Part 2 Energy efficiency

Question 1

How would you describe the transfers in an appliance e.g a lamp?

Answer 1

e.g electrical energy to Light energy and the wasted energy would be heat energy.

Question 2

what are sankey diagrams?

Answer 2

Sankey diagrams are a specific type of flow diagram, in which the width of the arrows is shown proportionally to the flow quantity. Sankey diagrams are typically used to visualize energy or material or cost transfers between processes

Question 3

What is useful and waste energy?

Answer 3

useful energy is the energy’s used in an energy transfer and wasteful energy is the leftover from that energy transfer which is not being used.

Question 4

How do you calculate energy efficiency of a device?

Answer 4

The efficiency of a device such as a lamp can be calculated using this equation:
efficiency = ( useful energy transferred ÷ energy supplied ) × 100
The efficiency of the filament lamp is (10 ÷ 100) × 100 = 10%.