ECN and TNO have been working together for some time on halving CO₂ emissions of the built environment. The goal is for the built environment to be energy-neutral in 2050. The WAELS project is taking concrete steps towards achieving this. ECN is the lead communicator for this innovative project that includes TNO and the Eindhoven University of Technology as partners.

“WAELS is a Dutch acronym for Homes as an Energy Supplying System,” says Wim van Helden, project leader at ECN. “Measures to improve building energy performance are more difficult to implement for existing buildings than for new ones. So to create an energy-neutral built environment the newly built homes must inevitably be net suppliers of energy to the surrounding buildings”. In principle it is already possible to make new buildings energy-neutral by means of existing components, although a few structural difficulties must be eliminated before the new-builds can supply energy.

Long-terme project
The WAELS research project is being carried out as part of the Dutch EOS long-term programme to demonstrate that an energy-supplying home is one of the possibilities for the future. This is being done through research in three distinct fields of the project:
• Development of a building system
• Efficient conversion of sunlight
• Compact heat storage

Objectives
Van Helden: “TNO is heading up the part of the project that is developing the building system. An innovative building system has to be developed according to the wishes of users and the performance of the building. Key concepts of the system are an integrated design, far-reaching industrialisation of the building process and quality assurance. It is essential to achieve considerable integration within the building chain - from architect to housing corporations, project developers, contractors and subcontractors. There are a lot of potential gains simply through better consultation on the use of system elements”.
The WAELS project is exploring the preconditions for successfully introducing energy-supplying homes on a large scale. The preconditions span the entire process, the role of the different players and the techniques to be employed.
ECN is responsible for developing the technology for converting sunlight into electricity and heat more efficiently. Van Helden: “This is being done on two parallel paths”:

• For the medium term a proof-of-principle is being designed for a highly efficient module that generates heat and electricity from sunlight according to an integral approach. “One of our trainees, Jochem Nijs, has described various matters in a thesis for which he received the KIVI NIRIA 2007 thesis award. These PVT modules are already in use in England but are being optimised here. So a search is under way for potential industrial cooperation partners to introduce these modules in the market.”
• For the long term, the development of Solar Collector 2030 is going to be started. By using new materials and production technologies the collector will have a fundamentally better price/performance ratio that allows large-scale application. “Various parties have joined forces within the European Union to develop entirely new materials and create new concepts. These include intelligent materials like ‘plastic with a memory’ and variable reflective materials”. This research is taking place at the VU Amsterdam. ECN examined the embedding of the system and the requirements of the market as part of the research. 

The principle of the heat battery. In summer heat from the sun (for example) is used to split a material into two components. They are stored separately until winter. If heat is required in winter, the two materials are put back into the heat battery. They react with each other and reconstitute the original substance. This releases usable heat.

Heat battery
Heat storage is an entirely different discipline. Van Helden: “All three project partners are working on the development of compact storage for sustainably generated heat”. This is again taking place in two parallel paths. For the medium term, a proof-of- technology is being worked out for compact heat storage with suspended hydrates. For the long term, storage principles are being devised using new compact heat storage materials capable of storing the heating required by a home for an entire season. “You can then speak of ‘heat batteries’, a heat converter usable to save heat in a compact way, just like electricity in an ordinary battery,” says Van Helden. With one of the compact heat storage materials we have demonstrated that it is theoretically possible to store ten times more heat than can be saved in water. “We looked at industry to get an understanding of how the heat can best be put into and got out of the material,” says Van Helden. “A few of the processes used in industry on a large scale were selected for further development”. He expects a prototype ‘heat battery’ to be available for research purposes towards the end of 2009.

Contact
Wim van Helden
ECN Efficiency & Infrastructure
Tel.: +31 (0)224 - 564483
vanhelden@remove-this-part-removethis.ecn.nl

Information
The long-term programme is linked to the EOS-LT programme Approach to Systems in the Built Environment of SenterNovem and the Platform for Energy Transition in the Built Environment (PeGO). Project information about “Using Homes as an Energy Supplying System’ (WAELS) can be found on the website.