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Final Report Summary - WIFEEB (Wireless Friendly Energy Efficient Buildings)

Wireless Friendly Energy Efficient Buildings

FP7 MC-IAPP project 286333 WiFEEB
Partners: The University of Sheffield, UK, Ranplan UK and the Czech Technical University, Prague, CZ.

This project addresses how buildings and the built environment can be both energy efficient and wireless friendly providing a low energy consumption building with good wireless signal coverage for users, e.g. mobile telephone connectivity and wifi.
This project’s objectives are to develop and verify the new concept of the wireless friendly, energy efficient building, specifically
To develop and verify the new concept of the wireless friendly, energy efficient building
To design and evaluate construction materials
To show how existing buildings can be reconfigured and how new buildings can be designed
To simulate several case studies and verify some of them by experiment
To use energy resources more efficiently – the wireless friendly zero carbon building.

Work Progress

The materials used to construct and insulate buildings have properties that are not well documented. In order to calculate the energy and wireless performance of a building these properties must be known. Hence the wireless propagation properties of building and insulation materials have been assessed by measurements from 400 MHz to 65 GHz to include both current and future wireless networks and systems. Thermal properties of materials have also been assessed. Materials included concrete, bricks, woods, plasters, facades, window blinds and novel green insulation walls. The results have been used in our subsequent designs and simulations. A table is published on the web site.

To improve the design of buildings and create new constructions the project has studied two particular novel structures: 1. Frequency selective (FSS) building components such as walls, windows and facades and 2. Intelligent walls.
1. FSS are simple printed metallic patterns which can be applied to insulation, windows or as standalone panels and act as filters to wireless signals allowing some frequency bands to pass while rejecting others, e.g. passing mobile telephone signals and stopping WiFi signals. This solution allows the use of metal backed insulation which does not interfere with some of the wireless signals while rejecting others. A number of passive FSS have been designed for use in buildings during the project. The results show that although FSS can be useful in passing signals their ability to stop signals is limited, reducing a signal by about 90%. Further work has produced active surfaces that can be changed in real time to allow reconfiguration of a building in line with user’s requirements at any particular time.
2. Intelligent walls. This solution provides designers with the ability to reconfigure a building for different clientele. The project has investigated the dynamic reconfiguration of buildings to provide improved wireless connectivity or security in selected parts of the building. For example, a conference centre has to accommodate movements in people at different times of the day and in accordance with the conference programme. In order to provide fast communication, signal levels in certain areas or rooms need to be boosted where there are lots of people while in other areas they can be reduced as there are fewer people in those areas. A good example of this is during conference presentation times when most delegates will be in lecture rooms and few in the coffee area while at coffee time everyone gathers in the coffee area. To this end intelligent walls controlled dynamically have been designed with hidden antennas and active FSS to change signal power and coverage within the conference centre.
Simulation Tools - A major part of this project is the development and optimisation of computer aided design (CAD) tools that for the first time combine wireless propagation models with energy efficiency models producing a complete simulation model for the built environment. The software iBuildnet from Ranplan has been developed in a number of ways to calculate both the wireless and energy performance of a building. 3D modelling capability of the software iBuildnet has been implemented allowing CAD data for a building to be input directly, setting up the model for simulation and giving 3D outputs. The input CAD data specifies the construction of the building including dimensions, all the materials used, the layout etc. This enables the software to specify the wireless and energy properties of the building by assigning propagation properties and thermal properties to the structure for simulation. An energy efficiency module Energy+ has been linked to iBuildnet as a plug in, enabling for the first time a combined energy/wireless efficiency model giving complete simulation of a building. Energy+ is a widely used software package for calculating the insulation/thermal properties of a building and the energy consumption for different insulation scenarios and external weather conditions. The wireless performance of the software has been improved to include calculations of coverage efficiency and capacity in buildings for wireless systems and networks.

Several case studies have been modelled in iBuildnet including a secure building, a smart home including smart energy metering, the use of intelligent reconfigurable structures and a mixed use shopping & commercial environment. Results have been verified experimentally for range of scenarios. One example is a UK Victorian house with two floors and a basement. The propagation of wireless signals through the Victorian house on 3 levels was calculated for different frequencies showing that propagation at low frequencies (433 MHz) is far superior to that at higher frequencies (5.8 GHz) which is important for WiFi and smart meter applications. Materials within a building can be changed to improve the wireless signal performance and the effects of human occupation show that signals are absorbed by the body reducing signal coverage locally.

Improving wireless efficiency can reduce thermal performance and a compromise may be necessary as insulation materials often have foil backing which blocks wireless signals. This can result in reduced signal levels within parts of a building resulting in low transfer data rates. Conversely if individual rooms are lined with foil backed insulation it can actually improve the amount of data that can be sent wirelessly by isolating network cells and hence reducing interference between rooms or areas within a building. In addition, using FSS metal coatings can improve performance as discussed earlier.
Securing buildings, where the internal wifi needs to be confined to a building or external signal propagation (mobile phones) needs to be stopped (such as a prison), remains a significant challenge. Lining the external walls with metal to create a Faraday cage is not practical as any crack or open door will allow signals to creep into or out of a building. However, the project has developed a switched frequency selective surface that scrambles a mobile phone signal preventing reception or transmission.

Training: Fellows have been trained in using iBuildnet and CST, an electromagnetic simulation tool.
Language training has been available within the two Universities for fellows to access.

Impact: Socio economic impact has arisen from the ability to provide an efficient network for wireless signal coverage while reducing the energy consumption of the building. The further development of “iBuildnet” gives Ranplan a world leading network simulation tool.

Overall the project has for the first time developed tools for optimising a building for both wireless signal performance and energy efficiency.

For further information contact: Professor Richard Langley, WiFEEB project coordinator
Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, UK
Tel: +44 1142225583 Email:

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