KEC Sustainable Details

It seems there are a few highlights to every high performance building or sustainable building project.  However this project really takes advantage of sustainable design and construction in virtually every aspect of the project.  As I look back on the blogs over the past 16 months, this aspect is lost in the details.  So here is a recap of the sustainable details of the KEC.

The Net Zero Energy operation of the KEC is possible because all the energy required to run the facility in a year is generated onsite by an acre of photovoltaic panels (296kW array).

All walkway materials are reclaimed milled asphalt and lined with LED bollard lights activated by motion sensors to limit energy consumption.

Corridor walls are lined with tapped maple, salvaged from local sugar maple farms in VT.

Bathrooms are equipped with low flow Kohler plumbing fixtures to conserve water.

This shower head was specially engineered for this project.  It provides low flow as standard pressure and has a push button for a brief surge of pressure which comes in handy when trying to rinse out the shampoo.

granite counters

Dorm room lights are all controlled with Lutron lighting control systems.  Fan light and desk lamps are all switched by the door and are also tied into an occupancy sensor to turn off if nobody is in the room to conserve energy.

Windows are high performance argon filled double glazed Marvin units.

The cedar sunshade shades the southern exposure in summer while allowing winter sunlight in.

Exterior siding materials include FSC certified cedar and recycled content Certainteed cement board siding.

The controller for the Cinco Solar Evacuated Tubes allows you to evaluate your system needs and optimize your systems with the hot water produced by solar energy.  It also allows you to monitor and program system performance. 

Furniture selection also utilized reclaimed materials as you can see from this oak end table.

Locally sourced stone was used as a stone veneer feature on select elevations of the exterior.

Flow meters were installed which are integrated into the building dashboard.  This will allow the end users to monitor and meter systems performance and usage.

Polished concrete floors were selected for corridors, labs, and the commons.  This reduces material usage as tile, wood, or carpet will not be used in these spaces.  The corridor classroom will pick up solar gain in the winter from southern exposure for passive heating.  

KEC Geothermal Ground Source Heat Pumps

The KEC utilizes a very efficient mechanical system known as Ground Source Heat Pumps, or more commonly and incorrectly referred to as Geothermal.  True Geothermal heat comes from hot springs in the Earth and looks like this:

Ground Source Heat Pumps are used to efficiently heat and/or cool a building and looks more like this:

Dissapointing I know, sorry for that.

So what is it and how does it work?  I can share what I have learned from installing the system at the KEC, speaking with the project mechanical engineer, and doing some of my own research online.  These visuals were very helpful for me to understand.

Geothermal heat pumps don't create heat by burning fuel, like a furnace does. Instead, in winter it collects the Earth's natural heat through a series of pipes, called a loop, installed below the surface of the ground or submersed in a pond or lake. Fluid circulates through the loop and carries the heat to the house. There, an electrically driven compressor and a heat exchanger concentrate the Earth's energy and release it inside the home at a higher temperature. Ductwork distributes the heat to different rooms.

In summer, the process is reversed. The underground loop draws excess heat from the house and allows it to be absorbed by the Earth. The system cools your home in the same way that a refrigerator keeps your food cool - by drawing heat from the interior, not by blowing in cold air.

The Consumer Energy Center site was very helpful.

Here are some images from the design and installation at the KEC site.  During preconstruction we performed a test well to accurately measure the flow rates and temperates of our specific site so the assumed design could be fine tuned.  The ground temperatures range between 51 and 53 degrees.  The design for the KEC called for (25) wells 450' in depth.  Each well has a plastic pipe loop that goes down to the bottom of the well and then back up.  There is over 4 MILES of piping associated with this work!!  Sima Drilling performed this work.

[click to enlarge]

[well drilling]

[well drilling]

[piping at wells]

[piping from well field to building]

[piping from well field to building]

KEC Earth Duct

An Earth Duct is a design technique that uses natural ventilation to help temper the air.  This helps pre-heat or pre-cool air depending on the season.  For this project there are (2) runs of precast concrete pipe 24" in diameter and approximately 1000' in total length that are installed at least 4' below grade.  One end of the 2 pipes is open to allow fresh air to be drawn in.  The other end of the 2 pipes is connected to a fan that pulls the outside air in through the inlet, underground for 500 feet side by side, and then up into the building where it mixes it with indoor conditioned air.  

The earth duct is designed to provide a 15 degree temperature differential between outside air temperature and the air being delivered to the air handling units.  This pre-conditioned air will require the geothermal heat pumps to “work less” to condition the air that is ultimately supplied to the building for space conditioning than if straight outside air was delivered to the air handling units.  The outside air is mixed with air returning from the building before it is conditioned and delivered back to the building. 

The system was designed through collaboration between, Kohler Ronan, an MEP engineer with a specialization in sustainable design, Atelier Ten a consulting firm with a specialization in sustainable design, and Landtech, an environmental and engineering consulting firm.

Above is a photo where the earth duct enters the building from the site through the foundation wall.  On the other side of the wall, the earth duct continues under the slab and then rises up to mix with the air in the mechanical equipment in the attic before it is delivered to the building.

Above is a photo of the precast concrete pipe which is installed a minimum of 4' below grade.  Air will be drawn in through the top of the precast structures, then through the pipes where the earth will pre-heat or pre-cool the outside air before mixing it with the building air to reduce the amount of work and energy that the building systems need to use.

KEC Week 29

The tower framing and sips panels were prefabricated on the ground and hoisted up to the top of the tower. This approach was taken because it is much easier and safer to construct on the ground than 40 feet in the air.

Steel for the stair towers is complete.  About 60% of the steel on this project is post-consumer recycled and 15% is pre-consumer recycled.  Post consumer recycled means that the steel was originally used for something else, then it was salvaged and melted down and reused for the steel structure of this building.  Pre-consumer means that the manufacturer has some scrap steel as part of their own fabrication process and they melt down their own scrap and reuse it in production of new steel.

Stone veneer has started. The stone is from a local source in Connecticut about 45 miles from the project site.

Exterior vapor barrier Typar is being installed on the wall sheathing and 30# felt vapor retarder is installed on the roof. This prevents moisture from penetrating the exterior wall into the interior space.

Interior load bearing partitions are being framed.

Interior slab grinding is in progress.

The geothermal vault has been installed. This is where all of the piping from the wells is consolidated through a manifold into two larger supply and return lines that enter the building.

The earth duct piping and vaults are being installed.

The hot water piping that heats the greenhouse is being run from the East wing to the greenhouse underground under the courtyard. This hot water is made using a waste oil boiler in the mechanical room which uses recycled vegtable oil.

Next month the metal roofing, siding, and windows will start on the exterior and mechanical and electrical wiring and piping will start inside.

KEC Week 26

Site activity over the past few weeks has been focused on completion of the timber framing, continuing the stick framing, and starting the exterior wall sheathing and SIPS roof panels.  There is a big push to install the exterior sheathing and SIPS panels so that the interior work, which is weather sensitive, can begin this fall.

The pedestrian bridge is substantially complete.

Geothermal wells are complete and most of the piping from the well field to the building is installed.  The next step is to set the vault and run the piping into the building.

Stick framing continues with the focus on bearing walls and exterior walls.  As the exterior walls are installed the plywood sheathing is also installed.  All the stick framing and plywood sheathing on the project is FSC certified material.

SIPS panels are being installed on the roof.  These panels provide both the roof structure and the roof insulation.  The code requires and R-value of R-20 for roofs however these SIPS panels will provide an R-44 value.  This extra insulation significantly reduces the amount of energy needed to condition the interior space.

Structural steel is being installed at the stair towers.  Steel is a building material that typically consists of a very high recycled content rate.

The South access road and parking area work is substantially complete.  The road and parking surface is 100% reclaimed asphalt which has been pulled up from other road demolition projects.  The surface is permeable which helps return rainwater to the watertable instead of sheet draining off to a stormwater drainage system.

Concrete masonry units are being installed as a starter course around the courtyard perimeter walls.

FSC certified stamps