Performance Testing of a Parabolic Solar Concentrator for Solar Cooking

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Ndiaga Mbodji ◽  
Ali Hajji
Keyword(s):  
Tracking System ◽  
Experimental Studies ◽  
Performance Testing ◽  
Front Face ◽  
Maximum Temperature ◽  
Solar Concentrator ◽  
Heat Transfer Medium ◽  
Energy And Exergy ◽  
Overall Heat Loss Coefficient ◽  
Local Materials

The objective of the present work is to conduct a worthwhile experimental study of the performance of a parabolic solar concentrator for solar cooking. The literature survey briefly highlights the standard performance tests of solar cookers and gives the experimental studies obtained by some authors. Our experimental device, made from simple means using local materials, consists of a parabolic concentrator having a 0.80 m diameter and 0.08 m depth as well as a cylindrical absorber with a 0.10 m diameter and is 0.20 m long. The testing period started on April 24th, 2014 and continued till July 10th of the same year, in Rabat (33°53′ N, 6°59′ W), Morocco. The average ambient temperature is 24 °C. The results show that using synthetic oil as the heat transfer medium has achieved a maximum temperature of 153 °C against 97 °C with water. The overall heat loss coefficient is estimated to be 17.6 W m−2  °C−1. The energy and exergy efficiencies are, respectively, 29.0–2.4% and 0.1–0.5%. Adding a glass cover on the front face of the absorber improved the maximum temperature by 15 °C. Automatic two-axis sun tracking system also increased the maximum temperature by 13 °C compared to manual tracking system.

scholarly journals A Study on Vision-Based Backstepping Control for a Target Tracking System

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 105
Author(s):  
Thinh Huynh ◽  
Minh-Thien Tran ◽  
Dong-Hun Lee ◽  
Soumayya Chakir ◽  
Young-Bok Kim
Keyword(s):  
Control System ◽  
Visual Servoing ◽  
Tracking System ◽  
Experimental Studies ◽  
Imaging Geometry ◽  
Control Scheme ◽  
Decoupled Control ◽  
Control Configuration ◽  
A New Technique ◽  
Pointing Control

This paper proposes a new method to control the pose of a camera mounted on a two-axis gimbal system for visual servoing applications. In these applications, the camera should be stable while its line-of-sight points at a target located within the camera’s field of view. One of the most challenging aspects of these systems is the coupling in the gimbal kinematics as well as the imaging geometry. Such factors must be considered in the control system design process to achieve better control performances. The novelty of this study is that the couplings in both mechanism’s kinematics and imaging geometry are decoupled simultaneously by a new technique, so popular control methods can be easily implemented, and good tracking performances are obtained. The proposed control configuration includes a calculation of the gimbal’s desired motion taking into account the coupling influence, and a control law derived by the backstepping procedure. Simulation and experimental studies were conducted, and their results validate the efficiency of the proposed control system. Moreover, comparison studies are conducted between the proposed control scheme, the image-based pointing control, and the decoupled control. This proves the superiority of the proposed approach that requires fewer measurements and results in smoother transient responses.

Quantitative Experimental Study of SiO2-Water Nanofluids on Backward-Facing Step Flow under Low Reynolds Number

2018 ◽  
Vol 916 ◽  
pp. 221-225
Author(s):  
Ji Zu Lv ◽  
Liang Yu Li ◽  
Cheng Zhi Hu ◽  
Min Li Bai ◽  
Sheng Nan Chang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Reynolds Number ◽  
Volume Fraction ◽  
Pure Water ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Thermal Engineering ◽  
Heat Transfer Medium ◽  
Step Flow

Nanofluids is an innovative study of nanotechnology applied to the traditional field of thermal engineering. It refers to the metal or non-metallic nanopowder was dispersed into water, alcohol, oil and other traditional heat transfer medium, to prepared as a new heat transfer medium with high thermal conductivity. The role of nanofluids in strengthening heat transfer has been confirmed by a large number of experimental studies. Its heat transfer mechanism is mainly divided into two aspects. On the one hand, the addition of nanoparticles enhances the thermal conductivity. On the other hand, due to the interaction between the nanoparticles and base fluid causing the changes in the flow characteristics, which is also the main factor affecting the heat transfer of nanofluids. Therefore, a intensive study on the flow characteristics of nanofluids will make the study of heat transfer more meaningful. In this experiment, the flow characteristics of SiO2-water nanofluids in two-dimensional backward step flow are quantitatively studied by PIV. The results show that under the same Reynolds number, the turbulence of nanofluids is larger than that of pure water. With the increase of nanofluids volume fraction, the flow characteristics are constantly changing. The quantitative analysis proved that the nanofluids disturbance was enhanced compared with the base liquid, which resulting in the heat transfer enhancement.

Optical Analysis of a Heliostat Array With Linked Tracking

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
M. T. Dunham ◽  
R. Kasetty ◽  
A. Mathur ◽  
W. Lipiński
Keyword(s):  
Concentration Ratio ◽  
Tracking System ◽  
Average Concentration ◽  
Solar Concentrator ◽  
Optical Performance ◽  
Optical Analysis ◽  
Optical Efficiency ◽  
The North ◽  
The Individual ◽  
East West

The optical performance of a novel solar concentrator consisting of a 400 spherical heliostat array and a linked two-axis tracking system is analyzed using the Monte Carlo ray-tracing technique. The optical efficiency and concentration ratio are compared for four different heliostat linkage configurations, including linkages of 1 × 1, 1 × 2, 2 × 2, 4 × 4, and 5 × 5 heliostats for 7-hour operation and the selected months of June and December. The optical performance of the concentrator decreases with the increasing number of heliostats in the individual groups due to increasing optical inaccuracies. In June, the best-performing linked configuration, in which 1 heliostat in the east-west direction and 2 heliostats in the north-south direction are linked, provides a monthly-averaged 7-hour optical efficiency and average concentration ratio of 79% and 511 suns, respectively. In December, the optical efficiency and the average concentration ratio decreases to 61% and 315 suns, respectively.

EXPERIMENTAL STUDIES OF THE HEATING TEMPERATURE OF THE GREENHOUSE RADIATOR INSTALLATIONS

2020 ◽  
Vol 15 (1) ◽  
pp. 76-80
Author(s):  
Nadezhda Kondrat'eva ◽  
Dmitriy Filatov ◽  
Pavel Terent'ev ◽  
Bulat Ziganshin
Keyword(s):  
Energy Efficiency ◽  
Supply Voltage ◽  
Heating Temperature ◽  
Experimental Studies ◽  
Maximum Temperature ◽  
Thermal Imager ◽  
Voltage Level ◽  
Radiation Sources ◽  
Measurement Results ◽  
Nominal Mode

The thermal regime of plants determines the temperature of the environment, the evaporation of moisture by plants, and the heating of plants by radiation from irradiation plants. Today, induction and LED greenhouse irradiators are promising for replacing irradiators with sodium lamps in terms of energy efficiency. Experimental studies were performed to assess the possibility of proximity of irradiators with induction lamps and LED irradiators to plants to increase their level of irradiation, in comparison with sodium radiation sources. When setting up the experiment, a complex was used, including a Fluke ti32 thermal imager, PHO-250-2-M linear autotransformer, 220V power supply, and a greenhouse irradiator. Processing of the measurement results was carried out in the Fluke SmartView 3.1 program. The heating temperature was determined when reaching the nominal mode, with the nominal mode of operation of the irradiators, with a change in the supply voltage level. Sodium and induction irradiators heat up to a maximum temperature 10 times faster than LED ones. The heating temperature of optical radiation sources with sodium lamps is 5 times higher than LED and 2.5 times higher than induction. A change in the supply voltage level affects the heating temperature of the sodium irradiator with electromagnetic ballasts, the heating temperature of sodium and induction irradiators with electronic ballasts, as well as LED irradiators, remains unchanged and equal to the nominal value at a supply voltage level of ± 10% of Unom.. Low heating temperatures of induction and LED irradiators can reduce the height of their suspension and bring them closer to plants, which will increase the irradiation of plants by increasing the level of illumination or reduce the power of irradiators, that is, increase the energy efficiency of irradiation systems

Performance Evaluation of Concentrating Solar Cooker Under Indian Climatic Conditions

2008 ◽  
Author(s):  
S. K. Shukla ◽  
S. K. Gupta
Keyword(s):  
Performance Evaluation ◽  
Holistic Health ◽  
Climatic Conditions ◽  
Maximum Temperature ◽  
Modeling And Analysis ◽  
Energy And Exergy ◽  
Indian Climatic ◽  
Low Efficiency ◽  
And Performance ◽  
Experimental Values

The work presented in this paper essentially consists of modeling and analysis of energy and exergy efficiency of a community solar cooker, installed at Holistic Health and Food Centre, I.I.T. Delhi India in March 1998. The cooker is meant for community cooking, which consists of a linear parabolic concentrator with concentration ratio of 20. The experiments, on this cooker, were performed in summer and winter, both the climatic conditions. The measurements were done by using microprocessor based on line data acquisition system using class I solar pyranometer and Pt. 100 temperature sensors. Based on the experimental data obtained by testing and performance evaluation of this concentrating type of solar cooker, the energy and exergy efficiencies are calculated. From an analysis of the experimental values the average efficiency of this cooker is measured as 14% only. The different losses contributes to low efficiency are optical losses (16%), geometrical losses (30%) and thermal losses (35%) accounts for more than, 80% energy waste from the radiation coming to the reflector. The rest of the losses are due to edge losses etc. the maximum temperature of water was recorded 98°C during water heating tests.

Experimental Studies of a Ranque-Hilsch Vortex Tube

2013 ◽  
Vol 390 ◽  
pp. 670-674 ◽  
Author(s):  
Azizul Mohamad ◽  
Nasrul Amri Mohd Amin ◽  
Zuradzman Mohamad Razlan ◽  
Mohd Shukry Abdul Majid
Keyword(s):  
Vortex Tube ◽  
Experimental Studies ◽  
The Other ◽  
Maximum Temperature ◽  
Physical Parameters ◽  
Inlet Temperature ◽  
Heating Effect ◽  
Design Features ◽  
Air Mass ◽  
Very High

Vortex tube is a device that separates a compressed flow of gas into two streams simultaneously, one giving kinetic energy to the other, resulting one hotter than the inlet temperature and one lower, without having any moving part. This research focuses on investigating the effects of various physical parameters on the performance of the vortex tube, namely cold nozzle diameter, length of the tube, and air mass flow rate at the hot end of the tube. In general, there are two major design features associated with the vortex tube, namely (a) maximum temperature differentials in vortex tube to produce small amount of air with very low and very high temperatures, and (b) maximum cooling/heating effect by producing large quantity of air with moderate temperatures. By considering the experimental results, an optimized set of parameters that contribute to the most efficient vortex tube design would be proposed depending on the desired design features.

scholarly journals An automated barcode tracking system for behavioural studies in birds

2017 ◽  
Author(s):  
Gustavo Alarcon-Nieto ◽  
Jacob Graving ◽  
James A. Klarevas-Irby ◽  
Adriana Maldonado-Chaparro ◽  
Inge Mueller ◽  
...  
Keyword(s):  
Statistical Power ◽  
Tracking System ◽  
Experimental Studies ◽  
Human Perception ◽  
Automated System ◽  
Data Sets ◽  
Image Capture ◽  
Advantages And Disadvantages ◽  
Long Timescales ◽  
Machine Readable

1. Recent advances in technology allow researchers to automate the measurement of animal behaviour. These methods have multiple advantages over direct observations and manual data input as they reduce bias related to human perception and fatigue, and deliver more extensive and complete data sets that enhance statistical power. One major challenge that automation can overcome is the observation of many individuals at once, enabling whole-group or whole-population tracking. 2. We provide a detailed description for implementing an automated system for tracking birds. Our system uses printed, machine-readable codes mounted on backpacks. This simple, yet robust, tagging system can be used simultaneously on multiple individuals to provide data on bird identity, position and directionality. Further, because our codes and backpacks are printed on paper, they are very lightweight. 3. We describe the implementation of this automated system on two flocks of zebra finches. We test different camera options, and describe their advantages and disadvantages. We show that our method is reliable, relatively easy to implement and monitor, and with proper handling, has proved to be safe for the birds over long periods of time. Further, we highlight how using single-board computers to control the frequency and duration of image capture makes this system affordable, flexible, and adaptable to a range of study systems. 4. The ability to automate the measurement of individual positions has the potential to significantly increase the power of both observational and experimental studies. The system can capture both detailed interactions (using video recordings) and repeated observations (e.g. once per second for the entire day) of individuals over long timescales (months or potentially years). This approach opens the door to tracking life-long relationships among individuals, while also capturing fine-scale differences in behaviour.

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