ENERGY M ANAGEMENT & SUSTAINABILITY(ENERGY) HARVEST FOR THE WORLD
There has never been a more pressing need to husband the world’s resources and reduce
global energy consumption. Developments in building automation are a promising way
forward; in particular, using self-powered devices that harvest energy from the environment
and manual operation, says Graham Martin, Chairman and CEO, EnOcean Alliance.
The need is urgent. Most of the world’s offices areunderused, thereby overusing power and materials
just when these resources are becoming scarcer
and more costly. In the past year, energy prices havedoubled or tripled in parts of the world, for example,
Europe. Couple that with similar increases of interest
rates and mortgages, eye-watering inflation, and global
consequences of famine and strife.
The coronavirus pandemic may be over, but the trend to
hybrid working casts its shadow. Post-Covid-19, officespaces remain 50% to 70% occupied - leaving 30% to 50%
energy wasted and a legacy of unnecessary CO2 output.
Meanwhile, cabling and batteries are draining resources
such as copper and lithium. This is taking place in thecontext of pressure from world leaders to reduce carbon
emissions and reverse the impact of global climate change.
Emissions from buildings are a significant issue.
Globally, buildings account for almost 40% of the world’s
energy usage and are responsible for 36% of global
CO2 emissions. To meet the United Nations and otherclimate goals, it is imperative to make buildings moreenergy efficient. Retrofitting old buildings is quicker thanbuilding new ones and is the only option that can meet theincreasingly urgent climate and sustainability goals.
On a governmental level, Europe’s ‘Green Deal’ initiative
starts from the premise that the production and useof energy accounts for more than 75% of the EU’s
greenhouse gas emissions. Main pillars are to promote
innovative technologies and modern infrastructure, whilst
boosting energy efficiency and promoting eco-design inproducts. Forward thinking businesses are responding.
Deutsche Telekom has pledged to become climate neutral
by 2025 and similarly the EU by 2050. Whilst Microsoft
wants to be CO2 negative by 2030.

Break free from proprietary
standards and hard-wired tech

Responding to these challenges highlights significantdifferences between hard-wired, proprietary solutions
and wireless, standardised, extensible solutions. Suchchallenges can be addressed by open wireless systems.
These benefit from an open data interface and even theoption to extend the existing system with sensor types(such as CO2, desk utilisation or temperature sensors).
Wired sensors are not cost-effective. With wiring costsof over 100 euros per sensor, the typical acquisition costs
are tripled. A wired solution is also inflexible; each time

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a change is made, time is lost, and new wiring costs areincurred. Wire-free communication eliminates the needfor installing new cabling and for physical access tothe existing building automation system. Self-powered
sensors further optimise the installation - with anopen system configuration alongside broad support for
additional sensor types.

Smart buildings on the way for
flexible data harvestingWith new buildings, smart features can be designed in theearly planning stage. They can then be implemented whileeliminating cables and removing reliance on batteries.
Maintenance-free wireless devices with energyharvesting technology use environmental energy as theirsource of power. Innovations over the past ten years
have demonstrated the success of greener self-powered
devices, where kinetic energy, light, magnetic fields andtemperature differences can all be used to generatesufficient electricity.
Thanks to these sensors, the smart building can monitor
the status of its environment and use this data to makeany necessary adjustment or for analytical purposes.
The data is gathered and processed by a cloud-based IT
platform, as a digital twin if required. The physical spaceis combined with digital services and analytical tools. A
dashboard can then present the data in a user-friendly
way for managers and decision makers to view and act on.
These advances are highlighted in the example of 'The
Squaire' – a smart building in Frankfurt, Germany. Herethe installation of more than 20,000 wireless and batteryfree sensors and switches saved over 95km of cabling andmany person-years of installation time.

Reaping the energy harvest

Let us review four effective ways to harvest energy that’s
freely available in the typical building environment andusing it to power sensors that collect data and evenactuators to control outputs.
Smart-building devices can generate electricity fromkinetic energy. One press of a button can generateenough power to send a radio signal to dim the lights.
The PTM switch module has created an international
industry standard that makes it particularly easy
for manufacturers to integrate the module into allcommon switch design variants. The basis for this is
the electromechanical energy converter which – like abicycle dynamo – generates energy when the switch istwitter.com /TomorrowsFMbeing pressed. This energy harvesting technology, kinetic
switches are a resource-saving alternative to batterypowered or wired switches. An identifying code embeddedin each radio transmission matches a particular switch to
an individual light, allowing thousands of switches to beused in the same building without any interference. Eachsignal can be received up to 300 metres away.
Another option is to harvest the ambient light, bygenerating and storing electricity from solar cells.
A solar-powered sensor can measure for example
temperature, humidity, occupancy, air quality or door/
window status with low power consumption and highreliability. The modules’ tiny internal storage enablestransmission of measured values even in total darkness
for many days.

"Wired sensors are
not cost-effective. Withwiring costs of over 100
euros per sensor, thetypical acquisition costs
are tripled."
Thermoelectric effects offer further energy resourcesthat can be harvested: this time using tiny temperature
differences to create electricity through long-known
physics principle the Seebeck Effect using Peltierelements. Temperature differences offer the ability to

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harvest a great deal of energy. For example, the warmingof a drop of water by one degree Celsius requires thesame amount of energy needed to send about 10,000
EnOcean wireless telegrams. That is enough to operate
not just a wireless sensor, but even wireless actuatorssuch as heating valve actuators. Using a DC/DC converter
combined with a Peltier element, manufacturers canalso utilize thermo-electric powered applications. As
EnOcean wireless modules are optimised for a wide
input voltage range, the converter is a complete matchfor energy harvesting applications that take advantage oftemperature differentials.
Rounding out the quartet of possibilities there ismagnetics. Electrons flowing in cables can deliver energy
through magnetism ready to harvest. This goes beyond
simply measuring energy consumption through theelectrical buses. Harvesting some of the energy from thebus is utilized to send data to the building system.

Conclusion

The combination of intelligent wireless buildings withenergy-harvesting controls and operation is the key that
unlocks the potential of smart buildings and makes thetechnology economic and practical in new construction
and retrofit situations. The elimination of cabling
minimises installation costs, the elimination of batteries
eliminates operating costs, and together they create asolution that is maintenance-free and can be quickly andeasily adapted to changing operational requirements
whilst optimising energy use and costs at any time.

www.enocean-alliance.org

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