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Experience from Green Lighthouse shows that users are a decisive factor in sustainable buildings

Eighteen months after the Green Lighthouse at Copenhagen University opened its doors for the first time, it has proved to be a good model for sustainable public buildings of the future, with excellent daylight conditions and indoor climate.

However, the users are a factor that must be given more consideration in the design and operational phases if sustainability is to be ensured.

Green Lighthouse is Denmark’s first carbon-neutral public building. As an innovation project, it is intended to provide experience for the sustainable buildings of the future. The first ex-perience gained is that user requirements and behaviour are decisive for the sustainability of such buildings. The building has generated enormous attention and attracted several thousands of visitors, including the Russian President Medvedev and New York’s mayor, Mi-chael Bloomberg. So it has functioned as a place of work and a showroom for sustainable public buildings of the future at the same time.

“Green Lighthouse has been warmly received by the public, and both companies and deci-sion makers at home in Denmark and internationally have shown great interest in the build-ing. We are delighted with that. We are also more than happy to be able to pass on to oth-ers the invaluable experience we have gained about its operation. It has become very clear that the users’ requirements and behaviour play a decisive role in a building’s sustainabil-ity,” says Chairman of the Green Lighthouse Steering Committees and Prorector of Univer-city of Copenhagen Thomas Bjørnholm.

Sharing experience from the building’s operation is an integral part of the project. Brand new products and technologies were used in the building of Green Lighthouse to ensure very low energy consumption – and the best possible indoor climate. So the partners in the project are taking part in follow-up measures such as The Energy Technology Development and Demonstration Programme (EUDP) intended to ensure that the building will continue to be closely followed and carefully monitored, and that experience gained from the experi-ment is passed on.

Experience after the first 18 months
One of the exciting challenges of the first 18 months of Green Lighthouse's operation is that it has been very much in use – far more in use than expected. Since it opened, it has been in operational use for 3,000 hours/yr – and in the first six months, for 1,850 hours (corre-sponding to 3,700 hours/yr). Design calculations were made in accordance with BE06, the tool in use at that time. One of the parameters for that tool is that a building should be used for 2,250 hours a year, but Green Lighthouse has attracted enormous attention.
In addition, there were some building errors and deficiencies, now corrected, that resulted in a draft in the building. One of the consequences was that users opted for a higher tem-perature than the 20 degrees determined by BE06.

During the running-in phase, the agreed monitoring procedures detected that the solar cell arrays were not connected properly and that a main baffle in the ventilation system was missing; it was installed only four months ago. Finally, it has taken longer than expected to learn to control the building – factors such as arriving at the optimum level of regulation of heating in all rooms. This has given the partners particular experience in handing over new sustainable buildings to the user.

Initial constructional and control teething problems, and the building’s enormous popularity, have resulted in higher energy consumption than calculated. In the first year, energy con-sumption for heating and ventilation was more than twice that predicted in the original cal-culations.

But Green Lighthouse also shows great potential for improvement in energy performance in the future. Consumption for domestic hot water, automation, pumps, operational and stand-by equipment and cooling are somewhat lower than expected. Because of the large amount of daylight in the building, energy consumption for electric lighting is lower than calculated, even when adjustments are made for the unexpectedly high usage of the building.
Users are very positive about the high level of daylight and clean, fresh air in Green Light-house.

Green Lighthouse being followed up in an EUDP project
For the next 18 months, Green Lighthouse will be followed just as closely as the partners have joined forces in an Energy Technology Development and Demonstration Programme (EUDP) that will monitor its energy consumption throughout this summer and present its report in September 2012. For this reason, energy consumption is now monitored even more closely and a watchful eye is being kept on the defects and deficiencies that plagued the building in the start-up phase. As a result, it looks highly probable that the target of becoming carbon neutral will be reached in the second year of operation. The partners’ par-ticipation in the EUDP project will ensure continual dialogue between the building partners and optimal monitoring.

Partners’ experience in the first 18 months of Green Lighthouse’s operation:

1. Energy calculation tools: the Green Lighthouse experiment and our measurements of the building show that existing tools such as BE06 and BE10 are not entirely realistic as they do not take user behaviour into account. In the future, we will have to work with scenarios that include means of doing just that.

2. Users and visitors: users have given Green Lighthouse a very warm welcome and re-gard the indoor climate and the light in the building as unique. We have also learned that the users have needs that only became apparent when they started using the building – heating, for example, was greater than predicted. As was the huge num-ber of visitors in the first 18 months – they were not included in the energy calcula-tions either.

3. Monitoring: continual monitoring of Green Lighthouse ensures that we register devia-tions instantly and can correct them. This is essential if we are to ensure optimal op-eration at all times.

4. Operation: when working with a brand new type of building like Green Lighthouse, in which experiments are being conducted with both design and technologies, it makes sense to incorporate its operation over a three-year period, for example, rather than for just one year. Green Lighthouse has several brand new technologies and func-tions very differently from many conventional buildings. It is important that those responsible for its operation are given the chance to climb the learning curve.

5. Partnership: apart from a partnership award from the Confederation of Danish In-dustries and the continuing collaboration with EUPD, the experience gained from planning and constructing a building in public-private partnership has given us the opportunity to pass on this learning to similar prospective project partnerships.

6. Technologies: Green Lighthouse is an experiment in using familiar and new tech-nologies in a unique energy concept that has been tried out in Denmark for the very first time. We are passing on this new-found knowledge through EUPD and through similar technologies that are now coming into play on a far greater scale than ever seen before. One good example is the town hall now under construction at Viborg. In this context, it is essential to understand that, in the future, time and processes should be planned into any project using new technologies.

If you would like further information, please contact one of the partners:

  • Jacob Sølling, Copenhagen University, head of section, jacs@adm.ku.dk, +45 35 32 26 30 / +45 28 75 26 30 
  • Anders Edstrand, City of Copenhagen, Finance Committee, aed@okf.kk.dk, +45 33 66 22 14
  • Lone Ellersgaard, Corporate Press Manager, VELUX A/S, lone.ellersgaard@velux.com, +45 4516 4818/ 40407156
  • Sajet Mahmudovski, Danish University and Property Agency, sam@ubst.dk, + 45 3395 1255/ + 45 2565 8932
  • Reto Michael Hummelshøj, COWI, rmh@cowi.dk, +45 4597 2766

About the VELUX Group
The VELUX Group creates better living environments with daylight and fresh air through the roof. The VELUX product programme contains a wide range of roof windows and skylights, along with solutions for flat roofs. The Group also supplies many types of decoration and sun screening, roller shutters, installation products, products for remote control and thermal solar panels for installation in roofs. The VELUX Group, which has manufacturing companies in 11 countries and sales companies in just under 40 countries, represents one of the strongest brands in the global building materials sector and its products are sold in most parts of the world. The VELUX Group has about 10,000 employees and is owned by VKR Holding A/S, a limited company wholly owned by foundations and family. For more details, visit www.velux.com.