“Shaping” Our Homes

By David Li
Intermediate Category (Grades 9-10)
Experiment | Engineering and Computer Science

Does using shapes in engineering affect how well buildings retain heat?

Official Question:
Does designing and constructing buildings in different shapes (such as geodesic domes versus rectangular prisms) affect how heat is retained in such a building, and if so, to what extent do geometric variations in the design and construction of buildings affect (detrimentally or beneficially) heat retention in a building?

If I take 3 2V-Style geodesic hemispheres and 3 pentagonal prisms approximately 20 cm in length each; made of 1 cm thick cardboard and heat-resistant glue, remove their bases, and place a small tealight, then cover the 6 tealights separately with the 6 containers, and monitor them using an infrared thermometer for 15 min, then the curved geodesic-dome buildings will retain higher concentrations of heat than the faceted pentagonal prisms when scanned and monitored over time.

This is because the flat surfaces, edges, and vertices present in many suburban house designs; which here represented by the stereotypical house-shaped pentagonal prism; are allowing for heat accumulation and heat loss as the hot air rises and is lost as it dissipates on the flat surface of the roof. Furthermore, the dome has less surface area, resulting in less heat loss.

Experimental Procedure:
I took cardboard sheets, double-layered them by gluing one layer atop another, and fabricated them into triangles or rectangular panels, attaching them together with hot glue to create scale structures to test for shape-heat retention. After closing blinds, shutting windows, and more to ensure the environment was controlled, I lit 6 tealights and covered them with the six structures. I took down data on Building Heat (℃), which was measured with the Internal/External Panels Temp, Building Temp, and Surface Temp, and qualitative observations by touch regarding areas of heat loss and heated areas; done every 5 minutes for 15 minutes. I kept water on hand for safety reasons; I worked with an open flame.

There was little to no difference between the dome (Experimental) and the prism (Control) in terms of heat retention in general over time and over testing. Both series of values and lines (representing temperatures) remained fairly similar. However, this heat loss was spread evenly across the top of the dome and the dome itself was evenly heated, although both structures’ internal heat, both qualitatively (Heat Map) and qualitatively (Line Graph) were alike.

The data being similar across both structures; I did not necessarily observe a relationship between building shape and heat retention, although heat was more even within the dome. Heat loss occurred from the prism roof and the top of the dome. There were also sources of error, such as heat loss from gaps in the structure. All in all, this disproves my hypothesis, but I am still confident that a better, heat-efficient design is the key to consuming less of our natural resources on an individual scale.

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