A High-Precision Control System Used for Optical Efficiency Measurements of Parabolic Trough Collectors at NREL

2012 ◽  
Author(s):  
Guangdong Zhu ◽  
Judy Netter ◽  
Allison Gray
Keyword(s):  
Control System ◽  
Tracking Control ◽  
Incidence Angle ◽  
Control Program ◽  
Tracking Accuracy ◽  
Parabolic Trough ◽  
Optical Efficiency ◽  
Test Loop ◽  
Challenges And Opportunities ◽  
Monitoring And Diagnostics

The testing facility called the Outdoor Collector Test Loop (OCTL), which is located at the Solar Industrial Mesa Top Area (SIMTA) of National Renewable Energy Lab (NREL), measures the optical efficiency of parabolic trough collectors. It uses a dual-axis, large-payload solar tracker to hold a parabolic trough collector module and track the sun. Due to the growing need for measurement accuracy and efficiency, a new tracking control system for the tracker has been acquired and successfully commissioned as of February 2012. As part of the customization needed to address the unique testing requirements at the OCTL, new tracking modes have been designed and embedded into the new controller. In particular, the incidence angle modifier (IAM) and fixed-azimuth modes allows the OCTL to readily measure the IAM values for a trough collector, significantly improving the speed and efficiency of IAM data collection compared to the previous controller (with test times of days versus weeks). The Siemens S7 1200 PLC integrates various hardware components (such as the hydraulic pump, encoders, sun sensor and wind sensor) through corresponding communication channels, and a Simatic HMI panel provides a powerful user-friendly interface for operation, monitoring, and diagnostics. In addition, NREL integrated the Siemens tracking control program with the existing LabVIEW program that serves as a user interface of the thermal fluid loop, and calibrated the tracking platform as a whole to characterize its tracking accuracy. At last, the challenges and opportunities for the control system in the area of concentrating solar power (CSP) are briefly discussed.

scholarly journals Incidence-Angle Modifier and Average Optical Efficiency of Parabolic Trough Collectors

1980 ◽  
Vol 102 (1) ◽  
pp. 16-21 ◽  
Author(s):  
H. Gaul ◽  
A. Rabl
Keyword(s):  
Incidence Angle ◽  
Open Water ◽  
Operating Conditions ◽  
Parabolic Trough ◽  
Optical Efficiency ◽  
Arbitrary Length ◽  
Polynomial Fit ◽  
Test Loop ◽  
Single Number ◽  
Solar Energy Research Institute

The incidence-angle modifier for parabolic troughs is investigated in order to clarify the connection between collector tests and prediction of long-term energy delivery by collector arrays. The optical efficiency of a parabolic trough collector decreases with incidence angle for several reasons: the decreased transmission of the glazing and the absorption of the absorber; the increased width of the solar image on the receiver; and the spillover of the radiation from troughs of finite length. In order to be able to apply test results from a short collector module to collector arrays of arbitrary length, it is necessary to separate analytically the end loss from the first two effects. This analysis is applied to several collectors that have been tested at Sandia Laboratories and at the Solar Energy Research Institute (SERI). The measurements of the incidence-angle modifier at SERI were, carried out at low temperature with an open water test loop for improved accuracy. The results are presented in two forms: as a polynomial fit to the data; and as a single number, the all-day average optical efficiency for typical operating conditions.

scholarly journals Investigation on the Optical Design and Performance of a Single-Axis-Tracking Solar Parabolic trough Collector with a Secondary Reflector

2021 ◽  
Vol 13 (17) ◽  
pp. 9918
Author(s):  
Chinnasamy Subramaniyan ◽  
Jothirathinam Subramani ◽  
Balasubramanian Kalidasan ◽  
Natarajan Anbuselvan ◽  
Thangaraj Yuvaraj ◽  
...  
Keyword(s):  
Incidence Angle ◽  
Optical Design ◽  
Operating Conditions ◽  
Optical Performance ◽  
Ambient Conditions ◽  
Parabolic Trough ◽  
Tracking Errors ◽  
Optical Efficiency ◽  
Collector System ◽  
And Performance

The design of solar concentrating collectors for the effective utilization of solar energy is a challenging condition due to tracking errors leading to different divergences of the solar incidence angle. To enhance the optical performance of solar parabolic trough collectors (SPTC) under a diverged solar incidence angle, an additional compound parabolic concentrator (CPC) is introduced as a secondary reflector. SPTC with CPC is designed and modeled for a single axis-tracking concentrating collector based on the local ambient conditions. In this work, the optical performance of the novel SPTC system with and without a secondary reflector is investigated using MATLAB and TRACEPRO software simulations for various tracking errors. The significance parameters such as the solar incidence angle, aperture length, receiver tube diameter, rim angle, concentration ratio, solar radiation, and absorbed flux are analyzed. The simulation results show that the rate of the absorbed flux on the receiver tube is significantly improved by providing the secondary reflector, which enhances the optical efficiency of the collector. It is found that the optical efficiency of the SPTC with a secondary reflector is 20% higher than the conventional collector system for a solar incidence angle of 2°. This work can effectively direct the choice of optimal secondary reflectors for SPTC under different design and operating conditions.

scholarly journals Performance Simulation Comparison for Parabolic Trough Solar Collectors in China

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinping Wang ◽  
Jun Wang ◽  
Xiaolong Bi ◽  
Xiang Wang
Keyword(s):  
Mathematical Model ◽  
Solar Collector ◽  
Incidence Angle ◽  
Accurate Estimation ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Optical Efficiency ◽  
Different Seasons ◽  
Shadowing Effect ◽  
Parabolic Trough Solar Collector

Parabolic trough systems are the most used concentrated solar power technology. The operating performance and optical efficiency of the parabolic trough solar collectors (PTCs) are different in different regions and different seasons. To determine the optimum design and operation of the parabolic trough solar collector throughout the year, an accurate estimation of the daily performance is needed. In this study, a mathematical model for the optical efficiency of the parabolic trough solar collector was established and three typical regions of solar thermal utilization in China were selected. The performance characteristics of cosine effect, shadowing effect, end loss effect, and optical efficiency were calculated and simulated during a whole year in these three areas by using the mathematical model. The simulation results show that the optical efficiency of PTCs changes from 0.4 to 0.8 in a whole year. The highest optical efficiency of PTCs is in June and the lowest is in December. The optical efficiency of PTCs is mainly influenced by the solar incidence angle. The model is validated by comparing the test results in parabolic trough power plant, with relative error range of 1% to about 5%.

The Experiment of Trajectory Tracking Control of Joint Manipulator with PC-Based

2011 ◽  
Vol 101-102 ◽  
pp. 431-434
Author(s):  
Mei Qin Zhang ◽  
Wu Feng ◽  
Hui Di Zhang ◽  
Xian Chen Wang
Keyword(s):  
Control System ◽  
Tracking Control ◽  
Robot Control ◽  
Control Program ◽  
High Price ◽  
Trajectory Tracking Control ◽  
System A ◽  
The Poor ◽  
Articulated Robot ◽  
Robot Control System

For the disadvantages of the poor open and high price of the special joint robot control system, a general PC-based three degree articulated robot control system is proposed. After modeling kinematics of the robot, the kinematics trajectory is planned and the trajectory algorithm is designed in a given error condition. Finally, the control program is done with VB, and it is verified by an example.

Performance Study of Solar Trough Tracking Control System

2014 ◽  
Vol 541-542 ◽  
pp. 1433-1437 ◽  
Author(s):  
Hai Li Li ◽  
Cheng Mu Xu ◽  
Xu Ji ◽  
Ming Li ◽  
Li Jun Tan
Keyword(s):  
Control System ◽  
Thermal Efficiency ◽  
Tracking Control ◽  
Tracking System ◽  
Experimental Results ◽  
One Dimension ◽  
Performance Study ◽  
Tracking Accuracy ◽  
Solar Tracking ◽  
The Relationship

In this paper, the tracking accuracy of one-dimension north-south solar tracking system is analyzed. The method of indirectly measuring one-dimension north-south solar tracking system is given according to the variation of sun position, and the relevant formulas are derived. The experiment on measuring the relationship between tracking accuracy and thermal efficiency of trough system is also conducted. Experimental results show that the system tracking deviation is 0.04 0.065°; the peak of tracking deviation of trough system is 0.875°.

scholarly journals Research on trajectory tracking control of 7-DOF picking manipulator

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042110033
Author(s):  
Sun Cong ◽  
Cao Liang
Keyword(s):  
Control System ◽  
Trajectory Tracking ◽  
Mechanical Model ◽  
Tracking Control ◽  
Tracking Error ◽  
Control Force ◽  
Tracking Accuracy ◽  
Trajectory Tracking Control ◽  
Applied Torque ◽  
Force Moment

In order to solve the problem of poor robustness of the traditional method of calculating torque in the mechanical model of 7-DOF picking manipulator, this paper proposes a control strategy of calculating torque plus fuzzy compensation by using adaptive fuzzy logic system to compensate the uncertain part of the mechanical model of 7-DOF picking manipulator. By using Lagrange method, the dynamic model of 7-DOF manipulator is established, and the relationship between joint motion and applied torque (force) is obtained. Using ADAMS and MATLAB to establish a co-simulation platform, the manipulator and trajectory tracking control system are simulated. The results show that the trajectory tracking error of each joint in the algorithm is obviously reduced and the convergence trend is obvious. The average trajectory tracking accuracy of joint 1 to joint 7 was improved by 70.22%, 94.78%, 0.62%, 74.23%, 89.78%, 86.45%, and 67.15%, respectively. In this control scheme, the control force (moment) of each joint changes regularly, and the output force (moment) does not appear chattering and mutation when the disturbance signal is added. The research results can provide support for the further study of picking manipulator trajectory tracking control system.

Commissioning brownstock washing controls for an evaporator limited mill

TAPPI Journal ◽  
2016 ◽  
Vol 15 (7) ◽  
pp. 459-464
Author(s):  
RICARDO SANTOS ◽  
PETER HART
Keyword(s):  
Control System ◽  
Negative Impact ◽  
Black Liquor ◽  
Pulp Mill ◽  
Control Program ◽  
Separation Point ◽  
Water Control ◽  
Oxygen Delignification ◽  
Percentage Points

An automated shower water control system has been implemented to reduce the volume and variability of weak black liquor being sent from the pulp mill to the evaporators. The washing controls attempt to balance the need for consistent and low soda carryover to the bleach plant with consistently high weak black liquor solids being sent to the evaporators. The washer controls were implemented on two bleachable grade hardwood lines (one with oxygen delignification, one without oxygen delignification) and one pine line. Implementation of the control program resulted in an increase in black liquor solids of 0.6 percentage points for the hardwood lines. Significant foam reduction was realized on the pine line since the pine black liquor solids were able to be consistently maintained just below the soap separation point. Low black liquor solids excursions to the evaporators were eliminated. Bleach plant carryover was stabilized and no negative impact on chemical consumption was noticed when controlling weak black liquor solids to recovery.

Sign in / Sign up

Export Citation Format

Share Document