0
votes
2answers
65 views

Inequality of Clausius

I'm having some trouble understanding the inequality of Clausius. My treatment of the inequality applies to an engine operating in a cycle between two temperatures (i.e. like a Carnot engine). The ...
0
votes
1answer
102 views

Enthalpy Change in Reversible, Isothermal Expansion of Ideal Gas

For the reversible isothermal expansion of an ideal gas: $$ (1)\ {∆H}={∆U}=0 $$ This is obvious for the case of internal energy because $$ (2)\ {∆U} = \frac {3}{2} n R {∆T} = 0 $$ and $$ (3)\ {∆U} = ...
1
vote
1answer
264 views

Adiabatic proccess and Carnot cycle in a photon gas

I am making a comparation between the photon gas and the ideal classic gas for my Thermodynamics class. The photon gas is defined by the equations: $$U=aVT^4 $$ $$P=\dfrac{1}{3}aT^4$$ I found this ...
2
votes
1answer
118 views

Volume quotient in Carnot-cycle

Problem: One kilomole of an ideal, monatomic gas undergoes a reversible Carnot-processes between temperatures 300 °C and 20 °C. The work done during one cycle is 1500 kJ. a) Find the ...
1
vote
1answer
121 views

What is the importance of state functions in physics?

I'm currently reading about the Carnot cycle and its significance on the formulation of entropy (because I want to try to understand the concept better), but I can't seem to answer the following ...
3
votes
1answer
2k views

Efficiency of Stirling engine and Carnot's theorem

I want to calculate the efficiency of this Stirling cycle for an ideal gas $pV = nRT$ The mechanical work is $$ \Delta W_{12} = - \int_{V_1}^{V_2} p(V) \mathrm{d}V = -nRT_2 \ln \frac{V_2}{V_1}\\ ...
1
vote
2answers
513 views

Must a reversible engine be a carnot engine?

I have this homework question: "Show that any reversible engine operating between T1 and T2 is a carnot engine." I think I have a solution, but it feels very hand-wavy. We know that any process that ...
3
votes
1answer
93 views

Net work output of an engine performing Carnot cycle?

My problem gives me a Carnot cycle heat engine with water as its working fluid, with $T_H$, $T_L$, and the fact that it starts from saturated liquid to saturated vapor in the heating process. I need ...
2
votes
1answer
90 views

Where does the energy flow differ between a forward and reverse process?

Mathematically ($W=\int PdV$) and by the First Law, I understand that $1 \rightarrow 4 \rightarrow 3 \rightarrow 2 \rightarrow 1$ and $1 \rightarrow 2 \rightarrow 3 \rightarrow 4 \rightarrow 1$ are ...
2
votes
1answer
168 views

Are Carnot theorem and Carnot Cycle related?

This has been in my head for a while, and I think I finally have the answer. I was wondering what was so special about the Carnot cycle so it was used to demonstrate the Carnot theorem; the ...
6
votes
5answers
2k views

Can I take heat from the air and convert it to electricity?

Its a summer day and the air in my house has been heated up. I could switch on my air conditioning, but then I'd be using energy from the grid in order to reduce the amount of energy in my house. ...
1
vote
2answers
192 views

Carnot cycle: What happens to the rest of the energy?

In a Carnot cycle, the work potential is $W =Q_{in}( 1-\frac{T_0}{T_R})$ where $T_0$ is the temperature of the sink, $T_{R}$ is the temperature of the source heat reservoir, and $Q_{in}$ is the heat ...