An Introduction to Thermal Physics
1st Edition
ISBN: 9780201380279
Author: Daniel V. Schroeder
Publisher: Addison Wesley
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Chapter 4.4, Problem 32P
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 reservoir temperatures.
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A Carnot heat engine delivers P = 5 x 105 Btu / hr of power while operating between reservoirs at Tc = 470 °F and Th = 1680 °F.
a)Write an expression for how much energy it receives per hour from the high temperature thermal reservoir in terms of the absolute temperatures Tc and Th.
b) Solve numerically for the amount of energy, in BTUs, that is rejected per hour to the low temperature thermal reservoir.
A Carnot heat engine delivers P = 5 x 105 Btu / hr of power while operating between reservoirs at Tc = 470 °F and Th = 1680 °F.
a) Write an expression for how much energy it receives per hour from the high temperature thermal reservoir in terms of the absolute temperatures Tc and Th.
b) Solve numerically for the amount of energy, in BTUs, that is rejected per hour to the low temperature thermal reservoir.
2 moles of a monatomic ideal gas undergoes a cyclic process as depicted in the figure below. The processes AB and CD are isobaric and the process DA is adiabatic. For
the given values PA= 11.5 atm, VA= 5.7 L, V3= 2.85 L, Pc=34.5 atm, and Vc=1.476 L answer the following questions.
(use R=8.314
J
1 atm = 1.013x105 Pa, 1 L = 10-3 m³) .
mol · K'
Volume
1. Calculate the temperature TA=
K
2. What type of process is the process BC?
3. Calculate the work done by the gas in the process DA. WDA =
4. Calculate the magnitude of the net heat entering the cycle. Q =
5. Calculate the magnitude of the net heat leaving the cycle. Qc =
6. Calculate the net work done by the gas. W=
7. Calculate the thermal efficiency of the cycle. e =
%
8. Calculate the change in the entropy in the process AB. Include the sign (positive or negative) in your answer as well. ASAB =
K
Chapter 4 Solutions
An Introduction to Thermal Physics
Ch. 4.1 - Prob. 1PCh. 4.1 - At a power plant that produces 1 GW ( 109 watts)...Ch. 4.1 - A power plant produces 1 GW of electricity, at an...Ch. 4.1 - It has been proposed to use the thermal gradient...Ch. 4.1 - Prove directly (by calculating the heat taken in...Ch. 4.1 - To get more than an infinitesimal amount of work...Ch. 4.2 - Why must you put an air conditioner in the window...Ch. 4.2 - Can you cool off your kitchen by leaving the...Ch. 4.2 - Prob. 9PCh. 4.2 - Suppose that heat leaks into your kitchen...
Ch. 4.2 - What is the maximum possible COP for a cyclic...Ch. 4.2 - Explain why an ideal gas taken around a...Ch. 4.2 - Under many conditions, the rate at which heat...Ch. 4.2 - Prob. 14PCh. 4.2 - In an absorption refrigerator the energy driving...Ch. 4.2 - Prob. 16PCh. 4.2 - Prob. 17PCh. 4.3 - Prob. 18PCh. 4.3 - The amount of work done by each stroke of an...Ch. 4.3 - Derive a formula for the efficiency of the Diesel...Ch. 4.3 - The ingenious Stirling engine is a true heat...Ch. 4.3 - A small-scale steam engine might operate between...Ch. 4.3 - Prob. 23PCh. 4.3 - Calculate the efficiency of a Rankine cycle that...Ch. 4.3 - In a real turbine, the entropy of the steam will...Ch. 4.3 - A coal-fired power plant, with parameters similar...Ch. 4.3 - In Table 4.1, why does the entropy of water...Ch. 4.3 - Imagine that your dog has eaten the portion of...Ch. 4.4 - Liquid HFC-134a at its boiling point at 12 bars...Ch. 4.4 - Consider a household refrigerator that uses...Ch. 4.4 - Suppose that the throttling valve in the...Ch. 4.4 - Suppose you are told to design a household air...Ch. 4.4 - Prob. 33PCh. 4.4 - Consider an ideal Hampson-Linde cycle in which no...Ch. 4.4 - The magnetic field created by a dipole has a...Ch. 4.4 - Prob. 36PCh. 4.4 - A common (but imprecise) way of stating the third...
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