Electrochromic (EC) Technology
Keeping pace with technology for most people is like trying out a new fashion. At first, there is uncertainty that fades with more knowledge.
One technology that has grown over the last decade is the global electrochromic glass market. It is often referred to as “smart glass” because it can detect changes in light and heat.
The definition of electrochromic technology is fairly basic and easy to understand. Light sensitive devices are equipped with lithium ions and electrons capable of bleaching or coloring certain types of materials such as film, paper and glass.
This technological process that relies on ions and electrons is inserted between material layers to effect the ability to make materials sensitive to sunlight and/or heat.
Electrochromics are also a science involving coloring various organics, polymers and metal oxides. So there is also a chemical component to this science as well as an electrical component to electrochromic smart glass and electrochromic glazing.
The Long History of Electrochromic Technology
Scientists and inventors have used light to discover new applications and to develop new technologies, long before the dawn of the electrochromic window technology that we know today.
The actual history of solar radiation and color changing EC glazing technology began in 1704, when Swiss dye and pigment producer, Johann Jacob Diesbach discovered that hexacyanoferrate, known as Prussian Blue, changes from its transparent state to blue when oxidation of iron is introduced.
Pigments are derived from plants or animals. Thus, Prussian Blue pigment is derived from ferrous ferrocyanide salts, and has inspired the liquid crystal used in many smart glass products or electrochromic device technology today.
By the 1930s, Kobosew, Nekrassow and T. Krauss of Lichtenstein advanced technology with more detailed and advanced coloration studies using bulk tungsten and tungsten oxide.
By 1969 S.K. Deb first demonstrated electrochromic coloration using tungsten on film through the application of an activated electric field. Many attribute this experimentation with an ion storage layer and transparent conductor as the birth of electrochromic technology.
The First Use of Electrochromic Glass
In order to fully understand the first use of electrochromic glass, it’s important to know the composite materials of glass to show how electrochromic glass or any EC device is used.
The composite materials in electrochromic material are soda ash, limestone and sand. These are melted at high temperatures to form glass. When ordinary glass is heated at high temperatures, it structurally resembles a liquid.
Glass changes to solids at ambient temperatures. Thus, when ordinary glass is used in electrochromic devices such as a window, the glass material receives an electrochromic coating or tint that creates a smart window capable of changing color, sensing daylight, and preventing loss of heat.
The first use of electrochromic glass was likely glass lenses in the optical industry. When seven layers are applied to glass lenses, the lenses are able to adjust the human eyes to strong sunlight or other harsh light. This was the advent of sunglasses such as the daylight sensing transition glasses which were made of similar electrochromic material.
By applying smart tint to sunglasses, they become quickly adaptable to changes in sunlight. Today sunglasses and night vision goggles rely on electrochromic technology and the adaptability of this type of electrochromic glass is referred to as smart glass because it detects changes in sunlight.
The Wide World of Electrochromic Glass
Once the optical world advanced the use of electrochromic glass for vision, a door opened for broadening the uses of electrochromic glass and smart glass windows.
When voltage, heat or light is applied to glass, it alters glass properties that can change from transparent to translucent and reverse from translucent to transparent. This is referred to as switchable glass or smart glass.
Ref: http://large.stanford.edu/courses/2020/ph240/lutnick2/
Dynamic glass or smart glass windows can switch on demand to control brightness and heat. This type of glass is energy efficient and reduces the cost of energy appreciably for homes and buildings. For home buyers energy efficiency in EC windows is one of the key considerations.
The auto industry began to make use of EC technology for vehicle windshields. By using electrochromic glazing or an electrochromic layer on vehicle windows, drivers found less eye strain and less chances of sun and snow blindness as well as less diminished vision over longer periods of driving time. Thus, this type of glazing or even electrochromic film is also a safety feature.
New model vehicles are sold with EC glass for greater driving safety and are no longer considered optional.
Smart Glass for Windows
The building, home design and construction industries have benefitted greatly from smart widows and doors. By adding smart windows and doors to homes and buildings, selling values increase, as well as property values.
In terms of savings, solar technology has a proven track record for solar heat in homes and buildings. By using dynamic glass for solar panels, solar storage increases.
Solar panels are actually collectors of sunlight used as energy sources. These panels are placed on roof tops or flat roofs. The panels have photovoltaic (PV) cells that store sunlight and transfer that as heat or cooling to the interior of a home or building.
However by using electrochromic glass on solar panel collectors, the amount of stored energy increases and can be used for hot water heating.
Solar vacuum tube collectors are used to heat homes and buildings as well as hot water heaters, pools and for cooling for air conditioning systems.
A solar vacuum tube collector has two layers of glass and a vacuum situated between the layers.
The outer solar vacuum tube layer is made from borosilicate glass which is low in iron, consisting of two layers of glass with a vacuum in between the layers. This allows 98% light energy as throughput. In order to increase the energy efficiency of solar vacuum tubes, dynamic glass is used for greater energy savings for EC devices.
Creating a More Useful Environment
One factor overlooked is the effect of electrochromatics on the environment. When homes and buildings are built with switchable glass windows and solar panels are equipped with smart glass, the result is not only energy saving efficiency but also these devices encourage more responsible attention to renewable energy.
Already many newly built skyscrapers are designed and engineered with more than 50% of smart glass technology applied to interior and exterior doors and windows. You can recognize these by the bounce reflection of sunlight on exterior windows and doors.
Today switchable glass is found in many office conference rooms and office cubicles where privacy is required or where proprietary work is done.
Newly built school buildings are also designed with switchable glass. When a light switch is flipped in commercial office buildings with switchable glass, the room darkens for training and orientation films for students and newly hired employees. Switchable glass walls make viewing simple and easy and serve as a viable means of privacy.
In homes, dynamic glass panel sections help contain and control heat and light in open areas.
When coupled with ergonomically designed interiors, stores and retail business make use of dynamic glass as a selling point that creates a comfortable shopping environment.
Many casinos and sporting resorts have installed dynamic glass, smart glass and switchable glass to facilitate their need to maintain vigilance of the activities taking place during hours of operation.
Where Else EC Glass Is Found
In addition to homes, buildings, offices and entertain resorts, there are many other place where you find EC glass. This includes:
. Municipal buildings
. Police stations
. Hotel skylights
. Industrial clean rooms
. Laboratories
Benefits and Efficacy of EC Glass
The best way to judge the benefits and efficacy of EC glass is best shown in numbers that include:
. Reduction in home and building energy consumption up to 20%
. Reduction of glare which means doors and windows do not require shades or other types of light blockage
. Provides a variable solar heat gain of 0.47 – 0.09
. Provides 62% – 2% light transmission variability within multiple independent zones in each window
. Reduces building HVAC costs by up to 30% and lighting costs by 60
. Reduction annual seasonal cooling loads in commercial buildings by 20%
. Reduction in peak electricity demand in most of the United States by 19% to 26%
Qs and As About EC Glass
What is the average cost to install EC glass?
Costs depend on structure size and specificity of location of EC glass, for example the size of a commercial building’s roof vs. that of a residence. Adding EC glass for solar heating and cooling should be discussed with the installer.
Can I Replace Existing Windows and Doors with Dynamic Glass?
Yes. Choose a window and door installer licensed and experience with dynamic glass experience.
Can Smart Glass be Adapted to a Computerized System?
Yes. In fact, today’s smart glass installed in homes and buildings can be operated from a home or building’s existing automated system and also from a smart phone device.
Wrapping Up
Now that you know what EC glass is, what it does and how it can make your life more convenient and energy efficient, the future of EC glass has no limits. With new uses for this technology found every day, it’s easy to imagine what would happen to virtual reality glasses when EC glass lenses are applied.
It is also easy to see how 5G technology will affect the use of anti reflective glasses (AR) readapted as smart glasses that are computer-capable, wearable glasses.
In sync with 5G. smart glasses would add extra information and 3D images including videos and animation. This process could overlay computer-generated and digital information for users.
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