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A basement wall extends 6 ft (1.8 m) below grade and is insulated with R-12.5 (R-2.2). The inside is finished with
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- QUESTION 58 A domestic refrigerator with inner dimensions of 0.7 m by 0.7 m at the base and height 1 m was designed to maintain a set temperature of 6 °C. The bodies consist of two 10-mm-thick layers of Aluminium (k 225 W/mK) separated by a 30 mm polyurethane insulation (k=0.028 W/mK). If the average convection heat transfer coefficient at the inner and outer surfaces 11.6 W/m2K and 14.5 W/m2K are respectively, calculate: the outer surface temperature of the Aluminum in °C to 2 decimal places.arrow_forwardCalculate the heat loss through a 3-in. thick insulation board that has an area of 2- ft² and a k-value of 0.25. Assume the average temperature difference across the material is 70°F. Q = 11.66-Btu/hr Q = 10.99-Btu/hr Q = 10.66-Btu/hr Q = 11.99-Btu/hr Hide hint for Question 1 Utilize the (Q = k*A*AT/thickness) equation.arrow_forwardQuestion 5 Heat transfer A domestic refrigerator with inner dimensions of 0.7 m by 0.7 m at the base and height 1 m was designed to maintain a set temperature of 6 °C. The bodies consist of two 10- mm-thick layers of Aluminium (k = 225 W/mK) separated by a 30 mm polyurethane insulation (k=0.028 W/mK). If the average convection heat transfer coefficient at the inner and outer surfaces are 11.6 W/m2K and 14.5 W/m2K respectively, calculate: WAO Data: Hgt = L2 = ho3= W = k2 = hi = L1 = L3 3= T01= m, k;= k3 = To2 = %3D %3D %3D %3D %3D %3D %3D Area= 5.1 the individual resistance(R) for each thermal layer, as well as for the total of the refrigerator,arrow_forward
- a pipe with an outside diameter of 2.5 inches is insulated with 2 inches layer of asbestos ( K= 0.396(btu-in)/(hr-ft-F) followed by a layer of cork 1.5 inches thick ( K= 0.30 (btu-in)/ft (hr-ft-F). if the temperature of the outer surface of the cork and pipe is 90 F and 290 F RESPECTIVELY, calculate the heat loss per 100 ft of insulated pipe in btu/hrarrow_forwardA small metal building is to be constructed of corrugated steel sheet walls with a total wall overall surface area of about 300 m2. The air conditioner consumes about 1kW of electricity for every 4kW of cooling supplied. Two wall constructions are to be compared on the basis of cooling costs. Assume that electricity costs 10.15 Php/kWh. Determine the electrical energy savings of using 260mm of fiberglass insulation instead of 159 mm of fiberglass insulation in the wall. Assume an overall temperature difference across the wall of 20 ° (Uo (260-mm fiberglass)=0.17W/m2 °C and Uo (159-mm fiberglass)=0.31W/m2 °C)arrow_forwardDetermine the rate of heat transfer and the overall heat transfer coefficient for the composite wall shown below assuming the width is 1m. 10cm T1 = 100°C h=6W/m2.K 20cm Ka 1.9 W/m.K 10cm Kb=0.05 W/m.K Kc 0.1 W/m.K 10cm Kd=3 W/m.K 10cm T2 = 35°C h₂ = 10 W/m2.Karrow_forward
- The cooling load for a house is determined in part by using the same formulaused to find the heat load. The temperature difference used in designing acooling system is 25°F. The corner room shown does not face the sun so noadditional cooling load is required. The windows are single pane, and thewalls are brick veneer with 31⁄2 inches of insulation (R-11). The ceiling has31⁄2 inches of insulation (R-11), and the floor has no insulation. The room isbuilt over a vented crawl space with a vented attic above it. Find the coolingload for this room.arrow_forwardSuppose a 3 in schedule 80 steel pipe is covered with 1 in of an insulation havingk = 60 mW/moC and the outside of the insulation is exposed to an environmenthaving h = 10 W/m2oC and Tf = 20oC. The temperature of the inside of the pipe is250oC. For unit length of the pipe calculate (a) the overall thermal resistance and(b) the heat loss (in Watts).arrow_forward6. A 1.5 m pipe of negligible thickness holding a hot fluid at 140°C and having an outer diameter of 0.4 m is insulated with three layers of each 50 mm thick insulation of k₁ = 0.02; k2 = 0.06; and k3= 0.16 W/m-K (starting from inside). The outside surface temperature is 30°C. Determine a. the heat loss in Watts, b. the temperatures between interfaces of insulating layers in °Carrow_forward
- QUESTION 15 A domestic refrigerator with inner dimensions of 0.7 m by 0.7 m at the base and height 1 m was designed to maintain a set temperature of 6 °C. The bodies consist of two 10-mm-thick layers of Aluminium (k = 225 W/mK) separated by a 30 mm polyurethane insulation (k=0.028 W/mK). If the average convection heat transfer coefficient at the inner and outer surfaces are 11.6 W/m²K and 14.5 W/m2K respectively, calculate: the resistance(R) for the outer fluid thermal layer in K/W to 5 decimal places.arrow_forwardOn a multi-layered square wall, the thermal resistance of the first layer is 0.005 ° C / W, the resistance of the second layer is 0.2 ° C / W, and the third layer is 0.1 ° C / W. The overall temperature gradient in the wall is multilayered from one side. to the other side is 70 ° C. a. Determine the heat flux through the walls. = Answerwatts / m2. b. If the thermal resistance of the second layer is changed to 0.4 ° C / W, what is the effect in% on heat flux, assuming the temperature gradient remains the same? = AnswerAnswer%.arrow_forward12. A 3.1 cm long straight rectangular fin has a thickness of 2.7 mm. The thermal conductivity is 52 W/m K. The fin is attached to a wall maintained at 190 °C and is exposed to a convection environment at 40 °C and h- 31 W/m2 K. What is the fin efficiency? Express your answer in percent.arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning