Answered

Welcome to Westonci.ca, the place where your questions find answers from a community of knowledgeable experts. Join our platform to get reliable answers to your questions from a knowledgeable community of experts. Connect with a community of professionals ready to provide precise solutions to your questions quickly and accurately.

The walls of a refrigerator are typically constructed by sandwiching a layer of insulation between sheet metal panels. Consider a wall made from fiberglass insulation of thermal conductivity ki 0.046 and thickness Li 50 mm and steel panels, each of thermal conductivity kp 60 and thickness Lp 3 mm. If the wall separates refrigerated air at T,i 4 C from ambient air at T,o 25 C, what is the heat transfer rate per unit surface area

Sagot :

batolisis

Answer:

14.12 w /m^2

Explanation:

Determine the heat transfer rate per unit surface area

First step : determine the thermal resistance of the composite wall considering all present forms of heat transfer

Rth = 1 / h₀ + Lp / Kp + Li / Ki  + Lp / Kp  + 1 / hi  --------- ( 1 )

where : h₀ and hi = 5 W/m^2  ,  Li = 50 mm , Ki = 0.046 W/m.k,  Lp = 3 mm,

            Kp = 60 W/m.k  

Insert values into equation 1 above

Rth = 1.487 m^2. K/W

Next : determine the heat gain per unit surface area ( heat transfer rate )

Q = ( To - Ti ) / Rth

   = 21° C / 1.487

   = 14.12 W/m^2

Thanks for stopping by. We are committed to providing the best answers for all your questions. See you again soon. We appreciate your time. Please come back anytime for the latest information and answers to your questions. Get the answers you need at Westonci.ca. Stay informed by returning for our latest expert advice.