P1.3 Flashcards
What can energy be measured in?
kWh when power is kW and time is hours
Joules when power is w and time is seconds
Cost of electricity =
Amount/number of kWh used x cost per unit/kWh
What do sankey diagrams show us?
The width of the arrow tells us the total energy in and the useful and wasted energy out
What does cost effective mean?
Best value for money taking into account all the different costs for example running costs, maintenance and insulation costs
What is payback time?
The time it takes for an appliance or installation to pay for itself in terms of energy savings
How can waste energy be useful?
In heat exchangers which reduce the amount of energy that is lost by pumping a cold fluid through wasted heat which heats the water and this water can be used to generate electricity or the energy from the heated water can be converted to useful energy
What is a kilo watt hour?
The amount of electrical energy used by a 1 kilowatt appliance left on for an hour
How to read meter readings?
Look at the units
Read it off
But if there’s two readings then subtract the smallest from the biggest
What does the amount of energy of an appliance transfer depend on?
How long the appliance is in and its power
