#### • Class 11 Physics Demo

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Answers:Environmental issues are important and sustainable energy is high on that list. However, for it to move from a philosophical discussion to practical mass applications every one needs to be involved. The masses talk the talk but do not walk the walk in many areas. So from a purely consumer point of view, they worry about their own pocket book. Advantage: 1) One time cost of the system. (Engineer your solar system correctly and you may have no power bills.) 2) No worry about rising power cost. Disadvantage: 1) High initial startup cost. ($40K of solar panels on your roof hurts the pocket book) 2) Uncertainty of new technologies. (I know many of them have been out for years but just not implemented greatly - so some people still worry needlessly) 3) Wind turbines make noise - I kind of think is sounds cool but some people complainabout the looks and sound of them. 4) Wind turbines can kill birds. - Sad but true- Solutions may be fourth coming to negate this. 5) Water turbines need rain. - Good companion with Solar Cells Question:disadvantages and advantages of hydroelectric energy? need help for homework Answers:once it is in place the only cost is maintenance. so the advantage is that it is very cheap to produce. also when used by powering a water wheel it can be used without any stoppage on a year around stream or river. The disadvantage is that in is not usually centrally located, and takes a lot of.power lines to take it to where it is needed. The other disadvantage is that most dams are used for water control, so that the water is used for irrigation and not alway running through the dam. Question:Evaluate the advantages and disadvantages of using direct solar energy to heat buildings and water, and to produce energy. Answers:The sun is providing free energy every day. How much energy depends mainly on the latitude and to some extent on climate. The question that you are asking is to evaluate our use of this energy to heat buildings and water and presumably other uses. Advantages: This energy is free at source and is totally renewable, as far as we know for thousands of years. Disadvantages: To harness this energy we need to employ materials and resources and to use our ingenuity to provide technical solutions appropriate to the economic and physical situation and location. There is a capital cost and possibly maintenance costs. The actual harnessing of the energy can only happen in daylight hours so there may be problems of storing the energy at night. The advantages are greatest in hot sunny climates but the need for energy is often greater in colder, northern or southern latitudes. Methods What are the methods that we can use? Where are the different methods most appropriate? Buildings For buildings we need to consider internal climate control and hot water supply and for both these we can use passive and active methods. It is also much easier to incorporate suitable provisions into new domestic, commercial and public construction, although significant improvements can be made to existing buildings. Passive methods: The four methods for domestic construction in the northern hemisphere that make use of greenhouse effect are: South facing windows (large windows on south, small or none on north side) other elevations as appropriate with solar shading or solar glazing and thermal insulation. South facing roof space: usually pitched roof used as a solar collector. May need small fan and duct to circulate hot air. Conservatory: South side glazed volume. Trombe wall. South glazed wall with heavy masonry or concrete wall painted black. And for larger buildings one might use a climate wall i.e. glazed external wall with significant air space between external and internal wall (internal wall can be fully or partially glazed or incorporate thermal mass for storage of heat) Active methods use solar voltaic panels or solar collectors with water pumped to storage or direct use. Thermosiphon systems, where the storage tank is placed above the collector, do not need a pump and are therefore regarded as a passive system. Standard units are used for hot water supply throughout the Mediterranean countries and middle east. The use of thermal chimneys is also an anchient passive method of internal climate control with modern uses. This is a very big subject and I have only touched on a brief outline. One could also discuss earth sheltering, construction methods, sustainability, low technology methods for emerging third world countries such as solar ovens and all sorts of related subjects. Although all the above information is from my own personal knowledge, I have used references in the past such as Wikipedia, (on line encyclopaedia) the Energy Trust Website (a non- profit making Trust based in London) and for low cost energy saving technology: http://www.energygreed.com/. This site offers a manual for building your own solar power array and wind turbine, with sources for free batteries and claims to save you 80% on electricity costs. In the future I think we will have better gas fired boilers that are not only more efficient like condensation boilers, but combine heating and power generation, so that you will be able to sell back your surplus electricity to the national grid in Britain or the power utility company in USA and Canada. Meanwhile we have to rely on the present technology and in cold climates improved insulation or more heavily insulated new construction, double or triple glazing. Solar methods can be quite useful depending on the payback period. Heat pumps with ground collection systems usually take longer to payback and depend on your having a large volume low energy heat source such as a large pond or coils in the ground. Wind energy is another useful method, and although intermittent can have an acceptable payback period. Question:Help???? Thinking about swiching electricity companys! Answers:Advantages: low cost to maintain. relatively clean energy low or no emissions of carbon dioxide, methane or carbon monoxide or ozone. disadvantages: high emission of water vapour, a potent green house gas. expensive to build danger of larva flow. hard to find places where the geothermal energy can be exploited. From Youtube Solar Energy Advantages Disadvantages :www.MagEnergy.ustutorial and testimony of building a magnetic free energy device that generates free electric energy for home use, to find out how this has been done visit www.MagEnergy.us Follow this easy set of plans to build your own Magniwork Magnetic Electricity Generator for your home or business. A complete system can be built AND installed easily, and for less than$100! The Magniwork plans are getting rave reviews. Great business opportunity for those who wish to build and install these systems! http What are the Benefits of Magniwork? By constructing the magniwork power generator, you will be able to generate completely free electric energy, meaning , create energy without needing any source of renewable or non-renewable energy. The generator powers itself and creates energy by itself, without requiring solar energy, heat, water, coal or any kind of resource. This generator powers itself and works indefinitely, without stopping, creating a large amount of energy. Here are some of the benefits that Magniwork has: Works in every home, it requires only a small amount of space You can eliminate your power bill by 50% or even completely, depending on how you implement the magniwork generator Works in all condition, can work in extreme hot or cold without any problem The Material needed to build the magniwork generator is cheap and easily accessible anywhere in the world We have simplified the process, The steps are easy to follow, even a complete novice would be able ...