Smart Glass and Its Potential in Energy Savings

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Kaufui V. Wong ◽  
Richard Chan
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Energy Demand ◽  
Energy Savings ◽  
Suspended Particle ◽  
Light Transmittance ◽  
Voltage Source ◽  
Glass Technology ◽  
Ion Conductor ◽  
Advantages And Disadvantages

Smart glass is such that its properties may be changed by application of a potential across it. The change in properties may be engineered to alter the amount of heat energy that can penetrate the glass which provides heating and cooling design options. Therein lies its potential in energy savings. Smart glass may be classified into three types: electrochromic, suspended particle, and polymer dispersed liquid crystal (PDLC). Each of these types has their own mechanisms, advantages, and disadvantages. Electrochromic smart glass is the most popular, currently it utilizes an electrochromic film with an ion storage layer and ion conductor placed between two transparent plates. The electrochromic film is usually made of tungsten oxide, owing to the electrochromic nature of transition metals. An electric potential initiates a redox reaction of the electrochromic film transitioning the color and the transparency of the smart glass. Suspended particle smart glass has needle shaped particles suspended within an organic gel placed between two electrodes. In its off state, the particles are randomly dispersed and have a low light transmittance. Once a voltage is applied, the needle particles will orient themselves to allow for light to pass through. PDLC smart glass works similarly to the suspended particle variety. However, in PDLC smart glass, the central layer is a liquid crystal placed within a polymer matrix between electrodes. Similar in behavior to the suspended particles, in the off position the liquid crystals are randomly dispersed and have low transmittance. With the application of a voltage, the liquid crystals orient themselves, thereby allowing for the transmittance of light. These different smart glasses have many different applications, but with one hindrance. The requirement of a voltage source is a major disadvantage which greatly complicates the overall installation and manufacturing processes. However, the integration of photovoltaic (PV) devices into smart glass technology has provided one solution. Photovoltaic films attached in the smart glass will provide the necessary voltage source. The photovoltaic film may even be designed to produce more voltage than needed. The use a photovoltaic smart glass system provides significant cost savings in regards to heating, cooling, lighting, and overall energy bills. Smart glass represents a technology with a great deal of potential to reduce energy demand. Action steps have been identified to propagate the popular use of smart glass.

scholarly journals Liquid Crystal Devices for Beam Steering Applications

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 247
Author(s):  
Rowan Morris ◽  
Cliff Jones ◽  
Mamatha Nagaraj
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Adaptive Optics ◽  
Beam Steering ◽  
Optical Components ◽  
Advantages And Disadvantages ◽  
Liquid Crystal Devices

Liquid crystals are valuable materials for applications in beam steering devices. In this paper, an overview of the use of liquid crystals in the field of adaptive optics specifically for beam steering and lensing devices is presented. The paper introduces the properties of liquid crystals that have made them useful in this field followed by a more detailed discussion of specific liquid crystal devices that act as switchable optical components of refractive and diffractive types. The relative advantages and disadvantages of the different devices and techniques are summarised.

Financial Viability of Energy Conservation Using Natural Light in an Academic Building in Temperate Zone

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Pooja Sharma ◽  
Dibakar Rakshit
Keyword(s):  
Energy Demand ◽  
Energy Savings ◽  
Energy Requirement ◽  
Luminous Flux ◽  
Light Transmittance ◽  
Natural Light ◽  
New Delhi ◽  
Artificial Lighting ◽  
Flux Level ◽  
Academic Building

The environment of a regularly occupied space can be extensively improved by maximum utilization of natural light/daylight, which is available in abundance. In Indian climate, availability of sufficient day light in both direct and diffused form of radiation can lead to reduction in dependency on artificial lighting thus, decreasing energy demand for artificial lighting system. In this study, an institutional building in New Delhi, India is analyzed for its daylighting characteristics. The academic block of a building comprising all categories of regularly spaces is modeled and simulated using Integrated environmental solutions - virtual environment (IES VE). The objective is to analyze the extent of penetration of natural light into these spaces of the building for reducing energy requirement for artificial lighting by studying a room, which performs the worst as per present case parameters. The conclusion puts forth the optimal solutions for utilizing maximum day light in a work space, complying with standards set forth by building construction council by utilizing the principles for increasing luminous flux level through visual light transmittance, window-to-wall ratio, and controlled usage of artificial lighting. Considering all these factors in the analysis, energy savings and carbon mitigation due to these savings in regularly occupied spaces are finally evaluated.

scholarly journals Recent Advances in Adaptive Liquid Crystal Lenses

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 272 ◽  
Author(s):  
José Francisco Algorri ◽  
Dimitrios C. Zografopoulos ◽  
Virginia Urruchi ◽  
José Manuel Sánchez-Pena
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Focal Length ◽  
Research Field ◽  
Performance Characteristics ◽  
External Stimulus ◽  
Future Prospects ◽  
Advantages And Disadvantages ◽  
Recent Advances ◽  
Active Research

An adaptive-focus lens is a device that is capable of tuning its focal length by means of an external stimulus. Numerous techniques for the demonstration of such devices have been reported thus far. Moving beyond traditional solutions, several new approaches have been proposed in recent years based on the use of liquid crystals, which can have a great impact in emerging applications. This work focuses on the recent advances in liquid crystal lenses with diameters larger than 1 mm. Recent demonstrations and their performance characteristics are reviewed, discussing the advantages and disadvantages of the reported technologies and identifying the challenges and future prospects in the active research field of adaptive-focus liquid crystal (LC) lenses.

scholarly journals Measuring system for liquid level determination based on linear electro-optical effect of liquid crystal

2018 ◽  
Vol 226 ◽  
pp. 02005
Author(s):  
Olga Denisova
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Liquid Level ◽  
Measuring System ◽  
Light Transmittance ◽  
Practical Significance ◽  
Liquid Media ◽  
Optical Cell

This article describes an updated system for measuring and controlling the level of liquid media. Well-known capacitance method for determining the liquid level is modernised. The new scheme proposes the use of electro-optical cell with a nematic liquid crystal. Homeotropically oriented liquid crystal is sandwiched between two plates, one of which is glass, and the other – crystal – cadmium sulfide CdS photoconductor. liquid crystal cell serves as an indicator. Its light transmittance depends on the applied voltage. Cell is designed so that the dependence of the phase delay of the voltage is linear. The article describes a mathematical model showing linear dependence, confirmed experimentally. Application of linear electrooptic effect observed in liquid crystals, allows to improve the accuracy and speed of measurement of liquid media, as the liquid crystal is an anisotropic medium more sensitive than solid crystals. The relaxation time of the orientation effects in liquid crystals is ~10-6 s. From the point of view of practical significance, this method will be of interest for application in the fuel and energy complex, in particular, oil and gas industry for the commercial accounting of petroleum products.

New structure induced by elastic anisotropy in cylindrical nematic liquid crystal

2017 ◽  
Vol 13 (2) ◽  
pp. 4705-4717
Author(s):  
Zhang Qian ◽  
Zhou Xuan ◽  
Zhang Zhidong
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Elastic Anisotropy ◽  
Nematic Liquid Crystals ◽  
Gennes Theory

Basing on Landau–de Gennes theory, this study investigated the chiral configurations of nematic liquid crystals confined to cylindrical capillaries with homeotropic anchoring on the cylinder walls. When the elastic anisotropy (L2/L1) is large enough, a new structure results from the convergence of two opposite escape directions of the heterochiral twist and escape radial (TER) configurations. The new defect presents when L2/L1≥7 and disappears when L2/L1<7. The new structure possesses a heterochiral hyperbolic defect at the center and two homochiral radial defects on both sides. The two radial defects show different chiralities.

An electrically light-transmittance-switchable film with a low driving voltage based on liquid crystal/polymer composites

2019 ◽  
Vol 47 (1) ◽  
pp. 106-113 ◽  
Author(s):  
Chunxin Li ◽  
Mei Chen ◽  
Lanying Zhang ◽  
Wenbo Shen ◽  
Xiao Liang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Polymer Composites ◽  
Liquid Crystal Polymer ◽  
Light Transmittance ◽  
Driving Voltage ◽  
Crystal Polymer

scholarly journals Energy Performance Assessment of Innovative Building Solutions Coming from Construction and Demolition Waste Materials

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1226
Author(s):  
Beatriz Fraga-De Cal ◽  
Antonio Garrido-Marijuan ◽  
Olaia Eguiarte ◽  
Beñat Arregi ◽  
Ander Romero-Amorrortu ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Energy Demand ◽  
Energy Savings ◽  
Flow Analysis ◽  
Weather Conditions ◽  
Energy Performance ◽  
Construction And Demolition Waste ◽  
The European Union ◽  
Demolition Waste ◽  
The Impact

Prefabricated solutions incorporating thermal insulation are increasingly adopted as an energy conservation measure for building renovation. The InnoWEE European project developed three technologies from Construction and Demolition Waste (CDW) materials through a manufacturing process that supports the circular economy strategy of the European Union. Two of them consisted of geopolymer panels incorporated into an External Thermal Insulation Composite System (ETICS) and a ventilated façade. This study evaluates their thermal performance by means of monitoring data from three pilot case studies in Greece, Italy, and Romania, and calibrated building simulation models enabling the reliable prediction of energy savings in different climates and use scenarios. Results showed a reduction in energy demand for all demo buildings, with annual energy savings up to 25% after placing the novel insulation solutions. However, savings are highly dependent on weather conditions since the panels affect cooling and heating loads differently. Finally, a parametric assessment is performed to assess the impact of insulation thickness through an energy performance prediction and a cash flow analysis.

scholarly journals A Systematic Literature Review of Multi-Criteria Decision-Making Methods for Sustainable Selection of Insulation Materials in Buildings

2021 ◽  
Vol 13 (2) ◽  
pp. 737
Author(s):  
Indre Siksnelyte-Butkiene ◽  
Dalia Streimikiene ◽  
Tomas Balezentis ◽  
Virgilijus Skulskis
Keyword(s):  
Decision Making ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Energy Demand ◽  
Energy Performance ◽  
Future Research ◽  
Multi Criteria Decision Making ◽  
Insulation Materials ◽  
Advantages And Disadvantages ◽  
Selection Of

The European Commission has recently adopted the Renovation Wave Strategy, aiming at the improvement of the energy performance of buildings. The strategy aims to at least double renovation rates in the next ten years and make sure that renovations lead to higher energy and resource efficiency. The choice of appropriate thermal insulation materials is one of the simplest and, at the same time, the most popular strategies that effectively reduce the energy demand of buildings. Today, the spectrum of insulation materials is quite wide, and each material has its own specific characteristics. It is recognized that the selection of materials is one of the most challenging and difficult steps of a building project. This paper aims to give an in-depth view of existing multi-criteria decision-making (MCDM) applications for the selection of insulation materials and to provide major insights in order to simplify the process of methods and criteria selection for future research. A systematic literature review is performed based on the Search, Appraisal, Synthesis and Analysis (SALSA) framework and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. In order to determine which MCDM method is the most appropriate for different questions, the main advantages and disadvantages of different methods are provided.

scholarly journals A Computer Vision-Based Occupancy and Equipment Usage Detection Approach for Reducing Building Energy Demand

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 156
Author(s):  
Paige Wenbin Tien ◽  
Shuangyu Wei ◽  
John Calautit
Keyword(s):  
Deep Learning ◽  
Real Time ◽  
Energy Demand ◽  
Energy Savings ◽  
Internal Heat ◽  
Electrical Equipment ◽  
Building Energy ◽  
Hvac Systems ◽  
Equipment Usage

Because of extensive variations in occupancy patterns around office space environments and their use of electrical equipment, accurate occupants’ behaviour detection is valuable for reducing the building energy demand and carbon emissions. Using the collected occupancy information, building energy management system can automatically adjust the operation of heating, ventilation and air-conditioning (HVAC) systems to meet the actual demands in different conditioned spaces in real-time. Existing and commonly used ‘fixed’ schedules for HVAC systems are not sufficient and cannot adjust based on the dynamic changes in building environments. This study proposes a vision-based occupancy and equipment usage detection method based on deep learning for demand-driven control systems. A model based on region-based convolutional neural network (R-CNN) was developed, trained and deployed to a camera for real-time detection of occupancy activities and equipment usage. Experiments tests within a case study office room suggested an overall accuracy of 97.32% and 80.80%. In order to predict the energy savings that can be attained using the proposed approach, the case study building was simulated. The simulation results revealed that the heat gains could be over or under predicted when using static or fixed profiles. Based on the set conditions, the equipment and occupancy gains were 65.75% and 32.74% lower when using the deep learning approach. Overall, the study showed the capabilities of the proposed approach in detecting and recognising multiple occupants’ activities and equipment usage and providing an alternative to estimate the internal heat emissions.

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