1. Description of Work (2011)

The service is entitled "Computation of the annual lighting energy savings resulting from the control of blinds and artificial lights by daylight, for building design and retrofit, energy regulation policy planning, and private investment".


Involved partners and contacts: the partner in charge of the development of the product and the service is ENTPE - Dominique Dumorter (dominique.dumortier(-at-)entpe.fr and Joris Boffard (joris.boffard(-at-)entpe.fr)

Prime-user: Estia (Switzerland)

Expectations of the prime-users: CLow energy buildings have to rely on a larger use of daylight to reduce the use of artificial light as much as possible. Artificial light should be seen as a complement to daylight, so its power should be controlled according to the amount of daylight available indoor. Bringing more daylight into the building should not lead to occupants’ discomfort. Blinds should be available and controlled according to daylight. There is a strong link between daylight availability, blinds use and artificial light use. The energy savings resulting from a larger use of daylight cannot be evaluated ignoring this link. Users need a reference tool to know how much energy, can be saved every year, from increasing and optimizing the use of daylight with control systems. This information is essential to compute the return on investment and make decisions on building design or retrofitting, energy regulation policies, product development…

Objectives of the service: The service will compute the annual energy consumption used for lighting a room in which blinds and lights will be controlled by daylight. The users of the service will be able to define the size and the shape of the room, the reflection factors of the surfaces, the number, size and orientation of the windows, the transmission of the glass and of the blinds, the lighting system. The blinds and the lights in the room will be controlled by daylight to satisfy visual comfort and performance. The users of the service will be able to select different control systems available on the market; they will be able to define their own control strategies. The service will allow users to compare different scenarios: number and size of windows, control strategies... Users will be able to produce results for any site in Europe.

Area of interest:

Exploited GMES downstream services:

Innovation: Computing the path of daylight from the sky vault, through the windows and through the blinds, onto the various surfaces of the building, then evaluating its impact on the occupant’s comfort, adjusting the blinds and the artificial light accordingly, is a complex task. Daylight is dynamic and the distribution of light on the sky vault may change within minutes. Since controls are used for the blinds and the artificial lighting system, this dynamic has to be taken into account: light simulations have to be performed at least every 15 min during a whole year. This is only recently that methods and tools have started to be available for this. New computation engines have been developed which are both faster and more accurate. Methods have been developed specifically to speed up the computation time resulting from taking into account the light distribution on the sky vault. These methods and tools have been developed by research groups; they can only be used by experts; they only have access to a reduced set of climatic data. The proposed service will innovate by making these methods available to non-experts: (1) a simplified interface will allow describing easily the room, the equipment and the control strategies; (2) users will have access to daylight climatic data for any site in Europe at a 15 min time step; (3) simulations will be faster since users will benefit from the computing power of the server; (4) results will be presented in a format easy to understand; (5) access to the service will be made on the Web, i.e., in a easy and fast way, with a few clicks.

Possibility to explore shading control strategies.