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energy efficiency

Whereas, wind power, he says, has

is an in-use rating and very few countries

moving parts, which involves maintenance,

around the world have anything equivalent.”

and the environment around most buildings

What Bannister would most like to see

is too turbulent and unpredictable for it to

for the future in Australia is the lessons

work effectively. He also predicts that co-

learnt with HVAC in the upper end of the

generation and trigeneration are not going

commercial building sector make their way

to advance much, except in Victoria, largely

into the rest of the sector. We have identified

a lot more attractive to improve the ‘front

due to gas prices.

it is possible to make up to 50% energy-

of house’ rather than to improve ‘back of

efficiency improvements with HVAC, but that

house’ efficiency.

Dr Paul Bannister

The future

hasn’t extended outside the NABERS-based

“There has been a massive upskilling to

Recently engaged by the Better Buildings

office building domain. He says we don’t see

the [air-conditioning] industry over the last

Partnership in the United Kingdom, Bannister

the same transformation happening in hotels,

5–10 years, so I’d like to think that that is

is setting off for London soon to develop

shopping centres and at the institutional level,

going to lead to [HVAC] energy efficiency in

a scheme to guarantee the in-use energy

such as hospitals.

more than just the office sector, but I may

performance of new offices, based on Aus-

“With the office building sector it became

tralia’s NABERS rating scheme. “One of the

just as attractive to improve the efficiency of

things that has characterised the Australian

the building as it was to improve the look of

industry is the use of NABERS because it

the foyer. Whereas for most hotels it is still

be dreaming!” *International Energy Agency report — http://www.iea.org/publications/freepublications/ publication/BuildingEnergyPerformanceMetrics.pdf

Nanostructures enable smart windows Researchers have created a new type of smart window that could

room to less than 5% — compared with the 20–30% achieved

cut window-cleaning costs, reduce heating bills and boost worker

by other prototype vanadium dioxide-coated, energy-saving

productivity. Developed by University College London (UCL) with

windows — with this reduction in ‘glare’ providing a big boost

support from the Engineering and Physical Sciences Research

to occupant comfort.

Council (EPSRC), the window utilises pyramid-like nanostructures

Windows made of the glass could be especially well suited

engraved onto glass and combined with a thermochromic coating.

to high-rise office buildings. As noted by Dr Papakonstantinou,

The window is ultraresistant to water, so rain hitting the

“Because of the obvious difficulties involved, the cost of cleaning

outside forms spherical droplets that roll easily over the surface

a skyscraper’s windows in its first five years is the same as

— picking up dirt, dust and other

the original cost of installing them.

contaminants and carrying them

Our glass could drastically cut this

away. This is due to the pencil-like,

expenditure, quite apart from the

conical design of nanostructures

appeal of lower energy bills and

engraved onto the glass, trapping air

improved occupant productivity thanks

and ensuring only a tiny amount of

to less glare.”

water comes into contact with the

Discussions are now underway

surface. This is different from normal

with UK glass manufacturers with

glass, where raindrops cling to the

a view to driving this new window

surface, slide down more slowly and

concept towards commercialisation.

leave marks behind.

The key is to develop ways of scaling

The glass is coated with a very thin (5–10 nm) film of vanadium dioxide, a cheap and abundant material. During cold periods, the window

up the nanomanufacturing methods A smart glass prototype developed by the UCL team. The dark areas are decorated with the nanostructures which significantly suppress reflections and repel water. Image courtesy of Alaric Taylor, UCL.

will stop thermal radiation escaping

that the team has developed to produce the glass, as well as scaling up the vanadium dioxide coating process. “We also hope to develop a smart

and so prevent heat loss; during hot periods, it will prevent

film that incorporates our nanostructures and can easily be added

infrared radiation from the sun entering the building. The UCL

to conventional domestic, office, factory and other windows on a

team calculates that this could result in a reduction in heating

DIY basis to deliver the triple benefit of lower energy use, less

bills of up to 40%.

light reflection and self-cleaning, without significantly affecting

Finally, the design of the nanostructures also gives the

aesthetics,” Dr Papakonstantinou said.

windows the same antireflective properties found in the eyes

Smart windows could begin to reach the market within

of moths and other creatures that have evolved to hide from

around 3–5 years, depending on the team’s success in securing

predators. It cuts the amount of light reflected internally in a

industrial interest.

10 Sustainability Matters - Feb/Mar 2016

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Sustainability Matters Feb/Mar 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...

Sustainability Matters Feb/Mar 2016  

Sustainability Matters is a bi-monthly magazine showcasing the latest products, technology and sustainable solutions for industry, governmen...