Heat Loss from a Liquid

The model is set to run for 120 minutes with 5-minute time steps. Run the model and open the result element ‘Coffee Temperature Results’ to see the time history of the coffee temperature as it cools over time.

The internal energy of the coffee (in calories) is modeled using an Integrator element. An equation of the following form is used for the cooling rate: k*(T1-T2), where ‘k’ represents a generic heat conduction coefficient with units, cal/K-min and T1 and T2 are respectively the coffee temperature and the room temperature. The heat transfer rate is, therefore, proportional to the difference in temperature between the coffee and the surrounding air. This results in the coffee temperature asymptotically approaching room temperature.

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