Modeling and Design of Direct Solar Steam Generating Collector Fields

Solar Energy ◽  
2004 ◽  
Author(s):  
M. Eck ◽  
W.-D. Steinmann
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Design Procedure ◽  
Design Tool ◽  
Solar Thermal ◽  
Test Facility ◽  
Process Conditions ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Critical Process

The direct steam generation (DSG) is an attractive option regarding the economic improvement of parabolic trough technology for solar thermal electricity generation in the multi megawatt range. According to [1] and [2] a 10% reduction of the LEC is expected compared to conventional SEGS like parabolic trough power plants. The European DISS project has proven the feasibility of the DSG process under real solar conditions at pressures up to 100 bar and temperatures up to 400°C in more than 4000 operation hours [3]. In a next step the detailed engineering for a pre-commercial DSG solar thermal power plant will be performed. This detailed engineering of the collector field requires the consideration of the occurring thermohydraulic phenomena and their influence on the stability of the absorber tubes. A design tool has been developed at DLR calculating all relevant process parameters including pressure drop, temperature field and stress in the absorber tubes. The models implemented in this design tool have been validated in detail at the DISS test facility under real DSG conditions for pressures between 30 and 100 bar and inner diameters between 50 and 85 mm. The models have been implemented into a MATLAB® program to allow for a first quick determination of critical process conditions. Once critical process conditions have been identified the FEM package ANSYS® is used for a detailed investigation. This article summarises the models used and shows the design procedure for a DSG collector field. The design program has proven to be a reliable tool for the detailed design of DSG collector fields.

Comparison of Two Linear Collectors in Solar Thermal Plants: Parabolic Trough vs Fresnel

2011 ◽  
Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Heat Transfer Fluid ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Research Activity ◽  
Optical Efficiency ◽  
Synthetic Oil ◽  
Yearly Average

Parabolic trough can be considered the state of the art for solar thermal power plants thanks to the almost 30 years experience gained in SEGS and, recently, Nevada Solar One plants in US and Andasol plants in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, since several years research activity has been trying to develop new solutions with the aim of cost reduction. This work compares commercial Fresnel technology with conventional parabolic trough plant based on synthetic oil as heat transfer fluid at nominal conditions and evaluates yearly average performances. In both technologies, no thermal storage system is considered. In addition, for Fresnel, a Direct Steam Generation (DSG) case is investigated. Performances are calculated by a commercial code, Thermoflex®, with dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology have an optical efficiency of 67% which is lower than 75% of parabolic trough. Calculated net electric efficiency is about 19.25%, while parabolic trough technology achieves 23.6%. In off-design conditions, the gap between Fresnel and parabolic trough increases because the former is significantly affected by high radiation incident angles. The calculated sun-to-electric annual average efficiency for Fresnel plant is 10.2%, consequence of the average optical efficiency of 38.8%, while parabolic trough achieve an overall efficiency of 16%, with an optical one of 52.7%. An additional case with Fresnel collector and synthetic oil outlines differences among investigated cases. Finally, because part of performance difference between PT and Fresnel is simple due to different definitions, additional indexes are introduced in order to make a consistent comparison.

The DISS Project: Direct Steam Generation in Parabolic Trough Systems. Operation and Maintenance Experience and Update on Project Status

2002 ◽  
Vol 124 (2) ◽  
pp. 126-133 ◽  
Author(s):  
Eduardo Zarza ◽  
Loreto Valenzuela ◽  
Javier Leo´n ◽  
H.-Dieter Weyers ◽  
Martin Eickhoff ◽  
...  
Keyword(s):  
Power Plants ◽  
New Technology ◽  
Thermal Power ◽  
Test Facility ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Solar Thermal Power ◽  
Operation And Maintenance ◽  
Direct Steam ◽  
New Generation

The DISS (DIrect Solar Steam) project is a complete R+TD program aimed at developing a new generation of solar thermal power plants with direct steam generation (DSG) in the absorber tubes of parabolic trough collectors. During the first phase of the project (1996-1998), a life-size test facility was implemented at the Plataforma Solar de Almerı´a (PSA) to investigate the basic DSG processes under real solar conditions and evaluate the unanswered technical questions concerning this new technology. This paper updates DISS project status and explains O&M-related experience (e.g., main problems faced and solutions applied) with the PSA DISS test facility since January 1999.

Comparison of Two Linear Collectors in Solar Thermal Plants: Parabolic Trough Versus Fresnel

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
A. Giostri ◽  
M. Binotti ◽  
P. Silva ◽  
E. Macchi ◽  
G. Manzolini
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
The United States ◽  
Solar Thermal ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Annual Average ◽  
Optical Efficiency ◽  
Levelized Cost Of Electricity ◽  
Synthetic Oil

Parabolic trough (PT) technology can be considered the state of the art for solar thermal power plants thanks to the almost 30 yr of experience gained in SEGS and, recently, Nevada Solar One plants in the United States and Andasol plant in Spain. One of the major issues that limits the wide diffusion of this technology is the high investment cost of the solar field and, particularly, of the solar collector. For this reason, research has focused on developing new solutions that aim to reduce costs. This paper compares, at nominal conditions, commercial Fresnel technology for direct steam generation with conventional parabolic trough technology based on synthetic oil as heat-transfer. The comparison addresses nominal conditions as well as annual average performance. In both technologies, no thermal storage system is considered. Performance is calculated by Thermoflex®, a commercial code, with a dedicated component to evaluate solar plant. Results will show that, at nominal conditions, Fresnel technology has an optical efficiency of 67%, which is lower than the 75% efficiency of the parabolic trough. Calculated net electric efficiency is about 19.25%, whereas PT technology achieves 23.6% efficiency. In off-design conditions, the performance gap between Fresnel and parabolic trough increases because the former is significantly affected by high incident angles of solar radiation. The calculated sun-to-electric annual average efficiency for a Fresnel plant is 10.2%, which is a consequence of the average optical efficiency of 38.8%; a parabolic trough achieves an overall efficiency of 16%, with an optical efficiency of 52.7%. An additional case with a Fresnel collector and synthetic-oil outlines the differences among the cases investigated. Since part of the performance difference between Fresnel and PT technologies is simply due to different definitions, we introduce additional indexes to make a consistent comparison. Finally, a simplified economic assessment shows that Fresnel collectors must reduce investment costs of at least 45% than parabolic trough to achieve the same levelized cost of electricity.

Modelling and Design of Direct Solar Steam Generating Collector Fields

2005 ◽  
Vol 127 (3) ◽  
pp. 371-380 ◽  
Author(s):  
M. Eck ◽  
W.-D. Steinmann
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Final Project ◽  
Direct Steam ◽  
Attractive Option ◽  
The Stability ◽  
Eu Project

The direct steam generation (DSG) is an attractive option regarding the economic improvement of parabolic trough technology for solar thermal electricity generation in the multi megawatt range. According to Price, H., Lu¨pfert, E., Kearney, D., Zarza, E., Cohen, G., Gee, R. Mahoney, R., 2002, “Advances in Parabolic Trough Solar Power Technology,” J. Sol. Energy Eng., 124 and Zarza, E., 2002, DISS Phase II-Final Project Report, EU Project No. JOR3-CT 980277 a 10% reduction of the LEC is expected compared to conventional SEGS like parabolic trough power plants. The European DISS project has proven the feasibility of the DSG process under real solar conditions at pressures up to 100 bar and temperatures up to 400°C in more than 4000 operation hours (Eck, M., Zarza, E., Eickhoff, M., Rheinla¨nder, J., Valenzuela, L., 2003, “Applied Research Concerning the Direct Steam Generation in Parabolic Troughs,” Solar Energy 74, pp. 341–351). In a next step the detailed engineering for a precommercial DSG solar thermal power plant will be performed. This detailed engineering of the collector field requires the consideration of the occurring thermohydraulic phenomena and their influence on the stability of the absorber tubes.

The DISS Project: Direct Steam Generation in Parabolic Troughs — Operation and Maintenance Experience — Update on Project Status

2001 ◽  
Author(s):  
Eduardo Zarza ◽  
Loreto Valenzuela ◽  
Javier León ◽  
H.-Dieter Weyers ◽  
Martin Eickhoff ◽  
...  
Keyword(s):  
Power Plants ◽  
New Technology ◽  
Thermal Power ◽  
Test Facility ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Solar Thermal Power ◽  
Operation And Maintenance ◽  
Direct Steam ◽  
New Generation

Abstract The DISS (DIrect Solar Steam) project is a complete R+TD program aimed at developing a new generation of solar thermal power plants with direct steam generation (DSG) in the absorber tubes of parabolic trough collectors. During the first phase of the project (1996–1998), a life-size test facility was implemented at the Plataforma Solar de Almería (PSA) to investigate under real solar conditions the basic DSG processes and evaluate the open technical questions concerning this new technology. This paper updates DISS project status and explains O&M-related experience (e.g. main problems faced and solutions applied) with the PSA DISS test facility since January 1999.

Detailed Modeling of Parabolic Trough Collectors for the Part Load Simulation of Solar Thermal Power Plants

2012 ◽  
Author(s):  
F. Zaversky ◽  
S. Bergmann ◽  
W. Sanz
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Solar Thermal ◽  
Thermal Power Plants ◽  
Steam Generation ◽  
Parabolic Trough ◽  
Solar Thermal Power ◽  
Direct Steam

Solar thermal power plants are a promising way of providing clean renewable electric energy. These plants concentrate the incoming solar direct irradiation in order to heat up a heat transfer fluid. The collected thermal energy can be stored or instantly delivered to a power block where part of the thermal energy is converted to electrical energy in a turbine with the connected generator. The parabolic trough collector plant is the today’s most developed solar thermal power plant type. There the solar irradiation is focused on receiver tubes which are concentrically placed to the focal lines of the parabolic trough collectors. A high temperature oil is pumped through these receiver tubes, which collects the heat and delivers it later on to the steam generator of the connected Rankine steam cycle. In order to improve the efficiency of these solar thermal power plants, the direct steam generation (DSG) within the parabolic trough collector receiver tubes is being investigated. Both types of parabolic trough collectors, the conventional type using oil as heat transfer fluid and the direct steam generation type, are subject of this paper. A detailed steady-state parabolic trough collector model was developed for each type, using the thermodynamic simulation software IPSEpro. The developed models consider the cosine-loss attenuation factor, the shading attenuation factor, optical losses, as well as thermal losses. Appropriate heat transfer and pressure loss correlations were implemented for both collector types. For the direct steam generation model, distinct collectors for the preheating section, the evaporation section and the superheating section were used. Furthermore, the suitable length of discretization for the modeling of one collector loop within a center-fed solar field was investigated. Calculated solar field performance data for the oil concept were compared to validated data available in open literature. Finally, a power plant simulation with each collector type, over the course of one reference day, showed the great potential of the direct steam generation, as well as the suitability of IPSEpro for running solar thermal power plant yield simulations.

Sign in / Sign up

Export Citation Format

Share Document