•Chemical Energy can be transformed into Thermal Energy when wood, or coal is burned. •Environmental Impacts: pollution caused by the burning of these fossil fuels
Electrical Energy
•Electricity is produced in many ways. • Hydro-electric dams use the force of gravity which pulls the water over the dam to turn turbines, which are attached to generators, to produce the electrical energy from the mechanical energy of the generators. •Electricity can also be produced at thermo-electric (fuel-burning) generating stations that burn fossil fuels.
•Environmental Impacts: •wildlife in the area of the dam lose valuable habitat, •plants may perish when the river which was blocked overflows its banks to create the reservoir for the dam, •commercial enterprises may be adversely affected, •pollution by the burning of fossil fuels, heated waste water can affect organisms in lakes where this waste water is dumped.)
Mechanical Forces
Mechanical forces that push or pull objects often release thermal energy, as do Frictional forces.
Geothermal Energy
•Volcanoes, hot springs and geysers are sources of geothermal energy - energy from the interior of the earth. •The thermal energy from these events can produce hot water or steam, which can be then piped to a power plant at the surface. •This can be used to run turbines which produce electrical energy. Water can also be pumped into cracks in the earth's crust. It returns to the surface as steam, which can be used to generate electricity.
•Environmental Impacts: more extensive use of this clean and environmentally friendly technique, could reduce the threat of oil spills, the pollution caused by burning fossil fuels and the wastes from mining fossil fuels.
Solar Energy
•Solar energy is clean and is guaranteed not to run out. It is not available all the time (nighttime, less in winter/ than in summer). There are two techniques that can help to overcome these issues. (See Figure 3.32, page 243) •Passive solar heating - uses the materials in the structure to absorb, store and release the solar energy. Active solar heating - uses mechanical devices to collect and distribute the thermal energy.
Wind Energy
•Wind energy is the energy of moving air, and is a result of solar energy and convection. As the sun heats up the air, the warm air rises and cools off. The cooler air falls, creating the convection currents called thermals. These convection currents on a global basis, form the Earth's wind systems. The windmill is a turbine (a wheel with fan blades), which is connected to a generator. When the windmill spins the generator produces electricity.
More sources of Thermal Energy
•The living organisms burn food (chemical energy) in their bodies to generate body heat (thermal energy). A composter is another source of thermal energy. Decomposers break down food and as these chemical changes occur, thermal energy is produced, which in turn helps speed up the process of decomposition.
Fossil Fuels
•An energy resource is anything that can provide energy in a useful form. Most energy supplies come from fossil fuels (in Alberta and throughout the world). Fossil Fuels are chemicals from plants and other organisms that died and decomposed millions of years ago and have been preserved underground. •(Environmental Impacts: global warming, changing climate zones around the world, plant growth, depleted water resources and thermal pollution)
•The widespread use of fossil fuels has created 2 primary problems. •1- these energy sources are non-renewable and their supplies are running out •2- they produce toxic chemicals which can harm the environment by producing a •greenhouse effect resulting in global warming
Co- Generation
•Co-generation uses some of the two-thirds of the energy release by the burning of fossil fuels as thermal energy, to heat a building, or a fuel, to generate electrical energy.
Conserving Fossil Fuels
•Despite the many disadvantages of using fossil fuels, we continue to use them. •Coal is burned to generate electricity. Oil and natural gas are abundant in Alberta and we use it, maybe more than we should. •Alternatives to using these non-renewable resources need to be utilized, so that future generations of Albertans can continue to thrive in our beautiful province.
Thermostats
•Programmable thermostats and other technologies have provided many ways to conserve energy and save money. • A recirculating hot water system (Figure 3.41, p. 252) saves energy and produces instant hot water at all times.
Refrigerators and Air Conditioners
•Refrigerators and air conditioners are thermal energy movers. •A thermal energy mover is a device that transfers thermal energy from one location to another at a different temperature. The operation of these devices require refrigerants (liquids that evaporate easily at low temperatures) to remove thermal energy from food. As the refrigerant evaporates, it absorbs the thermal energy from the food so it cools down. This warmed gas is then compressed and releases the thermal energy into the room.
Dangers of Thermal Energy
•Some harmful effects of thermal energy are: •burning ourselves on a hot utensil (us) •forest fires (our environment) •burning houses (our belongings) •Storage and use of fossil fuels can pose a forest fire risk, but also can pollute •the environment, by leaking into the groundwater and soil.
By- Products of Thermal Energy Use
•Not all the dangers of using thermal energy are as obvious as the ones already discussed. •One of the products (carbon dioxide) that is released from the burning of fossil fuels is a greenhouse gas, which traps heat energy in our atmosphere and leads to global warming. •Sulfur-dioxide is released when coal and natural gas are burned. This gas is an irritant to the eyes, nose and throat. •Carbon monoxide is produced when a fire burns without enough oxygen. It is clearless, odorless and very lethal. It hinders the brain's reasoning ability and can kill you. •Smoke detectors and carbon monoxide detectors should be installed in every building to protect the people from being overcome by these lethal gases.