Heat Engines and Work: Combining Two Engines

AI Thread Summary
The discussion revolves around combining two heat engines, specifically a Carnot engine and a refrigerator. The first engine (ENGINE 1) has a heat input of 100 J and a work output of 50 J. The second engine (ENGINE 2) requires drawing a diagram for a Carnot refrigerator that extracts 100 J from a hot reservoir at 450 K and dumps heat to a cold reservoir at 270 K. Participants express confusion about the problem's wording and the relationship between the two engines, emphasizing the need for clarity. The conversation highlights the complexities of thermodynamic principles and the challenges in understanding engine combinations.
hockeybro12
Messages
14
Reaction score
0

Homework Statement



There is a heat engine with Th on top at 100 J pointing down, Tc on bottom pointing down with 50 J and the work output is 50 J pointing right out of the engine. (ENGINE 1)

a) Draw the diagram for a carnot refrigerator which draws 100 J of heat from the hot reservoir (Th = 450 K and Tc = 270 K). we have to find the work output and the heat dumped to the cold reservoir. Using this information, make a new heat engine. (ENGINE 2)

b) what is the engine that results when you combine the two engines. (#1 and 2)

c) what is interesting about this combination?


Homework Equations



efficiency = 1 - QL/QH
ideal efficiency = 1 - TL/TH


The Attempt at a Solution



A carnot engine is basically one in which everything is perfect. This can never exist in reality. In the refrigerator heat engine, the arrow for TH should point up, the arrow for TL(TC) should point up and the energy should point in. However, I am not able to figure out the values for them besides the fact that TH is 100 J since that is given. Without this information, I can't do part B and C
 
Physics news on Phys.org
Why does no one know this? Please ask me if you are having trouble understanding the problem.

Bump
 
hockeybro12 said:

Homework Statement



There is a heat engine with Th on top at 100 J pointing down, Tc on bottom pointing down with 50 J and the work output is 50 J pointing right out of the engine. (ENGINE 1)

a) Draw the diagram for a carnot refrigerator which draws 100 J of heat from the hot reservoir (Th = 450 K and Tc = 270 K). we have to find the work output and the heat dumped to the cold reservoir. Using this information, make a new heat engine. (ENGINE 2)
A refrigerator moves heat from the cold reservoir to the hot reservoir. What you are describing is a heat engine, not a refrigerator.

The reason no one has responded so far may be because the question makes no sense. Please give us the exact wording.

AM
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top