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IDL - Bozeman eNEWS - April 2013 - Vol. 6 No. 4



We have updated our website to include more projects that IDL_Bozeman has recently helped with. These projects include the Boys and Girls Club of Carbon County, the Greater Yellowstone Coalition Headquarters (certified LEED Gold), the Crow Mercantile, and the Downtown Bozeman Community Co-Op.

Click on the Projects tab in the left menu to learn more about IDL_Bozeman and these projects!


Rehau Eco Smart House Construction Completed in Bozeman

The Rehau Eco Smart House is a project sponsored by Rehau, an international manufacturer of polymer based innovations and systems.  The Creative Research Lab (CRLab) of Montana State University in Bozeman assisted in the design and is monitoring the house, utilizing the lab supervisor and several students from the university to gather comparative research data from the experimental house.  The project uses numerous sustainable systems and materials throughout the house, aiming to compare these different options and use the comparisons to expand the knowledge base of the industry regarding environmental and human sustainability.  In addition to sustainable mechanical systems and products, the house incorporates the concept of human sustainability with elements such as telemedicine and advancements in human comfort and accessibility. 

Technologies throughout the residential construction include geothermal ground loop heat exchange, ground-air heat exchange, solar thermal and photovoltaic panels, vinyl window and door design, hybrid curtain wall, radiant heating and cooling, and tambour cabinetry for accessibility.  Sunlight responsive thermo-chromic glazing was also installed, having innovative technology to automatically tint the window glazing when in the path of direct sunlight, but adjusting to no tint and allowing full daylight to be brought in on cloudy or overcast days.  A thermal storage heat sink was also installed, capturing heat throughout the year and storing it under the patio in the ground to then use for winter heating and snow and ice melting.  The construction of the residence utilized insulating concrete forms (ICFs) on the first floor and structural insulated panels (SIPs) on the second floor and roof.  Together, these systems create a tight building with limited air leaks, providing better occupant air condition and less heat transfer through materials.  Multi-generational living was also a primary design consideration to accommodate three generations in one house.  To achieve this, the team designed an elevator, no door thresholds, smooth flooring materials, and telemedicine communication technology throughout the house so that accessibility was not an issue for the family.  

For more information about the various technologies mentioned or any other information regarding the Rehau Eco Smart House, click here.


Daylighting Guide for Commerical Offices - Part 2

Window Covering Design

Window covering is another important aspect when designing for daylight spaces.  Spaces must be designed to block glare, allow the view, and achieve energy savings at the same time.  Exterior shading devices are the best option to keep the space cool because they block the heat gain before it enters the space.


To block glare, select a window covering that is opaque enough to block the sun, such as fabric window covering that has 3% or less openness.  Horizontal blinds could also be used but tend to block more of the view than fabric shades.


Manually operated systems can be effective if properly used.  Since they rely on constant user attention to maintain glare control, these systems are usually installed in private offices or in “worst-case” scenarios.   This typically results in poor daylight performance and elimination of views throughout much of the year.


Automated glare control has the advantage of being deployed only when needed and retracting without the user intervening.  This creates greater energy savings when coupled with daylight controls while also allowing for longer periods of unobstructed views to the exterior.



TIP for Shading and Exposure

Northern Exposure – Shading typically isn’t needed with the exception of buildings angled to the east or west which may require shading on the north side in the early morning or late afternoon.

Southern Exposure – Less variable sun angles, making it easier to design shading systems.  Good access to strong illumination.

Eastern/Western Exposure – Shading design is difficult but critical for occupant comfort.


Influence of Furniture

Workstations must be kept low (42” or less) and directed parallel to the daylight source to ensure the views to the exterior.  Where higher panels (48” or greater) are needed or desired for privacy, they should be oriented perpendicular to the perimeter glazing.  Creating this workstation orientation allows for the most efficient use of natural daylight.

Workstations should be designed so that the occupant’s task view is parallel to the perimeter glazing, meaning that the daylight is coming from either side of the occupants view instead of straight ahead or behind.  This helps lessen the contrast between the task view plane (dark) and the daylight penetrating the glazing (bright).  This also helps prevent the shadow of the view from falling on the task view plane.


Interior Surface Finishes

When choosing interior finishes, the walls are another important surface to remember.  The “back wall” (wall opposite of the glazing) of a space is crucial to the perception of the space, since it is the furthest from the glazing and attains the smallest amount of daylight.  If this wall is brighter in appearance (higher reflectance value,) it will help balance out the bright glazing wall.  Having a lower contrast between the glazing wall and the back wall will give the perception of a larger space.  With this perception, occupants will be less likely to turn on the electric lighting.

            This effect can be done with the remaining walls and ceiling to make the space appear brighter.  However, the larger the space, the more difficult this effect becomes due to the inherent initial contrast.


Electric Lighting and Control Integration

Different Types of Controls

Photocell Controls: Automatically adjusts the light output based on detected illuminance.  This can be configured as step lighting (on/off) or be configured with a dimming capability.

Occupancy Sensors:  Turn lights on and off by detecting motion within the space.

Vacancy Sensor:  Requires user to manually turn on lights, but will automatically turn lights off after a pre-set duration.


A good rule of thumb for control systems is to place occupancy sensors in spaces with low occupancy numbers, such as private offices and bathrooms.  Spaces with low occupancy numbers (private offices being the best example) also utilize vacancy sensors.  Daylight sensors, or photocell controls, work best in spaces with large occupancy numbers.  This is due to the way the control works by automatically adjusting the electric lighting to coincide with the daylight addition.  This creates an environment that is self-efficient and is not dependent on the occupants of the space.  


Guidelines for specific spaces are as follows:

Open Office Areas: Where daylight is present, utilize daylighting controls.

Workstations: Utilize occupancy sensor controlled plug strips to control plug loads.

Restroom/Copy/Storage:  Install occupancy sensor controlled lighting.

Private Offices/Conference Room/Break Rooms: Install vacancy sensor controlled lighting.


Organizing Lighting Controls

            A daylight “control zone” is a group of fixtures in locations of similar daylight availability that are controlled together via a photocell to reduce light output when daylight is present, thus reducing the energy consumption.

            Automated lighting controls should be prioritized to areas where daylight contribution is expected to be high over time and where individual occupant control of lighting is not realistic, such as open office areas or lobby areas.

To read the full article, click here.


Daylighting Guide for Commercial Offices - Part 1

Benefits of Daylit Offices

Providing a daylit space creates a healthier and higher quality interior environment.  Increased individual productivity and human comfort is also found with daylit spaces.  Natural daylight allows for mental and visual stimulation necessary for proper regulation of human brain chemistry.  In addition to health benefits, allowing daylight to enter the space shows substantial energy savings throughout the building.

Design Inquiries for Designing Daylit Offices

Before you begin the spatial programming of the building, a few items should be in the forefront of your mind when deciding.  These inquiries include interior surface design and selection, shading for glare control, and shading for thermal comfort and heat gain control.  Interior surface selection has the opportunity to increase the daylight appearance dramatically, while shading control allows the building to effectively take advantage of natural daylight.

Best Practice Foot Candle Levels

Another thing to keep in mind when designing daylit spaces are the common lighting levels for different spaces.  The following footcandle levels describe the “best practice levels,” or in other words, the goals to achieve as opposed to the average level attained. 

            Reception Area:  5 fc   

           Working Spaces for Simple Visual Tasks:  10 fc

            Performance of Visual Tasks of High Contrast and Large Size:  30 fc

            Performance of Visual Tasks of High Contrast and Small Size or Visual Tasks of Low Contrast and Large Size:  50 fc

            Performance of Visual Tasks of Low Contrast and Small Size:  100 fc

Programming Criteria

When spatially programming the space, ask the following of each space:  Is daylight important for this space?  Are views to the exterior important?  How frequently is this space used?  What time of the day and time of the year will the space be occupied?

An example spatial programming might include the following:  Open Office Space – Daylight and view desired, occupants have individual glare control.  Private Office Space – Daylight and view desired, occupants have individual glare control.  Support Spaces – Minimal daylight or view opportunities required.  Building Core Spaces – No daylight or view opportunities are necessary.

After you have specified the spaces that desire daylight, ask the following of each of the daylight spaces:  What are the minimum daylight requirements?  How crucial is direct sun control?  What is the minimum footcandle level for the task that is performed in this space?  What might be the ideal solar orientation?  What might be the best strategy for providing daylight?  Side lighting?  Top lighting?  Are there maximum light levels required?

TIP for Programming Spaces  

“Daylight and view are typically preferred in areas that are most heavily occupied for extended periods of time, such as open office areas.  Corridors, circulation paths, break areas, copy/print zones or other short term gathering spaces may be tolerate of direct sunlight whereas fixed workstations or reception desks will almost never remain comfortable with the presence of direct sun.”

Space Planning

It is well known that open offices are typically occupied for almost the entire work day, while private offices are only occupied one-third of the time.  Also, since open office layouts are communal spaces, the shading blinds are not adjusted frequently.  This differs from private offices where the ownership is clearly defined, and the blinds are adjusted frequently.  The following values are the recommended distances from the glazing (illumination source) needed to provide adequate daylight and views to all spaces in need.

Locate open office areas within 18-20 feet of the perimeter zone (glazing wall) and at areas where direct sun penetration is limited (North) or less varied (South).

Position individual offices where low direct sun may otherwise be problematic (East and West), while allowing for individual control within the space with manual shading devices.

Top Lighting Strategies

Studies show that top lighting provides the most effective daylight into the building.  Designing them to be a diffuse light source easily takes care of any glare potential.  Compared to side lighting, top lighting covers a much larger area of the space.

Stay alert for part 2, discussing window coverings, shading and exposure tips, furniture influence, and daylighting controls.  For read the full article, click here.


Register Now for Northwestern Energy Presentation

Adjustable Speed Drives and energy Efficiency

Presented by Northwestern Energy

August 23, 2012

Billings, MT

 Northwestern Energy will be giving a seminar on the benefits and various types of adjustable speed drivers and the energy savings associated with them.  The presentation will begin at 8 am and last until 4 pm, with breakfast, lunch, and breaks included. 

Registration deadline is August 9th.  This event is free to employees of companies that are Northwestern Energy customers.  The registration cost is $139 for all others interested.  There is a limit of two attendees from any one company as seating is limited.

Click here for more information on this presentation and other education opportunities.