A Numerical Model for Off-Design Performance Calculation of Parabolic Trough Based Solar Power Plants

2010 ◽  
Author(s):  
Andrea Giostri ◽  
Claudio Saccilotto ◽  
Paolo Silva ◽  
Ennio Macchi ◽  
Giampaolo Manzolini
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Design Calculation ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
Design Algorithm ◽  
Energy Balances ◽  
Steam Cycle

The paper deals with the development and testing of an innovative code for the performance prediction of solar trough based CSP plants in off-design conditions. The code is developed in MS Visual Basic 6.0 with Excel as user interface. The proposed code originates from a previously presented algorithm for on-design sizing and cost estimation of the solar field lay-out, as well as of the main components of the plant, including connecting piping and the steam cycle. Off-design calculation starts from data obtained through the on-design algorithm and considers steady-state situations. Both models are implemented in the same software, named PATTO (PArabolic Trough Thermodynamic Optimization), which is very flexible: the optical-thermal model of collectors can simulate different kinds of parabolic trough systems in commerce, including a combination of various mirrors, receivers and supports. The code is also flexible in terms of working fluid, temperature and pressure range, and can also simulate direct steam generation plants (DSG). Regarding the power block, a conventional steam cycle with super-heater, eventually a re-heater section, and up to seven regenerative bleedings is adopted. The off-design model calculates thermal performance of collectors taking into account proper correlations for convective heat transfer coefficients, considering also boiling regime in DSG configurations. Solar plant heat and mass balances and performances at off-design conditions are estimated by accounting for the constraints imposed by the available heat transfer areas in heat exchangers and condenser, as well as the characteristic curve of the steam turbine. The numerical model can be used for a single calculation in a specific off-design condition, as well as for a whole year estimation of energy balances with an hourly resolution. The model is tested towards real applications and reference values found in literature; in particular, focusing on SEGS VI plant in the USA and SAM® code. Annual energy balances with ambient condition taken from TMY3 database are obtained, showing good accuracy of predicted performances. The code potentiality in the design process reveals twofold: it can be used for plant optimization in feasibility studies; moreover it is useful to find the best control strategy of a plant, especially the mass flow of heat transfer fluid in each operating condition.

A Numerical Model for Off-Design Performance Prediction of Parabolic Trough Based Solar Power Plants

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Giampaolo Manzolini ◽  
Andrea Giostri ◽  
Claudio Saccilotto ◽  
Paolo Silva ◽  
Ennio Macchi
Keyword(s):  
Numerical Model ◽  
Performance Prediction ◽  
Power Plants ◽  
Solar Power ◽  
Operating Conditions ◽  
Working Fluid ◽  
Design Calculation ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
Design Algorithm

This paper deals with the development and testing of an innovative code for the performance prediction of solar trough based concentrated solar power (CSP) plants in off-design conditions. Off-design calculation starts from data obtained through the on-design algorithm and considers steady-state situations. The model is implemented in flexible software, named patto (parabolic trough thermodynamic optimization): the optical-thermal collector model can simulate different types of parabolic trough systems in commerce, including a combination of various mirrors, receivers and supports. The code is also flexible in terms of working fluid, temperature and pressure range, and can also simulate direct steam generation (DSG) plants. Solar plant heat and mass balances and performance at off-design conditions are estimated by accounting for the constraints imposed by the available heat transfer areas in heat exchangers, as well as by the characteristic curve of the steam turbine. The numerical model can be used either for single calculation in a specific off-design condition or for complete year simulation, by generating energy balances with an hourly resolution. The model is tested with a view to real applications and reference values found in literature: results show an overall yearly efficiency of 14.8% versus the 15% encountered in the Nevada Solar One. Moreover, the capacity factor is 25%, i.e., equal to the value predicted by sam®. Code potential in the design process reveals two different aspects: it can be used not only to optimize plant components and layout in feasibility studies but also to select the best control strategy during individual operating conditions.

Development of an Innovative Code for the Design of Different Parabolic Trough Solar Fields

2009 ◽  
Author(s):  
Ennio Macchi ◽  
Giampaolo Manzolini ◽  
Paolo Silva
Keyword(s):  
Solar Energy ◽  
Energy Demand ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
High Solar Radiation ◽  
Power Block ◽  
The Usa ◽  
Solar Field ◽  
Steam Cycle

The role of renewable energies and in particular solar energy could be fundamental in future scenarios of worldwide increase of energy demand: thermodynamic solar energy can play an important role in country with high solar radiation. This paper discusses the development and testing of an innovative code for the prediction of thermodynamic performances at nominal conditions and the estimation of costs of the whole plant, for different parabolic trough solar fields. The code allows a preliminary design of the solar field lay-out, the sizing of the main components of the plant and the optimization of the steam cycle. The code, named PATTO (PArabolic Trough Thermodynamic Optimization), allows to separately calculate the thermal efficiency of (i) parabolic trough systems in commerce as well as (ii) combination of components of various commercial systems, in order to exploit different technology solutions: combination of mirrors, receivers and supports. Using the selected parabolic troughs, the plant configuration is then completed by connecting pipes, heat exchangers, the steam cycle, and storage tanks. The code is also flexible in terms of working fluid, temperature and pressure range. Regarding the power block, a conventional steam cycle with super-heater and re-heater sections and up to seven regenerative bleedings is adopted. It is possible to use also simpler configuration as without re-heater or with less regenerative bleedings. Moreover, thanks to simple or sophisticated economic correlations depending on available data, the code calculates the overall investment cost for the considered solar field and the power block. The code performs steady state analysis at nominal conditions, while future developments are planned regarding part load analysis and transient simulations. The model is tested towards real applications and reference values found in literature; in particular, focusing on SEGS VI plant in the USA. Detailed results showing code potentiality, are presented in terms of solar field and power block energy balances, plant auxiliaries, piping and economic analysis.

A 3-D Model Simulation of High Temperature Solar Cavity Receiver

2017 ◽  
Author(s):  
Huayi Feng ◽  
Yanping Zhang ◽  
Chongzhe Zou
Keyword(s):  
Heat Transfer ◽  
Radiation Intensity ◽  
Large Scale ◽  
Model Simulation ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Fluid Temperature ◽  
Heat Transfer Efficiency ◽  
Direct Normal Irradiance

In this paper, a 3-D numerical model is proposed to investigate the capability of generating high operating temperature for a modified solar cavity receiver in large-scale dish Stirling system. The proposed model aims to evaluate the influence of radiation intensity on the cavity receiver performance. The properties of the heat transfer fluid in the pipe and heat transfer losses of the receiver are investigated by varying the direct normal irradiance from 400W/m2 to 1000W/m2. The temperature of heat transfer fluid, as well as the effect of radiation intensity on the heat transfer losses have been critically presented and discussed. The simulation results reveal that the heat transfer fluid temperature and thermal efficiency of the receiver are significantly influenced by different radiation flux. With the increase of radiation intensity, the efficiency of the receiver will firstly increase, then drops after reaching the highest point. The outlet working fluid temperature of the pipe will be increased consistently. The results of the simulations show that the designed cylindrical receiver used in dish Stirling system is capable to achieve the targeted outlet temperature and heat transfer efficiency, with an acceptable pressure drop.

The effect of heat loss on the performance of a solar-driven heat engine

2009 ◽  
Vol 223 (7) ◽  
pp. 1615-1621
Author(s):  
O S Sogut ◽  
A Durmayaz
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Loss ◽  
Transfer Process ◽  
Rankine Cycle ◽  
Heat Transfer Process ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
Thermal Reservoir

An optimal performance analysis of a parabolic-trough direct-steam-generation solar-driven Rankine cycle power plant at maximum power (MP) and under maximum power density (MPD) conditions is performed numerically to investigate the effects of heat loss from the heat source and working fluid. In this study, the ideal Rankine cycle of the solar-driven power plant is modified into an equivalent Carnot-like cycle with a finite-rate heat transfer. The main assumptions of this study include that: (a) the parabolic collector is the thermal reservoir at a high temperature, (b) the heat transfer process between the collector and the working fluid is through either radiation and convection simultaneously or radiation only, and (c) the heat transfer process from the working fluid to the low-temperature thermal reservoir is convection dominated. Comprehensive discussions on the effect of heat loss during the heat transfer process from the hot thermal reservoir to the working fluid in the parabolic-trough solar collector are provided. The major results of this study can be summarized as follows: (a) the working fluid temperature at the hot-side heat exchanger decreases remarkably whereas the working fluid temperature at the cold-side heat exchanger does not show any significant change with increasing heat loss, (b) the MP, MPD, and thermal efficiencies decrease with increasing heat loss, and (c) the effect of heat loss on the decrease of thermal efficiency increases when convection is the dominant heat transfer mode at the hot-side heat exchanger.

Integration Between Gas Turbines and Concentrated Parabolic Trough Solar Power Plants

2012 ◽  
Author(s):  
Roberto Cipollone ◽  
Andrea Cinocca
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Solar Power ◽  
Electrical Energy ◽  
Energy Generation ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
Solar Power Plants

Parabolic Trough Concentrating Solar Power plants (PT-CSP) technology has the capability to give, in the mean future, a strong contribution to the electrical energy generation. In the long term, inside a new framework of relationships concerning energy production, many aspects would justify a significant contribution to the phase out of fossil sources use. The paper concerns about a theoretical modeling aimed at improving the performances of CSP which approaches the energy generation from a system point of view. Thanks to it, the attention is focused on the use of gases as heat transfer fluid inside the solar receivers and on the possibility to use it as working fluid inside unconventional gas turbines for a direct electricity generation. The success of this concept is related to the possibility to increase the fluid temperature above the actual maximum values: this requires that the receiver efficiency has to be recalculated as a function of the fluid temperature. An innovative integration between the solar field and the gas turbine power plant, modified in order to maximize thermal energy conversion, is discussed.

scholarly journals EXPERIMENTAL INVESTIGATIONS OF A SOLAR PARABOLIC TROUGH COLLECTOR FOR CIRCULAR AND ELLIPTICAL ABSORBER

2017 ◽  
Vol 13 (7) ◽  
pp. 6348-6355
Author(s):  
Suresh. R ◽  
Subash Chandra Bose.R ◽  
Arumugam. K ◽  
Anbazhagan. R ◽  
Sathiyamoorthy. V ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Energy Demand ◽  
Transfer Rate ◽  
Working Fluid ◽  
Experimental Investigations ◽  
Outlet Temperature ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
Parabolic Trough Collector

             Solar parabolic trough collector is one of the most efficient and an effective technology to deal with environmental pollution and it has gained much attention due to the recent energy demand. The solar parabolic trough collector is one of the most promising techniques for absorbing the heat from the sun. This heat is utilized for electricity generation and other industrial heating applications. This paper describes the theoretical and experimental assessment of performance of the circular and elliptical absorbers used in solar parabolic trough collector. The absorber tube of parabolic trough collector is used to transfer the heat to the working fluid. The working fluid considered over here is water which is the best operating medium in direct steam generation. The mass flow rate of water in absorber tube is analyzed in 3 stages as 0.016, 0.024 and 0.030 kg/s respectively. The experimental test is done in Chennai-Tamilnadu, Southern part of India which experiences a superior temperature throughout the year. The experiment is conducted for the period of one year from June 2015 to May 2016. The performance improvement focuses on collector efficiency, useful heat transfer rate, outlet temperature of working fluid, temperature gradient, overall heat transfer rate and the thermal losses.

scholarly journals Nonlinear Adaptive Control of Heat Transfer Fluid Temperature in a Parabolic Trough Solar Power Plant

Energies ◽  
2017 ◽  
Vol 10 (8) ◽  
pp. 1155 ◽  
Author(s):  
Antonio Nevado Reviriego ◽  
Félix Hernández-del-Olmo ◽  
Lourdes Álvarez-Barcia
Keyword(s):  
Heat Transfer ◽  
Adaptive Control ◽  
Power Plant ◽  
Solar Power ◽  
Heat Transfer Fluid ◽  
Fluid Temperature ◽  
Solar Power Plant ◽  
Parabolic Trough ◽  
Nonlinear Adaptive Control

scholarly journals Molten Nitrate Salt Development for Thermal Energy Storage in Parabolic Trough Solar Power Systems

2008 ◽  
Author(s):  
Robert W. Bradshaw ◽  
Nathan P. Siegel
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Molten Salt ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Parabolic Trough ◽  
Heat Transfer Fluids

Thermal energy storage can enhance the utility of parabolic trough solar power plants by providing the ability to match electrical output to peak demand periods. An important component of thermal energy storage system optimization is selecting the working fluid used as the storage media and/or heat transfer fluid. Large quantities of the working fluid are required for power plants at the scale of 100-MW, so maximizing heat transfer fluid performance while minimizing material cost is important. This paper reports recent developments of multi-component molten salt formulations consisting of common alkali nitrate and alkaline earth nitrate salts that have advantageous properties for applications as heat transfer fluids in parabolic trough systems. A primary disadvantage of molten salt heat transfer fluids is relatively high freeze-onset temperature compared to organic heat transfer oil. Experimental results are reported for formulations of inorganic molten salt mixtures that display freeze-onset temperatures below 100°C. In addition to phase-change behavior, several properties of these molten salts that significantly affect their suitability as thermal energy storage fluids were evaluated, including chemical stability and viscosity. These alternative molten salts have demonstrated chemical stability in the presence of air up to approximately 500°C in laboratory testing and display chemical equilibrium behavior similar to Solar Salt. The capability to operate at temperatures up to 500°C may allow an increase in maximum temperature operating capability vs. organic fluids in existing trough systems and will enable increased power cycle efficiency. Experimental measurements of viscosity were performed from near the freeze-onset temperature to about 200°C. Viscosities can exceed 100 cP at the lowest temperature but are less than 10 cP in the primary temperature range at which the mixtures would be used in a thermal energy storage system. Quantitative cost figures of constituent salts and blends are not currently available, although, these molten salt mixtures are expected to be inexpensive compared to synthetic organic heat transfer fluids. Experiments are in progress to confirm that the corrosion behavior of readily available alloys is satisfactory for long-term use.

scholarly journals Thermal performance and design parameters investigation of a novel cavity receiver unit for parabolic trough concentrator

2020 ◽  
Author(s):  
Khaled Mohamad
Keyword(s):  
Heat Transfer ◽  
Radiant Energy ◽  
Theoretical Background ◽  
Heat Transfer Fluid ◽  
Design Parameters ◽  
Fluid Temperature ◽  
Parabolic Trough ◽  
Simulation Code ◽  
Chi Squared ◽  
Receiver Unit

In this paper, we discuss an improved concept for a cavity receiver unit for Solar Parabolic Trough Collectors (PTC) with the application of hot mirror coating (HMC) on a cavity aperture. This design aims to lessen radiant energy losses while operating at higher temperatures by incorporating a variety of optically active layers. We present the theoretical background, which we derived in previous work, and the resulting implementation in a simulation code. We next discuss the layout and results of an experiment, which allowed us to make contact with the simulation with minor adjustments It was seen that the correspondence between the experiment and simulation results was encouragingly close (Chi-squared p > 0.8 and p > 0.95), and we proceeded to investigate simulations of different receiver designs. Simulated outcomes for the temperature of the heat transfer fluid, temperature maps, and efficiencies are presented. Our proposal indicates temperature-related benefits when compared to other popular designs in terms of the heat transfer fluid temperature and efficiency.

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