Heating and Cooling systems

Question 1

State the main components in cooling a car’s engine:

Answer 1

-Thermostat
- Radiator fins
- Radiator
- Fan
- Pump

Question 2

Define the function of a thermostat:

Answer 2

The thermostat is a control gateway through which high temperature coolant/water is allowed to pass through to the radiator.

Question 3

Define the function of a radiator:

Answer 3

Is a set of tubes surrounded by little metal fins called radiator fins to regulate and decrease the coolants temperature and in-turn the engines.

Question 4

Define the function of the radiator fins:

Answer 4

Metal fins surrounding the radiator to ensure a greater surface area to increasing thermal energy exchange with surroundings through conduction. Helps cool down the coolant and in-turn regulate internal temperature of the engine.

Question 5

Define the function of the fan in car engine:

Answer 5

The fan pulls air out of the radiator to further cool down the coolant and increase cooling rate.

Question 6

Define the function of the pipes in car engine:

Answer 6

The pipes act as a mean of transport to allow for the coolant to get around the engine readily.

Question 7

List the components in a heat pump:

Answer 7

• Condenser
• Evaporator
• Compressor
• Expansion valve

Question 8

Define the function of condenser in heat pump:

Answer 8

The condenser consists of a series of pipes that draw heat away from the high pressure high temperature vapour and condenses it into a liquid.

Question 9

Define the function of evaporator in heat pump.

Answer 9

The evaporator consists of a set of tubes that draw thermal energy from surrounding air through conduction to heat up and vaporise the low pressure, low temperature liquid coolant.

Question 10

Define the expansion valve in heat pump:

Answer 10

The expansion valve depressurises high temp high pressure liquid which in-turn decreases its temperature turning it into low pressure, low temperature liquid/coolant.

Question 11

Define the compressor in heat pump:

Answer 11

The compressor pressurises low temp low pressure vapour and increases it’s temp turning it into high temp high pressure gas/vapour.

Question 12

Define Gay-Lussac’s Law:

Answer 12

P ∞ T –> Pressure is proportional to temperature.

Question 13

Describe function of Evaporative Air-conditioning:

Answer 13

• Hot air is forced through a wet pad by a fan.
• This heat is absorbed and evaporates the water in the heat pad
• “Water evaporation cooling principle” –> cool air gets draw into the house via a vent and a fan.