Incident Solar Radiation Research Articles

Solar radiation limits the use of paddocks by laying hens raised in the free-range system.

Laying hens on the free-range systems are susceptible to challenging situations in relation to the rearing environment. Therefore, this work evaluated how solar radiation influences the behavior of laying hens raised in a free-range system, in the Brazilian Savanna. The activities included data collection of meteorological variables and behavioral analysis of 300 commercial laying hens in relation to the frequency of use of indoor and outdoor areas of rearing housing. The solar radiation is the main factor that directly affects the heat gain of production animals, in this experiment had a high amplitude during all day, going from 33.42 to 756.98Wm-2. It was observed that the highest frequency of 79% and 91% use of the barn areas by the hens was at 8 am and 4pm, respectively. The internal area of the housing was more used by hens 87% and 68% at 12h and 14h, respectively. Hens were not observed in the paddocks at noon and 2pm. Hens spend more than 6h of the day inside the housing to provide shelter from solar radiation. Which the conclusion the solar radiation influences the behavior of laying hens, at times of the day of the higher incidence of radiation, and high air and global temperatures, it was not observed the presence of hens in the external areas of the housing, especially with the use of the paddocks; at these times the hens seek shelter inside the housing to get away from the incidence of direct solar radiation.

Impact of Microstructure on Solar Radiation Transfer Within Sea Ice During Summer in the Arctic: A Model Sensitivity Study

The recent rapid changes in Arctic sea ice have occurred not only in ice thickness and extent, but also in the microstructure of ice. To understand the role of microstructure on partitioning of incident solar shortwave radiation within the ice and upper ocean, this study investigated the sensitivity of the optical properties of summer sea ice on ice microstructures such as the volume fraction, size, and vertical distribution of gas bubbles, brine pockets, and particulate matter (PM). The results show that gas bubbles are the predominant scatterers within sea ice. Their effects on the scattering coefficient and ice albedo are 5 and 20 times stronger respectively than the effect of brine pockets. Albedo and transmittance of ice decrease with higher concentration and larger size of PM particles. A 4-cm top layer of ice with high PM concentration (50 g/m3) results in a 10% increase in radiation absorption. The role of ice microstructure in the partitioning of radiation transfer is more important for seasonal than for multiyear ice, and more important for ponded than for snow-covered ice. Varying ice microstructure can obviously alter solar radiation transfer in the ice-ocean system, even with a constant ice thickness. Our results suggest that numerical models should take the variable microstructure of sea ice into account to improve model accuracy and to understand the interaction between internal variations in Arctic sea ice and the ocean, especially in summer.

The dynamic behaviour of sunscreens under in-service conditions.

Discussion continues over various aspects of sunscreen science: regulation, test methods, sun protection factor (SPF), labelling claims, potentially harmful components, among others. In this paper the UV transmission properties of a number of commercial sunscreens have been determined at constant sunscreen film thickness under different local UV Index conditions. The data demonstrate difficulties facing the public and the sunscreen industry as a whole, even though SPF values and other data stated on the sunscreen packaging are assumed to be correct according to standard testing methods. This work has shown that at realistic application rates the critical factors are the intensity of the incident solar radiation and the accumulated erythema UV dose transmitted over time. In one example, on 'Extreme' UV Index days, an SPF 30 sunscreen under test transmitted one minimal erythema dose (MED) of UV in only 35min. In another example, although it should not, in theory, transmit one MED until several hours of exposure, this level was reached in 1h by an SPF 50 sunscreen under these typical Australian summer conditions (UV Index 12) in Wollongong, NSW (34.4°S). Such properties could have severe consequnces if these sunscreens were used by individuals with Fitzpatrick Skin Type 1, organ transplant recipients or other immuno-compromised individuals.

Experimental, Analytical and ANSYS Computation of Novel Cascade Solar Desalination Still

This study presents a simple device using solar radiation as a source of energy to convert brackish water to freshwater. To enhance the productivity of the cascade of solar stills, a new structure of the absorber plate with sloped surfaces and baffles was proposed to present a slight water layer thickness and improve the amount of solar radiation incident. A physical model is developed taking into account various parameters which affect the distillate yield of solar sills. In the present work, the modeling of the cascade solar still uses ANSYS Fluent V18 to investigate the yield. A three-dimensional model was considered to simulate the temperature of the water, absorber plate, and freshwater productivity. A comparison was conducted based on the CFD simulation results, experimental and approximate analytical model data. It showed a reasonable agreement of the results obtained using the analytical model with the experimental and the simulation using ANSYS Fluent of different working parameters especially the productivity. The best performance was obtained on 15/07/2018, with a productivity rate of more than 1.67 kg/m2.hr.

Solar still performance for small-scale and low-cost seawater desalination: Model-based analysis and water yield enhancement techniques

Water stress particularly affects developing regions. It is necessary to develop low-cost and small-scale solutions that do not require advanced technology and abundant energy resources to produce fresh water. A viable solution for rural coastal areas is seawater desalination using the solar still — a device that only relies on solar radiation to operate. The present work focuses on improving the solar still water yield. To achieve this objective, an alternative thermal model, which compromises a coupled energy balance for each solar still component, was proposed. This model increases the simulation accuracy for different designs, locations, and ambient conditions, predicting the water yield with a maximum deviation of 6% for the evaluated experiments. In addition, for a selected experiment, a parametric analysis was performed and, it was concluded that the potential parameters to enhance the water yield are: water depth, structure design, insulation, incident solar radiation, and basin-glass temperature difference. Based on the parametric study and the identified improvement solutions from the literature, feasible options were studied, such as: implementing reflectors, solar still design modification, increasing inner convection (insignificant improvement), using a porous medium (relevant for large water depths in the solar still) and separating evaporation/condensation (largely conditioned by ambient conditions).

Self-adhesive thermotropic smart films for adaptive solar control under various climate conditions

Energy conservation has become a crucial concern for reducing carbon dioxide emissions; thus, smart windows that selectively control incident solar radiation are attracting considerable attention. While extensive research has worked towards rendering the adaptive modulation of optical transparency, the wide application of traditional glass-type smart windows is limited by their high-cost installation that requires the removal of existing glazing. In this work, we report the preparation of a smart film that can be easily attached to any surface shape. A multilayer smart film comprising a transparent polyethylene terephthalate substrate, a thermotropic poly(N-isopropylacrylamide) (PNIPAm) hydrogel, an acrylic adhesive, and a release film was prepared based on robust interface chemistry to ensure its stability. Field tests for optical switching between transparent and opaque states were demonstrated in response to the outdoor temperature. Furthermore, the developed smart film could be cut into specific shapes, namely letters, and attached to glass windows, indicating its potential to display various forms of information. The switching temperature could be finely tuned for various climatic conditions by copolymerizing the PNIPAm hydrogel with hydrophilic or hydrophobic comonomers. In addition, the attached film can be easily removed on demand without leaving any residue.

Decision-making process for thermal comfort and energy efficiency optimization coupling smart-window and natural ventilation in the warm and hot climates

Many studies were conducted to reduce energy demand and consumption in buildings related to HVAC systems, mainly in warm and hot climates, where heat gain from the envelope is relevant. In this context, the window is the component that demands more attention as it usually shows a low thermal performance and represents the weakest component in the building envelope. This work proposes a method to evaluate window performance considering operation strategies regarding dynamic solar control and passive cooling in commercial buildings in subtropical and tropical climates. Parametric simulations were run for three Brazilian cities testing three windows compositions – laminated, insulated, and electrochromic glazing – with hybrid ventilation. Personalized codes were developed to establish rules for window control and prioritize actions to meet energy-saving and thermal comfort for five electrochromic and five hybrid ventilation controls. It was proposed the Pareto-optimal frontier to obtain the optimal set of solutions. The results showed that electrochromic windows reached an energy saving of up to 6.1% to 8.6% in the studied cities. The most influential variables were solar radiation incidence, external illuminance level, and outdoor air temperature. The method is adequate to establish guidelines for window controlling in warm and hot climates, especially coupling different techniques.

Caloric Value of Biomass based Power Plants, Life Cycle Assessment and Techno Economic of Different Crops for M.P. (India)

<p>Solar radiation incident on green plant and other photo synthesis organism performs two basic functions such as temperature control for chemical reaction to proceed and the process of photosynthesis. The fundamental conversion process in green plant is photosynthesis which is process of combining CO<sub>2</sub> from the atmosphere with water and light energy to produce oxygen and carbohydrates<sup>1</sup>.</p><p> X [CO<sub>2</sub>] + Y [H<sub>2</sub>O] + light energy photosynthesis X[O<sub>2</sub>] + Y [Cx H<sub>2</sub>O]</p><p> Y [Cx H<sub>2</sub>O] is used to indicate the carbohydrates.</p><p>The world population has increased at an explosive rate from 1.65 billion to just over 6 billion in the 20<sup>th</sup> century, and continues to increase. In the same century, mankind has consumed over 875 billion barrels of oil and it is very likely that even more oil will be consumed in the present century. Annual energy use in developing countries has risen from 55 to 212 kg oil equivalent over the last thirty years, while developed countries use as much as 650 kg oil equivalent per person. In his synopsis ‘Trilemma’ Three major problems threatening world survival’, foresees a three-fold challenge in the 21st century: how can we achieve economic growth, supply food and energy resources, while conserving the environment? To overcome the Trilemma, developing and introducing more efficient energy conversion technologies is therefore important, for fossil fuels as well as renewable fuels. This thesis addresses the question how biomass may be used more efficiently and economically than it is being used today. Wider use of biomass, a clean, renewable and CO<sub>2</sub> neutral feedstock may extend the lifetime of our fossil fuels resources and alleviate global warming problems. Another advantage of using of biomass as a source of energy is to make developed countries less interdependent on oil- exporting countries, and thereby reduce political tension. Furthermore, the economies of agricultural regions growing energy crops benefit as new jobs are created<sup>1</sup>. Biomass primary energy sources: Past, present and future in particular wood, has historically been an important energy source for fires, ovens and stoves. During the Industrial Revolution, coal displaced biomass because of its high energy content and because it is available in large quantities at low cost. At the beginning of the 20th century, oil supplied only 4 % of the world’s energy. Decades later it became the most important energy source. Especially developed countries are highly dependent on oil, which supplies about 96 % of their transportation energy. With world energy demand projected to rise by about 40 % from now to 2020, photosynthesis. Rajiv Gandhi Proudyogiki Vishwvidhalaya implemented the National Policy for Management of Crop Residues to protect the parali (crop residue). On December 10, 2015, the National Green Tribunal (NGT) had banned crop residue burning in the states of Rajasthan, Uttar Pradesh, Haryana and Punjab. Burning crop residue is a crime under Section 188 of the IPC and under the Air and Pollution Control Act of 1981. The Delhi high court had also ordered against burning residues, while Punjab government imposed a penalty of Rs 73.2 lakh farmers in 2016 for burning of crop residue<sup>3</sup>.</p>

Numerical study of the amplification effects of cold-front passage on air pollution over the North China Plain

Cold-front systems provide scavenging mechanisms for air pollution in the North China Plain (NCP), but the transport of pollutants with cold fronts aggravates air quality downstream. The impact of cold fronts on PM2.5 concentrations over the NCP during 8–14 December 2019 was studied using the WRF-Chem model. Results indicate that cold fronts directly influence PM2.5 concentration through regional transport of pollutants and adjustment of meteorological systems, and they indirectly affect air quality by influencing aerosol–radiation interaction. Pollutants affecting downstream areas may be transported to altitudes of ~3 km along the frontal surface, with near-surface PM2.5 concentrations increasing temporarily at up to 15 μg·m−3·h−1 behind the surface frontal line owing to the inversion layer triggered by the oblique frontal surface. The transport process plays an essential role in affecting air pollution levels, more than vertical mixing and chemical reaction processes. Changes in the meteorological system (eastward shift of the high-pressure center) occurring with the passage of cold fronts facilitate the accumulation and transport of pollutants in the NCP, reducing air quality in the western and northern NCP. Cold fronts may also indirectly exacerbate near-surface pollutant diffusion conditions by affecting solar radiation incidence, with a reduction of the 2-m temperature by as much as 1 °C, increasing near-surface (<1 and 0.5 km agl on the pre- and post-frontal sides, respectively) PM2.5 concentrations by up to 40 μg·m−3, while reducing upper-layer concentrations by up to 30 μg·m−3. This study emphasizes the amplification effect of cold fronts on air pollution, with inter-regional cooperation being essential in improving air quality in the NCP region.

Charging and Discharging Characteristics of a Battery-Capacitive Energy Storage Device for Stand-Alone Photovoltaic System

The purpose of the research is to study the charging-discharging characteristics of a hybrid energy storage device which consists of two parallel connected battery and capacitive parts to assess the work efficiency of its circuit design as a part of standalone photovoltaic system. The charge current kinetics of a hybrid storage device from a solar panel was carried out under natural conditions at a specific power of incident solar radiation of 800–850 W/m2. The discharge current kinetics of battery and capacitive storages were obtained with a resistive load and disconnected solar battery. The dynamics of charging and discharging processes of the battery and capacitive parts of the energy storage device were monitored by the voltage rise/fall rate. The battery part of the drive is charging and starting the device based on a lead-acid gel battery with a charging capacity of 11 A·h, 12.8 V maximum voltage, and 15 A maximum discharge current. The capacitive part consisted of a new generation INSPECTOR Booster supercapacitor starting the device with an electrostatic capacity of 80 F, 15.5 V voltage, and 800 A starting current. As the energy source a solar battery was used, with a 12 V nominal voltage and 100 W peak power. A 6 Om rheostat with 15 A consumption current was used as a load during the storage device discharge. A Morningstar ProStar-15 charging/discharging controller with a pulse-width modulation function was used to monitor and control the photovoltaic system. Quantitative charging and discharging characteristics of a battery-capacity energy storage device were obtained for the use in the development of standalone photovoltaic system.

Novel mathematical modeling, performance analysis, and design charts for the typical hybrid photovoltaic/phase-change material (PV/PCM) system

As a type of hybrid PV/T solar collector, the PV/PCM system is typically used to produce and store both electrical and thermal energy in a variety of applications. Specialized computational-fluid-dynamic (CFD) models such as Ansys FLUENT and COMSOL are currently used to simulate the operation of these systems. However, the relatively long computation time of these models, which can range from a few hours to a few days for even simple system variables, poses a challenge. Therefore, the effort in this study has been devoted to developing an alternative mathematical model for PV/PCM systems that is sufficiently accurate, fast to compute, and simple to use. The proposed model is based on an exact five-parameter photovoltaic model coupled with a well-established photovoltaic/thermal network. The overall heat transfer coefficient of the thermal component (PCM) within the system's network is determined using two novel formulas in relation to the PCM's average temperature across its solid, melting, and liquid phases. The proposed model was implemented in MATLAB as a code that utilizes straightforward numerical functions without the use of mesh patterns. The model was then validated via both CFD and experimental verification. The results indicated that the model is reasonably accurate in terms of percentage errors and correlation coefficients. The model's computation time for system temperatures and PV power is less than 14 s, with a total simulation time of 2.2 h at a time step of 2.5 min, compared to 16 h for CFD. Thus, the developed model can substantially help in conducting comprehensive investigations of PV/PCM performance characteristics, parametric analyses, and design charts using a diverse range of system variables. Two performance indexes for the PV/PCM system were introduced: the PCM melting time interval and thermal efficiency. It was found that the PCM performs better in its upper layer, and this layer, which accounts for only about 5%–6% of the total PCM thickness, primarily governs the aforementioned performance indexes as well as the overall heat transfer coefficients. The melting time interval was found to increase linearly with PCM thickness, whereas the thermal efficiency increases logarithmically with incident solar radiation, with greater rates at lower solar radiation levels. However, over the three phases, the PV efficiency varies within a narrow range of 15.5–17.3%. The parametric analyses showed that thermal efficiency increases approximately fivefold as ambient temperature increases from 0 to 35 °C, but decreases by 55% as wind speed increases from 0 to 4 m/s.

Drawing the borders of the mesophotic zone of the Mediterranean Sea using satellite data

The 30–150 m bathymetric range is commonly adopted in the literature to constrain the mesophotic zone. However, such depth interval varies depending on sunlight penetration, which is primarily a function of solar radiation incidence and water clarity. This is especially obvious in the Mediterranean Sea with its peculiar biophysical properties. Integrating information on light regime in the estimation of the bathymetric range of the mesophotic zone would provide a more robust definition, orienting conservation actions targeting its ecosystems. We present a first assessment of the spatial and vertical extension of the mesophotic zone in the Mediterranean Sea based upon light penetration, comparing our prediction with literature data. Our study also represents a baseline to monitor future variations in the bathymetric interval associated with the mesophotic zone in the Mediterranean Sea in relation to global changes.

Modeling the CO2+ Ultraviolet Doublet Emission from Mars with a Multi-Instrument MAVEN Data Set

With the aid of a multi-instrument data set gathered by the Mars Atmosphere and Volatile Evolution (MAVEN) during ten selected periods, we make detailed calculations of the CO2+ Ultraviolet Doublet (UVD) emission brightness profiles which are then compared to the Imaging Ultraviolet Spectrometer limb observations. Our calculations confirm that the photoionization of atmospheric CO2 is the predominant process driving CO2+ UVD emission at high altitudes, whereas the photoelectron impact ionization of CO2 becomes more important at low altitudes. The data–model comparisons show good agreement near and above the emission peak at around 120 km with an intensity of 27–45 kR. A special case is found for period 3 coincident with a regional dust storm during which the peak altitude rose by 20 km. Of particular interest is the significant discrepancy below the peak, which is likely associated with the uncertainties in either atmospheric density or incident solar irradiance. A detailed investigation suggests that the latter uncertainty is more likely responsible for such a discrepancy, in that the solar irradiance shortward of a wavelength threshold below 30 nm should be adjusted to achieve reasonable data–model agreement over the entire altitude range. This result highlights the necessity to improve the accuracy of any solar irradiance model used for planetary aeronomical studies.

EXPERIMENTAL INVESTIGATION OF SOLAR VORTEX POWER GENERATION SYSTEM INTEGRATED WITH SENSIBLE THERMAL ENERGY STORAGE

Solar updraft power technologies suffer low efficiency and require a large collection area. Enhancement techniques are essential to overcome these setbacks. This paper investigates and discusses the effect of extended Sensible Thermal Energy Storage (STES) outside the canopy of the Solar Vortex Power Generation (SVPG) system. The extended sensible thermal energy storage integration is evaluated experimentally utilizing an SVPG model installed in the solar research site in Universiti Teknologi PETRONAS. The system consists of an (8-m-Dia). solar collector and a vortex generator. The selected material of the STES is black-painted pebbles that covered the ground underneath the canopy of the solar collector and then extended by 1 m outside the canopy. The variables considered for the performance evaluation are ambient, air inlet and outlet of the collector temperatures, incident solar irradiance, and air outlet velocity. Two cases have been studied, one with black painted pebbles covering the ground up to the outer diameter of the canopy (8-m-Dia) and the second is 1.0 m extended coverage outside the canopy (10-m-Dia). The performance of the SVPG is proven to enhance by the extension of the STES beyond the collector area. The extension of STES increased the mean thermal efficiency value by 0.85% and increased the mass flow rate by 0.01 kg/s. The performance indicator is increased by around 19.3%. It could be concluded that the extension of pebbles outside the canopy increases the amount of solar photothermic conversion, leading to improved efficiency of the SVPG system.&#x0D; Keywords: natural convection, photothermic conversion, sensible thermal energy storage, solar vortex engine, solar updraft power

Design and analysis of a renewable energy driven greenhouse integrated with a solar still for arid climates

Closed or protected agriculture in arid climates requires a significant amount of energy to maintain optimum conditions due to the harsh external environment and unavailability of water for irrigation of crops. Therefore, this study proposes a novel greenhouse system integrated with a solar still that reduces the cooling load by absorbing a part of the incident solar irradiance. The greenhouse utilizes the humidification-dehumidification phenomena to supply cooling and water for the plants from the ambient air. The complete system consists of an evacuated tube collector, a greenhouse unit integrated with a solar still, an absorption cooling cycle, and thermal energy storage. A comprehensive thermodynamic model is developed and analyzed using the 1st and 2nd laws of thermodynamics. Moreover, the effect of solar irradiance, ambient temperature, and greenhouse operating parameters on the system’s performance is evaluated, demonstrating that the system can operate in a continuous and stable mode. Results illustrate that the humidification-dehumidification system inside the greenhouse produces sufficient water and cooling in an environment-friendly manner while the solar still reduces the cooling load by almost 20%. Moreover, the greenhouse maintains optimum temperature and relative humidity throughout the year while providing a space cooling load of 1437.95 kW and 4.03–5.20 m3/day of water. The proposed system provides an opportunity for year-round agriculture in harsh climates with a scarcity of fresh water. In addition, the system is flexible depending on the crop requirement and geographical location of the site.

Control of the Solar Radiation Reception Rate (SRRR) Using a Novel Poly-Tilted Segmented Panel (PTSP) in the Region of Makkah, Saudi Arabia

This work deals with controlling the solar radiation reception rate (SRRR) (ratio of the incident solar radiation on tilted panel to the global incident solar radiation). Controlling the SRRR will permit the amount of the received solar energy on solar panels to be adjusted. This SRRR control is very useful for several technological applications such as solar thermal and photovoltaic technologies in extremely sunny regions around the world, such as the case of Makkah, Saudi Arabia. Thus, the sustainability of the cities and villages, located in such regions, is promoted. A novel design proposing a poly-tilted segmented panel (PTSP) is proposed as an original techno-logical solution enabling the control of the SRRR. Design technical details are clearly explained. The proposed design presents a cheap, simple and effective alternative to conventional sun tracking systems. The SRRR on the proposed PTSP is mathematically modeled. The influence of the combinations “number of segment/tilt angles” on the SRRR is assessed for the most significant days in the year: equinox, summer solstice and winter solstice. A specific “document-aided design”, showing the SRRR level reached by each specific combination “num-ber of segment/tilt angles”, is provided. Based on these documents, the adequate combination “number of segment/tilt angles” is easily determined by knowing the desired SRRR level. The SRRR level is determined based on the global incident solar radiation and the desired level of the incident so-lar radiation on the tilted panel. Results are properly presented, discussed and interpreted for each segment/tilt angles combination.

Calculation of the Optimum PV Panel Incline Angle for Mediterranean Climate

Due to the increasing energy needs and the limited resources that are depleted, more importance is given to renewable energy sources and their use with the highest efficiency in many areas. In order to benefit from solar energy, which is one of the most important renewable energy sources, with the highest efficiency, various parameters must be optimized. In this study, the optimization of the photovoltaic (PV) panel angle is emphasized. By using the values of solar radiation incident on the horizontal plane, the optimum PV panel angle for Adana province related to the months was determined according to the south direction. In total, 12 different panel-angle estimation models specific to region were developed and brought to the literature. When the results are reviewed, it is thought that the usability of these data for designers and academics is appropriate.

Parametric building forms rationalizing the incident direct solar irradiation

The article presents an innovative procedure that allows for an analysis of the influence of the shape and mutual arrangement of external building partitions on the amount of the direct solar irradiation incident on these partitions during a heating season. The conducted analysis related interdisciplinary issues in the field of solar radiation, unconventional forms of buildings and artificial neural networks. The developed algorithm made it possible to obtain a relationship between the general building form and the amount of their radiation falling on the facade walls and roof of the examined building type. The developed artificial network allows the above irradiation to be calculated during the changes in the geometrical characteristics of the utilized type of buildings and design of effective building forms and rational arrangements of their external solar partitions. The satellite data and online tools published on the website of the European Commission are used. The practicable ranges of the relative changes in the amount of the incident direct irradiation and the corresponding values of the independent variables defining the considered building forms are given, which is an important hint for the application of the obtained results in the design and further research works on more complex relationships.

Responses of Tropical Background State and ENSO Behaviors to Mid-Holocene Forcing Simulated by PMIP3 and PMIP4 Models

The mid-Holocene (MH), a period about 6,000 years ago, provides an opportunity to understand climate change in response to orbital forcing change. Numerical model simulation is an effective tool through which we can study the climate change in the MH, although the climate in the MH can be partly inferred from proxy data. As the Paleoclimate Model Inter-comparison Project phase 4 (PMIP4) recently released the latest simulations for different past climate scenarios, we investigated tropical climate changes, including both the basic state and interannual variability, and tried to find out whether the PMIP phase 3 (PMIP3) and PMIP4 results can be reconciled. Almost all the modelling results show that the inter-hemisphere contrast was enhanced over the tropical Pacific, with warmer and wetter condition on the northern side of the equator and an intensified cross-equatorial flow in the MH than at present, and the annual cycle of the sea-surface temperature (SST) during the MH was reduced. Such background mean state changes arose from the seasonal changes of the solar incident radiation in the MH. In addition to the consistent changes in background mean state changes, some El Niño-Southern Oscillation (ENSO) features, such as the seasonal phase locking feature and periodicity, show consistent changes across the PMIP3 and PMIP4 models, that is, both suites of models exhibit no marked difference in the MH with respect to present-day simulations. In contrast, the modeling results show only agreement on the sign of the ENSO amplitude change (i.e., decrease in the ENSO amplitude in the MH), while the range of reduction varied with model and region. Additionally, the occurrence probability of central Pacific El Niño events increases in the MH, whereas the significance is quite marginal. The modeled changes in the mean state and ENSO serve as a test bed for studying tropical climate system’s response to natural warming, which may provide some insights into understanding climate changes in response to the current anthropogenic warming.

Theoretical Model for Photovoltaic Panel Thermal Analysis

Abstract The process of energy conversion of incidental solar radiation to useful electric energy in photovoltaic (PV) panels is affected by several external factors, of which panel operational temperature is of utmost importance. The present study attempts to clarify the theoretical components of thermal behaviour of PV panels, by taking into account the detailed structure of thermal resistances of panel layers. The numerical model, developed from the theoretical analysis, shows a good agreement with experimental data provided by manufacturer for the photovoltaic panel Suntech STP280 - 24/Vd.