Learning Materials
Features
Discover
Chapter 4: 4.9 (page 129)
Estimate the maximum possible COP of a household air conditioner. Use any reasonable values for the reservoir temperatures.
COP=21
Over 30 million students worldwide already upgrade their learning with 91影视!
All the tools & learning materials you need for study success - in one app.
Get started for free
Recall Problem 1.34, which concerned an ideal diatomic gas taken around a rectangular cycle on a diagram. Suppose now that this system is used as a heat engine, to convert the heat added into mechanical work.
(a) Evaluate the efficiency of this engine for the case .
(b) Calculate the efficiency of an "ideal" engine operating between the same temperature extremes.
Suppose you are told to design a household air conditioner using
HFC-134a as its working substance. Over what range of pressures would you have it operate? Explain your reasoning. Calculate the COP for your design, and compare to the COP of an ideal Carnot refrigerator operating between the same extreme temperatures.
Imagine that your dog has eaten the portion of Table 4.1 that gives entropy data; only the enthalpy data remains. Explain how you could reconstruct the missing portion of the table. Use your method to explicitly check a few of the entries for consistency. How much of Table 4.2 could you reconstruct if it were missing? Explain.
A coal-fired power plant, with parameters similar to those used in the text above, is to deliverof power. Estimate the amount of steam (in kilograms) that must pass through the turbine(s) each second.
At a power plant that produces 1 GW109 watts) of electricity, the steam turbines take in steam at a temperature of 500o, and the waste heat is expelled into the environment at 20o
(a) What is the maximum possible efficiency of this plant?
(b) Suppose you develop a new material for making pipes and turbines, which allows the maximum steam temperature to be raised to 600o. Roughly how much money can you make in a year by installing your improved hardware, if you sell the additional electricity for 5 cents per kilowatt-hour? (Assume that the amount of fuel consumed at the plant is unchanged.)
What do you think about this solution?
We value your feedback to improve our textbook solutions.
Explanations 
Textbooks 
Flashcards 
91影视 AI 
Notes 
Study Plans 
Study Sets 
Find a degree 
Magazine