A house has a composite wall of wood (k = 0,12 W/(m.K), fiberglass insulation (k = 0,038 W/(m.K), and plaster board (k = 0,17 W/(m.K), as indicated below. On a cold winter day the convection heat transfer coefficients are ho= 57 W/(m2.K) and hi = (42 W/m2.K). The total wall surface area is 450 m2. (a) Determine a symbolic expression for the total thermal resistance of the wall, including inside andoutside convection effects for the prescribed conditions. (b) Determine the total heat loss through the wall. (c) If the wind were blowing violently, raising ho to 350 W/(m2.K), determine the percentage increase in the heat transfer rate. (d) What is the controlling resistance that determines the heat transfer through the wall?

A house has a composite wall of wood (k = 0,12 W/(m.K), fiberglass insulation (k = 0,038 W/(m.K), and plaster board (k = 0,17 W/(m.K), as indicated below. On a cold winter day the convection heat transfer coefficients are ho= 57 W/(m2.K) and hi = (42 W/m2.K). The total wall surface area is 450 m2. (a) Determine a symbolic expression for the total thermal resistance of the wall, including inside andoutside convection effects for the prescribed conditions. (b) Determine the total heat loss through the wall. (c) If the wind were blowing violently, raising ho to 350 W/(m2.K), determine the percentage increase in the heat transfer rate. (d) What is the controlling resistance that determines the heat transfer through the wall?

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.

Chapter6: Forced Convection Over Exterior Surfaces

Section: Chapter Questions

Problem 6.14P

See similar textbooks

Similar questions

The aluminum fuel tank (α = 23.8 x 10-6 m/moC) on a sailboat measures 40 cm by 50 cm by 75 cm. If it is filled with 10oC gasoline from an underground tank, how much fuel will leak out when the fuel and the tank return to 28oC ambient temperature?
Q2/ How much fluid is required to raise the pressure in a thin cylinder of length 3 m, internal diameter 0.7 m, and wall thickness 12mm by 70kN/m*? E = 210GN/m* and v = 0.3 for the material of the cylinder and K = 2.1 GN/m* for the fluid.
A geothermal well produces from total depth at 1000m and produces dry (saturated) steam with a temperature of 200°C. Shut-in wellhead pressure is 5000kPa, and the wellhead flowing pressure is 1000kPa when the well is flowing 100 tons/hour. Determine the downhole pressure and temperature in each case ( for shut-in case and the flowing case). Assume: Casing diameter =0.2m a Casing roughness =0.0005m Please answer fast i give you upvote.
A saturated steam at 410K is being transported in a pipeline (brass drawing tubing) at a rate of 1 grams/second. Pipe has inside diameter of 0.025 m . The tube is 100m long. The pressure at the entrance is 80kPa. (use Perry's Handbook for the properties and constants) R = 8314J/kgmol.K; MW=18.02g/mol What is the a.) value of G in kg/s.m2? b.)value of friction factor? 3 significant figures c.)the % of pressure drop? d.)the outlet pressure? e.) compressible or not?
How is the maximum shear stress determined using a stress concentration factor?
Is it true or false? if false please justify/defend your answer. > Chlorine gas at 45 ̊C is under a pressure of 480 kPa. Assume a gas constant of 117 N-m/kg-K. Its specific volume is 0.87. > A 5-mm diameter tube is inserted in mercury and later in water. Assuming the tube is clean so that its angle of contact with mercury is 140 ̊ and the surface tension is 0.5140 N/m, the amount of depression is -2.36 mm.
Calculate the mixing ratio (w) and saturation mixing ratio (ws) if T=35c and Td=10c. Assume p=1 atmosphere (1013.25 hPa. Use temperature appropriate values of lv.
A saturated steam at 410K is being transported in a pipeline (brass drawing tubing) at a rate of 1 grams/second. Pipe has inside diameter of 0.025 m . The tube is 100m long. The pressure at the entrance is 80kPa. (use Perry's Handbook for the properties and constants) R = 8314J/kg mol K; MW=18.02g/mol a. What is the value of G in kg/s.m2? b. What is the value of friction factor? c. What is the % of pressure drop? d. Calculate the outlet pressure.
With a 0.50 in diameter hole in the support bar, what is the approximate value of the stress concentration factor at the hole? Note that the bar width is 1.50 in where the hole is located and the plate carries direct tension. Find the stress concentration factor, Kt. a) 2.00 b) 2.30 c) 3.20 d) 3.30
Fundamental Problem
A vertical steel stand-pipe (a cylindrical tankopen at the top and having a vertical axis), is3m in inside diameter and 30 m high. The tankis filled with water having a weight density of104 N/m3. The material is structural steel havinga yield point of 270 MPa and a safety factor of2 is to be used. (a)What is the requiredthickness in terms of millimeters, of steel platenecessary at the bottom of the tank if thewelded longitudinal seam is presumed to be asstrong as the solid metal? (b) What wallthickness in terms of millimeters, is required ifthe seam is only 72% as strong as the solidmetal?
A cylinder has an internal diameter of 230 mm, has walls 5 mm thick and is 1 m long. It is found to change in internal volume by 12.0 x 10-6 m3 when filled with a liquid at a pressure p. If E = 200GN/m2 and v = 0.25, and assuming rigid end plates, determine the values of hoop stress