Drawing (on) Gravity

Sometimes gravity is an architect’s friend.

In fact, architects can use gravity to human advantage in all sorts of ways.  In Ecology class today, I showed some diagrams of systems that use “thermosiphoning.”  That’s a fancy word referring to gravitation pull that moves fluids (like air or water).

The idea is that warm air (or water) rises and cold air (or water) sinks… because a  liquid is heavier and more dense when it is cold.

So, we can let gravity do the work if we think a system through.  Sometimes we need to move liquids in directions they don’t naturally want to go, and then we need to add electric pumps or fans to our systems.

Today, I showed my second year architecture students a tromp wall system as well as a diagram of an open loop solar hot water system.  In that type of system, you let the sun heat the same water that you will use to shower, wash dishes, or drink.

I also showed a few diagrams of basic heat exchangers… like the one in a car.  That one takes the heat from the combustion process and uses it to warm the air in the car without bringing in the “smog.”

The students were seeming to “get” the ideas, but they didn’t seem particularly jazzed up about them.  (I knew that because they were fidgeting and clearly wanted to text.)

To get them involved, I turned posed a problem for them to solve.

I asked them to pull out a sketchbook and combine the solar collector and the heat exchange into a single diagram.  They needed to figure out how you could use water with water with glycol (i.e., antifreeze) in it to collect the sun’s heat and then use that same liquid to warm the water for someone’s shower.

The challenge was to transfer the warmth into potable water without tainting it.  A couple of students caught on fast. After everyone had given it a try, I let them help each other.  More and more people got it.

At about the same time, I asked a four of the students who caught on quickly to draw their diagrams on the board and then explain how they worked to the class.  We all put our heads together to analyze the designs.


  1. So how would you do this so the system can heat in the wintertime and be removed in the summer? Any way you could use this for summertime cooling?



  2. Really like the application part, next step – mockups? I’ve found that students get into the aesthetics of systems too, with heat involved, potential for “thermal delight” (Lisa Heschong’ s concept).



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