LearnChemE

Lumped Capacitance Method for Analyzing Transient Conduction Problems: Summary

The answers to the ConcepTests are given below and will open in a separate window. 
ConcepTest 2 Answer — see this screencast for an explanation
Key points from this module:
  1. Lumped capacitance provides a relatively simple way to calculate the temperature of an object that warms up or cools off over time.
  2. It is very limited, however. Before using it, you must first confirm that Bi < 0.1 or your results will be meaningless.
From studying this module, you should now be able to:
  • Identify whether lumped capacitance is appropriate in a given scenario.
  • Sketch a qualitatively-accurate graph of the temperature of an object as a function of time.
  • Predict when an object will reach a specified temperature.

Prepared by Jeffrey Knutsen, Department of Mechanical Engineering, University of Colorado Boulder