PHYS/ENVS 3070 Homework Assignment #4: Problem #1: An inventor claims to have developed a wonderful new heat engine that operates with a relatively cool (and therefore non-polluting) flame at 150 degrees Celsius and discharges waste heat to the environment at 20 degrees Celsius. His promotional literature advertises that 45% of the fuel energy is converted into useful work. Calculate the maximum efficiency that can be expected for such an engine and compare it to the inventor's claim. Problem #2: Give three examples where cogeneration is used. Problem #3: Decide whether each of the following statements are true or false. a. Cogeneration offers considerable promise of reducing energy waste b. The Principle of Conservation of Energy is one of the laws of thermodynamics. c. A diesel truck engine is a type of heat engine. d. If an ordinary household refrigerator is left operating in a closed, perfectly insulated room with the refrigerator door standing open, after a long time, the temperature in the room will go down. e. A heat engine produces heat from electricity. f. A person is an example of a heat engine.Problem #4: The Valmont Power Station has a 150 MegaWatt coal fired heat engine generating electricity for Boulder. The high temperature furnace is at around 1000 degrees Fahrenheit, the cooling pond might be around 55 degrees Fahrenheit. What is the Carnot efficiency (i.e. the best possible efficiency the plant could possibly have for generating electricity)? Problem #5: The plant in reality has an efficiency only half of what you calculated in the previous problem (due to friction losses, etc.). Given that the power output of electricity is 150 MegaWatts, how much coal (in tons) do they have to burn every day? Note just to be clear, if the efficiency from the problem above is 40% that implies the plant is only 20% efficient. Problem #6: A single train car might carry 90 tons of coal. Given your answer to the previous question, how many train cars of coal arrive at the Valmont Power Station per day? Problem #7: How much carbon dioxide is emitted from this plant every day?Problem #8: If they sell electricity at $0.08 per kiloWatt-hour, how much money does the Valmont Power Station takes in each year? (Note that this is not the same as the company profit). Problem #9: Read the linked Press Release from Colorado Governor Ritter on Oil Shale. Write 1-2 paragraphs of what you think related to scientific facts. Include references for other material used. Make sure to read at least one other relevant
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