Case studies

Self-Powered EnOcean Wireless Technology for a Green Home in Stuttgart (2/7/2008)

In the residential building market there is an increasing number of houses that are striking, not just for their modern architecture but also for the modern technology installed in them. One example is a modern house owned by a young couple situated on the fringe of a small town near Stuttgart, Germany. The couple wanted an environmentally-friendly building, and a structure with clear lines in light-coloured concrete, so the architects designed a compact building with rooms and levels that flow into one another. The ground floor with kitchen, living room, dining room and entertaining area is open-plan with large glass panels and windows. The upper floor, with its long narrow windows, conceals private spaces.

The new build outside Stuttgart, incorporating self-powered wireless technology for energy-efficiency.

Green design

The heating and air-conditioning of the house are unconventional, future-oriented and well-conceived. The heating is under floor and controlled by a heat exchange pump, for which two holes were bored, each 136 meters deep. Air-conditioning is controlled via a central ventilation system with heat recovery. In summer, the temperature can be cooled through the ventilation system by means of a small air heat pump, which can also be used to moderately heat in spring and autumn if required. It is also possible to use rain water with a cistern and separate installation, for the building's toilets.

Installation

The electrical installation of the lighting and blind control system initially looked like it was going to be complex and costly. The large window areas required 30 blind mechanisms. In addition, the subtle light throughout the house with ceiling spotlights, uplights and downlights, pendant and specular-reflector luminaries, and indirect lighting in suspended ceilings, meant that there were more than 40 lighting points to be switched. Added to which the light-coloured concrete did not allow for any corrections to be made to the interior later on.

A PHC bus control system from PEHA was consequently chosen, which is operated by self-powered EnOcean Easyclick transmitters. EnOcean sensors are powered by energy drawn from movement, light or even changes in temperature in their surrounding environment. This harvested energy is used for transmitting sensor information over a distance of up to 30 meters within a building.

Battery-free switches for lighting, blind and temperature control.

The two systems for blinds and lights respectively, are linked by a 940 FU-C interface. The heating is regulated by a Thermokon SR07P wireless room sensor and SRC-ADO BCS receivers. Only the power outlets were installed conventionally. To complement the light-coloured concrete, AURA glass aluminium switches were selected.

For the sake of simplicity, electrical distribution units were installed on both the ground floor and upper floor, connected by a bus cable. There is also an Easyclick receiver and antenna in the centre each the floor, with additional sockets provided for the installation of repeaters. Despite the reinforced concrete construction however, it was possible to dispense with the repeaters entirely. The whole installation presented no problems for an experienced contractor, and the owner of the house was able to program the bus system and set the wireless transmitters themselves.

Conclusion

Self-powered wireless sensors from EnOcean make a home intelligent and energy-efficient, and the technology's ability to offer interoperability between the different operating facets of a building puts it on a par with EIB/KNX or LON.

This house near Stuttgart benefitted from significant installation time and cost savings by installing wireless monitoring and control technology that requires no wires, no batteries and no maintenance. In addition, having virtually no restrictions on where the sensors or switches can be mounted, means that these home owners have unlimited flexibility should they need to move them at a later date.

Equipment list

PEHA PHC-Easyclick transmitters.
Thermokon wireless-thermostat.

EnOcean GmbH is a pioneer in self-powered wireless sensor technology based on energy harvesting techniques for intelligent green buildings. To further develop the technology and ultimately see it become a formal international standard for sustainable buildings, a group of key companies across Europe and North America has united to form the EnOcean Alliance.

www.enocean-alliance.org