scholarly journals State-of-the-Art Measurement Instrumentation and Most Recent Measurement Techniques for Parabolic Trough Collector Fields

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7166
Author(s):  
Alex Brenner ◽  
Tobias Hirsch ◽  
Marc Röger ◽  
Robert Pitz-Paal
Keyword(s):  
Measurement Techniques ◽  
Heat Transfer Fluid ◽  
Test Facility ◽  
Recent Measurement ◽  
Parabolic Trough ◽  
Measurement Systems ◽  
Measurement Devices ◽  
Solar Field ◽  
Standard Instrumentation ◽  
Equipment Laboratory

The presented review gives reliable information about the currently used measurement instrumentation in parabolic trough fields and recent monitoring approaches. The usually built-in measurement equipment in the solar field, clamp-on systems for flexible measurements of temperature and flow, solar irradiance measurements, standard meteorological equipment, laboratory devices for heat transfer fluid analyses and instruments related to the tracking of solar collector assemblies are presented in detail. The measurement systems are reported with their measurement uncertainty, approximate costs and usual installation location for the built-in instrumentation. Specific findings related to the installation and operation of the measurement devices are presented. The usually installed instrumentation delivers a lot of measurements all over the field at the expense of measurement accuracy, compared to special test facility equipment. Recently introduced measurement approaches can improve the standard instrumentation in terms of accuracy, frequency, spatial distribution or can even extend the amount of measurands. The information about available measurands is the basis for future operation and maintenance solutions based on data-driven approaches.

Comparison of Two-Tank Indirect Thermal Storage Designs for Solar Parabolic Trough Power Plants

2009 ◽  
Author(s):  
Joseph Kopp ◽  
R. F. Boehm
Keyword(s):  
Power Generation ◽  
Molten Salt ◽  
Heat Exchangers ◽  
Power Plants ◽  
Thermal Storage ◽  
Heat Transfer Fluid ◽  
Base Case ◽  
Parabolic Trough ◽  
Trade Offs ◽  
Solar Field

The performance of a solar thermal parabolic trough plant with thermal storage is dependent upon the arrangement of the heat exchangers that ultimately transfer energy from the sun into steam. An indirect two-tank molten salt storage system that only transfers heat with the solar field heat transfer fluid is the most commercially acceptable thermal storage design. Annual electricity generation from two differing indirect two-tank molten salt storage designs and a base case with no thermal storage were modeled. Four components were characterized in a quasi-steady state analysis dependent upon key ambient and operational parameters: solar field, storage, heat exchangers, and power block. The parameters for the collector field remained constant for all models and were based on the SEGS VI plant. The results of net power generation favor storage though the design that maximizes annual output depends on whether maximum power generation or power generation during the evening peak demand hours is desired. Additionally, the economic trade offs are discussed for the three arrangements.

Assessment of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field

2003 ◽  
Vol 125 (2) ◽  
pp. 170-176 ◽  
Author(s):  
D. Kearney ◽  
U. Herrmann ◽  
P. Nava ◽  
B. Kelly ◽  
R. Mahoney ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Mojave Desert ◽  
Storage System ◽  
Eutectic Mixture ◽  
Heat Transfer Fluid ◽  
Diphenyl Oxide ◽  
Parabolic Trough ◽  
Electricity Cost ◽  
Solar Field

An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS (Solar Electric Generating Systems located in Mojave Desert, California) plants currently use a high temperature synthetic oil consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems exist, and the quantification of performance and electricity cost using preliminary cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% CaNO32, 7% NaNO3, and 45% KNO3). Assuming a two-tank storage system and a maximum operation temperature of 450°C, the evaluation showed that the levelized electricity cost can be reduced by 14.2% compared to a state-of-the-art parabolic trough plant such as the SEGS plants. If higher temperatures are possible, the improvement may be as high as 17.6%. Thermocline salt storage systems offer even greater benefits.

Evaluation of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field

Solar Energy ◽  
2002 ◽  
Author(s):  
D. Kearney ◽  
U. Herrmann ◽  
P. Nava ◽  
B. Kelly ◽  
R. Mahoney ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Eutectic Mixture ◽  
Heat Transfer Fluid ◽  
Diphenyl Oxide ◽  
Parabolic Trough ◽  
Solar Salt ◽  
Electricity Cost ◽  
Critical Issues ◽  
Solar Field

An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS plants currently use a high temperature synthetic oil consisting of a eutectic mixture of biphenyl/diphenyl oxide. The scope of this investigation included examination of known critical issues, postulating solutions or possible approaches where potential problems existed, and the quantification of performance and electricity cost using preliminary, but reasonable, cost inputs. The two leading candidates were the so-called solar salt (a binary salt consisting of 60% NaNO3 and 40% KNO3) and a salt sold commercially as HitecXL (a ternary salt consisting of 48% Ca(NO3)2, 7% NaNO3, and 45% KNO3).

scholarly journals Feasibility Study of Freeze Recovery Options in Parabolic Trough Collector Plants Working with Molten Salt as Heat Transfer Fluid

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2340 ◽  
Author(s):  
Cristina Prieto ◽  
Alfonso Rodríguez-Sánchez ◽  
F. Ruiz-Cabañas ◽  
Luisa Cabeza
Keyword(s):  
Heat Transfer ◽  
Molten Salt ◽  
Molten Salts ◽  
Heat Transfer Fluid ◽  
Operational Experience ◽  
Parabolic Trough ◽  
Solar Salt ◽  
Parabolic Trough Collector ◽  
Overall Performance ◽  
Solar Field

Parabolic trough collector (PTC) technology is currently the most mature solar technology, which has led to the accumulation of relevant operational experience. The overall performance and efficiency of these plants depends on several components, and the heat transfer fluid (HTF) is one of the most important ones. Using molten salts as HTFs has the advantage of being able to work at higher temperatures, but it also has the disadvantage of the potential freezing of the HTF in pipes and components. This paper models and evaluates two methods of freeze recovery, which is needed for this HTF system design: Heat tracing in pipes and components, and impedance melting in the solar field. The model is used to compare the parasitic consumption in three molten salts mixtures, namely Solar Salt, HiTec, and HiTec XL, and the feasibility of this system in a freezing event. After the investigation of each of these subsystems, it was concluded that freeze recovery for a molten salt plant is possible.

Practical Field Alignment of Parabolic Trough Solar Concentrators

2006 ◽  
Vol 129 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Richard B. Diver ◽  
Timothy A. Moss
Keyword(s):  
Test Facility ◽  
Parabolic Trough ◽  
Rotating Platform ◽  
Solar Concentrators ◽  
Photographic Images ◽  
Parabolic Dish ◽  
A New Technique ◽  
Solar Field ◽  
Practical Field ◽  
Alignment Uncertainty

In this paper a new technique for parabolic trough mirror alignment based on the use of an innovative theoretical overlay photographic (TOP) approach is described. The technique is a variation on methods used to align mirrors on parabolic dish systems. It involves overlaying theoretical images of the heat collection element (HCE) in the mirrors onto carefully surveyed photographic images and adjustment of mirror alignment until they match. From basic geometric principles, for any given viewer location the theoretical shape and location of the reflected HCE image in the aligned mirrors can be predicted. The TOP approach promises to be practical and straightforward, and inherently aligns the mirrors to the HCE. Alignment of an LS-2 mirror module on the rotating platform at the National Solar Thermal Test Facility (NSTTF) with the TOP technique along with how it might be implemented in a large solar field is described. Comparison of the TOP alignment to the distant observer approach on the NSTTF LS-2 is presented and the governing equations used to draw the theoretical overlays are developed. Alignment uncertainty associated with this technique is predicted to be less than the mirror slope error.

Practical Field Alignment of Parabolic Trough Solar Concentrators

Solar Energy ◽  
2006 ◽  
Author(s):  
Richard B. Diver ◽  
Timothy A. Moss
Keyword(s):  
Test Facility ◽  
Parabolic Trough ◽  
Rotating Platform ◽  
Solar Concentrators ◽  
Photographic Images ◽  
Parabolic Dish ◽  
A New Technique ◽  
Solar Field ◽  
Practical Field ◽  
Alignment Uncertainty

In this paper a new technique for parabolic trough mirror alignment based on the use of an innovative Theoretical Overlay Photographic (TOP) approach is described. The technique is a variation on methods used to align mirrors on parabolic dish systems. It involves overlay of theoretical images of the Heat Collection Element (HCE) in the mirrors onto carefully surveyed photographic images and adjustment of mirror alignment until they match. From basic geometric principles, for any given viewer location the theoretical shape and location of the reflected HCE image in the aligned mirrors can be predicted. The TOP approach promises to be practical and straightforward and inherently aligns the mirrors to the HCE. Alignment of an LS-2 mirror module on the rotating platform at the National Solar Thermal Test Facility (NSTTF) with the TOP technique along with how it might be implemented in a large solar field is described. Comparison of the TOP alignment to the distant observer approach on the NSTTF LS-2 is presented and the governing equations used to draw the theoretical overlays are developed. Alignment uncertainty associated with this technique is predicted to be less than the mirror slope error.

scholarly journals Comparative Accuracy Analysis of Truck Weight Measurement Techniques

2021 ◽  
Vol 11 (2) ◽  
pp. 745
Author(s):  
Sylwia Stawska ◽  
Jacek Chmielewski ◽  
Magdalena Bacharz ◽  
Kamil Bacharz ◽  
Andrzej Nowak
Keyword(s):  
Measurement Techniques ◽  
Highway Traffic ◽  
Highway Infrastructure ◽  
Measurement Systems ◽  
Motion System ◽  
Weigh In Motion ◽  
Comparative Accuracy ◽  
Bridge Weigh In Motion ◽  
Rational Management ◽  
Truck Weight

Roads and bridges are designed to meet the transportation demands for traffic volume and loading. Knowledge of the actual traffic is needed for a rational management of highway infrastructure. There are various procedures and equipment for measuring truck weight, including static and in weigh-in-motion techniques. This paper aims to compare four systems: portable scale, stationary truck weigh station, pavement weigh-in-motion system (WIM), and bridge weigh-in-motion system (B-WIM). The first two are reliable, but they have limitations as they can measure only a small fraction of the highway traffic. Weigh-in-motion (WIM) measurements allow for a continuous recording of vehicles. The presented study database was obtained at a location that allowed for recording the same traffic using all four measurement systems. For individual vehicles captured on a portable scale, the results were directly compared with the three other systems’ measurements. The conclusion is that all four systems produce the results that are within the required and expected accuracy. The recommendation for an application depends on other constraints such as continuous measurement, installation and operation costs, and traffic obstruction.

scholarly journals Assessing recent measurement techniques for quantifying black carbon concentration in snow

2012 ◽  
Vol 5 (3) ◽  
pp. 3771-3795 ◽  
Author(s):  
J. P. Schwarz ◽  
S. J. Doherty ◽  
F. Li ◽  
S. T. Ruggiero ◽  
C. E. Tanner ◽  
...  
Keyword(s):  
Black Carbon ◽  
Single Particle ◽  
Carbon Concentration ◽  
Mass Concentration ◽  
Measurement Techniques ◽  
Integrating Sphere ◽  
Recent Measurement ◽  
Atmospheric Sampling ◽  
Careful Assessment ◽  
Snow Samples

Abstract. We evaluate the performance of the Single Particle Soot Photometer (SP2) and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) in quantifying the concentration of refractory black carbon (BC) in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60%) than for atmospheric sampling (<30%). Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow tends to larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow and ice using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.

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.

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