Calculate Change in Entropy of Factory Furnace per sq m/sec

  • Thread starter Thread starter neon612
  • Start date Start date
  • Tags Tags
    Change Entropy
AI Thread Summary
The discussion revolves around calculating the change in entropy for a factory furnace with a specific thermal setup. The furnace operates at 175 degrees C, while the outer surface of its insulation is at 42 degrees C, with a heat escape rate of 125 W per square meter. The key formula for entropy change, ΔS = Q/T, is highlighted, but there is confusion regarding the relationship between heat transfer (H) and the heat (Q) involved in the calculations. The user is trying to determine whether to calculate the entropy change inside the furnace and compare it with the entropy change outside. Ultimately, the focus is on understanding how to apply the given thermal properties and equations to find the entropy change per square meter per second.
neon612
Messages
5
Reaction score
0

Homework Statement


A large factory furnace maintained at 175 degrees C at its outer surface is wrapped in an insulating blanket of thermal conductivity 5.50×10−2 W/(m * K) which is thick enough that the outer surface of the insulation is at 42.0 degrees C while heat escapes from the furnace at a steady rate of 125 W for each square meter of surface area.

By how much does each square meter of the furnace change the entropy of the factory every second?

Homework Equations


\DeltaS = Q/T


The Attempt at a Solution


I know:
k = 5.50*10-2 W/(m*K)
H = 125 W
TH = 175 C = 448K
TC = 42 C = 315K

H = \DeltaQ/\Deltat

I know there is some type of relationship between H and Q, I just can't figure out what it is. Or how they work together.
 
Physics news on Phys.org
H =\DeltaQ/\Deltat = kA((TH - TC)/L)

L = 5.85 cm
But, does this help me in anyway?

S = Q/T
Am I supposed to figure out the entropy inside the furnace (Q/175 deg C) and add/subtract it from the entropy on the outside (Q/42 deg C)?
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Calculate change in entropy per minute.
Replies
4
Views
1K
Heat Transfer: Finding temperature at the junction
Replies
3
Views
3K
Entropy Change of Touching Blocks That Reach Equillibrium
Replies
7
Views
5K
Entropy change of system two substances
Replies
9
Views
3K
Working out signs of work and heat for entropy change question
Replies
10
Views
3K
Finding entropy change when house leaks heat
Replies
3
Views
3K
Does This Engine Violate the First or Second Law of Thermodynamics?
Replies
5
Views
13K
Thermal physics - entropy change (latent heat, specific heat etc)
Replies
2
Views
5K
What Is the Entropy Change When Ice Melts in a Room at 20 Degrees Celsius?
Replies
1
Views
9K
Thermodynamics Ice Melting Question
Replies
4
Views
3K

Hot Threads

Recent Insights

Back
Top