scholarly journals A Comparative Study on Daylight Performance Assessment of Light Shelves Based on Inclination

2020 ◽  
Vol 39 (4) ◽  
pp. 800-805
Author(s):  
Sadaf Noshin ◽  
Humaira Kanwal ◽  
Abrar Ahmad
Keyword(s):  
Control Strategies ◽  
Design Parameters ◽  
Winter Solstice ◽  
Lighting Control ◽  
Control Scheme ◽  
Superior Effect ◽  
Illuminance Level ◽  
Daylight Performance ◽  
Sky Conditions ◽  
Overcast Sky

Energy consumption of lighting can be reduced by using different daylight control strategies. The rise in environmental distresses requires the necessity of natural light control systems. Light shelf is considered as excellent lighting control scheme that provides great lighting production and inexpensive prospect via entering the daylight inside the space. The aims of this study shows that the daylight efficiency and visual productivity are affected by the design parameters of light shelf such as its angle, location and height. In this research, Autodesk Ecotect 2011 is used for the daylight simulation of summer solstice and winter solstice days under overcast sky conditions on a nominated theoretical study space of an institutional building. Daylight simulation is carried out to evaluate the illuminance requirement within the selected space and analysis is also executed on the model with selected categories of light shelves including different positions, heights and angles. The acquired data is then exported on Radiance software intended for complete day-light investigation. The results of this research shows that external light shelf at a height of 7' and an angle of 20˚ is the most appropriate choice in prevailing the glare and it also enhanced the illuminance level to11.5% in 21st June and 10.6% in 21st December as compared to without light shelves. Furthermore, the shaded range is decreased by the rise in the angle of Light shelf which has a tendency to increase the inside average lighting. Hence, significant consideration should be given to the height and position of light shelves, since it has a superior effect on light shelf performance.

scholarly journals Partial Daylight Autonomy (DAp): A New Lighting Dynamic Metric to Optimize the Design of Windows for Seasonal Use Spaces

2021 ◽  
Vol 11 (17) ◽  
pp. 8228
Author(s):  
Alejandro Ruiz ◽  
Miguel Ángel Campano ◽  
Ignacio Acosta ◽  
Óscar Luque
Keyword(s):  
Energy Consumption ◽  
Natural Light ◽  
Indoor Space ◽  
Lighting Control ◽  
Simulation Process ◽  
Illuminance Level ◽  
Sky Conditions ◽  
The Impact ◽  
Dynamic Metrics ◽  
Accurate Indicator

Nowadays, daylight dynamic metrics are the most useful indicators to quantify the use of natural light, with daylight autonomy (DA) being one of the most widespread among all of them. This metric represents the percentage of the occupied time throughout the year in an indoor space when daylight reaches the minimum illuminance level to develop a specific task. Accordingly, the higher the percentage of DA, the shorter the switching on time of electric lighting. However, this metric considers for its calculations all business days of a whole standard year, and is thus not an accurate indicator for seasonal use spaces such as school classrooms. In this context, a variant of this metric is proposed, namely partial daylight autonomy (DAp), which is a non-lineal derivation of DA that considers those seasonal use spaces, helping to define the real percentage of indoor daylight use in order to properly quantify the accurate switching on time of electric lighting and therefore its energy consumption. As deduced from the analysis, the more precise results provided by DAp reach divergences close to 10% in comparison with the original conception of DA. Thus, this metric serves to estimate more accurately the impact on energy consumption if an electric lighting control system is implemented through lux meters. This new proposal has been monitored under real sky conditions in a test cell, providing converging results with those observed in the simulation process.

scholarly journals Illuminance levels based on different sky conditions by considering daylight harvesting

2020 ◽  
Vol 19 (3) ◽  
pp. 1219
Author(s):  
Nik Sahidah Nik Ahmad ◽  
N. H. Radzi ◽  
Mohd Noor Abdullah
Keyword(s):  
Energy Consumption ◽  
Greenhouse Effect ◽  
Weather Conditions ◽  
Lighting System ◽  
Artificial Lighting ◽  
Harvesting Systems ◽  
Illuminance Level ◽  
Sky Conditions ◽  
Daylight Harvesting ◽  
Overcast Sky

Daylight Harvesting Systems (DHS) offer the most effective and significant to reduce energy consumption. In the lighting system, there are various problems which include waste of energy consumption, inappropriate lighting and increasing greenhouse effect. Therefore, the waste of energy consumption should be reduced by controlling the dimming levels of artificial lighting according to the standard thus reducing the greenhouse effect. Hence, this paper considered the daylight adaptive for the lighting system to determine the dimming level and illuminance level for the office room. The simulation has been carried out using DIALux simulation lighting software to simulate the average daylight and average illuminance level with different conditions sky, which is clear, average, and overcast sky. Based on the result, the illuminance level has complied with the European Standard EN12464-1. Furthermore, the presence of daylight and weather conditions plays an essential role in the lighting system. The illuminance and dimming levels are different depending on the time and type of sky condition at that time. Therefore, the daylight adaptive in the lighting system can reduce the use of artificial light in the room.

Continuous Finite-Time Torque Control for Flexible Assistance Exoskeleton with Delay Variation Input

Robotica ◽  
2020 ◽  
pp. 1-26
Author(s):  
Tao Xue ◽  
ZiWei Wang ◽  
Tao Zhang ◽  
Ou Bai ◽  
Meng Zhang ◽  
...  
Keyword(s):  
Finite Time ◽  
Disturbance Rejection ◽  
High Performance ◽  
Control Strategies ◽  
Fractional Power ◽  
Critical Issue ◽  
Human Robot Interaction ◽  
Torque Control ◽  
Finite Time Stability ◽  
Control Scheme

SUMMARY Accurate torque control is a critical issue in the compliant human–robot interaction scenario, which is, however, challenging due to the ever-changing human intentions, input delay, and various disturbances. Even worse, the performances of existing control strategies are limited on account of the compromise between precision and stability. To this end, this paper presents a novel high-performance torque control scheme without compromise. In this scheme, a new nonlinear disturbance observer incorporated with equivalent control concept is proposed, where the faster convergence and stronger anti-noise capability can be obtained simultaneously. Meanwhile, a continuous fractional power control law is designed with an iteration method to address the matched/unmatched disturbance rejection and global finite-time convergence. Moreover, the finite-time stability proof and prescribed control performance are guaranteed using constructed Lyapunov function with adding power integrator technique. Both the simulation and experiments demonstrate enhanced control accuracy, faster convergence rate, perfect disturbance rejection capability, and stronger robustness of the proposed control scheme. Furthermore, the evaluated assistance effects present improved gait patterns and reduced muscle efforts during walking and upstair activity.

scholarly journals Daylighting design with lightscoop skylights: Towards an optimization of proportion and spacing under overcast sky conditions

2012 ◽  
Vol 49 ◽  
pp. 394-401 ◽  
Author(s):  
Ignacio Acosta ◽  
Jaime Navarro ◽  
Juan José Sendra ◽  
Paula Esquivias
Keyword(s):  
Sky Conditions ◽  
Overcast Sky

A comparison of lighting control strategies for open offices

2019 ◽  
Vol 149 ◽  
pp. 68-78 ◽  
Author(s):  
Tatiana Lashina ◽  
Sanae van der Vleuten-Chraibi ◽  
Marija Despenic ◽  
Paul Shrubsole ◽  
Alexander Rosemann ◽  
...  
Keyword(s):  
Control Strategies ◽  
Lighting Control

scholarly journals Dynamic Daylight Metrics for Electricity Savings in Offices: Window Size and Climate Smart Lighting Management

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3143 ◽  
Author(s):  
Ignacio Acosta ◽  
Miguel Ángel Campano ◽  
Samuel Domínguez-Amarillo ◽  
Carmen Muñoz
Keyword(s):  
Energy Efficiency ◽  
Net Present Value ◽  
Energy Savings ◽  
Performance Metrics ◽  
Control Strategies ◽  
Window Size ◽  
Weather Conditions ◽  
Worst Case ◽  
Daylight Performance ◽  
Dynamic Metrics

Daylight performance metrics provide a promising approach for the design and optimization of lighting strategies in buildings and their management. Smart controls for electric lighting can reduce power consumption and promote visual comfort using different control strategies, based on affordable technologies and low building impact. The aim of this research is to assess the energy efficiency of these smart controls by means of dynamic daylight performance metrics, to determine suitable solutions based on the geometry of the architecture and the weather conditions. The analysis considers different room dimensions, with variable window size and two mean surface reflectance values. DaySim 3.1 lighting software provides the simulations for the study, determining the necessary quantification of dynamic metrics to evaluate the usefulness of the proposed smart controls and their impact on energy efficiency. The validation of dynamic metrics is carried out by monitoring a mesh of illuminance-meters in test cells throughout one year. The results showed that, for most rooms more than 3.00 m deep, smart controls achieve worthwhile energy savings and a low payback period, regardless of weather conditions and for worst-case situations. It is also concluded that dimming systems provide a higher net present value and allow the use of smaller window size than other control solutions.

Recurrent Higher Order Neural Network Control for Output Trajectory Tracking with Neural Observers and Constrained Inputs

2010 ◽  
pp. 286-311 ◽  
Author(s):  
Luis J. Ricalde ◽  
Edgar N. Sanchez ◽  
Alma Y. Alanis
Keyword(s):  
Neural Network ◽  
Tracking Error ◽  
Network Control ◽  
Design Parameters ◽  
The Neural Network ◽  
Control Scheme ◽  
Output Trajectory ◽  
Error Dynamics ◽  
Adaptation Law ◽  
Constrained Inputs

This Chapter presents the design of an adaptive recurrent neural observer-controller scheme for nonlinear systems whose model is assumed to be unknown and with constrained inputs. The control scheme is composed of a neural observer based on Recurrent High Order Neural Networks which builds the state vector of the unknown plant dynamics and a learning adaptation law for the neural network weights for both the observer and identifier. These laws are obtained via control Lyapunov functions. Then, a control law, which stabilizes the tracking error dynamics is developed using the Lyapunov and the inverse optimal control methodologies . Tracking error boundedness is established as a function of design parameters.

Research on Integrated Control System of the Gas Pressure in Coke Oven

2013 ◽  
Vol 397-400 ◽  
pp. 1214-1219
Author(s):  
Xia Bai ◽  
Da Lu Guan ◽  
Chen Rui
Keyword(s):  
Control System ◽  
Control Strategies ◽  
Integrated Control ◽  
Control Object ◽  
Coke Oven ◽  
Pressure Control ◽  
Expert Control ◽  
Control Scheme ◽  
Hardware Reliability ◽  
Pressure Control System

This paper combines hardware reliability and software mobility with modern intelligent control through the analysis of the control object using intelligent decoupling control scheme to control the pressure control system of the large gas collector in coke oven. By using expert control strategies based on the DCS, the paper develops the system design which is versatile and effective.

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