Inginning Thermohome in your default browser Set as defaulok.pdfpressure definitionⒸF|C/Users/erice/Desktop/REY/1s%20TERM20-Teaching/E-boo****Mer of PerformanToyda Spor The Impoft******tafsson **SEsatel336 /1009supplied.6-47E A heat pump with a COP of 1.4 is to produce a100,000 Btu/h heating effect. How much power does thisdevice require, in hp?6-48 An air conditioner removes heat steadily from a houseat a rate of 750 kJ/min while drawing electric power at a rateof 5.25 kW. Determine (a) the COP of this air conditioner and(b) the rate of heat transfer to the outside air. Answers:(0) 2.38, (b) 1065 kJ/min6-49 A household refrigerator that has a power input of 450 Wand a COP of 1.5 is to cool 5 large watermelons, 10 kg each,to 8°C. If the watermelons are initially at 28°C, determinehow long it will take for the refrigerator to cool them. Thewatermelons can be treated as water whose specific heatis 4.2 kJ/kg-°C. Is your answer realistic or optimistic?Explain. Answer: 104 min6-50 When a man returns to his well-sealed house on a sum-mer day, he finds that the house is at 35°C. He turns on the aironditioner, which cools the entire house to 20°C in 30 min.f the MD of the air mattinaina murtom in 20

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6-47E A heat pump with a COP of 1.4 is to produce 100,000 Btu/h heating effect. How much power does this device require, in hp?

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.29P

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2.2 A small dam, which is idealized by a large slab 1.2 m thick, is to be completely poured in a short Period of time. The hydration of the concrete results in the equivalent of a distributed source of constant strength of 100 W/m3. If both dam surfaces are at 16°C, determine the maximum temperature to which the concrete will be subjected, assuming steady-state conditions. The thermal conductivity of the wet concrete can be taken as 0.84 W/m K.
Determine the rate of heat transfer per meter length to a light oil flowing through a 2.5-cm-ID, 60-cm-long copper tube at a velocity of 0.03 m/s. The oil enters the tube at 16C, and the tube is heated by steam condensing on its outer surface at atmospheric pressure with a heat transfer coefficient of 11.3 kW/m K. The properties of the oil at various temperatures are listed in the following table: Temperature, T(C) 15 30 40 65 100 (kg/m3) 912 912 896 880 864 c(kJ/kgK) 1.80 1.84 1.925 2.0 2.135 k(W/mK) 0.133 0.133 0.131 0.129 0.128 (kg/ms) 0.089 0.0414 0.023 0.00786 0.0033 Pr 1204 573 338 122 55
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Hi, can you help me with the following problem? A thermally insulated tank of water 2 m x 2 m, depth 1 m is stirred with a paddle for threehours. If the paddle is driven by a motor whose shaft power is 8 kW determine the rate ofchange of temperature in degrees C per hr and the increase in temperature of the water.The specific heat of water is 4200 J/kgC. Identify a system and start your analysis from anappropriate form of the Fist Law of Thermodynamics
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