Concept explainers
Fiberglass is a popular, economical, and fairly effective building insulation. It consists of fine glass fibers—often including recycled glass—formed loosely into rectangular slabs or rolled into blankets (Fig. 16.18). One side is often faced with heavy paper or aluminum foil. Fiberglass insulation comes in thicknesses compatible with common building materials—for example, 3.5 inch and 6 inch for wood-framed walls. Standard 6-inch fiberglass has an R-factor of 19.
Want to see the full answer?
Check out a sample textbook solutionChapter 16 Solutions
Essential University Physics Volume 1, Loose Leaf Edition (4th Edition)
Additional Science Textbook Solutions
University Physics Volume 2
Glencoe Physical Science 2012 Student Edition (Glencoe Science) (McGraw-Hill Education)
An Introduction to Thermal Physics
Conceptual Physics (12th Edition)
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
- A pure aluminum plate is part of a heat shield for a manufacturing process. The aluminum plate has a thickness of 3.60 mm. The aluminum plate is insulated (on one side only) with Board and Slab insulation (Cellular glass, density of 145 kg/m3) 6.00 cm thick; which in turn is covered with a layer of Particle board (high density) 1.00 cm thick (The composite wall goes: aluminum/cellular glass insulation/Particle board). The temperature on the exposed surface of the aluminum plate is measured to be 78.0°C, while the outside surface of the Particle board is exposed to convection, T = 22.0°C, h = 17.0 W/(m2-K). The plate has dimensions of 11.50 m long by 3.50 m tall. • Draw and label a sketch of this system. Includedimensions, known temperatures, etc. • Draw and completely label the corresponding 1-Dsteady-state conduction resistor diagram. • Determine the heat transfer rate through thiscomposite plate. • Calculate the temperature at the Cellular Glassinsulation/Particle board interface.arrow_forwardA thermal window, with an area of 6.0m ^ 2, is constructed of two layers of glass, each 4.0mm thick, separated from each other by a 5.0mm air gap. If the inner surface is at 20.0 ° C and the outer surface is at -5.0 ° C, what is the rate of energy transfer by conduction through the window? The thermal conductivity of glass is 0.8 W⁄ (m. ° C) and that of air is 0.023 W⁄ (m. ° C)arrow_forwardA walrus transfers energy by conduction through its blubber at the rate of 150 W when immersed in −1.00ºC water. The walrus’s internal core temperature is 37.0ºC , and it has a surface area of 2.00 m2 . What is the average thickness of its blubber, which has the conductivity of fattytissues without blood?arrow_forward
- An electric stove burner has surface area 325 cm² and emissivity e = 1. The burner consumes 1500 W and is at 900 K. If room temperature is 300 K, what fraction of the burner's heat loss is from radiation?arrow_forwardA small electric immersion heater is used to heat 94 g of water for a cup of instant coffee. The heater is labeled "81 watts" (it converts electrical energy to thermal energy at this rate). Calculate the time required to bring all this water from 21°C to 100°C, ignoring any heat losses. (The specific heat of water is 4186 J/kg.K.) Number Unitsarrow_forwardApproximately how long should it take 9.5 kg of ice at 0 °C to melt when it is placed in a carefully sealed Styrofoam ice chest of dimensions 25 cm × 35 cm x 55 cm whose walls are 1.1 cm thick? Assume that the conductivity of Styrofoam is double that of air and that the outside temperature is 35 °C. Express your answer using two significant figures. VE ΑΣΦ ? Sarrow_forward
- The tungsten filament of a light bulb has an operating temperature of about 2100 K.If the emitting area of the filament is 1 cm2, and its emissivity (ε) is 0.68, what is the power output of the light bulb?arrow_forwardThermography is a technique for measuring radiant heat and detecting variations in surface temperatures that may be medically, environmentally, or militarily meaningful.(a) What is the percent increase in the rate of heat transfer by radiation from a given area at a temperature of 34.0C compared with that at 33.0C, such as on a person’s skin? (b) What is the percent increase in the rate of heat transfer by radiation from a given area at a temperature of 34.0C compared with that at 20.0C, such as for warm and cool automobile hoods?arrow_forwardWhat is the rate of heat transfer by radiation, with an unclothed person standing in a dark room whose ambient temperature is 22.0ºC . The person has a normal skin temperature of 33.0ºC and a surface area of 1.50 m2 . The emissivity of skin is 0.97 in the infrared, where the radiation takes place.arrow_forward
- A 10-in nominal pipe (outside diameter = 10.75in) is covered with a composite pipe insulation consisting of 2.0 in of insulation I placed next to the pipe and 1.5 in of insulation II placed upon insulation I. Assume that the inner and outer surface temperatures of the composite insulation are 900F and 150F respectively, and that the thermal conductivity of material I is 0.05 BTU/hr-ft-F and for material II is 0.039 BTU/hr-ft-F. What is the individual thermal resistance of insulation I?arrow_forwardPlease asaparrow_forwardDuring a plant visit, it was noticed that a 12-m-long section of a 10-cm-diameter steam pipe is completely exposed to the ambient air. The temperature measurements indicate that the average temperature of the outer surface of the steam pipe is 75°C when the ambient temperature is 5°C. There are also light winds in the area at 10 km/h. The emissivity of the outer surface of the pipe is 0.8, and the average temperature of the surfaces surrounding the pipe, including the sky, is estimated to be 0°C. Determine the amount of heat lost from the steam during a 10-h-long work day. Steam is supplied by a gas-fired steam generator that has an efficiency of 80 percent, and the plant pays $1.05/therm of natural gas. If the pipe is insulated and 90 percent of the heat loss is saved, determine the amount of money this facility will save a year as a result of insulating the steam pipes. Assume the plant operates every day of the year for 10 h. State your assumptions.arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning