Intrigued, I did some research. Apparently, France is home to the world's oldest known geothermal district heating system. The system in Chaudes-Aigues has been in use since the 14th century, though the Romans already employed under floor heating systems in Pompeii. In more recent history, in 1881, Birdsill Holly, an engineer from Lockport, New York patented a system of “district heating” that used centralized boilers and a network of main and branch pipelines to deliver steam heat directly to their homes. Installations were tested in cities such as Denver, Detroit and Springfield, Massachusetts.
New York was the biggest of the test markets. Apparently, the system performed flawlessly during the Blizzard of 1888, but subsequent cracks in pipes led to escaping steam, water leaks that seeped into residential basements, and increased heat in the city’s sewer lines, resulting in some very smelly explosions. The situation was deemed to have created “conditions dangerous and detrimental to life and health,” and the city shut down the system. Though the system was restored, the old pipes continue to cause problems. As a result of this first experience with steam heating, district heating in the US is now only found in large settings such as universities, public buildings and hospital complexes, but not as centralized residential heating, as Holly had intended.
Much has changed since the early days of implementation. Certainly, pipe material is more durable and less prone to cracking and corrosion. And the advantages are numerous. Operating and maintenance, which can be sporadic in individual buildings, can be centralized for greater attention but also economic gains from reduced redundancy. The increased efficiency of one unit operating at peak efficiency means less waste and less CO2 and other pollutants. Even capital costs are less, since the savings of a centralized plant is offsets the extra cost of the distribution lines.
Birdsill Holly must be smiling from his grave, because district heating is very much alive and well in Europe, and increasingly included in new residential complexes. For example, in Denmark district heating provide 60% of the country's heating needs. What is even more existing is the marriage of alternative fuels sources with district heating. In many ways, this is a perfect solution for geothermal. We often hit the “problem” with ICF houses or apartment complexes that the demand was so low that the capital expenditure for geothermal systems had a questionable cost/benefit. If
the same installation could service several buildings, then it would pencil out.
|Biomass boilers supplies 11 units of |
This distributed concept could be applied to other technologies, as well. I’m thinking of my favorite heat to energy concept, Cool Energy. Using solar thermal to provide heat to a tank, and converting this to electricity on demand by means of Stirling Engine technology. This company has long stated it’s intent to adapt this for residential use. However, there are capital costs, implementation and innovation that are better adapted to a larger setting. But this could be implemented in a new development – with the panels on top of a local school or grocery store, and thermal heat and electricity distributed throughout the neighborhood. This would be far more “green” than subsidizing PVC panels for every house. Think about it..