Airflow through a long, 0.15-m-square air conditioning duct maintains the outer duct surface temperature at 10°C. If the horizon
tal duct is uninsulated and exposed to air at 35°C in the crawlspace beneath a home, what is the heat gain per unit length of the duct? Evaluate the properties of air at 300 K. For the sides of the duct, use the more accurate Churchill and Chu correlations for laminar flow on vertical plates.
1 answer:
The complete Question is:
Airflow through a long, 0.15-m-square air conditioning duct maintains the outer duct surface temperature at 10°C. If the horizontal duct is uninsulated and exposed to air at 35°C in the crawlspace beneath a home, what is the heat gain per unit length of the duct? Evaluate the properties of air at 300 K. For the sides of the duct, use the more accurate Churchill and Chu correlations for laminar flow on vertical plates.
What is the Rayleigh number for free convection on the outer sides of the duct?
What is the free convection heat transfer coefficient on the outer sides of the duct, in W/m2·K?
What is the Rayleigh number for free convection on the top of the duct?
What is the free convection heat transfer coefficient on the top of the duct, in W/m2·K?
What is the free convection heat transfer coefficient on the bottom of the duct, in W/m2·K?
What is the total heat gain to the duct per unit length, in W/m?
Answers:
- 7709251 or 7.709 ×10⁶
- 4.87
- 965073
- 5.931 W/m² K
- 2.868 W/m² K
- 69.498 W/m
Explanation:
Find the given attachments for complete explanation
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Answer:
no of unit is 17941
Explanation:
given data
fixed cost = $338,000
variable cost = $143 per unit
fixed cost = $1,244,000
variable cost = $92.50 per unit
solution
we consider here no of unit is = n
so here total cost of labor will be sum of fix and variable cost i.e
total cost of labor = $33800 + $143 n ..........1
and
total cost of capital intensive = $1,244,000 + $92.5 n ..........2
so here in both we prefer cost of capital if cost of capital intensive less than cost of labor
$1,244,000 + $92.5 n < $33800 + $143 n
solve we get
n >
n > 17941
and
cost of producing less than selling cost so here
$1,244,000 + $92.5 n < 197 n
solve it we get
n >
n > 11904
so in both we get greatest no is 17941
so no of unit is 17941