Light Levels and Effective Aperture Area in Greenhouses

Over the past months we have posted a few blogs on a new sustainable greenhouse prototype we are developing.  We have received comments from a number of traditional greenhouse users with concerns that this new prototype will not be capable of plant starts because of inadequate light levels.  The prototype does push the envelope of greenhouse design but through the use of careful daylighting strategies not typically implemented it is capable of effective plant starts.  The Research and Development greenhouse that is the basis for our prototype started over 1,000 tomato plants last spring without the use of supplemental light.

To understand how this works a typical all glass or plastic glazed greenhouse has no reflective surfaces and the glazing reduces light transmission into the greenhouse by up to 40%, or more.  This means that the light levels entering a traditional greenhouse are first significantly reduced by passing through the glazing and then any light that does not immediately hit a plant surface is either absorbed by the ground or passes back through the glass and out of the greenhouse.

The sustainable greenhouse prototype uses some of the clearest glazing available and a number of reflective surfaces to increase light levels inside the greenhouse.  First, reflective surfaces on the outside of the greenhouse, i.e. light shelves and reflective roof surface, bounce additional light into the greenhouse.  This reflected light allows more sunlight through each window than would direct light alone increasing the effective aperture size without more or larger windows.  Next, the clear glazing allows more of this light to pass into the greenhouse compared to a similar area of glazing on a typical greenhouse.  Finally, although the greenhouse is made up of a number of opaque walls and roofs each of these is covered with a white reflective surface.  The reflective surfaces inside the greenhouse mean that any light that does not immediately hit a plant or the ground is bounced around inside the greenhouse until it does.  Through a combination of thoughtful daylighting strategies our prototype greenhouse achieves adequate light level for plant growth and plant starts with fewer windows than a traditional greenhouse.

Sharing the Experience of IST with the Community

If you have been following our blog postings, you’ve noted our commitment to Science, Technology, Engineering, and Math (STEM) programs, and the pride we’ve shared with the Cherry Creek School District (CCSD) and other project team members in bringing their award winning Institute of Science & Technology (IST) to life.  Now that the school is open, we’ve been pleased to support the interest of the education and design community with presentations and tours of the facility.  Toward the end of last year, IST hosted the USGBC’s Emerging Green Builders for a presentation and tour.  The design of high performance STEM schools is about more than just the building.  At this event, we were able to present the collaborative program and concept development we shared with the CCSD, school administrators, teachers, and the local community.  This process led to the development of a facility that is not just energy efficient, but also inspiring, specific, and adaptable to the curriculum needs of IST’s STEM program.

After the presentation, the USGBC members were given a tour of the facility to see how daylighting strategies were integrated into the classroom; the unique learning opportunities that are an integral part of the facility (including the basement mechanical room that was detailed to provide an educational opportunity for students); and the laboratory classrooms that support advanced learning.  These include a physics lab with ceiling-mounted hangers and tracks for advanced experiments; an avionics lab with flight simulators; a robotics lab; and chemistry/biology labs with lecture and experiment-based learning stations.  The tour also included the collaborative teacher lounge that is now in demand from other teachers on the Overland Campus.  Others that have toured the facility include: the Council for Educational Facility Planners International (CEFPI), the Chinese Mayoral Delegation, various parent groups, and other local school districts.

In our earlier posting on the Kent Denver School, you will also find that we work hard to integrate learning into the physical structure of many of our schools.  IST was another opportunity to do so.  In addition to an active daylight tracking device that provides both light in the main stairwell as well as opportunities for experiment, there is an LED starfield of the north sky in the lobby, latitude and longitude markers integrated into the floor throughout the building, and outdoor plazas based on mathematical concepts such as the Fibonacci sequence.

IST is an excellent example of the possibilities of collaboration. On February 28,2012  we have an exciting tour and information session planned as part of the upcoming Green Schools National Conference in Denver.   Additionally, if your district, school, or professional group is interested in touring this facility at another time, please contact us and we’d be honored to assist you.

By Alan Doggett

Links to other STEM/IST posts from HAS:   STEM for All, IST Wins Peak Award, Kent Denver Science Sun Path, STEM Education- January 2011, Dr. Gubser Speaks

Global Weirding – Weather Extremes Coming To a Location Near You

2011 certainly was an interesting one in terms of weather.  After record snowpack in the Rockies, the current winter has many wondering what is in store for the ski season this year.  It may be hard to remember, but August was one of the hottest on record in the Denver metro area.  Nationally, after the eastern seaboard shook off tropical storm Irene, a late fall snowstorm had people digging out.  Now, those Northeast backdrops for the GOP Presidential Candidates have something very unusual – no snow.  With all of these atypical weather patterns, it is a good time to discuss the concept of “Global Weirding”.

Global Weirding is a term that has been used to help explain a wide range of weather events that may be related to the rise in global temperatures.  These events may include violent storms, heavier snowfall, flooding, heat waves, and drought.  Further, these may trigger or aid in the spread of other events such as flooding, fires, and even economic loss.  Here is a reminder of some of the other weather and environmental extremes from 2011:

• Record heat across the majority of Texas
• Extreme drought conditions from Arizona across the gulf coast and into Georgia
• Significant, if not record, wildfires in Arizona and Texas
• Record flooding along the Mississippi river basin
• An EF5 tornado with a 300 yard-wide eye that cut a destructive path through Joplin, MO
• Extreme drought in the southeast corner of Colorado
• Duststorms in Phoenix, AZ that stretched 100 miles long and thousands of miles high
• Record blizzards in the Northeast the last two years

Often lost in the memory of these events is the cumulative national, regional, and personal cost that they incur.  However, the impact is not limited to just large weather events.  Long standing traditions and regional patterns based on seasons can be effected.  More often, we seem to be hearing anecdotal stories of unexpected weather, flowers blooming early, or even plants growing in regions where they formerly did not.  It may be difficult to pin any one of these smaller environmental events as weird, or even as a specific sign of climate change.  However, cumulative events across a region can begin to take on that effect.  These smaller impacts may be subtle, but the broader economic impact of the change can be significant.  A recent Associated Press article notes the impact of current weather on winter tourism on areas in Maine, New Hampshire, and upstate New York that simply have no snow.  Even here in Colorado, the tubing hills are seeing increased business, while many ski areas have bases only now approaching 24”. Obviously, the weather can quickly change with a series of spring storms, but more direct personal impacts are already happening.

So, what do we make of all this?  It may be years before we can track some of the recent patterns.  However, some indicators are already occurring. Nevertheless, taking the extremes of the past five years, it is possible to make a connection with ‘Global Weirding’ starting to occur across the country and the world.  Time will tell about what impacts these events may have on how we, as architects, analyze the local conditions for our buildings.  Despite the ongoing effort to politicize the debate about climate change and frame it away from scientific findings, these are issues worthy of our consideration.  How soon we’ll have to deal with them depends on how “weird” you think it is going to get!

By Alan Doggett

Awards – The Ability to Empower Users

When a team wins an award, such as the CSDA Award, many people share the news with those around them.  These people do one of two things: they either smile and nod or they start an internet search for “CSDA Awards”.  This is because in our world of changing names and acronyms, although is both difficult to keep track of everything, we always want to know what others are doing or what we can learn about.  However, back to the CSDA Awards.  The search brings up some interesting contenders, first the California Special Districts Alliance, next the Clinical Scientist Development Award, then the Colorado Sustainable Design Awards.  The last sounds close to home, let’s go with that one.

As we get deeper into the web, surfing around in the sustainable buildings pages of the Colorado Biz magazine from November 2011, one thing is certain, the amount of information given on the projects is just enough to wet ones appetite for more.  Our project, Sangre de Cristo, in the Civic division, received first place and one picture.  When we submit for awards, there is typically 10 times the amount of text and pictures than shown in the magazine release.  It is understandable that this amount of text and pictures are not incorporated in the magazine, yet in a digital format the additional text, pictures, and plans can assist those of us who want to know more about the buildings around us.  What makes them work?  Why is it award winning?  Describe to designers or interested parties the whole picture.  How about using a “More Information” button (a personal favorite).  This could allow additional exploration, making us all more learned and able to take the next steps in both sustainability and building practices.  This also makes the magazine to look more informed, and given they typically have consent to print the information, it seems like a win-win situation.

What are your thoughts and questions?  How can buildings and awards be presented to make you want to hit the “More Information” button?

By Kerrie Kannberg