Showing papers by "Soteris A. Kalogirou published in 2011"

FPGA-based implementation of intelligent predictor for global solar irradiation, Part I: Theory and simulation

Abstract: Recent advances in artificial intelligent techniques embedded into a Field Programmable Gate Array (FPGA) allowed the application of such technologies in real engineering problems (robotic, image and signal processing, control, power electronics, etc), however, the application of such technologies in the solar energy field is very limited The embedded intelligent algorithm into FPGA can play a very important role in energy and renewable energy systems for control, monitoring, supervision, etc In this paper, the software as well as the implementation of intelligent predictors for solar irradiation on reconfigurable FPGA is described FPGA technology was employed due to its development, flexibility and low cost An experimental dataset of air temperature, solar irradiation, relative humidity and sunshine duration in a specific area is used; this database has been collected from 1998 to 2002 at Al-Madinah (Saudi Arabia) Initially, a MultiLayer Perceptron (MLP) is trained by using a set of 1460 patterns and then a set of 365 patterns are used for testing and validating the MLP-predictor Six MLP-predictors (configurations) are proposed and developed by varying the MLP inputs data, while the output is always the global solar irradiation for different configurations [[email protected]?(t,T,S,RH),[email protected]?(t,T,S),[email protected]?(t,T,RH),[email protected]?(t,S,RH)[email protected]?(t,T)[email protected]?(t,S)] Subsequently, the different MLP-predictors developed are written and simulated under the Very High Speed Integrated Circuit Hardware Description Language (VHDL) and ModelSim(R) The best designed architecture for different MLP-predictors is then implemented under the Xilinx(R) Virtex-II FPGA (XC2v1000) The developed hardware devices permit the prediction of global solar irradiation using available air temperature, relative humidity and sunshine duration; therefore, the designed configurations are very suitable especially in areas, where there are no instruments for measuring the solar irradiation data

Soft Computing in Green and Renewable Energy Systems

Abstract: Soft Computing in Green and Renewable Energy Systems provides a practical introduction to the application of soft computing techniques and hybrid intelligent systems for designing, modeling, characterizing, optimizing, forecasting, and performance prediction of green and renewable energy systems. Research is proceeding at jet speed on renewable energy (energy derived from natural resources such as sunlight, wind, tides, rain, geothermal heat, biomass, hydrogen, etc.) as policy makers, researchers, economists, and world agencies have joined forces in finding alternative sustainable energy solutions to current critical environmental, economic, and social issues. The innovative models, environmentally benign processes, data analytics, etc. employed in renewable energy systems are computationally-intensive, non-linear and complex as well as involve a high degree of uncertainty. Soft computing technologies, such as fuzzy sets and systems, neural science and systems, evolutionary algorithms and genetic programming, and machine learning, are ideal in handling the noise, imprecision, and uncertainty in the data, and yet achieve robust, low-cost solutions. As a result, intelligent and soft computing paradigms are finding increasing applications in the study of renewable energy systems. Researchers, practitioners, undergraduate and graduate students engaged in the study of renewable energy systems will find this book very useful.

Application of Artificial Neural Networks for the Prediction of a 20-kWp Grid-Connected Photovoltaic Plant Power Output

Abstract: Due to various seasonal, hourly and daily changes in climate, it is relatively difficult to find a suitable analytic model for predicting the output power of Grid-Connected Photovoltaic (GCPV) plants. In this chapter, a simplified artificial neural network configuration is used for estimating the power produced by a 20kWp GCPV plant installed at Trieste, Italy. A database of experimentally measured climate (irradiance and air temperature) and electrical data (power delivered to the grid) for nine months is used. Four Multilayer-perceptron (MLP) models have been investigated in order to estimate the energy produced by the GCPV plant in question. The best MLP model has as inputs the solar irradiance and module temperature. The results show that good effectiveness is obtained between the measured and predicted power produced by the 20kWp GCPV plant. The developed model has been compared with different existing regression polynomial models in order to show its effectiveness. Three performance parameters that define the overall system performance with respect to the energy production, solar resource, and overall effect of system losses are the final PV system yield, reference yield and performance ratio.

Concentrating Solar Power Plants for Electricity and Desalinated Water Production

Abstract: Electricity and water are two commodities which are usually both required in arid countries having a high solar insolation. A number of technologies exists for both systems, which are briefly reviewed in this paper. Among the most matured and suitable concentrated solar power (CSP) plants for electricity generation are the solar tower (ST) and the parabolic trough collector (PTC) systems, whereas for desalination these are the multiple effects distillation (MED) type evaporator and the reverse osmosis (RO). The paper shows also the possibilities that exist and the ways that these technologies can be combined in order to produce simultaneously electricity and water. The equipment required to be used for these systems (steam cycle components, MED or RO) is usually very expensive therefore, the system is required to operate continuously without complete shut down during the night. Such a system would be very suitable for arid countries, which due to the water shortage problem they face, locate power plants in coastal areas in order to use the seawater for the cooling needs of the steam cycle system (condenser). Therefore, in this case it would be comparatively easy to combine the power system with desalination as the resource for such a system, i.e., seawater would be readily available.

Design and simulation of a PV and a PV-Wind standalone energy system: A case study for a household application in Nicosia, Cyprus

Abstract: In this work the design and simulation of two stan d-alone renewable energy sources (RES) based systems for application in a household in Cyprus is presented. More specifically, the household is loc ated in Nicosia and is used as the residence of a typical C ypriot family for which a baseline scenario of ener gy consumption is specified in order to define the ann ual load profile of the house. The first system is based on photovoltaic (PV) modules for the generation of ele ctricity by harvesting the very high solar potentia l of Cyprus while the second one is a hybrid system combining P Vs with a domestic wind turbine in order to take ad vantage of the wind potential especially during winter. Sin ce both systems are stand alone the energy produced is stored in a battery bank. The software used for the modeli ng and simulation processes is TRNSYS. A comparison of the two systems in terms of both technical and econ omical aspects is presented in this study where it is concluded that the wind potential of the specific l ocation of the house, which generally applies on th e entire island, cannot substitute and compete in any way wi th the very high solar potential.

Soft Computing in Absorption Cooling Systems

Abstract: Absorption cooling systems make sense in many applications for process water cooling. Instead of mechanically compressing a refrigerant gas, as in the conventional vapor compression process, absorption cooling uses a thermo-chemical process. Two different fluids are used, a refrigerant and an absorbent. Heat directly from natural gas combustion, solar energy, waste-heat source or indirectly from a boiler, drives the process.

Investigation and determination of the geothermal parameters of the ground in cyprus for the exploitation of geothermal energy and the impact of the results in the design of the geothermal systems.

Abstract: The Energy Service of the Ministry of Commerce, Industry and Tourism has the overall responsibility for Energy matters in Cyprus and specifically for preparing and implementing programmes for energy conservation, the promotion of renewable energy sources (RES) and the development of technologies for the utilization of RES. The Government of Cyprus being aware of the benefits of geothermal energy and in order to increase the share of energy from renewable sources consumed in heating and cooling in 2020, promotes the geothermal energy systems through a Scheme that provides financial incentives for the utilization of RES for heating and cooling. However, the lack of valid data for the ground thermal properties in Cyprus was one of the main obstacles for the design of efficient geothermal systems, the implementation of the Schemes in the field of geothermal energy and the calculation of the share of energy from renewable sources for heating and cooling according to the methodology defined by the E.U in the directive 2009/28/EC. In an effort to identify suitable energy efficient systems for heating and cooling of buildings and the correct calculations of their contribution to the national targets, the Energy Service participated in a project founded by the Research Promotion Foundation of Cyprus to investigate and determine the geothermal parameters of the ground of Cyprus at six representative sites in Cyprus, for use in the design of ground heat exchanger applications and ground thermal storage. The paper presents the importance of the Isothermal map that helps consultants to design efficiently geothermal energy systems, calculate effectively heat losses of buildings to the ground and design the thermal energy storage equipment. The importance's of the results are analyzed by national authorities' experts' point of view for evaluating geothermal applications bridging in this way the gap between technical output and commercial reality.