New strategies for energy management emerge constantly as engineers, designers, and facility managers respond to limited resources, rising energy costs, and environmental impacts. While the need to do better with less on a building-by-building basis is a step in the right direction, the future of energy management and a sustainable lifestyle lies in tackling the issues on a much larger scale – a leap toward the eco-district.
An eco-district is a community of resources and people that create a self-contained sustainable environment. Similar to an ecosystem in nature, each part serves a purpose that supports the others and the system as an interdependent whole. The many facets of an eco-district include transportation, manufacturing, education, materials’ use, waste, and energy. In order to assure the eco-district system functions properly, diversity is key. In moving toward net-zero energy, in particular, eco-districts will become self-contained systems of energy exchange, where energy producers and energy consumers will interact to optimize energy production, use, and distribution.
Factors limiting the development of eco-districts include the lack of planning tools, financial strategies, and narrowly focused zoning. But city planners are examining ways to overcome these obstacles and to allow eco-districts to thrive. With energy a clear necessity, facility managers will be indispensible in the proper formation and operation of these districts.
Tom White, P.E., LEED AP
Forward-thinking facility managers can help their building owners prepare to become part of an eco-district or even assess their ability to serve as the catalyst for one. For example, recognizing that localized energy production is essential in an eco-district, you might look at implementing building systems now that tap into alternative energy sources, such as biofuels, photovoltaics, geothermal, or microturbine generators for combined heat and power.
As your building becomes part of an eco-district, it could offer a highly desired fuel source to supply the community of buildings and generate income. Moreover, armed with the knowledge that municipalities will be looking to create eco-districts, if you can generate a surplus of energy to feed adjacent uses, you are poised to suggest that an eco-district be created, with your building as part of the core.
Unlike operating a central plant on a campus, the complex energy management challenges of an eco-district require facility managers to think at a much more sophisticated level. In order to balance energy distribution for the loads and various users, you need to carefully examine where your energy sources are coming from and look at both how and when they are used. These factors need to be charted out on a daily, monthly, and annual basis.
Facility managers of an eco-district will be charged with intelligent energy resource integration and allocation. You will need to determine what type of users you need to attract in order to match the resources of energy production and storage with loads that vary by time-of-day, by season, and even by the scale, intensity, and quality of use. This is where diversity becomes critically important. As you look at your capacity for heating and cooling, the waste heat available for reuse, and the time of day that various users consume the energy, it’s essential to pinpoint what kind of consumers make sense in the eco-district. Who in the district will generate the energy and at what time of day? What type of uses will make sense given this energy production? The goal is to create synchronization between the energy generation and usage.
A Question of Balance
The energy puzzle of the eco-district also depends on capacity, and energy storage becomes an issue. For example, solar hot water systems atop a residential building provide hot water during the day but the majority of residents need hot water at night when the sun is no longer shining. A manufacturing facility in the eco-district could provide ample rooftop space for photovoltaic (PV) systems for generating electricity which could be stored in batteries. Likewise, the heat energy collected from an array of solar panels could be accumulated in water tanks and used by residents for showers and washing clothes at night. The amount of energy that can be produced also influences the size of the residential population that is feasible in the eco-district.
Heat recovery loop cycles would be prolific in eco-districts as zero waste is critical in mimicking a living system. Such a loop would serve as a heat source for some users and heat sink for others. The facility manager’s job would be to control the loop temperature to optimize the energy extracted and rejected, depending on the diversity of uses at a given time of day.
As you extrapolate the concept of heat recovery to multiple systems, the process becomes increasing complicated because the quality of energy degrades. In order to optimize the system as a whole, you have to figure out how to capture every Btu – even with cascading energy productivity. As an example, you may use biofuel in a micro-turbine to create electricity. With a combustion waste stream of 1,500 to 2,000 degrees F., this high-grade heat could be used at an industrial facility to support a food drying process. From the food dryer, the waste heat might fall to 150 degrees F., but even this still has value. At this level, the excess heat is high enough for office or residential space heating.
The above example shows how wasteful our current systems can be. These are exactly the types of inefficiencies that eco-districts – when wisely planned and managed – have the power to correct. It will require a new way of thinking about cities: one where varying uses co-exist to capitalize on one another’s strengths. Facility managers who begin to think about solutions now will be a position to not only help find creative ways to respond to our collective consumption, but also to assume a pivotal role in tomorrow’s eco-districts.
Tom White, P.E., LEED AP is technical director of Green Building Services Inc. His team provides technical and energy management solutions to building owners and facility managers throughout the nation. Tom can be reached at (866) 743-4277 or [email protected].