Merry Lea's Collegiate Facility

Building a Sustainable Future

 

ENERGY

The average single family home powered by natural gas sends about 27,000 pounds of CO2 emissions into the atmosphere each year. A building carefully designed to conserve energy can do much better than that. Engineers use computer modeling to project exactly how much energy a building will consume depending on its size, location and the conservation strategies employed. The graph below shows how one of the cottages in Merry Lea’s collegiate facility compares to a conventional home of the same size. Here’s how this is possible:

Photovoltaics
Solar cells, or photovoltaics, convert light energy from the sun into electrical energy. They produce no waste and are silent and long-lived. Because photovoltaics are placed near the site where the energy is used, solar power also requires less wiring. An array of photovoltaics, mounted on the collegiate facility’s south-facing roof, will power at least 20% of the buildings’ electrical needs. On a sunny day, the collegiate facility may be supplying power to the local electric company; in cloudy winter weather, it will need to draw on the electric company.

Ground Source Heat Pumps
Merry Lea’s future collegiate facility will be heated and cooled by 11 ground source heat pumps. This technology consists of an electric pump and a network of pipes buried in the ground. The pump pushes fluid through these pipes where it is cooled in the summer or warmed in the winter. Unlike a furnace that creates heat by burning a fuel, a ground source heat pump works by transferring heat from nearby ground water to heat a building. Unlike an air conditioner that cools by transferring heat to the surrounding air, GSHPs cool by moving heat from within a building to the groundwater. Because the earth’s water is a more constant temperature than air, it takes less energy to heat or cool a home using this technology. A ground source heat pump can cut the costs of heating and cooling a building by as much as 50%. To learn more about ground source heat pumps, go to www.igshpa.okstate.edu or www.waterfurnace.com.

Natural Strategies
The best way to cut fossil fuel consumption is not to need the energy in the first place. The future academic building and its cottages will use the following strategies to reduce the buildings’ energy load.

Passive solar design
Proper building orientation alone can save 30% on energy costs. Because the academic building is sited on a south-facing slope with its longest axis facing south, it can make maximum use of solar gains in the winter months. Roof overhangs and special glazing on the windows will keep summer sunlight out.

Earth berms
The slope behind the academic building will enable the lower level of its north side to be partially buried. Earth berms provide a thick layer of free insulation, keeping the building at a more constant temperature.

Natural ventilation
The prevailing winds on the site come from the southwest. Operable windows will take this into account, allowing wind to enter at an angle and provide cross-ventilation on all but the hottest days.

Daylight
Designing for minimal or no electric lighting in the building during most daytime hours will reduce the electricity required for lighting by at least 70%. Large windows with light shelves on the south side of the building and transom windows on the north will help accomplish this. Light colored interior surfaces with high reflectance values also reduce the need for electric lighting.