1. Using Thermal Energy—Chapter 6
Conduction, Convection, Radiation
Insulation, Conductors, Insulators
Solar Energy
Internal Combustion Engines
Thermal Energy

2. Conduction
Is the transfer of energy through matter by direct contact of particles
Temperature
Is a measure of the average kinetic energy of its particles
Particles are in constant motion
Energy is transferred when particles moving at different speeds bump into each other

3. Conduction Takes place in solids, liquids and gases
Solids because of their compacted particles conduct heat better than liquids or gases
Metals are good conductors of heat

4. Convection Is the transfer of energy by the bulk movement of matter
Important for thermal energy transfer in fluids
Fluid particles move from one location to another, carrying energy with them

5. Fluids Any material that flows Liquids and gases
Heat added to fluid the particles move faster and have more freedom to move, therefore they expand

6. Transfer by Currents
Transfer thermal energy from warmer to cooler parts of the fluid
Convection currents
Air currents
Ocean currents

7. Radiation Is the transfer of energy in the form of waves
Radiant energy
Does not require matter
Different materials absorb radiant energy differently
Dark-colored materials absorb more radiant energy than light colors

8. Insulators Do not allow heat to move easily through them
Wood, plastic, glass, fiberglass
Good insulators are poor conductors

9. Insulation Ratings R-value R indicates resistance to heat flow
Is a measure of the resistance that 1 m x 1m square slab of the material has to heat flow per centimeter of the materials thickness
House R-value of 19
Roof or ceiling R-value of 30-44
Depend on climate of area

10. Insulation Rating Windows Single pane R value of 1
Double pane reduce heat loss because traps air in between the two pieces of glass
Weather stripping also helps

11. Convectional Heating Systems
Source of energy, wood, coal, gas, fuel, electricity
Energy produced transferred to air by conduction, convection or radiation
Radiator Systems
Radiator is a device with a large surface area designed to heat the air neat it by conduction, convection currents then circulate the heat to all parts of the room
Pictures pages 162 in textbook

12. Convectional Heating Systems
Forced-Air System
Energy released in the furnace heats air, a blower forces the heated air through a system of ducts to vents in rooms throughout the house
Air is circulated by convection

13. Convectional Heating Systems
Electrical Heating Systems
Baseboard heaters
Heating coils are enclosed within floors or ceilings and hare heated by electrical energy, which heats surrounding air by conduction and air moves throughout by convection

14. Solar Heating Energy from the sun is called solar energy Free energy
Passive Solar Heating
No fans or mechanical devices to transfer heat from one are to another
Absorb radiant energy during the day and convert it to thermal energy (normally stored in absorbing materials until used at night)

15. Solar Heating Active Solar Heating Use solar collectors
Devices that absorb radiant energy which is used to heat water or air that is pumped through the house

16. Heat Engines
Are devices that convert thermal energy into mechanical energy
Burn fuel in a process called combustion (rapid burning

17. Heat Engines Internal Combustion Engine External Combustion Engine
Fuel burns inside the engine in chambers called cylinders
Each cylinder has at least two openings that open or close with valves. A piston inside each cylinder moves up and down, turning a crankshaft. The motion of the crankshaft is transferred to the wheels of the care through a series of moving parts
Only part of the fuel is converted in gasoline 12 percent and diesel 25 percent
External Combustion Engine
Fuel is burned outside the engine
Steam engines
Fuel is burned to boil water in a chamber outside the engine, steam passes through a valve in the engine, where it pushes a piston, the motion of the piston is transferred to the wheels

18. Heat Movers
A heat mover is a device that removes thermal energy from one location and transfers it to another location at a different temperature
Refrigerators use the process of evaporation to remove heat form the food inside
Air conditioner removes thermal energy from the house
heat engines in reverse
use mechanical energy to move thermal energy from cooler or warmer

19. Sweat—The Human Coolant
Heat is removed from your body as your perspiration evaporates, making you cooler
Humid days sweat doesn’t evaporate as fast and may condense instead of evaporate
Evaporation is a cooling process and condensation is a warming process