Answered step by step
Verified Expert Solution
Question
1 Approved Answer
A cold room has walls constructed of 0.24 m brick on the outside, 0.15 m foam insulation in the middle and 1.6 cm of
A cold room has walls constructed of 0.24 m brick on the outside, 0.15 m foam insulation in the middle and 1.6 cm of wood on the inside. The air temperature on the outside is constant at 20C, and the room is to be maintained at a temperature of -6 C (minus 6C). The convection heat transfer coefficient for air to brick is 15 W/m? K, and for wood to air is 30 W/m K. The thermal conductivities of wood, foam insulation and brick are 0.15, 0.025, and 1 W/m K respectively. Determine the overall thermal resistance of the composite wall by the summation (a) of the individual resistances and hence verify the overall heat transfer coefficient U= 0.155 W/m K (b) Calculate the heat transfer rate per unit area of the wall surface. Calculate the outside and inside surface temperature of the composite wall. (c) (d) Calculate the interface temperatures, of (i) the wood and the foam insulation, and (ii) the insulation foam and the brick. Calculate the amount of energy (MJ) to be removed by refrigeration in a 24 hour (e) period if the total wall area is 80 m?. Calculate the thickness of the wood layer required to maintain the inside and (f) outside air temperatures given in the question if the thickness of the brick was reduced to 0.12 m and the heat transfer rate is unchanged.
Step by Step Solution
★★★★★
3.54 Rating (154 Votes )
There are 3 Steps involved in it
Step: 1
Get Instant Access to Expert-Tailored Solutions
See step-by-step solutions with expert insights and AI powered tools for academic success
Step: 2
Step: 3
Ace Your Homework with AI
Get the answers you need in no time with our AI-driven, step-by-step assistance
Get Started