Episode 4 — Energy Transfer to Surroundings

Sankey Diagrams

Learners will be able to:

• List the equipment needed to draw an accurate Sankey diagram (graph/square paper, pencil, ruler, coloured pencils) • Extract relevant input, useful output and wasted output values from a written description of an energy transfer system • Draw a Sankey diagram to scale, using the width of blocks/arrows to represent proportional amounts of energy • Check that extracted energy values obey the law of conservation of energy before drawing a diagram • Identify the features of a well-drawn Sankey diagram, including neat straight lines, labelled arrows and accurate proportional widths • Calculate the percentage efficiency of a system (e.g. an LED torch) from a Sankey diagram