Hot water at 50 °C is routed from one building in which it is generated to an adjoining building in2.which it is used for space heating. Transfer between the buildings occurs in a steel pipe (k 60w/m.K) of 100-mm outside diameter and 8-mm wall thickness. During the winter,representative environmental conditions involve air at T.. = -5 °C and h 20 w/m2K in crossflow over the pipe.If the cost of producing the hot water is $0.05 per kwh, what is the representative dailya)cost of energy loss from an uninsulated pipe to the air per meter of pipe length?b)Determine the savings associated with application of a 10-mm-thick coating ofurethane insulation (k 0.026 W/m. K) to the outer surface of the pipe.

Answered: Hot water at 50 °C is routed from one…

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

Hello, sorry, I need an answer within 30 to 20 minutes, please
Include fbd and assumptions
Choose the right answer 1. The mean Nusselt number for fully developed laminar flow in a circular tube under a constant heat flux a. depends on Reynolds number b. depends on Prandtl number c. is constant 2. The value of Prandtl number for air is about а. О.1 b. 0.3 с. 0.7 3. In natural convection heat transfer, the Nusselt number is a function of a. Re and Pr b. Re and Gr c. Grand Pr 4. A fluid is flowing along a plate having a high uniform wall temperature. The heat transfer along the length a. decreases b. remain constant c. increases 5. For fully developed laminar flow and heat transfer in a heated long circular tube, if the flow velocity is doubled and the tube diameter is halved, the heat transfer coefficient will be a. four times of the original value before b. half of the original value с. same as d. double of the original value
Conceptually, what is the integral of heat transfer rate, Q dot?
An electric resistance heater is embedded in a long cylinder ofdiameter 30mm. When water with a temperature of 25 C and velocityof 1m/s flows crosswise over the cylinder, the power per unit lengthrequired to maintain the surface at a uniform temperature of 90 C is28kW/m. When air, also at 25 C, but with a velocity of 10m/s isflowing, the power per unit length required to maintain the samesurface temperature is 400W/m. Calculate and compare the convectioncoefficients for the flows of water and air.
(B) Air is flowing through a thick walled copper pipe that can be considered to be isothermal at 450 degrees C Inner diameter of the pipe is 3cm and 0 9m inng Air enters at 30 degrees C and exit buik temperature is 95 degrees C. if the length is now doubled assuming air mass flow rate and heat transfer coefficient remain the same in both iengths what is the new bulk temperature at the exit?
k. Q19-Water at 25°C flows across a horizontal copper tube 1.5cm outer diameter with a velocity of 2 mi/s. Calculate the heat transfer rate per unit length if the wall temperature is maintained at 75°C.
You are designing a pin-style heatsink for forced cooling of an IC. A small fan blows RT air into the heatsink at about 2.3 ? ? . The aluminum pins are 2mm in diameter and have a constant surface temperature of 120°?. The heatsink is 100mm x 100mm and the pins have an inline arrangement with a transverse pitch of 4mm and a longitudinal pitch of 6mm. What is the total heat dissipation of this heatsink? The pins are 30mm high. Note RT=25 celsius
Heat Transfer Questiion is image
Water flows through a tube of 5mm inside diameter with a volumetric flow rate of 7.8 cm3/s. Wall temperature of the tube is kept constant at 80oC. In a fully developed velocity and temperature profile region of 5m length, calculate the bulk temperature of exiting water if its inlet temperature is 20oC
A printed circuit board with constant surface temperature dissipates 100 W from one side over an area (0.3 mx 0.2 m). A fan is use to cool this board with a flow speed of 12 m/s parallel to the longest dimension of the board. Calculate: 1. The surface temperature of the board for an air temperature of 30 C. 2. Thickness of hydrodynamic and thermal boundary layer. 3. Amount of change in heat transfer rate if the flow parallel to the short dimension. Cp-1000 J/kg.K, k-0.03 W/m.C, Pr-0.667, u = 2 x 105 kg/m.s, p=1.15 kg/m³ Laminar flow, Nu= 0.664Rel/2Pr1/3, Turbule flow, Nu= 0.037Re4/5Prl/3
Hot air flows with a mass flow rate m = 0.09 kg/s through an uninsulated sheet metal duct of diameter D = 0.15 m, which is in the crawlspace of a house. The hot air enters at 110°C and, after a distance of L 5 m, cools to 80°C. The heat transfer coefficient between the duct surface and the ambient air at To 0°C is known to be h, = 9 W / m²K. (a) Calculate the heat loss from the duct over the length L. (b) Determine the heat flux and the surface temperature at x = L. (c) Determine the heat flux and the surface temperature at x = 0. Assume, for air at Tm 368 K: c, 1011 J/kg.K; for air at Tm.L = 353 K: k= 0.030 W/m.K, u = 209x10' N.s/m2, Pr = 0.70%; for air at Tm,0 = 383 K: k = 0.033 W/m.K, u=223x10" N.s/m2, Pr = 0.69. Show all calculations. Cold Air Hot air in -L-

SEE MORE QUESTIONS

Recommended textbooks for you

Elements Of Electromagnetics

Mechanical Engineering

ISBN:

9780190698614

Author:

Sadiku, Matthew N. O.

Publisher:

Oxford University Press

Mechanics of Materials (10th Edition)

Mechanical Engineering

ISBN:

9780134319650

Author:

Russell C. Hibbeler

Publisher:

PEARSON

Thermodynamics: An Engineering Approach

Mechanical Engineering

ISBN:

9781259822674

Author:

Yunus A. Cengel Dr., Michael A. Boles

Publisher:

McGraw-Hill Education

Elements Of Electromagnetics

Mechanical Engineering

ISBN:

9780190698614

Author:

Sadiku, Matthew N. O.

Publisher:

Oxford University Press

Mechanics of Materials (10th Edition)

Mechanical Engineering

ISBN:

9780134319650

Author:

Russell C. Hibbeler

Publisher:

PEARSON

Thermodynamics: An Engineering Approach

Mechanical Engineering

ISBN:

9781259822674

Author:

Yunus A. Cengel Dr., Michael A. Boles

Publisher:

McGraw-Hill Education

Control Systems Engineering

Mechanical Engineering

ISBN:

9781118170519

Author:

Norman S. Nise

Publisher:

WILEY

Mechanics of Materials (MindTap Course List)

Mechanical Engineering

ISBN:

9781337093347

Author:

Barry J. Goodno, James M. Gere

Publisher:

Cengage Learning

Engineering Mechanics: Statics

Mechanical Engineering

ISBN:

9781118807330

Author:

James L. Meriam, L. G. Kraige, J. N. Bolton

Publisher:

WILEY

SEE MORE TEXTBOOKS