thermal energy stem lab

10
Thermal Energy STEM Lab

Upload: rumor

Post on 25-Feb-2016

34 views

Category:

Documents


0 download

DESCRIPTION

Thermal Energy STEM Lab. Which gives off more Carbon Dioxide (air pollution) a house or a car?. House. Most energy consumed in homes comes from burning fossil fuels, like coal, oil, and natural gases. On average Americans spends $241 billion on energy bills. Uses of energy. - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Thermal Energy STEM Lab

Thermal Energy STEM Lab

Page 2: Thermal Energy STEM Lab

Which gives off more Carbon Dioxide (air pollution) a house or a car?House

Most energy consumed in homes comes from burning fossil fuels, like coal, oil, and natural gases.

On average Americans spends $241 billion on energy bills.

Page 3: Thermal Energy STEM Lab

Uses of energy

Page 4: Thermal Energy STEM Lab

Which household function uses the most energy?1. Heating2. Hot Water3. Lighting 4. Cooking

Page 5: Thermal Energy STEM Lab

A thermogram shows the distribution of heat over the surface of a house. It highlights where heat is being lost.

The white, yellow and red areas are the warmest, so these are the worst insulated parts of the house.

A poorly insulated house loses more energy and so costs more to heat. It also means that more pollution, particularlycarbon dioxide, is created in order to heat the house.

The blue and green areas are the coolest, so these are the best insulated parts of the house.

Page 6: Thermal Energy STEM Lab

Where is the most heat lost from a poorly insulated house?

walls 36%

roof 20%

windows 12%

doors 4%

Heat loss from houses

Page 7: Thermal Energy STEM Lab

The air warmed by radiators (and other heaters) is carried around a house by convection currents.

How can heat loss through a roof be reduced?

heat loss

loft insulation

Loft insulation contains trapped air and so forms an insulating layer between the loft and the rest of the house. This helps to reduce heat loss through the roof.

The house becomes heated but, if there is no roof insulation, the warm air continues to rise.

The heat eventually escapes through the roof and is lost due to conduction through the roof tiles.

Page 8: Thermal Energy STEM Lab

A lot of heat energy can be lost through windows.

Double glazing adds an extra pane of glass. The air trapped between the two panes acts as an insulator and reduces heat loss by conduction.

Can heat loss through windows be reduced?

The problems with double glazing are that it can be expensive and that it is difficult to break in emergencies without a special hammer.

side-viewof double glazing

insulating layer of air

Page 9: Thermal Energy STEM Lab

You can purchase spongy strips that can be used to close the gaps around doors and windows.

A lot of heat energy can be lost from a house due to heat escaping through gaps under doors and around windows.

How can heat loss through doors be reduced?

This is one of the easiest types of heat loss to prevent.

Page 10: Thermal Energy STEM Lab

The air trapped in the cavity acts as an insulator and reduces any heat loss due to conduction through the bricks.

Most outside walls have an empty space between the two layers of bricks called a cavity.

Heat loss can also occur due to convection within the cavity. Plastic foam insulation can be pumped into the cavity to prevent this.

convection currents

in the cavity

foam insulationprevents

convection currents

How can heat loss through be reduced?