Concept explainers
An ice chest (see sketch) is to constructed from styrofoam
Problem 1.72
Trending nowThis is a popular solution!
Chapter 1 Solutions
Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
- In addition , the space between the upper cap, the lower cap, and the cylindrical wall is filled with linear insulating material of permeability u.arrow_forwardPresents the diagram of the problem, necessary formulas, clearance and numerical solution: An iron plate 2 cm thick has a cross-sectional area of 5,000 cm2. One of the faces is at 150 ◦C and the other is at 140 ◦C. How much heat flows through the plate each second? For iron, kT = 80 W/m K.arrow_forwardAn office space contains one (6`x 3`) well- fitted door made of nominal 2" wood. The heat loss through door by infiltration is (3381 Btuh) if Tb.l.=80 F , To= -10 F , and Vwind=15 mph ? True or falsearrow_forward
- A computer room located on the second floor of a five-storey office building is 10m x 7m. The exterior wall is 3.5m high and 10m long; it is a metal curtain wall (steel-backed with 10mm of insulating board), 75mm of glass fiber insulation, and 16mm of gypsum board. The single-glazed window (U=5.9 W/m^2-K) make-up 30% of the exterior wall. Three (3) computer sets at 500 Watts each and 500 Watts of total lightning power in the room operate 24 hours per day. The indoor temperature is 20°C. Determine the following: 1. Heat load in KW if the outdoor condition is 32°C DBT and 23°C WBT a. 2.95 b. 3.17 c. 3.41 d. 3.67 e. 3.97 2. What would be the load in kilowatts if the windows were double-glazed (U=3.5 W/m^2-K) a. 2.95 b. 3.17 c. 3.41 d. 3.67 e. 3.97arrow_forwardA computer room located on the second floor of a five-storey office building is 10m x 7m. The exterior wall is 3.5m high and 10m long; it is a metal curtain wall (steel-backed with 10mm of insulating board), 75mm of glass fiber insulation, and 16mm of gypsum board. The single-glazed window (U=5.9 W/m^2-K) make-up 30% of the exterior wall. Three (3) computer sets at 500 Watts each and 500 Watts of total lightning power in the room operate 24 hours per day. The indoor temperature is 20°C. Determine the following: 1. Heat load in KW if the outdoor condition is 32°C DBT and 23°C WBT 2. What would be the load in kilowatts if the windows were double-glazed (U=3.5 W/m^2-K)arrow_forward(a) The temperature at the surface of the heating rod, T1. (b) If the salt solution temperature is 300 degree Celcius, what is the value of convection heat transfer coefficient, h of the salt solution ? (c) If the heating rod is not covered by metallic cylinder and corresponds to the result of part (a) and (b), how much the rate of energy transfer to the salt solution ? (d) Compare and discuss the difference of heat transfer with and without the matallic cylinder.arrow_forward
- The 12ft x 14 foot room illustration in figure 1.6a has an exterior wall at a surface temperature of 60°F, a window surface temperature of 40°F (double glazing on a cold day). The two interior wall surfaces are a temperature of 72°F. Determine the MRT sensation of a person standing in the center of the room. (See figure 1.6 below) Round your values to the nearsest hundreth decimal place (0.00). You will need to upload your mathematical work in question 4.arrow_forwardDoes the Rankine degree represent a larger or smaller temperature unit than the Kevin degree? Explain.arrow_forwardTo ensure a tight fit, the aluminum rivet used in airplane construction are made slightly larger than the rivet holes and cooled by dry ice (solid CO2) before being driven. If the diameter of a hole is 0.500 cm, what should be the diameter of a rive at 20 degree Celsius if its diameter is equal that of a hole when the rivet is cooled to -78 degree Celsius, the temperature of dry ice? Assume the coefficient of expansion to remain constant. (Given and solutions)arrow_forward
- a metal bar is made up of 3.0 cm of aluminum and 5.0 cm of steel. the free end of the aluminum bar is placed in contact with steam at 100 degree Celsius. at the other side, the free end of the steel bar maintained at 0 degree Celsius by placing it in contact with the ice. find the temperature at the point that connect the aluminum and the steal (junction)arrow_forwardA room has a pine ceiling [ k = 0.12 W/(m•C°) ] that measures 3.0 m x 4.0 m x 2.0 cm. On a cold day, the temperature inside the room is 20°C, and the temperature in the attic above is 8°C. If 6.0 cm of glass wool insulation [ k = 0.042 W/(m•C°) ] were put in above the ceiling, how much energy would be saved in one hour? Please use gresa methodarrow_forwardAs a designer working for a major electric appliance manufacturer, you are required to estimate the amount of fiberglass insulation packing (k = 0.035 W/m K) that is needed for a kitchen oven shown in the figure below. The fiberglass layer is to be sandwiched between a 2-mm-thick aluminum cladding plate on the outside and a 5-mm-thick stainless steel plate on the inside that forms the core of the oven. The insulation thickness is such that the outside cladding temperature does not exceed 40C when the temperature at the inside surface of the oven is 300C. Also, the air temperature in the kitchen varies from 15Cto33C, and the average heat transfer coefficient between the outer surface of the oven and air is estimated to be 12.0W/m2K. Determine the thickness of the fiberglass insulation that is required for these conditions. What would be the outer surface temperature when the inside surface of the oven is at 475C?arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning