Tuesday, October 14, 2008

Guest Post | Doug Pierce

Even though Sri Lanka and Minnesota have very different climates and we are far from being an island, a project like Embassy Medical Center in Minnesota could share many of the same features - a concrete frame; a building orientation that takes advantage of the sun; exterior shading, etc. The building form is still Ok, although it's proportions might change some to adapt to the cold winters.

I'm probably going to get in trouble with the Engineers here, but I know my technical limits as an Architect and I know we need the them for the heavy calculus -- so here are some big ideas on the 'mechanics'...

The basic energy strategies could be similar. Given the fact that we are surrounded by arable land, the facility could lease or by farmland (lots!), grow organic food crops for the patients, the cafeteria and the community, then use much of the non-nutritional crop residue in the high-temperature digester to create bio-gas. Some residue would be returned to the land as fertilizer. Digesters take very little water, so unlike corn ethanol, it would not be competing with other water uses. Plus the energy return is very good. The farm equipment could even be run with the digester bio-gas.

We have good solar access here, so the solar thermal domestic hot water would continue to be a good choice. In some ways, the sun is an underutilized resource, so if you have room, it's important to use it when you can. There's a finite amount of bio-mass available and we're going to need it for a wide range of things as oil continues to be more scarce over the next few decades.

Minnesota has outstanding resources, so we actually have more options available than Sri Lanka. For example, from an energy conservation side - earth tubes for pre-tempering make-up air before it enters the HVAC system could work here, but the ground temperature was to hot in Sri Lanka. You'd would need allot and you'd have to flush them clean on regular basis to avoid mold.

Wind electric, heat pumps and geo-thermal exchange are a nice combination for much of greater Minnesota. If the project was outside of a major metro area, in a windy location; three, four, maybe five big turbines could probably power it much of the time. This would shift the energy strategy from being what I like to think of as 'heat-centric' to 'electric-centric.' You might even use the wind to siphon air through the earth tubes, saving energy. You can't really 'use up' the wind, and like the sun, it's an underutilized resource making it a kind of 'ecological free ride' for the moment if you can catch some.

Even with the wind power, you'd still want the digester as a back-up when the wind is low and for times when you might need more domestic hot water than the solar thermal is providing. Since the digester must consistently compost 24 / 7 all year long to be effective, you would store bio-gas and then sell the surplus to the rest to the local community. The digester would also take care of sewage for the hospital and the community at large. A good constructed wetland would take of the remaining effluent.

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