A 2-in. schedule 40 steel pipe (ID=2.067in., OD = 2.375 in.) carries steam at 350F with a heat-transfer coefficient of 50 Btu/h*ft^2*F. The pipe is exposed to air at 70F with a heat-transfer coefficient of 2.0 Btu/h*ft^2*F. For safety reasons, as well as to conserve energy, it is desired to insulate the pipe so that the temperature of the surface exposed to air will be no greater than 120F. A commercial insulation vendor claims that using just 0.5 in. of his “high-efficiency” insulation will do the job. Is his claim correct? Notes: 1. The vendor’s literature states that a 6-in. thick layer of “high-efficiency” insulation has an R-value of 23.7.2. The thermal resistance of the pipe wall may be neglected in this calculation. Also neglect contact resistance and thermal radiation effects
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A 2-in. schedule 40 steel pipe (ID=2.067in., OD = 2.375 in.) carries steam at 350F with a heat-transfer coefficient of 50 Btu/h*ft^2*F. The pipe is exposed to air at 70F with a heat-transfer coefficient of 2.0 Btu/h*ft^2*F. For safety reasons, as well as to conserve energy, it is desired to insulate the pipe so that the temperature of the surface exposed to air will be no greater than 120F. A commercial insulation vendor claims that using just 0.5 in. of his “high-efficiency” insulation will do the job. Is his claim correct? Notes:
1. The vendor’s literature states that a 6-in. thick layer of “high-efficiency” insulation has an R-value of 23.7.
2. The thermal resistance of the pipe wall may be neglected in this calculation. Also neglect contact resistance and thermal radiation effects
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