The Trombe Wall and the Penny Farthing

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ArchDaily published an article on the Trombe Wall. Some quick reactions:

  • To learn the full history of the Trombe wall, please seek out my book!

  • It is authentically difficult to write about the relevance of historical methods to architecture today.

  • The ArchDaily article is an interesting summary and generally accurate, but to my mind it buries the lede. Near the end is the line: “A study by the National Renewable Energy Laboratory of the Zion National Park Visitor Center found that 20% of the building’s annual heating was supplied by its Trombe wall.” This is a new-ish building and these are significant savings.

  • I’m not interested in criticizing the author, but let’s simply acknowledge that ArchDaily is using student-interns to create serious content. This is the reality of architectural publishing.

Then on Twitter, Nick Grant posted:

Trombe tweet.jpg

Now here is an interesting question! Is the Trombe Wall comparable to the Penny Farthing? This raises deep issues of history, technology, and architecture. I have many scattered thoughts:

  • Technologies that are revolutionary and good in their time only seem quaintly ‘transitional’ in retrospect. For technologies or products or methods today, it’s difficult to know if they are mature or transitional. Your favorite Passivhaus housing project might look like a Penny Farthing someday. I’ll be bolder: it probably will.

  • Does the Trombe Wall work? Yes.

  • What are its fundamental limitations? 1) The heat stored during the day radiates both directions at night. Much is lost outward through the glass. 2) Thermal control is difficult. You might have overheating in some spaces and times.

  • Limitation 1 can be addressed by moveable insulation or heavy curtains, but low-tech solutions requiring user engagement aren’t popular in the green building community today. This is cultural. Limitation 2 can be addressed by asking people to tolerate a larger range, or use different spaces at different times. Likewise, this isn’t popular in the green building community today and also cultural.

  • If you assume the Trombe Wall is like the Penny Farthing, you are assuming that it can’t evolve into something better (like a chain-and-sprocket bicycle). I don’t agree with this assumption.

  • The better version of the Penny Farthing was a different bicycle, but same category of thing. As Nick suggests, the chain-and-sprocket technology was a major advance. Is it analogous to say insulation and air-tightness is the better version of the Trombe Wall? I’m not sure about that. Not the same category of thing.

There is no doubt that newer Passivhaus techniques (insulation, air-tightness, etc.) are more effective at reducing energy and providing comfort than older Passive Solar/Trombe Wall techniques. Yet it’s true that the Trombe Wall is not obsolete, because it works as a limited low-technology solution to collect and store free heat. With vastly reduced heating needs, can they be used together? Trombe parapets? Trombe curtains? Trombe furniture?