Chapter 6

Question 1

Define the term micro generation

Answer 1

The small scale generation of heat and power

Question 2

What is meant by the term micro electricity technologies

Answer 2

Small devices that are capable of producing electricity

Question 3

Two examples of micro electricity technologies

Answer 3

Solar PV
Wind

Question 4

What are micro heat technologies

Answer 4

Small devices that are capable of producing heat

Question 5

Three examples of micro heat technologies

Answer 5

Solar thermal
Biomass
Ground source heat pumps

Question 6

What are the main benefits of micro generation

Answer 6

Reduced energy cost
Enhanced security supply
Contribution to environmental targets

Question 7

What is a heat pump

Answer 7

A heat pump is a system that aims to transfer energy against natural temperature gradient

Question 8

What happens to gas when compressed

Answer 8

Temperature and pressure increases

Question 9

Describe the stages of how a heat pump works

Answer 9

The refrigerant enters the evaporator in liquid form but is then changed to a gas with a higher temperature but still to low to work.
It then passes from the evaporator to the compressor in gaseous form, the compressor compresses the gas which increases the pressure and temperature.
The refrigerant still a gas passes from the compressor to the condenser the refrigerant passes thermal energy to the external environment meaning it’s temperature decreases. It leaves the condenser as a mixture of gas and liquid
The refrigerant now travels to the expansion valve where it condenses and turn completely into a liquid
The refrigerant is now pumped to the evaporator where the process repeats itself

Question 10

What changes in a heat pump for it to become and AC unit

Answer 10

Evaporator and condenser switch
Direction of flow for refrigerant switches