Students propose micro-utility in Oregon

This story will delight my colleague Peter, who has an inexplicable fetish for district heating systems: a group of college students are attempting to set up a hyperlocal utility in Portland, Oregon by linking a network of renewable energy sources over a 54-square block neighborhood. The energy in question isn’t in the form of electricity, but rather heat.

The proposed system is, well, complicated:

> Planned system components include thermal solar collectors, mass thermal storage for heating and anticipated cooling, combining water to water and ground-coupled heat pump technology, waste heat recovery, PV arrays and biofuel boilers for boosting and back-up. A distribution system of hydronic insulated pipes will deliver hot and chilled water for space heating, cooling and domestic hot water to the school, several hundred nearby residences, and commercial buildings.

In plainer English, the planned system will consist of solar hot water heaters and other systems designed to capture clean energy. These energy capture devices will be scattered throughout the neighborhood, in particular taking advantage of roof space on the elementary school and local commercial buildings. Hot (“hydronic”) water will be pooled and stored in tanks beneath a local park, and a series of insulated underground pipes will carry the water to participating homes and businesses.

> Residential and commercial customers can convert from current fossil fuel systems by replacing them with metered heat exchangers which provide hot water on demand and space heating through conventional air handlers that utilize existing ductwork. Boiler systems are replaced with heat exchangers. Hydronic air handlers are installed in existing furnace systems.

Again, in English: once the hot water reaches local homes, it can either by used directly, allowing residents to get rid of their boilers, or it can be run through heat exchangers to provide hot air, allowing residents to get rid of their furnaces. Under alternative configurations, the system might also carry cool water to provide carbon-free air conditioning. Energy use will be metered, just as natural gas or electricity would.

In essence, the system is a giant version of a geothermal or solar hot water system that you might install in your own home. The difference is that the capital costs will be spread over a bigger group of people, efficiencies can be achieved through demand-pooling, and individual homeowners won’t have to deal with maintenance and repair.

The proposal is ambitious; maybe even a little utopian — the utility will be member-owned and will provide revenue to the local elementary school, which will house system controls and some equipment. But precedents for district energy systems do exist in other countries, such as Denmark and Canada. It’s a worthwhile experiment, and hopefully the student planners will find the money and the community support to get it off the ground.

Via Sightline.

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adam

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  1. Gene Meade - December 22, 2008

    In what way is this better or more efficient economically than individual homes, businesses or schools having their own privat systems? I would think that the cost of and loss of energy by piping to separate buildings from a central generating source would outweigh any other gaines. The difficulties of managing such a system would also be a drag on any efficiencies gained otherwise.

  2. Adam Stein - December 22, 2008

    Well, I haven’t seen their spreadsheets myself, but just generally speaking, doing something at greater volume is more efficient. That’s the reason we have electricity utilities, rather than running diesel generators in our backyards. Even accounting for things like transmission loss, it’s just more efficient to bundle electricity demand together.
    Likewise — installing a geothermal system might be nice for one house, but what if you found out your neighbor wanted one too? Should you both dig pipes (which is expensive), or should you just dig one set of pipes, make the combined system a little bit bigger, and split the costs?
    Now expand it a bit further, and you’ve got the system described above. I dunno, maybe it won’t work, but it seems like a worthy experiment.

  3. Dixon - December 22, 2008

    Assuming everyone is not scattered up and down hillsides, the energy to pump things around is very minimal. Hardly of the same magnitude and heating or cooling.
    This idea is proposed in Canada as well: http://www.treehugger.com/files/2006/01/planned_communi_1.php
    But think of the real “first movers” of this idea. Cliff Dwellers used these same ideas, where solar heat was absorbed and redistributed among dwellings based on the architecture of the site, and siting of the sun lines.
    As an engineer, I can say immediately, and without any hesitation, “heat mass storage and distribution is already a solved problem”. All they have to do is work out the best practice equipment and techniques and refine their numbers over a couple of installations. The concept really is simple – even thought the author may paint it otherwise. Your hybrid car is far more complicated than this solution, yet it works extremely well compared to existing solutions.

  4. Adam Stein - December 22, 2008

    Sorry, I didn’t mean to imply that the project is technologically complex. It’s just complicated to describe, as it involves a lot of different components that are unfamiliar to non-engineers.

  5. Marco - December 22, 2008

    Adam,
    Central HVAC is becoming very common in large scale construction projects in GCC; typically a unit handling a number of skyscrapers. They claim that it is economically better due to the scale and environmentally safer, esp if they deliver as an on-demand capability.

  6. Alex Kelley - December 22, 2008

    This plan seems to have more political or social obstacles than technical ones. As was mentioned by others, scaling a solar thermal or GSHP system up to accommodate more users is much more efficient than doing individual systems for all. If the local housing authority or neighborhood association is already on board with the plan, it should be fairly simple to implement. I would think that each building would still need some sort of back up heating system though.

  7. orion - December 22, 2008

    For one example of a large project already using this technology, look at Virginia Tech. Some of their buildings are heated from a single large boiler in a separate building. I think they use forced hot air. This has been in place there for decades.

  8. info - December 22, 2008

    From Drake Landing website in Alberta:
    # Solar energy began to flow into the borehole thermal energy storage system as of sunrise on June 21, 2007 – the summer solstice.
    # Early performance results indicate that the solar energy system is performing as expected and that the 90% solar fraction will be achieved by year five.
    # The final construction of the 52 homes was complete in August, 2007. There are 51 homes currently occupied with the last scheduled for October.
    http://www.dlsc.ca/index.htm
    Just for research and info.

  9. James Richmond - December 23, 2008

    The biggest advantage of this proposal is that load diversity between the buildings could contribute to the overall efficiency of the combined system, especially if there is air conditioning and heating. If one (residential) building needs heat while another nearby (commerical) building needs cooling, the heat removed from the cooled building is transferred via the district piping to the heated building. This multiplies overall system efficiency.

  10. veggieforce - December 23, 2008

    I’m no expert- but I just love the idea of geothermal heating. it makes so much sense to me. Why its taken us so long to consider it, I will never understand.
    I think this is a great project! I hope the city planners give it a thumbs up.
    which city are we considering here? Portland?

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