The walls of a refrigerator are typically constructed by sand- wiching a layer of insulation between sheet metal panels. Consider a wall made from fiberglass insulation of thermal conductivity k, = 0.046 W/m · K and thickness L, = 50 mm and steel panels, each of thermal conductivity k,= 60 W/m ·K and thickness L, = 3 mm. If the wall separates re- frigerated air at To,i what is the heat gain per unit surface area? Coefficients as- 4°C from ambient air at To= 25°C, sociated with natural convection at the inner and outer sur- faces may be approximated as h, = h, = 5 W/m² · K. Hint: SCHEMATIC: L = 0.050 m - e Lp = 0.003 m SRefrigerated air Ambient air Tooi = 4°C h = 5 W/m2-K To,o = 25°C ho = 5 W/m2-K To,i wowowawowo q" To,o Panel (2) kp = 60 W/m-K Insulation 1/h, Lp/kp L/k; Lp/kp 1/ho k; = 0.046 W/m-K
The walls of a refrigerator are typically constructed by sand- wiching a layer of insulation between sheet metal panels. Consider a wall made from fiberglass insulation of thermal conductivity k, = 0.046 W/m · K and thickness L, = 50 mm and steel panels, each of thermal conductivity k,= 60 W/m ·K and thickness L, = 3 mm. If the wall separates re- frigerated air at To,i what is the heat gain per unit surface area? Coefficients as- 4°C from ambient air at To= 25°C, sociated with natural convection at the inner and outer sur- faces may be approximated as h, = h, = 5 W/m² · K. Hint: SCHEMATIC: L = 0.050 m - e Lp = 0.003 m SRefrigerated air Ambient air Tooi = 4°C h = 5 W/m2-K To,o = 25°C ho = 5 W/m2-K To,i wowowawowo q" To,o Panel (2) kp = 60 W/m-K Insulation 1/h, Lp/kp L/k; Lp/kp 1/ho k; = 0.046 W/m-K
Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Kreith, Frank; Manglik, Raj M.
Chapter7: Forced Convection Inside Tubes And Ducts
Section: Chapter Questions
Problem 7.53P
Related questions
Question
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 2 steps
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Recommended textbooks for you
Principles of Heat Transfer (Activate Learning wi…
Mechanical Engineering
ISBN:
9781305387102
Author:
Kreith, Frank; Manglik, Raj M.
Publisher:
Cengage Learning
Principles of Heat Transfer (Activate Learning wi…
Mechanical Engineering
ISBN:
9781305387102
Author:
Kreith, Frank; Manglik, Raj M.
Publisher:
Cengage Learning