scholarly journals A stochastic model for the hourly solar radiation process for application in renewable resources management

2018 ◽  
Vol 45 ◽  
pp. 139-145 ◽  
Author(s):  
Giannis Koudouris ◽  
Panayiotis Dimitriadis ◽  
Theano Iliopoulou ◽  
Nikos Mamassis ◽  
Demetris Koutsoyiannis
Keyword(s):  
Solar Radiation ◽  
Stochastic Model ◽  
Renewable Resources ◽  
Renewable Energy Sources ◽  
Dependence Structure ◽  
Clearness Index ◽  
Radiation Process ◽  
Resources Management ◽  
Daily Data ◽  
Energy Conversion Systems

Abstract. Since the beginning of the 21st century, the scientific community has made huge leaps to exploit renewable energy sources, with solar radiation being one of the most important. However, the variability of solar radiation has a significant impact on solar energy conversion systems, such as in photovoltaic systems, characterized by a fast and non-linear response to incident solar radiation. The performance prediction of these systems is typically based on hourly or daily data because those are usually available at these time scales. The aim of this work is to investigate the stochastic nature and time evolution of the solar radiation process for daily and hourly scale, with the ultimate goal of creating a new cyclostationary stochastic model capable of reproducing the dependence structure and the marginal distribution of hourly solar radiation via the clearness index KT.

scholarly journals Effects of Aerosols and Clouds on the Levels of Surface Solar Radiation and Solar Energy in Cyprus

2021 ◽  
Author(s):  
Ilias Fountoulakis ◽  
Panagiotis Kosmopoulos ◽  
Kyriakoula Papachristopoulou ◽  
Panagiotis-Ioannis Raptis ◽  
Rodanthi-Elisavet Mamouri ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Renewable Energy Sources ◽  
Financial Loss ◽  
Low Latitude ◽  
High Quality ◽  
Surface Solar Radiation ◽  
Satellite Retrievals ◽  
Different Types ◽  
Fine Resolution

Cyprus plans to drastically increase the share of renewable energy sources from 13.9% in 2020 to 22.9% in 2030. Solar energy can play a key role in the effort to fulfil this goal. The potential for production of solar energy over the island is much higher than most of European territory because of the low latitude of the island and the nearly cloudless summers. In this study, high quality and fine resolution satellite retrievals of aerosols and dust, from the newly developed MIDAS climatology, as well as information for clouds from CMSAF are used in order to quantify the effects of aerosols, dust, and clouds on the levels of surface solar radiation (SSR) and the corresponding financial loss for different types of installations for production of solar energy. An SSR climatology has been also developed based on the above information. Ground-based measurements were also incorporated to study the contribution of different species to the aerosol mixture and the effects of day-to-day variability of aerosols on SSR. Aerosols attenuate 5 – 10% of annual GHI and 15 – 35% of annual DNI, while clouds attenuate ~25 – 30% and 35 – 50% respectively. Dust is responsible for 30 – 50% of the overall attenuation by aerosols.

scholarly journals The use of renewable resources is an opportunity and an obligation

2014 ◽  
pp. 13-17
Author(s):  
Zoltán Balla
Keyword(s):  
Solar Wind ◽  
Renewable Energy ◽  
Renewable Resources ◽  
Energy Production ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Rational Utilization ◽  
Security Of Supply ◽  
Harmful Substances

The renewable energy sources could be used in energy production, while no or only very slightly emit harmful substances to the environment. The solar, wind, hydropower, biomass and heat rational utilization of land contributes to greenhouse gas emissions.Renewable energy sources also reduces the dependence on fossil fuels, thus contributing to increase security of supply. The creation of local jobs to strengthen the area's population retaining ability.

scholarly journals Atjaunojamo energoresursu tiesiskuma nodrošinājums

2015 ◽  
Vol 1 (1) ◽  
pp. 55-63
Author(s):  
Kristīne Šeļepova
Keyword(s):  
Renewable Energy ◽  
Power Supply ◽  
Electricity Market ◽  
Renewable Resources ◽  
Renewable Energy Sources ◽  
Cost Effective ◽  
Energy Industry ◽  
Energy Sources ◽  
Power Base ◽  
Investment Priority

Raksta mērķis ir apzināt atjaunojamo energoresursu tiesisko regulējumu, tā atbalsta shēmas un problemātiku. Raksta autore skaidro, vai šo tiesību aizsardzības līmenis ir pietiekams, vai ir pieņemtas nepieciešamās materiālo tiesību normas, kā arī vai ir pietiekoši tiesiskie līdzekļi, kas nodrošina šo tiesību aizsardzības ievērošanu, kā arī nākamos soļus energoresursu liberalizācijas posmos. Use of renewable energy increases independence from imported energy, reduces greenhouse gas emissions, as well as increases security of energy supply. However, energy industry concedes that power becomes more vulnerable because of historical paradigms; independent power base is replaced with production from renewable energy sources. This is due to subsidies in the investment priority being cost-effective renewable resources projects. Thus, it is necessary to develop a solution defining how volatile and unpredictable renewable energy sources integrated into the European electricity market can be, while ensuring safe and uninterrupted power supply.

scholarly journals Potency of Solar Energy Applications in Indonesia

2012 ◽  
Vol 1 (2) ◽  
pp. 33-38 ◽  
Author(s):  
Noer Abyor Handayani ◽  
Dessy Ariyanti
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Oil And Gas ◽  
Renewable Energy Sources ◽  
Radiant Energy ◽  
Water Desalination ◽  
Solar Thermal Energy ◽  
Tropical Country ◽  
Solar Systems ◽  
Energy Applications

Currently, 80% of conventional energy is used to fulfill general public's needs andindustries. The depletion of oil and gas reserves and rapid growth in conventional energyconsumption have continuously forced us to discover renewable energy sources, like solar, wind,biomass, and hydropower, to support economic development in the future. Solar energy travels at aspeed of 186,000 miles per second. Only a small part of the radiant energy that the sun emits intospace ever reaches the Earth, but that is more than enough to supply all our energy demand.Indonesia is a tropical country and located in the equator line, so it has an abundant potential ofsolar energy. Most of Indonesian area get enough intensity of solar radiation with the average dailyradiation around 4 kWh/m2. Basically, the solar systems use solar collectors and concentrators forcollecting, storing, and using solar radiation to be applied for the benefit of domestics, commercials,and industrials. Common applications for solar thermal energy used in industry are the SWHs, solardryers, space heating, cooling systems and water desalination.

Prévision des températures de l'eau en rivières à l'aide d'un modèle conceptuel : le cas de la rivière Moisie

1994 ◽  
Vol 21 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Guy Morin ◽  
Tonino-Joseph Nzakimuena ◽  
Wanda Sochanski
Keyword(s):  
Solar Radiation ◽  
Water Temperature ◽  
Energy Budget ◽  
Production Capacity ◽  
Short Wave ◽  
Wave Radiation ◽  
Temperature Model ◽  
Salmon River ◽  
Daily Data ◽  
Temperature Impacts

Hydro-Québec is projecting to increase the hydroelectric production capacity of the St. Marguerite River by diversion of the tributaries Pékans and Carheil rivers of the Moisie River, the most productive salmon river of the whole Quebec. Along with substantial changes in hydrological regimes, this hydroelectric development is most likely to affect some physical environment factors such as the water temperature, which is of prime importance for the biotope and, in particular, for the salmon productivity. The objective of the present study is to simulate, over a long period of time, the river water temperatures under natural conditions as compare to those after the impoundment, to assess the consequences of the tributary diversion. We used the hydrological CEQUEAU model coupled with a temperature model.The temperature model developed is applicable to the ice-free period and calculates daily water temperatures in rivers by computing an energy budget to each element of the watershed. The energy budget considers the short-wave solar radiation, long-wave radiation, evaporation, and convection in the air as well as the advective heat of various inflows from surface runoff, interflow, and groundwaters. The estimation of the atmospheric thermal exchanges is based on the equations usually found in literature. The volumes of the various inflows are given by the hydrological model. The temperature model uses daily data for air temperature and monthly data for solar radiation, cloudiness, wind speed, and vapour pressure.The model has been applied to the Moisie River (Québec), using the measured values for the calibration. Both observed and calculated values show good agreement. The model was also used to simulate, over the whole watershed, the water temperatures for the 1961–1989 period and after the diversion. The results show that the tributary diversion contributed to increase the water temperature of the Moisie River and that this increase is gradually attenuated as we progress downstream. Key words: temperature, impacts, model, Moisie, Québec, diversion, hydrology.

Solar Chimney Power Plant Performance for Different Seasons Under Varying Solar Irradiance and Temperature Distribution

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Ulku Ece Ayli ◽  
Ekin Özgirgin ◽  
Maısarh Tareq
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Ambient Temperature ◽  
Solar Irradiance ◽  
Power Plants ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Three Dimensional ◽  
Plant Performance ◽  
Solar Chimney

Abstract One of the most promising renewable energy sources is solar energy due to low cost and low harmful emissions, and from the 1980s, one of the most beneficial applications of solar energy is the utilization of solar chimney power plants (SCPP). Recently, with the advancement in computer technology, the use of computational fluid dynamics (CFD) methodology for studying SCPP has become an extensive, robust, and powerful technique. In light of the above, in this study, numerical simulations of an SCPP through three-dimensional axisymmetric modeling is performed. A numerical model is created using CFD software, and the results are verified with an experimental study from the literature. The amount of solar radiation and surrounding weather (ambient temperature) were analyzed, and the effects of the irradiance and air temperature on the output power of the SCPP were studied. Ambient temperature is considered as one of the most important factors that influence collector efficiency in a negative or a positive manner. Solar irradiance is considered to be the most important factor that has an impact on SCPP performance. The investigation includes the study of the relationship between solar insolation and ambient temperatures during the daytime since the difference between the minimum and maximum power values and the performance are very important considering seasonal changes. According to the results, power values are dependent on the amount of solar radiation as well as the ambient temperature, and the importance of selection of location thus climate for an SCPP is found to affect the design of the SCPP.

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