
t r w g t c w g t
r g t
,
, , , , ,
, ,
+
− −
−
=
( ) + + +
( )
( )
−
∆
∆
α α ev
amb
−
−
+
−
q
m
T
c g t
g g
g t
, ,
,
amb
Cp
(23)
T
t q q q q
m
T
b t t
b t c w b t k x t
b b
b t
,
, , ,
,
+
− ′
=
+
( )− +
( )
+
∆
∆
Cp
(24)
T
t q q q
m c
T
t t
k x t
t
t
in
loss
in in
in
, ,
+
′
=
+
( ) −
+
∆
∆
(25)
T
t S I q q q q
w t t
w g d
t
c w b t r w g t c w g t t
,
, , , , , , ,
+
− − −
=
( ) +
( )− + +
( )
∆
∆ α τ ev
ρw w w
L
Cp
(26)
To calculate the instantaneous distilled water for time t,
we used the following equation:
Pro ev
fg
=
Q
h
(27)
A table with real-time temperature values of the cover,
absorber, insulator, and water, is also introduced into the
program. These initial temperatures are used to solve the
equations of each heat transfer type (radiation, convection,
and evaporation). The obtained heats are utilized in each
new discretized equation.
2.5.2. Physical model
The experimental results it was complemented by per-
formed simulations using the computational fluid dynamics
technique, with a general-purpose commercial computing
program Fluent from the company ANSYS (Headquartered
in the United States, South of Pittsburgh in Canonsburg,
Pennsylvania) [22]. This software includes design tools in
three dimensions (3D), the solution of the mathematical
equations that represent the phenomena studied, such as
heat transfer, etc., is obtained by the finite volume method
(FVM), through a process of discretization finding approx-
imate solutions of partial differential equations [23]. The
simulation consists of four stages: (i) design and definition
of properties of the materials, (ii) mesh or sub-division of
the 3D space, (iii) solution of the equations by the FVM [24],
and (iv) presentation of results and analysis (flow chart of
Fig. 6 [25]). This simulation is useful to know the speed and
temperature fields inside solar water still. The design was
made according to the physical dimensions and materials of
the manufactured still. For the mesh of the still, 405,970 vol-
umes of the tetrahedron type was used (Fig. 7). The elements
quality of the mesh was evaluated using the parameter of
“angle bias” and the equiangular and equi-size skew. These
two parameters are less than 0.5 for 92% and less than 0.25
for 51% of the elements; a value = 1 means a high bias of the
elements, which causes erroneous results.
3. Results and discussions
In order to analyze the production of distilled water,
experiments with two solar stills working with seawater and
drinking water, natural convection, and functioning simulta-
neously. Fig. 8 shows the water production obtained in each
still. It can be seen that regardless of the solar energy received,
daily production decreases as the salt concentration increases.
However, salt concentration has no significant influence on
the final amount of distilled water. Therefore, with a solar
resource of 4.2 kWh/m2
, the average water production is 0.58
and 0.56 L, while for a solar resource of 3.6 kWh/m2
, 0.49 and
0.47 L are obtained with fresh seawater, respectively. These
values are in good agreement with the literature [26,27].
For the brackish water case, initial concentration
was 24 ± 0.1 g/L, and remaining not distilled water has a
27.4 ± 0.1 g/L concentration. These results are consistent
with those obtained by [28,29].
Fig. 5. Climatological parameters affecting distillation.
7. 39
J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
The use of a conductivity meter Thermo Scientific Orion
Star A212 brand provided information to determine the
salinity of seawater (range from 0.001 to 3,000 µS, 0.001 µS,
and accuracy of 0.5%).
Fig. 9 shows a comparison between the irradiance and
temperatures measured in the black tray at the different
air velocities analyzed. It can be seen that at 6.9 m/s speed,
ambient temperature is higher than the outside glass because
the glass cools, inferring that under these conditions, there
will be less condensation and, consequently, a decrease
in water production.
3.1. Comparison of the theoretical model with the
experimental data
Fig. 10 shows experimental and theoretical temperatures
as a function of time. For all temperatures (Tb
, Tg
, Tw,
and
Tin
), simulation and experimental results are similar. When
the irradiance is lower, all these temperatures are almost
the same. However, at midday (high irradiance) where the
temperature reaches its maximum, the difference between
them is significant.
Fig. 11 presents a comparison between the measured
irradiance and water production. In this case, the tempera-
ture rises and enhances the evaporation, which augments
the still efficiency. Also, is presented the experimental
results of distilled water and the estimated production
by the theoretical model on the same day at 3.5 m/s wind
speed. The maximum water yield is obtained approxi-
mately at 13:00 h in both cases. Moreover, the theoretical
and experimental curves have almost the same qualitative
and quantitative behavior. The average deviation was
±0.052 L/h. The impact of the wind speed on the produc-
tion of distilled water is directly related to the temperature
difference between the glass and the water to be distilled.
It increases with the decrease in the temperature of the
roof. The heat transfer by convection from the deck to the
ambient air increases when the heat transfer by evaporation
and convection between the water and the house increases.
These results are consistent with those reported in [30].
Table 2 shows data obtained in the still with different
wind speeds. During test days, the average maximum irra-
diance (800 W/m2
) was presented at noon, corresponding
to 5.53 kWh/m2
daily, and the amount of distilled water
obtained was 0.7 L.
3.2. Simulation
For the simulation of the solar stills behavior, it is nec-
essary to consider the properties of the used materials in
the experiments, such as mass density, specific heat, ther-
mal conductivity, among others, not to underestimate or
overestimate the obtained results. It is necessary to reach
the number of iterations until the solution of the equations
converges to a fixed value, usually is 0.001 for the continuity
and momentum conservation equations and 1 × 10–6
for the
energy equations. Once this value is reached, it is possible
Fig. 6. Flow chart of the finite volume method. Adapted from [20].
Fig. 7. Isometric view of the still’s design with the mesh.
Fig. 8. Water production based on the solar energy received in
the collector.
8. J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
40
to find the variables information. The distribution of the
wind speed vectors inside the double slope is presented at
the left of Fig. 12. The bottom temperature of the wind tun-
nel is higher, which decreases the air density in this region;
thus, the wind speed augments. The increasing of the forced
convection decreases the solar still temperature, as shown at
the right of Fig. 12. Hence, this effect accelerates heat transfer
from the absorber to the top, and then the water temperature
is reduced.
The effect of wind speed on the temperature distribution
on the surface of the absorber was also analyzed. The initial
temperature of the absorber is 80°C. It is evident that the tem-
perature on the surface of the absorber decreases with higher
speed; these results are shown in Fig. 13. However, the area
that is interesting to cool, that is, the glass cover, would allow
a higher rate of water vapor condensation, and this should
be reflected directly in an increase in the efficiency of water
distillation.
Nevertheless, another satisfying result of this investi-
gation shows the dependence of water production on wind
speed, as shown in Fig. 14. For low wind speed v ≤ 5.5 m/s,
the water production increases with increasing wind speed.
After this critical speed, water production does not exhibit
a linear relationship with wind speed. In this case, water
production shrinks with the augmentation of wind speed.
Furthermore, we can have maximum production with
two speeds; 5.5 and 3.5 m/s. Nevertheless, this last wind
speed is the optimum one because we can have maximum
water production with a minimum energy consumption.
This theoretical result is in good agreement with experi
mental findings in [12].
Fig. 9. Comparison between the irradiance and temperatures
in the black tray at 2.5, 3.5, 5.5, and 6.9 m/s.
Fig. 10. Theoretical and experimental temperatures during
the day.
Fig. 11. Experimental and theoretical water production during
the day.
Table 2
Comparison of the production of distilled water at different wind speed concerning the solar radiation received.
Average speed
(m/s)
Average irradiation
(kWh/m2
)
Solar energy received
in the collector (kWh)
Distilled water*
obtained (L/d)
h (%)
2.5 5.22 0.860 0.61 46.4
3.5 5.18 0.854 0.75 58.0
5.5 4.91 0.810 0.76 62.3
6.9 5.10 0.842 0.62 48.9
*Manufacturer specified error (scales Tor-Rey): ±0.05 kg
9. 41
J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
4. Conclusions
The thermal behavior of two stills built working with
natural convection was analyzed. It is found that under
the conditions in which the experiment was conducted,
the water production is not affected by the salinity. With
a typical solar resource of 4.2 kWh/m2
, the analyzed
house still is capable to produce 0.58 L/d in the winter. By
increasing the wind speed from 0 to 6.9 m/s, the volume
of distilled water is increased to a maximum value that is
reached when the glass cover has the same temperature
as the environment. This result is achieved when wind
speed is 5.5 m/s. Moreover, the volume of water obtained
was 0.76 L at 4.9 kWh/m2
. The efficiency obtained for
these values is 62.3%, which is higher than the researcher
Fig. 12. Vectors speed in the double slope (left). Temperature profiles inside the house and the absorber at different speed (right):
(a) 2.5 m/s, (b) 3.5 m/s, (c) 5.5 m/s, and (d) 6.9 m/s.
Fig. 13. Temperature distribution at the base of the absorber for different wind speed: (a) 2.5 m/s, (b) 3.5 m/s, (c) 5.5 m/s, and (d) 6.9 m/s.
10. J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
42
Cooper estimate for single-house distillers without the
influence of roof cooling. For higher speed, the glass tem-
perature was lower than that of the environment, which
decreases the volume of distilled water.
Acknowledgments
The authors are grateful for the academic and finan-
cial support to develop this research to the Universidad
Politécnica del Estado de Guerrero, and M.C. Guadalupe
Manuel Estrada Segovia, Director of the Facultad de
Ingeniería of the Universidad Autónoma de Campeche.
Symbol
a — Absorbance, 1
h — Efficiency, 1
ρ — Mass density, kg/m3
t — Transmittance, 1
cp
—
Specific heat, J/kg/K
h —
Convective heat transfer coefficient, W/m2
/K
hfg
—
Latent heat of vaporization, J/kg
H —
Total exposure time, h
I, G — Solar irradiance, W/m2
k —
Thermal conductivity, W/m/K
L —
Length, thickness, depth, m
m —
Mass, kg
Nu — Nusselt number, 1
P —
Solar power, W
Pro — Production of distilled water, L
q —
Heat rate transfer, W
Q —
Energy transfer, J
S —
Surface of tray, m2
t —
Time, S
T —
Temperature, K
U —
Total heat transfer coefficient, m2
/K/W
V —
Distillate volume, L
Subscripts
a, air — Air
amb — Ambient
b — Basin or tray
c — Convective
d — Diffuse
dp — Dew point
ev — Evaporative
g — Glass
in — Insulator
k — Vertical tray thickness
loss — Losses
r — Radiative
u — Upper
w — Water
x — Horizontal tray thickness
References
[1] T. Rajaseenivasan, T. Elango, K. Kalidasa Murugavel,
Comparative study of double basin and single basin solar stills,
Desalination, 309 (2013) 27–31.
[2] M.M. Morad, H.A.M. El-Maghawry, K.I. Wasfy, Improving
the double slope solar still performance by using flat-plate
solar collector and cooling glass cover, Desalination, 373 (2015)
1–9.
[3] Q. Wang, S. Liang, Z. Zhu, G. Wu, Y. Su, H. Zheng, Performance
of seawater-filling type planting system based on solar
distillation process: numerical and experimental investigation,
Appl. Energy, 250 (2019) 1225–1234.
[4] H.N. Panchal, Enhancement of distillate output of double
basin solar still with vacuum tubes, J. King Saud Univ. Eng.
Sci., 27 (2015) 170–175.
[5] R.A. Kumar, G. Esakkimuthu, K.K. Murugavel, Performance
enhancement of a single basin single slope solar still using
agitation effect and external condenser, Desalination, 399 (2016)
198–202.
[6] A. Somwanshi, A.K. Tiwari, “Performance enhancement of a
single basin solar still with flow of water from an air cooler on
the cover”, Desalination, 352 (2014) 92–102.
[7] A.A.A. Attia, Thermal analysis for system uses solar energy as
a pressure source for reverse osmosis (RO) water desalination,
Sol. Energy, 86 (2012) 2486–2493.
[8] A.F. Mashaly, A.A. Alazba, A.M. Al-Awaadh, Assessing the
performance of solar desalination system to approach near-
ZLD under hyper-arid environment, Desal. Water Treat.,
57 (2016) 12019–12036.
[9] A. Johnson, L. Mu, Y.H. Park, D.J. Valles-Rosales, H. Wang,
P. Xu, K. Kota, S. Kuravi, A thermal model for predicting the
performance of a solar still with fresnel lens, Water, 11 (2019)
1860.
[10] V.K. Dwivedi, G.N. Tiwari, Experimental validation of thermal
model of a double slope active solar still under natural
circulation mode, Desalination, 250 (2010) 49–55.
[11] R. Kalbasi, A.A. Alemrajabi, M. Afrand, Thermal modeling, and
analysis of single and double effect solar stills: an experimental
validation, Appl. Therm. Eng., 129 (2018) 1455–1465.
[12] M. Castillo-Téllez, I. Pilatowsky-Figueroa, Á. Sánchez-Juárez,
J.L. Fernández-Zayas, Experimental study on the air velocity
effect on the efficiency and freshwater production in a forced
convective double slope solar still, Appl. Therm. Eng., 75 (2015)
1192–1200.
[13] J.A. Alanís Navarro, M. CastilloTéllez, M.A. Rivera Martínez,
G. Pedroza Silvar, F.C. Martínez Tejeda, Computational thermal
analysis of a double slope solar still using Energy2D, Desal.
Water Treat., 151 (2019) 26–33.
[14] Werlinger, Camilo, Krisler Alveal, Héctor Romo, Biología
marina y oceanografía: conceptos y procesos. Consejo Nacional
del Libro y la Lectura, 2004.
[15] R.V. Dunkle, Solar Water Distillation: The Roof Type Still and
a Multiple Effect Diffusion Still, In Proc. International Heat
Transfer Conference, University of Colorado, USA, 1961, vol. 5,
pp. 895.
Fig. 14. Water production as a function of time and wind speed.
11. 43
J.A.A. Navarroa et al. / Desalination and Water Treatment 192 (2020) 33–43
[16] M.A.S. Malik, V.V. Tran, A simplified mathematical model for
predicting the nocturnal output of a solar still, Sol. Energy,
14 (1973) 371–385.
[17] H. Al-Hinai, M.S. Al-Nassri, B.A. Jubran, Effect of climatic,
design and operational parameters on the yield of a simple
solar still, Energy Convers. Manage., 43 (2002) 1639–1650.
[18] M.N. Bahadori, Passive and Hybrid Convective Cooling
Systems, International Passive and Hybrid Cooling Conference,
American Section of the International Solar Energy Society,
Miami Beach, Florida, Nov. 1981, pp. 715–727.
[19] C. Beck, K. Crowther, H. Kessler, Radiative Cooling: Resource
and Applications, Los Angeles, CA, 1981.
[20] J.R. Welty, C.E. Wicks, R.E. Wilson, G.L. Rorrer, Fundamentals
of Momentum, Heat, and Mass Transfer, 5th ed., Hamilton
Printing, United States of America, 2008.
[21] I.N. Bronshtein, K.A. Semendyayev, G. Musiol, H. Muehlig,
Handbook of Mathematics, 5th ed., Springer-Verlag, New York,
2015.
[22] ANSYS, Engineering Simulation 3D Design Software |
ANSYS, 2019. Available at: https://www.ansys.com/ [Accessed:
03-Jun-2019].
[23] E. Oñate, S. Idelsohn, O.C. Zienkiewicz, R.L. Taylor, A finite
point method in computational mechanics. Applications to
convective transport and fluid flow, Int. J. Numer. Methods
Eng., 39 (1996) 3839–3866.
[24] F. Moukalled, L. Mangani, M. Darwish, The Finite Volume
Method in Computational Fluid Dynamics, Vol. 113. Berlin,
Germany, Springer, 2016.
[25] M. Ahsan, Numerical analysis of friction factor for a fully
developed turbulent flow using k–ε turbulence model with
enhanced wall treatment, Beni-Suef Univ. J. Basic Appl. Sci.,
3 (2014) 269–277.
[26] J.J. Hermosillo, D. Gudiño, Notas Sobre el Curso de Energía
Solar, Tlaquepaque, Jalisco, ITESO, 1995, pp. 158.
[27] S.H. Soliman, Effect of wind on solar distillation, Sol. Energy, 13
(1972) 403–415.
[28] R. Kalbasi, M.N. Esfahani, Multi-effect passive desalination
system, an experimental approach, World Appl. Sci. J., 10 (2010)
1264–1271.
[29] M.N.I. Sarkar, A.I. Sifat, S.M.S. Reza, M.S. Sadique, A review of
optimum parameter values of a passive solar still and a design
for southern Bangladesh, Renewables: Wind, Water, Solar,
4 (2017) 1–13.
[30] A.F. Muftah, M.A. Alghoul, A. Fudholi, M.M. Abdul-Majeed,
K. Sopian, Factors affecting basin type solar still productivity:
a detailed review, Renewable Sustainable Energy Rev.,
32 (2014) 430–447.