Section 10.3Section 10.3

Using HeatUsing Heat

Heating SystemHeating System

Heating Systems: Heating Systems: Def. p.340.Def. p.340.

1.1.Work can be done Work can be done to increase to increase temperature.temperature.

Example of this is Example of this is when you rub your when you rub your hands together.hands together.

2. The energy from food 2. The energy from food is transferred as heat is transferred as heat to blood moving to blood moving throughout the human throughout the human body.body.

The human body is a The human body is a type of heating system type of heating system because it maintains a because it maintains a constant temperature constant temperature of 37of 37ooC or (98.6C or (98.6ooF) F) irrespective of the irrespective of the external environmental external environmental temperature.temperature.

3.3. Heated HHeated H22O or air O or air transfers energy as transfers energy as heat in central heating heat in central heating systemssystems

A central heating A central heating system has a furnace system has a furnace that burns coal, fuel that burns coal, fuel oil or gas. The energy oil or gas. The energy released in the released in the furnace is transferred furnace is transferred as heat to Has heat to H22O, steam O, steam or air.or air.

4.4.Solar heating Solar heating systems also use systems also use warmed air or Hwarmed air or H22O.O.

In solar heating In solar heating systems, the main systems, the main source of energy is source of energy is from the sun.from the sun.

5.5.Usable energy Usable energy decreases in all decreases in all energy transfers.energy transfers.

When energy ex. in When energy ex. in the form of heat is the form of heat is transferred from one transferred from one place to the other, place to the other, the usable energy is the usable energy is decreased through decreased through conduction, conduction, radiation and even radiation and even convection.convection.

6.6.Insulation Insulation minimizes minimizes undesirable energy undesirable energy transfers.transfers.

Insulating Insulating materials such as materials such as glass, wood, brick glass, wood, brick help reduce the help reduce the loss of energy.loss of energy.

Cooling SystemsCooling Systems

Cooling Systems: Cooling Systems: Def. p.343.Def. p.343.

Cooling systems Cooling systems often use often use evaporation to evaporation to transfer energy transfer energy from these from these surroundings.surroundings.

An example of a An example of a cooling system is a cooling system is a refrigerator and it refrigerator and it cools with the help cools with the help of a refrigerant.of a refrigerant.

Refrigerant: Refrigerant: Def.p.344Def.p.344

CondensationCondensation Transfers energy to the Transfers energy to the

surroundings.surroundings. Condensation involves Condensation involves

transferring energy transferring energy from the vapor as heat, from the vapor as heat, this is why the this is why the temperature of the air temperature of the air outside the refrigerator outside the refrigerator increases.increases.

Air conditioning Air conditioning systems use the same systems use the same process as refrigerators.process as refrigerators.

Heat pumps can Heat pumps can transfer energy to or transfer energy to or from rooms.from rooms.

Heat pumps use the Heat pumps use the process of process of evaporation and evaporation and condensation of the condensation of the refrigerant to provide refrigerant to provide heating during winter heating during winter and cooling during and cooling during summer.summer.

In the refrigeration In the refrigeration cycle, there is a heat cycle, there is a heat pump which helps to pump which helps to reverse the cooling reverse the cooling cycle.cycle.