Resource efficiency: Buildings should share and share alike

EcoDistricts slow the march towards depletion and bring the hope of energy regeneration

Kirk Davis

There is change afoot in the development of business and industrial parks. Learning from the past, developers are embracing better practices for energy efficiency and building performance by connecting the systems of buildings within the same physical area, called “EcoDistricts.”

But, what is an EcoDistrict? Drawing an analogy from bicycle racing, consider the main group of riders at the front of the pack, or “peloton.” Pushing into the wind, the lead rider uses more energy than those who follow. To recover, the leader rotates in and out of this front position while the pack benefits from a fresh rider who moves to the front to carry the “wind” load. Rotating and sharing periods of heavy loads over time, in fact, reduces the energy drag in the middle of the pack by as much as 40 percent.

An EcoDistrict functions similarly. Particularly in developments with mixed uses (offices and residential mixed with retail), buildings’ energy needs change daily and seasonally. When one building requires cooling, another may require heating. The waste heat from a building that needs cooling, such as a warm office in the day, can be a resource to a building that needs heat, such as a residential tower at night, resulting in energy performance increases of 10 – 15 percent.

Today’s EcoDistrict Systems are gaining favor in three main areas of resource efficiency: energy, water, and waste.

Energy: Buildings can interconnect through a common condenser water loop, whereby buildings share heating and cooling energy. This loop captures waste heat that would otherwise be lost through exhaust and distributes this thermal energy to buildings that need it, drastically reducing the amount of heating and cooling energy used by each individual building. Fuel cells can also be used to locally generate power, and sometimes capture the waste heat from the cells for other purposes.

Water: Recent droughts in the U.S. have emphasized the value of clean water and new approaches to water efficiency. A district wastewater treatment system can turn sewage into reusable onsite resources, greatly reducing city sewer usage. Further, through “water streets” and artificial wetlands the “treatment plant” becomes a site amenity.

Waste: Waste is a sustainable resource. How can we convert refuse into a resource we can use? Disposing of solid waste requires landfills, and often, long distance transportation. However, technology already exists that turn much of this waste into a resource at a much smaller scale. A community-scale anaerobic digester ferments organic waste into methane and compost. The digester system, based on working examples in many countries around the world, can reduce solid waste by up to 40 percent, generate methane gas for use in the district, and recycle nutrients into agriculture-ready compost.

We have grown accustomed to large, invisible utilities serving our needs. EcoDistricts seek to locate these utilities closer to the user, thereby increasing efficiencies. Further, they help make the connection between our use of resources and the generation of those utilities.

The U.S. Green Building Council’s vision is to build buildings to “regenerate,” or give back to the energy grid and surrounding ecology. Even a LEED Platinum building does not achieve this goal. With the exception of the sun, wind and waste, the resources we use to power our buildings are finite. We will eventually run out of them. EcoDistricts slow the inevitable march towards depletion and bring the hope of energy regeneration in the future.

Kirk Davis, PE, LEED AP BD+C, is the regional director at Glumac, a full-service consulting engineering firm with an office in Portland. He can be reached at kdavis@glumac.com.

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