scholarly journals A Direct-Steam Linear Fresnel Performance Model for NREL’S System Advisor Model

2012 ◽  
Author(s):  
Michael J. Wagner ◽  
Guangdong Zhu
Keyword(s):  
Heat Loss ◽  
Mathematical Formulation ◽  
Model Performance ◽  
Performance Model ◽  
Electricity Production ◽  
Steam Generation ◽  
Time Step ◽  
Wide Range ◽  
Direct Steam ◽  
Solar Field

This paper presents the technical formulation and demonstrated model performance results of a new direct-steam-generation (DSG) model in NREL’s System Advisor Model (SAM). The model predicts the annual electricity production of a wide range of system configurations within the DSG Linear Fresnel technology by modeling hourly performance of the plant in detail. The quasi-steady-state formulation allows users to investigate energy and mass flows, operating temperatures, and pressure drops for geometries and solar field configurations of interest. The model includes tools for heat loss calculation using either empirical polynomial heat loss curves as a function of steam temperature, ambient temperature, and wind velocity, or a detailed evacuated tube receiver heat loss model. Thermal losses are evaluated using a computationally efficient nodal approach, where the solar field and headers are discretized into multiple nodes where heat losses, thermal inertia, steam conditions (including pressure, temperature, enthalpy, etc.) are individually evaluated during each time step of the simulation. This paper discusses the mathematical formulation for the solar field model and describes how the solar field is integrated with the other subsystem models, including the power cycle and optional auxiliary fossil system. Model results are also presented to demonstrate plant behavior in the various operating modes.

scholarly journals A Direct Steam Generation Solar Power Plant With Integrated Thermal Storage

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Jürgen Birnbaum ◽  
Markus Eck ◽  
Markus Fichtner ◽  
Tobias Hirsch ◽  
Dorothea Lehmann ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Storage System ◽  
Thermal Storage ◽  
Market Potential ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Power Block ◽  
Direct Steam ◽  
Solar Field ◽  
Operating Points

For the future market potential of parabolic trough power plants with direct steam generation (DSG), it is beneficial to integrate a thermal storage system. Heat storage media based on phase change materials offer heat transfer at constant temperatures needed for the evaporation process. Different options for a plant layout are presented and discussed. The interactions between the three subsystems—solar field, power block, and thermal storage—are analyzed, and boundary conditions arising from the thermal storage system are identified. Compared with a system without storage the number of operating points increases significantly since different combinations of storage charge and discharge operations go along with a varying power output of the solar field. It is shown that the large number of theoretical operating points can be reduced to a subset with practical relevance. Depending on the live steam parameters a reheat is necessary within the power block. Compared with parabolic trough fields with a single phase heat transfer medium such as oil, a special heat exchanger configuration is needed for a DSG plant. Different alternatives based on available technologies are presented and evaluated.

Experimental Investigation of Direct Steam Generation Dynamics in Solar Fresnel Collectors

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Marwan Mokhtar ◽  
Christian Zahler ◽  
Robert Stieglitz
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Steam Generator ◽  
Experimental Results ◽  
Steam Generation ◽  
Thermal Plant ◽  
Direct Steam ◽  
Solar Field ◽  
Economic Considerations

Abstract Direct steam generation (DSG) is a technology used to produce steam from a solar concentrated thermal plant directly in the solar field without the use of an intermediate steam generator. This technology is attractive due to economic considerations but is technically challenging. In this brief, the results of an experimental study of DSG dynamics are presented. The study provides a detailed description of these effects supported by experimental results and suggests ways to coping with them.

Study of Different Configurations of ISCC Parabolic Trough

2014 ◽  
Author(s):  
Dolores Duran ◽  
Rafael Almanza ◽  
Ivan Martínez
Keyword(s):  
High Pressure ◽  
Power Plants ◽  
Low Pressure ◽  
Pressure Level ◽  
Combined Cycle ◽  
Design Parameters ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Direct Steam ◽  
Solar Field

This work shows the study of different configurations of integrated solar combined cycle (ISCC) parabolic-trough power plant with Direct Steam Generation (DSG). This paper is a sequel of previous works (Duran), but in this case six different configurations are analyzed: two pressure level without reheater (2P), 2P considering the solar field the high pressure economizer of the heat recovery steam generator, 2P considering the solar field the low pressure superheater, two pressure level with reheater (2PR), 2PR considering the solar field the low pressure superheater, 2PR considering the solar field the high pressure economizer. The main objective is to achieve the thermoeconomic optimization (based on Thermodynamic 1st. Law) of the HRSG including the solar field, to determine the optimal design parameters of both systems. It is applied a genetic algorithm (GA) methodology employed in previous works for the optimization of combined cycle power plants. Also, a sensitivity analysis with respect to the variation of solar radiation is done for the configurations that yield better results. As a result it would be obtained the optimal parameters of the HRSG and the optimal solar energy contribution for the configurations analyzed.

Performance Analysis of Direct Steam Generation-Central Receiver Systems

2012 ◽  
Author(s):  
Javier Sanz-Bermejo ◽  
José Gonzalez-Aguilar ◽  
Manuel Romero
Keyword(s):  
Power Plants ◽  
Superheated Steam ◽  
System Analysis ◽  
Live Steam ◽  
Saturated Steam ◽  
Steam Generation ◽  
Central Receiver ◽  
Power Block ◽  
Direct Steam ◽  
Solar Field

This work presents a comparative study between direct steam generation central receiver solar power plants working at live steam conditions similar to those found in commercial plants. PS10 and PS20 by Abengoa Solar use a single-receiver, producing saturated steam, whereas Sierra SunTower by e-Solar and Ivanpah Solar Electric Generating System (ISEGS) by BrightSource use dual-receiver technology producing superheated steam. The system analysis includes individual studies for each subsystem: solar field, receiver and Rankine power block; as well as the overall-analysis of a 66.7 MWth plant. PS10 working conditions were analysed with and without intermediate reheat step. It was assumed that Sierra SunTower-configuration has non-reheat turbine and Ivanpah-cycle includes an intermediate reheat step. The reheat process in PS10 configuration was performed using a fraction of live steam coming from the receiver; while for Ivanpah-configuration exhaust steam from high pressure turbine stage was sent back to the superheated steam section of the dual-receiver. These concepts make possible to avoid hybridisation and assure special regimes (such as Spanish feed-in tariff). The analysis of the heliostat field for dual-receiver concepts reveals that the aiming strategy on the absorbers has not relevant influence on optical performances. However, receiver efficiency decreased from 91.9%, working with saturated steam, to 87.86–84.14% working with superheated steam related to operating temperatures and heat exchange surface area. This study reveals that the improvement achieved in the power block under Ivanpah configuration was able to compensate higher thermal losses at the receiver, increasing net power production by 25.5% compared with saturated steam conditions.

Hydrodynamic Analysis of Direct Steam Generation Solar Collectors

1999 ◽  
Vol 122 (1) ◽  
pp. 14-22 ◽  
Author(s):  
S. D. Odeh ◽  
M. Behnia ◽  
G. L. Morrison
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Operating Conditions ◽  
Tube Length ◽  
Solar Collectors ◽  
Flow Conditions ◽  
Steam Generation ◽  
Frictional Pressure Drop ◽  
Wide Range ◽  
Direct Steam

Direct steam generation collectors are considered with the aim to improve the performance of a parabolic trough collector leading to a reduction of operating costs of solar electric generation systems. In this study a hydrodynamic steady state model is developed and linked with a thermal model to optimize the performance of once-through direct steam generation solar collectors. The hydrodynamic model includes flow pattern classification and a pressure drop model. Flow pattern maps for typical DSG collectors with horizontal and inclined absorber tubes are generated to investigate the variation of flow conditions with radiation level, tube diameter, tube length and flow rate. Two-phase flow frictional pressure drop correlations for the range of operating conditions in a DSG collector are selected from the wide range of published correlations by comparison with experimental data for typical steam-water flow conditions in a DSG collector. Pressure drop is calculated for different operating conditions for both horizontal and inclined solar absorber tubes. Alternative operational strategies are evaluated to achieve optimum performance of a direct steam generation collector at different radiation levels. [S0199-6231(00)00101-5]

scholarly journals Performance Comparison of Different Models of Direct Steam Solar Plants Based on Parabolic Trough Technology by Simulink MATLAB

2018 ◽  
Vol 225 ◽  
pp. 02007
Author(s):  
Sanan T. Mohammad ◽  
Hussain H. Al-Kayiem ◽  
Syed I.U. Gilani ◽  
Ayad K. Khlief
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Electricity Production ◽  
Maximum Temperature ◽  
Steam Generation ◽  
Steam Quality ◽  
Comparison Results ◽  
Direct Steam

Solar thermal plants are among the most promising technologies to replace fossil fuel standing applications. Among solar thermal technologies, parabolic troughs are considered as the most mature application in the market. The objective of this paper is to elaborate on comparison results of three different topologies of solar parabolic troughs field, in terms of performances and energy production. Thermolib software was used to perform the proposed power plants simulation with direct steam generation. Applying the proposed models. These models simulate the behaviour of both the solar field and the power block of a 1.2 kW solar thermal power plant. The results of this analysis demonstrating that the use of steam separator and superheater in a stand-alone solar power plant model is more advantageous in terms of steam temperature, steam quality and net electricity production in comparison to other models. The optimum topology showed that the maximum temperature of steam outlet reach 221°C, steam quality reach 1 and efficiency of power plant around 19.6% for model 3.

scholarly journals Energy and Exergy (2E) Analysis of an Optimized Solar Field of Linear Fresnel Reflectors for a Conceptual Direct Steam Generation Power Plant

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4234
Author(s):  
Eduardo González-Mora ◽  
Ma. Dolores Durán-García
Keyword(s):  
Power Plant ◽  
Solar Irradiance ◽  
Power Plants ◽  
Solar Power ◽  
Thermal Power ◽  
Steam Generation ◽  
Promising Alternative ◽  
Energy And Exergy ◽  
Direct Steam ◽  
Solar Field

Direct steam generation is a promising alternative to conventional heat transfer fluids for solar thermal power plants using linear concentrators because water and steam do not have thermal and chemical stability problems. The novelty of this study, an energy and exergy (2E) analysis, was that it was performed on several configurations of a conceptual direct steam generation solar power plant with optimized Fresnel reflectors in Agua Prieta, Mexico coupled with a regenerative steam Rankine power cycle to quantify their efficiency and establish a reference for future implementation of this technology in concentrated solar power plants in Mexico. The thermal model was assumed to be a 1D steady-state flow and validated against results in the literature. It was then applied directly to a case study to determine the size of the solar field. The design point was the lowest solar irradiance day, and evaluating the solar multiple with the highest solar irradiance, taking care not to oversize the solar field, as suggested for solar plants without energy storage. Comparing the performance of the optimized Fresnel field against the FRESDEMO field of Plataforma Solar de Almería, a considerable decrease in the length of the loop has been demonstrated with a low reduction in thermal efficiency.

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