Refrigeration and Air Conditioning Technology (MindTap Course List)
8th Edition
ISBN: 9781305578296
Author: John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
Publisher: Cengage Learning
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Chapter 3, Problem 24RQ
Define enthalpy.
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A power transistor with three 0.8 mm diameter leads of a copper-silver alloy (k = 400 W/m-K) dissipates 3.5 Watts of
power. The printed circuit board (PCB) on which the transistor is mounted is maintained at 30 C. The air temperature is
20 C and the heat transfer coefficient for the leads is 60 W/m² K. The length of the leads from the transistor to printed
circuit board is 9.0 mm.
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(b) Determine the maximum lead temperature if convection is present.
T=20C
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and adjacent wall structure. Inside the building, the air temperature and heat transfer coefficient for the interior surface
are 21 °C and 9 W/m² K respectively. The window has a uniform thermal conductivity of 1.4 W/m K. If the outdoor air
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A thin electrical heater that dissipates 2 kW of thermal energy is position between two plane walls. The thickness of
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Chapter 3 Solutions
Refrigeration and Air Conditioning Technology (MindTap Course List)
Ch. 3 - Name three reasons why ice melts in an icebox:...Ch. 3 - What are the approximate temperature ranges tor...Ch. 3 - One ton of refrigeration is A. 1200 Btu. B. 12,000...Ch. 3 - Describe briefly the basic refrigeration cycle.Ch. 3 - What is the relationship between pressure and the...Ch. 3 - What is the function of the evaporator in a...Ch. 3 - What does the compressor do in the refrigeration...Ch. 3 - Define a superheated vapor.Ch. 3 - The evaporating pressure is 76 psig for R-22 and...Ch. 3 - If the evaporating pressure was 76 psig for R-22...
Ch. 3 - Define the term subcooled liquid.Ch. 3 - The condensing pressure is 260 psig and the...Ch. 3 - The condensing pressure is 260 psig and the...Ch. 3 - What is meant by a saturated liquid and vapor?Ch. 3 - What is meant by desuperheating a vapor?Ch. 3 - What happens to the refrigerant in the condenser?Ch. 3 - What happens to refrigerant heat in the condenser?Ch. 3 - The metering device A. cycles the compressor. B....Ch. 3 - What is adiabatic expansion?Ch. 3 - Describe flash gas, and tell how it affects...Ch. 3 - Quality means _________ when referring to a...Ch. 3 - Describe the difference between a reciprocating...Ch. 3 - List the cylinder color codes for R-12, R-22,...Ch. 3 - Define enthalpy.Ch. 3 - Define a pure compound refrigerant, and give two...Ch. 3 - Define net refrigeration effect as it applies to...Ch. 3 - Define heat of compression, and explain how it is...Ch. 3 - Define flash gas, and explain how it applies to...Ch. 3 - Define temperature glide as it pertains to a...Ch. 3 - Define a zeotropic refrigerant blend, and give an...Ch. 3 - Define a near-azeotropic refrigerant blend, and...
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