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Turtle Mountain Research Center



INNOVATIONS

INNOVATIONS

AGRICULTURAL AND RECYCLED MATERIALS

Goals of Innovation: To use materials made from agricultural byproducts or recycled content for their inherent structural, insulating or aesthetic value.

To reduce the overall environmental impact of the building by using locally produced or reclaimed products.

Description: Five materials used are made from agricultural byproducts or recycled content. Three of these materials are locally produced or acquired:

 The concrete foundation contains 30 percent fly ash. Fly ash is an industrial by-product which can replace a percentage of the cement in a concrete mixture to actually improve the strength of the finished material.

 Strawbales comprise the primary structure of the building, and also provide the primary insulation. Straw bales are available and cost-competitive within the northern plains region and are an agricultural byproduct. Visit the Red Feather Development Group website to learn more about Strawbale Construction.

 Agricultural board made of compressed sunflower seed hulls and wheat straw was used for all interior wall surfaces. The sunflower seed hulls provide a beautiful surface appearance which was enhanced by using a linseed oil finish rather than paint which requires more maintenance over time. The boards are locally produced in North Dakota by Primeboard from agricultural byproducts.

Kalwall panels, used for clerestory lighting on the north wall, introduce daylighting while providing much greater structural and insulating value than windows. The Kalwall panels used were reclaimed from a nearby hockey rink.

Cellulose fiber, used as a secondary form of insulation, is made from recycled newsprint.

Obstacles:
 Flyash content of concrete increases strength but can also accelerate curing time which gives less time to work the wet concrete.

 Strawbale walls built with the appropriate rebar supports and cross bracing are structurally robust below a height of roughly 10 feet. Throughout the construction process before finish stucco is applied, bales must be kept dry at all times and away from any sources of flame.

 Agricultural board is significantly more dense than a comparable material such as plywood, but not as strong.

Cost Information: The US Dept of Agriculture was the main funder on the ERC project. A major Community Facilities grant was awarded to Turtle Mountain Community College (TMCC) by the USDA for this project. Other funders included TMCC, Red Feather and the North Dakota Department of Commerce who funded the solar photovoltaic system.

Red Feather is able to obtain cost reductions in design, materials and especially installation by bringing pro-bono services and volunteer labor to drive down costs. Volunteer construction lends itself to stucco work and strawbale construction; Stuccoed strawbale walls are easy and fun to construct with large work groups.

The compressed sunflower seed and wheat straw wallboard was provided by Primeboard (ND) and installed entirely by volunteer workers reducing financial costs substantially. Because the raw materials are locally produced agricultural byproducts, and the boards are locally manufactured, the overall life-cycle costs and environmental impact of the boards is very small.

Similarly, the Kalwall panels were locally reclaimed, and installed by volunteers. The environmental cost of reclaiming materials with no degradation in quality is exclusively the impact of transportation and installation.

Given the above combination of pro-bono services, donated materials and grant funding the building was quite inexpensive to build. We estimate the cost of the building to be about $100 per square foot. It’s appraisal value would clearly be much higher.

LINE-TIE PV SYSTEM WITH A BUILDING-INTEGRATED PV

Goals of Innovation: To provide a sustainable alternative to energy consumption, while complementing the insulated structure of the TMCC ERC.

Description: The Line-Tie PV System is different than the Stand-Alone PV System in that, 1) the Line-Tie PV System does not include batteries or any other sort of on-site storage for electrical energy, and 2) the Line-Tie PV system is directly connected to the AC Service Panel (i.e. Breaker Box) in the home or building where it is installed.

A Line Tie PV System is made up of only a few components. The largest and most obvious component is the PV array. At Turtle Mountain, the PV array consists of United Solar Ovonic’s PV Laminate series of PV modules attached to the roof of the building. The modules are unique in that they are bonded directly to the metal roofing system that protects the roof and shields the building from the elements. The modules lay flat to the roof so their wind rating exceeds 160 mph, and their top surface material allows them to shed snow very easily. The array is oriented directly to the south and is at an optimum tilt angle for year-round production. All wiring for the PV array is located under the ridge cap at the peak of the roof. The power output of the array is rated at 2,232 watts.

The balance of the PV system components consist of a solar array fuse box, a solar array disconnect, a DC to AC Inverter, an AC disconnect and the associated wires and conduit that connect all the components together. The Inverter has a maximum rating of 3000 watts.

The output from the Inverter and AC disconnect (240 VAC, single-phase) is connected directly to a double pole, single throw 240 VAC, 15 amp breaker. The power from the solar energy system is fed directly to the AC Service Panel and can operate any loads that are connected to the Panel. If there is not enough power coming from the solar system to operate all the loads drawing power from the AC Service Panel, energy from the Utility power lines will be drawn into the Service Panel to operate the loads. If the solar system is producing more power than the electrical loads in the building require, the solar system energy will be pushed out onto the Utility power lines and spin the building’s electrical meter backwards. You could say that the building is “storing energy on the grid” in the form of “credits” toward future electrical use. Indeed the building occupants may use lights and other appliances at night when the solar system is not operating and the energy consumed by these appliances will spin the meter forward again. The net result of this forward and backward spinning of the electrical meter will represent the actual amount of energy the building will draw from the Utility company. Although it was not known exactly how much energy this building will consume during an average day, it is possible that the solar system installed at Turtle Mountain will supply all the electrical energy needs of the building especially given the efficient lighting, heating and insulation systems employed at the Turtle Mountain Project.

Obstacles: None.

Cost Information: Although Turtle Mountain could have used a smaller inverter to condition the power coming from the 2.2-kilowatt solar array, the system is now capable of accepting more solar modules without any change in the system configuration.


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