Can smart windows help us save energy, and emissions?
What’s happening? The 40-storey 825 Third Avenue building in Manhattan has been retrofitted with windows from smart-glass specialist View, which convert the windows into transparent digital screens. The technology uses in-built AI to automatically adjust to the sun’s brightness, which is designed to provide outdoor views while minimising heat, glare and energy consumption. (Smart Cities World)
Sounds smart – Quite. View offers dynamic smart glass windows that use electrochromic technology to control light and heat transfers into building spaces. Unlike photochromic technology (think transition lenses on glasses), which passively responds to changes in light levels, the company’s electrochromic solution allows building occupiers to actively control window tinting via a mobile app.
The 825 Third Avenue building is using View’s Immersive Experience product, which has added capabilities for communication, content-sharing and user interactions on the windows. The company’s standard dynamic smart glass windows, however, are marketed as an energy saving building enhancement.
How do they save energy? The technology uses the shading to stop temperatures from rising too greatly inside glass-coated buildings, therefore reducing the need to use air conditioning which consumes a lot of energy, leading to increased CO2 emissions. An independent study found a Seattle building retrofitted with View smart windows reduced its annual energy consumption by 17.7%, with peak cooling energy use loweredby up to 23%.
The technology could be particularly useful when it comes to all-glass skyscrapers, which are expensive to run and emissions-intensive due to the large energy requirements needed to regulate their internal temperature.
In 2019, New York City’s Mayor Bill De Blasio said he would pass a law to actually ban “incredibly inefficient” glass (and steel) skyscrapers in the city, due to their environmental impacts. “Putting up monuments to themselves that harm our Earth and threaten our future will no longer be allowed in New York City,” he said. The statement was later backtracked a little, with no outright ban but a promise to bring forward energy efficiency standards for these buildings.
What are the costs? View’s smart glass windows are around 40% more expensive than conventional curtain wall glass. The firm, however, says the combination of annual energy savings following their installation, along with the ability to use smaller heating and air conditioning units, results in a five-year payback from installation.
It’s worth pointing out lifecycle environmental analyses indicate View’s dynamic glass – and that of its competitor SageGlass – have significantly higher manufacturing emissions compared to traditional glass products. Previous analysis (albeit, from 2005) indicates, however, over their lifetime electrochromic windows save around 30 times the energy required to produce them.
Why don’t we all invest in energy efficiency? Good question. Time and again it’s pointed out as the lowest-cost and one of the most effective means of reducing emissions and tackling climate change. It’s a key part of emissions-reduction scenarios that are compatible with avoiding dangerous temperature rises.
The problem is to do with the high up-front costs, which can present challenges to financing models, a complex system of actors involved in the process of upgrading and retrofitting buildings, previous poorly designed support schemes (particularly in the UK), and irrational human behaviour.
These things will all need to be tackled to some degree if we are to make more use of the invisible fuel that is saving energy.