(a) Explanation Thermal resistance of the hot water can be negligible (refer below proof). There are three different sections, and the thermal resistance is to be found separately for these sections. Then heat transfer rate for each section can be found. Hence, we can find the total heat transfer rate. Calculation: At 80 C 0 , ρ = 971.8 k g m 3 μ = 0.355 × 10 − 3 k g m s Re = V m ρ D μ = 1.5 × 971.8 × 5 × 10 − 2 0.355 × 10 − 3 Re = 205309 .86 〉 10000 ⇒ flow is turbulent and L ≫ D ∴ thermal resistance of hot water can be negligible Where, D - Diameter of the hot water pipe r - radius of the hot water pipe z - depth to the pipe from surface of ground L 1 , L 2 , L 3 - length of the hot water pipe h - convection heat transfer coefficient of air k - conduction heat transfer coefficient of sand Section 01, section that pie on the ground. R 1 = 1 h × π D × L 1 = 1 22 × π × 0.05 × 2 = 0 (b) To determine To find: Temperature drops of the hot water

Heat and Mass Transfer: Fundamentals and Applications

6th Edition

ISBN: 9781260440058

Author: CENGEL, Yunus

Publisher: MCGRAW-HILL HIGHER EDUCATION

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Question

Chapter 3, Problem 159P

(a)

To determine

To find:Heat transfer rate from pipe to air.

(b)

To determine

To find:Temperature drops of the hot water

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Chapter 3, Problem 158EP

Chapter 3, Problem 160P

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Chapter 3 Solutions

Heat and Mass Transfer: Fundamentals and Applications

Ch. 3 - Consider heat conduction through a wall of...Ch. 3 - Consider heat conduction through a plane wall....Ch. 3 - What does the thermal resistance of a medium...Ch. 3 - Can we defme the convection resistance for a unit...Ch. 3 - Consider steady heat transfer through the wall of...Ch. 3 - How is the combined heat transfer coefficient...Ch. 3 - Why are the convection and the radiation...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Someone comments that a microwave oven can be...Ch. 3 - Consider two cold canned drinks, one wrapped in a...

Ch. 3 - The bottom of a pan is made of a 4-mm-thick...Ch. 3 - Consider a surface of area A at which the...Ch. 3 - How does the thermal resistance network associated...Ch. 3 - Consider steady one-dimensional heat transfer...Ch. 3 - Consider a window glass consisting of two...Ch. 3 - Prob. 16P Ch. 3 - Consider a person standing in a room at 20C with...Ch. 3 - Consider an electrically heated brick house...Ch. 3 - A12-cm18-cm circuit board houses on its surface...Ch. 3 - Water is boiling in a 25-cm-diameter aluminum pan...Ch. 3 - A cylindrical resistor element on a circuit board...Ch. 3 - Prob. 22P Ch. 3 - A1.0m1.5m double-pane window consists of two...Ch. 3 - Prob. 24P Ch. 3 - Prob. 25P Ch. 3 - Prob. 26P Ch. 3 - Prob. 27P Ch. 3 - Prob. 28EP Ch. 3 - To defog the rear window of an automobile, a very...Ch. 3 - A transparent film is to be bonded onto the top...Ch. 3 - To defrost ice accumulated on the outer surface of...Ch. 3 - Prob. 32P Ch. 3 - Prob. 33P Ch. 3 - Prob. 34P Ch. 3 - Prob. 35P Ch. 3 - Heat is to be conducted along a circuit board that...Ch. 3 - Prob. 37EP Ch. 3 - Consider a house that has a 10m20-m base and a...Ch. 3 - Prob. 39EP Ch. 3 - Prob. 40P Ch. 3 - Prob. 41P Ch. 3 - Prob. 42P Ch. 3 - Prob. 43P Ch. 3 - What is thermal contact resistance? 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A and B, with the same surface...Ch. 3 - Prob. 218P Ch. 3 - A room at 20C air temperature is losing heat to...Ch. 3 - Prob. 220P Ch. 3 - A 1-cm-diameter, 30cm-long fin made of aluminum...Ch. 3 - A hot surface at 80C in air at 20C is to be cooled...Ch. 3 - A cylindrical pin fin of diameter 0.6 cm and...Ch. 3 - A 3-cm-long. 2-nuti x 2-mm rectangular...Ch. 3 - Two finned surfaces with long fins are identical,...Ch. 3 - A 20-cm-diameter hot sphere at 120C is buried in...Ch. 3 - A 25-cm-diameter, 2.4-rn-long vertical cylinder...Ch. 3 - Prob. 228P Ch. 3 - The walls of a food storage facility are made of a...Ch. 3 - The equivalent thermal resistance for the thermal...Ch. 3 - Prob. 231P Ch. 3 - Prob. 232P Ch. 3 - Prob. 233P Ch. 3 - The fin efficiency is defined as the ratio of the...Ch. 3 - Prob. 235P Ch. 3 - In the United States, building insulation is...Ch. 3 - Prob. 237P Ch. 3 - A plane brick wall (k=0.7W/m.K) and is 10 cm...Ch. 3 - The temperature in deep space is close to absolute...Ch. 3 - In the design of electronic components, it is...Ch. 3 - Using cylindrical samples of the same material,...Ch. 3 - Find out about the wall construction of the cabins...Ch. 3 - Prob. 243P Ch. 3 - A house with 200-m2 floor space is to be heated...

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