Daylighting Prediction Tool Online Presented By: Eng.Reham Mostafa Mohamed Mohie El-Din By: Christoph Reinhart Web Address: Topic Number: 106 Date: not mentioned

Daylighting Prediction Tool Online: Because daylighting is such an important feature of virtually all sustainable buildings and because its quality and quantity are difficult to predict and evaluate through simple rules of thumb, there is a need for daylighting software with a high rate of acceptance and adoption by design professionals. Architects rely more than ever on solid performance measures to support their design decisions. In today's competitive environment, the value of information gained through any one simulation tool must be constantly weighed against the time and financial resources required.

To foster the use of daylighting concepts throughout the design of a building, the Lighting Group at the National Research Council Canada (NRC), in partnership with the Buildings Group at Natural Resources Canada (NRCan), has developed an online support service called Lightswitch Wizard. Lightswitch WizardLightswitch Wizard With little investment of time, the Wizard helps architects to design perimeter offices and classrooms with "enough but not too much" annual daylight, and it helps lighting designers assess the energy of lighting and window blind controls.

Addressing Designers' Needs: Lightswitch Wizard users do not require any previous knowledge of daylight simulation techniques because all simulation inputs are explained in the online technical background and the glossary sections. The tool offers a comparative, reliable, and quick analysis of the annual amount of daylight available in perimeter offices and classrooms as well as the lighting energy performance of automated lighting controls (occupancy sensors, photocells) relative to that of standard on/off switches. Blinds can be either manually or automatically controlled. The user can choose among 361 building sites across the Northern hemisphere.

Lightswitch wizard (active blind control):

Lightswitch wizard (blind fully retracted):

To reduce simulation times from hours to minutes without compromising simulation accuracy, daylight coefficients for a comprehensive set of building geometries have been precalculated with the Radiance raytracer. Radiance An online simulation run typically takes between one and three minutes, given moderate traffic on the server and a fast Internet connection. Lightswitch wizard can compare two lighting scenarios.

Lightswitch User Behavior Model: Field studies reveal that current daylight evaluation methods tend to overestimate One reason for unrealistic expectations is that these methods do not consider how occupants manage their electric lighting and shading controls. So it's important to model user behavior along with physical lighting variables. A unique feature of the Lightswitch Wizard is a strong emphasis on the description of the user (occupancy and behavior) and the lighting and blinds control systems. User occupancy is characterized by arrival and departure times on weekdays, which are processed by a stochastic occupancy model that breaks up the working day through temporary absences from the workplace.

A user behavior model combines annual illuminance profiles and occupancy profiles with behavioral patterns that are based on field studies throughout the Western world. The model predicts how building occupants use their lighting and blind controls (if available). For example, the model predicts when users will lower window blinds in response to glare, or when they will switch on the electric lighting. Users wanting to analyze more complex geometries can download NRC's expert daylighting analysis software DAYSIM which operates with the same models as Lightswitch Wizard but allows input of user-defined building geometries. Users wanting to analyze more complex geometries can download NRC's expert daylighting analysis software DAYSIM which operates with the same models as Lightswitch Wizard but allows input of user-defined building geometries.DAYSIM

Lightswitch wizard: 1. General

Lightswitch wizard: 2. Space(classroom/office)

Lightswitch wizard: 3. User