presentation for ELECTRICAL HEATING313 (2).ppt

PPT for electric heating

1. ELECTRICAL HEATINGELECTRICAL HEATING

2. OUTLINEOUTLINE

Introduction.Introduction.

Definition.Definition.

Electric Resistance Heating.Electric Resistance Heating.

Types of Electric Resistance Heaters.Types of Electric Resistance Heaters.

Mathematical analysisMathematical analysis

Fan heaters.Fan heaters.

Conclusion.Conclusion.

3. IntroductionIntroduction
The energy is converted from shape to The energy is converted from shape to
other shapeother shape
Such as:Such as:
Electrical energy thermal energyElectrical energy thermal energy

4. DefinitionDefinition
Electric heatingElectric heating is any process in which electrical energy is is any process in which electrical energy is
converted to heat. Common applications include heating of converted to heat. Common applications include heating of
buildings, cooking, and industrial processes.buildings, cooking, and industrial processes.
An electric heater is an electrical appliance that converts An electric heater is an electrical appliance that converts
electrical energy into heat . The heating element inside electrical energy into heat . The heating element inside
every electric heater is simply an electrical resistor, and every electric heater is simply an electrical resistor, and
works on the principle of joule heating: an electric current works on the principle of joule heating: an electric current
flowing through a resistor converts electrical energy into flowing through a resistor converts electrical energy into
heat energy.heat energy.
A heat pump uses an electric motor to drive a A heat pump uses an electric motor to drive a
refrigeration cycle, drawing heat from a source such as refrigeration cycle, drawing heat from a source such as
ground water or outside air and directing it into the space ground water or outside air and directing it into the space
to be warmed. Such systems can deliver two or three units to be warmed. Such systems can deliver two or three units
of heating energy for every unit of purchased energy.of heating energy for every unit of purchased energy.

5. Electric Resistance HeatingElectric Resistance Heating
Electric resistance heating converts nearly 100% Electric resistance heating converts nearly 100%
of the energy in the electricity to heat. However, of the energy in the electricity to heat. However,
most electricity is produced from oil, gas, or coal most electricity is produced from oil, gas, or coal
generators that convert only about 30% of the generators that convert only about 30% of the
fuel's energy into electricity. Because of electricity fuel's energy into electricity. Because of electricity
generation and transmission losses, electric heat is generation and transmission losses, electric heat is
often more expensive than heat produced in the often more expensive than heat produced in the
home or business using combustion appliances, home or business using combustion appliances,
such as natural gas, propane, and oil furnaces.such as natural gas, propane, and oil furnaces.

6. Types of Electric Resistance Types of Electric Resistance
HeatersHeaters

Electric FurnacesElectric Furnaces

Electric Baseboard HeatersElectric Baseboard Heaters

Electric Wall HeatersElectric Wall Heaters

Electric Thermal StorageElectric Thermal Storage

Control SystemsControl Systems

7. Mathematical analysisMathematical analysis
According to According to Joule's Law, the heat power produced by a , the heat power produced by a
resistor is:resistor is:
PP = = IVIV
wherewhere
PP is the power in watts is the power in watts
II is the current in amperes, and is the current in amperes, and
VV is the potential difference in volts, is the potential difference in volts,
and according to Ohm's Law and according to Ohm's Law II and and VV are related as follows: are related as follows:
VV = = IRIR
wherewhere
RR is the resistance of the heating element, in ohms. is the resistance of the heating element, in ohms.

8. Fan heatersFan heaters
A fan heater is a variety of convection A fan heater is a variety of convection
heater that includes an electric fan to speed heater that includes an electric fan to speed
up the airflow. up the airflow.
This reduces the thermal resistance between This reduces the thermal resistance between
the heating element and the surroundings, the heating element and the surroundings,
allowing heat to be transferred more allowing heat to be transferred more
quickly.quickly.

9. conclusionconclusion

Although they all use the same physical Although they all use the same physical
principle to generate heat, electric principle to generate heat, electric
heaters differ in the way they deliver heaters differ in the way they deliver
that heat to the environment.that heat to the environment.