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 Scientific background knowledge has become an important issue in the domain of solar shading. Helioscreen – one of the major manufacturers of coated fibreglass fabrics – claims that its products highly contribute to the level of comfort of the occupants of a building and to a more rational use of scarce energy sources. How do you sustain such a claim?
Architects and engineers want to know figures and numbers expressing the effect and the efficiency of a solar shading device, and ask questions such as "What will the indoor temperature be and how much energy in kWh can be saved with this product?"
“Will the shading device efficiently prevent glare and yet allow enough daylight into the room?” If these questions can be answered in the concept and design stage of a building, the effect of a shading device can be taken into account in for example the energy balance of the building. Helioscreen wants to play an advising role by making the correct information available in an early stage.
With the help of engineers and scientists Helioscreen developed two tools. One to measure thermal comfort, the other one to measure visual comfort.
 Thermal comfort
About ten years ago Helioscreen developed Capsol Vi: a simulation program to calculate the approximate energy gains for cooling after installing blinds.
Helioscreen’s Capsol Vi, is actually an adapted version of the full Capsol software designed by a renowned Belgian engineering company that can evaluate different heating, cooling, ventilation and sun shading systems. Because the aim of Helioscreen was to simulate only the effect of sunscreens, the decision was made to limit the available input parameters in the visual interface. This makes the input preparation process easier and the calculations much faster.
The variable parameters of the program include the orientation of the façade, the percentage and quality of glass and, of course, the geographical location. By running a comparison between simulations with and without solar shading, the results of the calculation helps in the decision process of which fabric should be used for optimum results. When air conditioning is used, the program shows the effect of the solar shading on energy needs for cooling, and that provides answers to the questions raised earlier.
The program is adaptable: extra climate zones can be added as well as extra solar shading devices. The Capsol Vi program is also available to Helioscreen customers. To activate it, a license key is required. But you can also simply request a Capsol calculation, which Helioscreen will then prepare for you.
 Visual comfort
Natural light optimization is very important for today’s architectural concepts. Designers have to create transparency, avoid reflection (monitors, displays) and find a balance between different surfaces.
Therefore Helioscreen developed the LightTool, an online instrument to assist the customer to create an optimal visual comfort in working and living areas. The program analyses the situation and delivers a ready-to-use report on how to use screen blinds to get the most optimal visual comfort.
How was this tool created? In an office at the Helioscreen building, experiments on ten types of solar shading were performed both on sunny and overcast days. The light was measured at seven different locations in the office at eight exposure times ranging from 1 millisecond to 3 seconds.
 With the results of these experiments a numerical model was developed. It is an accurate representation of an existing office, including furniture, lighting fixture and a computer. The complete model includes over 20,000 surfaces. In order to obtain a correct and a realistic visual impression of the room, it was decided to model the room and the furniture in fine detail.
The creation of the LightTool took two years to complete. The experiments started in 2002 and the program was finally finished in 2004.
The LightTool now allows you to simulate the effect of a sunscreen taking into account the weather, the orientation and location of the building and the amount of glass in the façade.
The results of the simulations are presented as views into the office. The views are human-sensitive images (photo-realistic simulations) or false color images, showing luminance or illuminance data on a fixed color scale.
Visual comfort is available when:
- The contrast levels on different surfaces inside the office are mastered.
- Sufficient light is available, preferably natural daylight.
- Illumination levels in between 500 and 1500 lux are ideal.
- There are no annoying reflections in the computer screen.
 The LightTool is an online software program that can be accessed through the Helioscreen website. Users can request a password for a test version which allows for three free calculations or you can choose a year subscription.
To request free Capsol and LightTool simulation reports (1 simulation per project), simply go to the Helioscreen website and fill out the forms.
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