Heat Pumps

Question 1

What do heat pumps do

Answer 1

Transfers energy against a natural temperature gradient

‘A high temperature body to a lower temperature body’

Question 2

Uses of a heat pump

Answer 2

Fridge freezer
- room = high temp
- transfers high temperature energy into less
Lower Temperature - Fridge

A/C

• car
• higher temperature than outside
• outside cools inside

Question 3

Changes of state —-> water

Answer 3

Ice = below 0*C
Water = above 0*C
Steam = above 100*C

Question 4

What is compress and expansion

Answer 4

Compress =
apply force, more internal energy, more KE,
increase temperature

Expansion =
Pressure reduce, less internal energy, reduced KE, decrease temperature

Question 5

5 components on a heat pump

Answer 5

Expansion valve = cools gas, by expanding
Compression valve = heats gas, by compressing
Evaporator = absorb low temp = liquid to gas
Condenser = emits thermal energy
Pipework

Question 6

Benefits of using heat from outside

Answer 6

Free

Question 7

What is Qh, W, Qc

Answer 7

Qh = energy supplied at hot end
W = Eletrical energy to pump 
Qc = energy absorbed at cold end

Question 8

What do you have to do to get a air conditioning heat pump

Answer 8

Reverse the components