scholarly journals Mathematical Modeling and Optimization of Vanadium-Titanium Black Ceramic Solar Collectors

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 618
Author(s):  
Ding Ding ◽  
Wenjing He ◽  
Chunlu Liu
Keyword(s):  
Computer Program ◽  
Reference Model ◽  
Collection Efficiency ◽  
Experimental Testing ◽  
Heat Removal ◽  
Optimization Method ◽  
Solar Collectors ◽  
Total Heat Loss ◽  
Vanadium Titanium ◽  
Cover Design

The vanadium-titanium black ceramic (VTBC) coating on all-ceramic solar collectors has both high absorptance (0.94) and high emissivity (90%). However, the thermal conductivity of ceramic is very low (1.256 W/mK). To improve the heat collection efficiency of VTBC solar collectors, this paper establishes a mathematical model based on the energy-conservation relationships under steady-state conditions and creates a corresponding computer program. Key parameters for VTBC solar collectors include the heat-removal factor, effective transmittance-absorptance product for the absorber, total heat loss coefficient, etc. Then, via experimental testing, this study proposes a reference model for domestic VTBC solar collectors in a cold location (η = 0.89 − 2.20Tm*). Last, this work analyzes the influences of fin design and transparent cover design on VTBC solar collectors individually, using the created computer program. Results show that the most effective optimization method is to increase the transmittance of the transparent cover. By increasing the transmittance from 0.93 to 0.96, this study creates an optimized VTBC solar collector theoretical model (η = 0.92 − 2.20Tm*).

Optimal Model Reference Control Scheme Design for Nonlinear Strict-Feedback Systems

2020 ◽  
Vol 38 (9A) ◽  
pp. 1342-1351
Author(s):  
Musadaq A. Hadi ◽  
Hazem I. Ali
Keyword(s):  
Reference Model ◽  
Feedback System ◽  
Optimization Method ◽  
Feedback Systems ◽  
Model Reference ◽  
Scheme Design ◽  
Model Reference Control ◽  
Control Scheme ◽  
Lyapunov Stability Analysis ◽  
Strict Feedback

In this paper, a new design of the model reference control scheme is proposed in a class of nonlinear strict-feedback system. First, the system is analyzed using Lyapunov stability analysis. Next, a model reference is used to improve system performance. Then, the Integral Square Error (ISE) is considered as a cost function to drive the error between the reference model and the system to zero. After that, a powerful metaheuristic optimization method is used to optimize the parameters of the proposed controller. Finally, the results show that the proposed controller can effectively compensate for the strictly-feedback nonlinear system with more desirable performance.

Simplified Modeling Research of Reinforced Concrete Based on the Dynamic Stiffness Equivalence

2012 ◽  
Vol 446-449 ◽  
pp. 458-462
Author(s):  
Jie Hu ◽  
Jia Quan Feng ◽  
Xi Nong Zhang
Keyword(s):  
Reinforced Concrete ◽  
Reference Model ◽  
Dynamic Stiffness ◽  
Optimization Method ◽  
Simplified Model ◽  
Response Analysis ◽  
Reinforced Concrete Structure ◽  
Optimization Function ◽  
Nature Frequency ◽  
Simplified Modeling

This paper proposed a simplified modeling method of reinforced concrete based on the equivalence of dynamic stiffness, the parameters of simplified model were modified to make the error of nature frequency between reference model and simplified model as small as possible, and an appropriate optimization function was designed. The essentiality of the proposed method is parameter optimization, with the advantages such as fewer elements and calculation assumption. The numerical simulation result indicated that this optimization method is suitable for the dynamic response analysis of complicated reinforced concrete structure.

scholarly journals Photon Collection Efficiency of Fluorescent Solar Collectors

2007 ◽  
Vol 61 (12) ◽  
pp. 780-786 ◽  
Author(s):  
Pattareeya Kittidachachan ◽  
Lefteris Danos ◽  
Thomas J. J. Meyer ◽  
Nicolas Alderman ◽  
Tom Markvart
Keyword(s):  
Collection Efficiency ◽  
Solar Collectors ◽  
Photon Collection

Experimental testing of ceramic solar collectors

Solar Energy ◽  
2017 ◽  
Vol 146 ◽  
pp. 532-542 ◽  
Author(s):  
Miroslaw Zukowski ◽  
Grzegorz Woroniak
Keyword(s):  
Experimental Testing ◽  
Solar Collectors

Effects of Landfill Cover Design on Methane Recovery Systems

1983 ◽  
Vol 105 (4) ◽  
pp. 528-535
Author(s):  
J. W. Massmann ◽  
C. A. Moore
Keyword(s):  
Finite Difference ◽  
Computer Program ◽  
Methane Yield ◽  
Methane Recovery ◽  
Landfill Cover ◽  
Recovery System ◽  
Clay Cover ◽  
Cover Design ◽  
Oxygen Poisoning ◽  
Reliable Methods

A finite difference computer program to aid in optimizing landfill cover design was developed by the authors. The program was used to compare the methane yield from sand-covered and clay-covered landfills equipped with methane recovery systems. The results of this comparison and a brief description of the finite difference program are presented in this paper. These results indicate that a clay cover can restrict air inflow into the landfill system, thus preventing oxygen poisoning of the methane-producing organisms. The practice of monitoring methane to air ratios in the pipelines of the recovery system in order to forewarn of oxygen infiltration into the fill material was shown to be ineffective in some situations. More reliable methods to forewarn of oxygen poisoning were suggested.

scholarly journals A New Soft Starting Method for Wound-Rotor Induction Motor

2011 ◽  
Vol 62 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Mohammad Sharifian ◽  
Mohammad Feyzi ◽  
Mehran Sabahi ◽  
Meysam Farrokhifar
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Computer Program ◽  
Equivalent Circuit ◽  
Induction Motor ◽  
Optimization Method ◽  
Starting Time ◽  
Three Phase ◽  
The Mathematical Model ◽  
Starting Torque

A New Soft Starting Method for Wound-Rotor Induction Motor Starting of a three-phase Induction motor using a starter rheostat in rotor circuit has some disadvantages. A new method for starting of a three-phase motor by using a parallel combination of resistors, self-inductors and capacitors in rotor circuit is proposed in this paper. The proposed method ensures the soft and higher starting torque as well as limited starting current as compared to shorted rotor method. The characteristic curves for both methods (shorted rotor and rotor with added elements) are provided. The mathematical model based on the steady-state equivalent circuit of the induction motor is expanded in frequency domain and the required computer program is prepared using an optimization method. The values for added elements to rotor circuit are calculated in such a way that minimum starting time considering current and torque limitations are achieved.

scholarly journals Economic Order Quantity Model for Growing Items with Incremental Quantity Discounts, Capacitated Storage Facility, and Limited Budget

2020 ◽  
Vol 22 (1) ◽  
pp. 1-10
Author(s):  
Yosi Agustina Hidayat ◽  
Veterina Nosadila Riaventin ◽  
Okky Jayadi
Keyword(s):  
Cycle Time ◽  
Reference Model ◽  
Optimization Method ◽  
Inventory Model ◽  
Economic Order Quantity ◽  
Economic Order ◽  
Quantity Discounts ◽  
Order Quantity ◽  
Planning Period ◽  
Numerical Example

The development of the inventory model started when Harris introduced the classic inventory model. It was firstly published by Wilson using the optimization method. He derived a mathematical equation model to obtain economic order quantities. Later, this model is known as the classic Economic Order Quantity (EOQ) or Wilson Model. The classic inventory EOQ model has some limitations. The model assumed that order items do not have physical changes during a planning period. This assumption becomes the weakness of the classical EOQ inventory model. Many items have material changes during a planning period, such as amelioration, deterioration, and growth. This research proposed a new mathematical model. The model relaxes three implicit assumptions of the classical EOQ: (1) the ordered items do not grow; (2) unlimited capacity; and (3) unlimited budget. A solution procedure to solve the model was developed and illustrated with a numerical example. A numerical example was performed to compare the result between the reference model and the new model. The number of ordered items per cycle time increased by 7%, and cycle time increased by 28%. It increased because the proposed model tends to choose large purchased quantities to get a cheap price. It caused the number of ordered items per cycle time to be larger and the cycle time to be smaller than the reference model. This research also provided sensitivity analysis. It showed the response of decision variables to some changes in input parameters.

Experimental Investigation on Heat Losses From Differentially Heated Cylindrical Cavity Receiver Used in Paraboloid Concentrator

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Ravindra D. Jilte ◽  
Jayant K. Nayak ◽  
Shireesh B. Kedare
Keyword(s):  
Nusselt Number ◽  
Heat Loss ◽  
Wall Temperature ◽  
Experimental Testing ◽  
Heat Losses ◽  
Total Heat ◽  
Radiative Loss ◽  
Total Heat Loss ◽  
Conduction Loss ◽  
Nusselt Number Correlation

In the present study, an experimental testing facility is created to analyze the heat losses from the cylindrical solar cavity. Tests are carried out under the temperature range from 225 °C to 425 °C for a cavity inclination from θ = 0–90 deg in steps of 30 deg. It is observed that for off-flux investigation of solar cavity receiver, near isothermal wall temperature condition can be realized with the differential heating arrangement. The total loss is found to be the highest when the cavity aperture is positioned at sideways (θ = 0 deg). It decreases by 43–51% when the cavity is inclined (θ = 90 deg). The conduction loss is found to be accounted for up to 32–34% of the total heat loss, whereas the cavity radiative loss is estimated to be 13%, 16%, and 20% of the total heat loss, respectively, for cavity wall temperature 225 °C, 325 °C, and 425 °C. The investigation of convective losses showed significant change with cavity tilt angles. It is 46–54% of the total heat loss when the cavity aperture is facing sideways (θ = 0 deg), whereas its value reduces up to 4% of the total heat loss when the cavity aperture is facing downward (θ = 90 deg). A Nusselt number correlation has been developed for predicting the convective heat loss from a open cavity. The Nusselt number correlation correlates 100% of data within ± 20% deviation.

Material and Design Requirements for Advanced Concentrators

2010 ◽  
Vol 74 ◽  
pp. 237-242
Author(s):  
Robert Pitz-Paal ◽  
Eckhard Lüpfert
Keyword(s):  
Collection Efficiency ◽  
Cost Effective ◽  
Solar Collectors ◽  
Solar Concentrators ◽  
Acceptable Error ◽  
Specular Reflectance ◽  
Reflector Surface ◽  
The Impact

Concentrating solar collectors direct the sunlight towards a focus point or focus line. Relevant parameters are the fidelity of the concentrator with respect to its ideal parabolic shape, its stiffness under wind and gravitational loads, the angular accuracy of the tracking and the solar weighted specular reflectance of the reflector. Additional aspects refer to the long term durability and ease of cleaning of the reflector surface. Solar concentrators require lower geometrical precision than astronomic apparatus. Therefore, more cost effective designs are possible by using up the overall acceptable error budget to a level that collection efficiency of the reflected sun rays is still very efficient. Understanding the impact of the different parameters describing the quality of the concentrator with respect to system performance and cost is necessary for an advanced and efficient concentrator design. DLR has recently developed guidelines to measure the most relevant concentrator characteristics in its qualification center QUARZ. This paper presents the relevant parameters of mirrors for concentrating solar collectors and discusses their economic impact.

Sign in / Sign up

Export Citation Format

Share Document