Coasule
Coasule was an experimental project that investigated the potential of a coffee coaster to reduce heat loss from conduction. It was identified that the ideal temperature for consuming coffee was within the range of 60 to 70 degrees Celcius. The aim was to design a coaster that would ensure the coffee would remain within this range for at least 15 minutes with no heat marks left on the table. It is to be emphasised that this was an experimental project with the goal of learning about thermal conductivity, where no significant difference was expected to be observed.
Ideation Phase
The coaster was designed for a home environment for a demographic of 25 to 34 year old Australian's. Wood was chosen for the material due to its low rate of heat conduction, durability and for its aesthetics.
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Design 1 is a basic circular layer of wood used as a comparison model. Designs 2 and 3 were inspired by double glazed windows, utilising a partially (2) and fully closed pocket of air (3). Research indicated that air conducted heat at a significantly lower rate, and hence was hypothesised that the coffee would maintain the optimal heat range for longer with the design.
CNC Machining
CNC machining was determined as the most efficient way of prototyping. Three spline paths were then created in 'Carbide' based on the ideation sketches and exported into 'G-Sender'. The designs were then cut from pinewood and are showcased in the second image. To recreate the 8mm encapsulated air pocket in concept 3, a dove-tail join system was used (see image 4).
Heat Conduction Testing
The three coasters were tested to see how long coffee would remain above 60 degrees Celsius from a 70-degree starting mark. As the experiment focused on heat conduction through the table, a wooden lid was used to cover the top of the cup. Through calculations completed previously, it was expected that all three designs should last longer than 15 minutes. Concepts 3, 2, then 1 would last the longest respectively with the greatest difference being between concept 1 and the other designs. The experiment replicated the general relationship, with concepts 1-3 staying within the temperature range for above 15 minutes:
Design 1: 15 min 15 sec
Design 2: 17 min 30 sec
Design 3: 17 min 26 sec
Although not significant, it can be seen that the addition of an air pocket aided in reducing the rate of heat loss from the cup.
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It is to be noted that there were a few errors observed in the methodology of the experiment. The second image shows water absorption through the lid of the cup. The water could have then affected the wood's properties, creating inaccuracies. Another issue was the lid warping due to heat (image 3). The orientation of the lid was flipped after too much warping, however, this still created inconsistencies.
