Renewable Energy Chapter 18

Solar cooker lab You will be building a solar cooker in class Wednesday and Thursday, Friday will be cooking day. All materials must be natural (nothing electronic) Some examples but not limited to: scotch tape black duct tape 1 box, any kind, any size, remember larger the box, the more space has to be heated 3-4 feet of aluminum foil Cellophane wrap scissors; must be strong enough to cut corrugated cardbaord if utility knives are not used (optional) glue 3-4 pieces of black construction paper ruler Pan/plate to cook on food item to be cooked on metallic pan with box, such as Break and Bake Cookies (pre-made cookie dough), Bagel Bites, etc...; best if the items are pre-cooked and only require warming Thermometer (I provide) oven mitts (can share among groups) graph paper

Solar cooker continued You will need to bring in the supplies to build in class It is highly recommended that you research solar cooker plans tonight!!!! Lab grade will be based on the following: 20 points for basic construction 60 points for write up (all the basics steps and purpose of lab should be here, standard type of lab write up) 20 points for cooking (basically did you get it hot enough to warm up item)

Hydroelectric Energy Electricity that is produced from the energy of moving water. Anything that has mass, and moves, has kinetic energy. Harnessing moving water is a clean, readily available source of energy. Has been around for centuries (water wheels) Roughly 20% of the worlds electricity is generated by flowing water.

How it works: water, behind the dam, is directed towards turbines. Water pushes against the blades, causes it to spin “run” This motion is transferred to coils of wires in generators Coils spin through a magnetic field Produces electricity

The pro’s and con’s of Dam’s Renewable Green Reliable Flexible Safe Flood control Recreation

Cons: Environmental consequence's Fish migrations Habitat destruction Relocation (includes humans) Drastic temperature changes Expensive to build Droughts

Other water sources: Tides Tidal surges are a great source of electricity (where available) Pro’s: renewable, very clean, not typically disrupting normal flow (migrations), Con’s: limited locations available, eye sore, affect benthic community. Waves Movement (up and down) waves create can be used to make electricity Pro’s: renewable, clean, mostly anywhere Con’s: expensive and difficult to harness, eye sore

Home work!! A1’s Read “A Super Efficient Home” page 458-459 Answer questions 1 and 2 on page 459 Also: In 2-3 sentences, explain whether or not this is a feasible solution to energy/water crisis found through out the world. A11’s Walk/drive around your neighborhood and list as many sources of biomass fuel as you can find. Answer: Are any large enough to be used as a fuel source? List 2 each; advantages and disadvantages of biomass as a fuel source. How many people do you think take advantage of fireplaces in the wintertime (guesstimate the approx. number of houses with fireplaces in your neighborhood) List 2 each; advantages and disadvantages of home fireplaces.

Solar Energy Energy from the sun (which technically is the source for hydro and wind power as well) Thermonuclear fusion (where the suns energy comes from) High temps (on the sun) cause hydrogen nuclei to fuse creating helium nuclei As helium forms, a loss of mass occurs, which is converted into heat and light energy. We actually receive a miniscule amount of the energy that is created by the sun. This energy can be harnessed and used to generate electricity.

7.Many Applications Pros 8.Shared Solar 1.Renewable 9.Silent 2.Abundant 10.Financial Support from Government/State 3.Sustainable 4.Environmentally Friendly 11.Low Maintenance 12.Technology is Improving 5.Good Availability 6.Reduces Electricity Costs

Cons 1.Expensive 2.Intermittent 3.Energy Storage is Expensive 4.Associated with Pollution 5.Exotic Materials 6.Requires Space

Active and passive solar energy: devices are used to collect, store, and circulate heat produced from solar energy. In active systems Tubes, tanks, fluids, pumps, fans, and other stuff are used to collect and distribute Can be used after the sun sets as well Make use of collectors (ex. Solar panels) In passive systems (collected, distributed, and stored naturally) Relies more on the positioning of the house and windows Oriented so open facing areas (windows) typical face south

Photovoltaic Cells: uses thin wafers of semiconductor material to produce electricity directly from the solar energy Also called the solar cell Produces electricity directly Made of elements like silicon and/or selenium Two layers, of the semiconductor, sun strikes it, causes electrons to move back and forth…viola electricity. Very common today, signs, watches, etc…

Wind Power Use of the wind to turn a source to generate electricity. Called aerogenerators. Same basic pro’s and con’s of solar Not as constant or steady though and elaborate storage devices are typically required Two basic types: Horizontal axis (traditional) Vertical axis (can be used in lower wind environments)

Geothermal Heat energy generated within the earth. Generated by the decay of radioactive elements Hot enough to melt rock (magma) Water trapped nears surface create steam (geysers) Geo is used in areas where this source of heat is closer to the surface Most of Iceland used geothermal to heat homes Green houses take advantage of the heat to grow produce all year long Several countries use it to produce electricity.

Pro’s and Con’s Pro’s Renewable Con’s Not available everywhere Air is often polluted with toxic hydrogen sulfide in areas where is available Mineral waste, salts, and toxic metals, tend to corrode pipes and boilers Often a lack of water in these areas.

Ocean thermal energy Conversion (OTEC) Makes use of the extreme temp difference in ocean levels Water is boiled in a vacuum chamber (very low temp when in a V. Cham.) Turns water to steam, etc…

Hydrogen fuel See text