Exergetic analysis of a solar thermal power system (original) (raw)
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Thermodynamic performance evaluation of solar and other thermal power generation systems: A review
Renewable and Sustainable Energy Reviews, 2015
In this communication, detailed review of the solar thermal power plants based on the available solar concentrator systems like parabolic trough, parabolic dish, central tower, linear Fresnel reflector system are reported. The aim of the paper is to summarize overall research work being carried out worldwide on the thermodynamic performance evaluation of solar and other thermal power generation systems using different thermodynamic cycles. An attempt has also been made to assess as well as compare the energetic and exergetic performance of such thermal power generation systems. It has been observed that the efficiencies of the solar concentrator aided coal fired thermal power plant, and combined-cycle power plants are higher as compared to a solar alone thermal power plants. Furthermore, there is much scope in the areas of solar aided thermal power generation for further research with the aim of quantifying energy and exergy losses, and exergy destructions in the components of the solar thermal power generation systems.
Analysis of photovoltaic (PV) and photovoltaic/thermal (PV/T) systems using the exergy method
Energy and Buildings, 2013
In this paper, a simple pass photovoltaic-thermal air heater system with slats has been considered to study its electrical and exergy performance by theoretical and numerical analysis. The collector has been modeled in such a way that the absorber plate is totally covered by photovoltaic modules. The climatic data (solar irradiation, ambient temperature) of the Far Nord region of Cameroon have been used. Thin metallic strips called slats have been attached longitudinally at the bottom side of the absorber plate of the system. The first and second laws of thermodynamics have been applied to write the equations describing the functioning of the system. These equations have been solved by numerical computation using the gradient conjugate method. The influences of some operating parameters on the electrical and overall exergy efficiencies were investigated. It was found that (i) it is of great importance to use slats as an integral part of the absorber surface in order to achieve better efficiencies of single pass photovoltaic-thermal systems and (ii) the instantaneous overall electrical and overall exergy efficiencies of a simple pass hybrid (PV/T) solar air heater varies between 9-12% and 11,5-18,5% respectively.
Exergy analysis of solar energy applications
Renewable and Sustainable Energy Reviews, 2012
Solar energy is a clean, abundant and easily available renewable energy. Usage of solar energy in different kinds of systems provides scope for several studies on exergy analysis. In the present work, a comprehensive literature review has been carried out on exergy analysis of various solar energy systems. The systems considered under study are solar photovoltaic, solar heating devices, solar water desalination system, solar air conditioning and refrigerators, solar drying process and solar power generation. The summary of exergy analysis and exergetic efficiencies is presented along with the exergy destruction sources.
Exergetic Studies on Domestic and Industrial Solar Water Heaters
International Conference on Information Engineering, Management and Security 2014, 2014
For a Solar Water Heater ,solar energy coming from sun in the form of solar radiations in infinite amount, when these solar radiations falls on any absorbing surface, then they gets converted into the heat, this heat is used for heating the water. Present study based on exergy theory. Exergy analysis is conducted with an objective of providing methods to save cost and to increase the efficiency of solar water heater. The calculation of exergy losses is also done. To optimize and allocate losses in energy systems exergy analysis has been widely used. Exergy is the indication for loss of available energy due to the creation of entropy in irreversible thermal systems or thermodynamic processes. The exergy loss in a system or process component is decided by multiplying the absolute temperature of the surroundings by the entropy increase. Exergy is defined as a maximum useful work that can be done by a system interacting with an environment. In the design, simulation and performance evaluation of energy systems Exergy analysis has been widely used.
Steady state operation exergy‐based optimization for solar thermal collectors
Environmental progress & sustainable energy, 2019
In this investigation, exergy based optimization was carried out on two configurations of solar thermal collectors. A set of control sensors were utilized to control the performance of the system and monitor the design variables, i.e. inlet and outlet temperature of the solar fluid, ambient temperature, incident solar flux, and required mechanical and electrical work in the system. The fluid temperature was considered to vary in the range of 120-180 ºC with respect to technical and economic considerations. The collector surface area was considered 606 m 2 in both configurations and a medium solar incident was considered about 520 W/m 2. The maximum acceptable temperature difference is obtained as function of the input temperature. The technical limitation is plotted for both configurations of solar collectors. It was noticed that the exergy flow of simple evacuated tubes can reach the maximum value when the input temperature is greater than 115°C for an incident solar flow, from 250W/m² up to the limit of 950 W/m². Exergy analysis demonstrated
Exergy Analysis of Parabolic Trough Solar Receiver
Applied Thermal Engineering, 2014
h i g h l i g h t s g r a p h i c a l a b s t r a c t A comprehensive exergy balance of a parabolic trough is performed. The thermal and exergy efficiency showed an opposite trend. The highest exergy destruction takes place at the absorber. The highest exergy losses are due to optical errors.
Thermodynamic simulation of solar thermal system
The 9th International Conference "Environmental Engineering 2014", 2014
An article presents the thermodynamic simulation study of operating solar thermal collector system. The target of this study is to examine improvement possibilities of actual system by identifying avoidable exergy destruction. The simulation model was created in TRNSYS environment and is based on the real operating solar thermal collector system, installed in Building Energy and Microclimate Systems (BEMS) laboratory. Advanced thermodynamic analysis methods were used for the assessment of the system performance. Presented simulation based method helps to identify the avoidable and unavoidable exergy destruction parts of the component, operated on transient boundary conditions, in the system. The findings of this study reveal that the additional improvements of the system may create more irreversibility than the actual system in the analyzed case. Considering the non-linear behavior of the system, the complex assessment must be used to identify the rational parameters system components, in order to reach the lowest entropy production rate.
Renewable energy, Exergoeconomic, Cogeneration system, Solar power Increasing environmental pollutions and the expense of fossil fuels necessitates employment of efficient instruments and easily producible clean sources as abasic solution to this problem. Cogeneration systems are used for their high performance with a performance of approximately eighty-five percent Cogeneration production system with renewable energy source is the best solution to fuel suitable and high cost Amon all renewable energy sources, use of solar power is of interest. Solar power is the best choice because it's free and clean. This project illustrates the analyzed exergy and eregyeconomic simulations of solar hybrid cycle. Thermo economic and exergoeconomic analysis where used in this research, with exergoeconomic we can analyze cycle cost, payback period and exergy performance. Case study for this project was a building with 480 m² or square meters area in Zahedan, Iran. In this study, a small scale hybrid solar heating, cooling and power generation set-up including solar collector, screw expender auxiliary heater, adsorption chiller, etc., was proposed and extensively investigated.
Experiments on a solar-assisted heat pump and an exergy analysis of the system
Applied Thermal Engineering, 2002
In this work a experimental study of a solar assisted heat pump with direct expansion of the refrigerant within the solar collector, is presented. The maximum exergy efficiency, defined as the ratio of the outlet to the inlet exergy flow in every component of the heat pump cycle, is determined taking into account the typical parameters and performance coefficients. The results of this exergy analysis point out that the main source of irreversibility can be found in the evaporator of the heat pump (that is, the solar collector) emphasizing that incoming solar radiation is not used to full advantage in this piece of equipment. Ó