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A wall exactly like the one described in Table construction 1, has dimensions of
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- Project 3: It is vital to optimize the heat loss from a house through well designed composition and proper selection of the insulation layer of the wall layers. Your role as a thermal power engineer to investigate the heat transfer performance of a composite walls. Your head of department asked you to analyze the composite walls structure in Figure.3 and determine the steady rate of heat transfer and total heat loss, if the following design specifications must be met: _Indoor room temperature must be maintained at 20??. − Outdoor temperature mostly is -10?? in a hard winter. − Wall is made of plywood with thermal conductivity constant of ?? = 0.115 ?/(?.?) . − Fiberglass insulation is used with thermal conductivity constant of ?? = 0.045 ?/(?.?) . − Plaster board is used as inner layer for decoration purpose with thermal conductivity constant of ?? = 0.27 ?/(?.?) . − Convection heat transfer coefficients for indoor and outdoor are ℎ?? = 34 ?/(?2.?) and ℎ?? = 65 ?/(?2.?) , respectively.…arrow_forward1. A composite furnace wall is made up of a 12-in. lining of magnesite refractory brick, a 5-in.thickness of 85% magnesia, and a steel casing 0.10-in. thick. Flue gas temperature is 2200 F andthe boiler room is at 80 F. Gas side film coefficient is 15 Btu/hr-sq.ft-F and air side is 4.0.Determine:a. The thermal current Q/Ab. Interface temperaturesc. Effect on thermal current and inside refractory wall temperature if the magnesia insulation weredoubled.arrow_forward(a) Find the refrigeration capacity if no insulation is used for the walls and ceiling. (b) Select insulation(s) for the wall and ceiling to reduce the refrigeration capacity. Evaluate the thickness required for the insulation you selected to reduce the refrigeration load by approximately 30%. (c) Add a 1m x 1m window glass to the room. Use the data collected from previous parts. Assume the internal surroundings surfaces (e.g., walls and ceilings) have the same temperature as the inside temperature, and the external surroundings (landscape, buildings, etc.) are also at the same temperature as the outside temperature. Assume the convection coefficients between air (internal and external) and the glass are the same as the walls and the air. If the glass has an emissivity of 0.9, calculate the rate of heat loss through the glass. Assume steady-state conditions, negligible temperature gradients in the glass, and both inner and outer surfaces exposed to large surroundings.arrow_forward
- partbarrow_forwardMild steel nails were driven through a solid wood wall consisting of two layers, each 15 mm thick, for reinforcement. If the total cross- sectional area of the nails is 0.75% of the wall area, determine the unit thermal conductance of the composite wall, total heat flow, heat flow through the nail alone and the percent of the total heat flow that passes through the nails when the temperature difference across the wall is 35'C. Neglect contact resistance between the wood layers. Wood (Pine) (ky) = 0.15 W/(m K); Mild steel (1% C) (kg) = 43 W/(m K) а. ANSWER: W/m²-K b. ANSWER:arrow_forwardA-For a general office room, the exposed wall (with a window, outside winter type) construction is 19 mm plaster outside (cement and sand) and 20 cm brick (building). The area of the window is 50% of the exposed wall. Calculate the heating load required for the office caused by the wall and window. Take Tout-5 °C and Tin-25 °C, exposed wall height=3 m and width=5 m, Inside and outside still air thermal resistance fi= 9.37 W/m²°C and fo= 34.1 W/m2 °C respectively. (6 marks)arrow_forward
- Task 1 Calculate the heat transfer rate for the following composite wall configurations: (A) Consider a composite plane wall that includes a 10 mm-thick hardwood siding, 50-mm by 120- mm hardwood studs on 0.7m centres with glass fiber insulation (paper faced, 28 kg/m³), and a 15 mm layer of gypsum wall board. What is the thermal resistance per unit area associated with this wall (having 10 studs, each 2.5 m high). In addition, given the temperature at the inlet and outlet surface is 20 °C and -15 °C, calculate the heat transfer rate though this wall. stud insulation 50mm wood Siding 120mm → wall boardarrow_forwardQUESTION 23 A wall facing southwest has a window area of 400 ft4. The window glass is 1/4 in single heat absorbing type glass with translucent roller shades. The building is heavy weight construction ands is located in Philadelphia. Find the solar cooling load in June at 4:00 pm solar time. O 18,800 BTU/hr O 28,400 BTU/hr 30,100 BTU/hr O 35,300 btu/HRarrow_forwardDetermine the heat flux through the composite walls as shown in Figure. The frontal area (normal to heat flow) for the layers of Fir brick and Brick is 1 sq.m. The frontal area for Asbestos and Earth layers are equal and the summation of the frontal areas of them is 1 sq.m. as shown required to answer. OPTIONS: 1.Heat flux is around 487.3 Watt 2.Heat flux is around 742.7 Watt 3.Heat flux is around 305.4 Watt 4.Nonearrow_forward
- Qigihar House in Heilongiiang Province, China Heat Loss Problems, BSCl 2101 Climate: Avg. remperature is 3.2°C Degree Days is 5000 Inside Air Temp. is 20°C Wall Construction, Inside to Out: 15mm Gypsum Plaster, Sand Aggregate Concrete Block, rectangular core, Sand and Gravi 15mm Cement Plaster, Sand Aggregate All 4 walls measure the same, 8m wide by 7mtall. The house is heated with electricity at a cost of $0.10kWh Calculate the RSI-total for the walls using the tabular method demonstrated in class, and the temperature drop through each element for the January 2.5% temperature. Calculate the rate of heat flow through the wall again for the January 2.5% temperature. Plot the temperature profile approximately to scale through a vertical cross-section of the wall. Calculate the January heating cost for the building. Calculate the annual heating cost for the building. Now add 2" ( 50.8mm ) of extruded polystyrene, smooth skin surface, 35kgm3 rigid insulation to the inside surfaces…arrow_forwardPlease provide the answer with appropriate inages and stepsarrow_forwardAn oil storage tank has 20mm steel walls covered with 50mm of fiber glass insulation. if the oil temperature is kept at 150 degree Celsius, what is the rate of heat loss when the outside temperature is 20 degree Celsius and external air coefficient is 20W/m². How much would the heat loss be reduced by doubling the thickness of the insulation?arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning