Using EES (or other) software, determine how much the thermal efficiency of the cycle in Prob. 1

Using EES (or other) software, determine how much the...

Key Concepts

Thermal Efficiency

Thermal efficiency is a measure of how well a system converts heat into work or useful energy. In thermodynamic cycles, it is calculated as the ratio of the net work output to the heat input. Understanding thermal efficiency is essential in assessing the performance and viability of power cycles and heating systems.

Pressure Drop

Pressure drop refers to the reduction in pressure that occurs when a fluid flows through a component such as a boiler or heat exchanger. This loss can affect the fluid's thermodynamic properties, leading to reduced performance and efficiency of the component, and in turn, the overall cycle. Recognizing and quantifying pressure drops is crucial in accurately modeling and predicting system behavior.

Thermodynamic Cycle Analysis

Thermodynamic cycle analysis involves studying the processes that a working fluid undergoes in a complete cycle, including heat addition, work output, and heat rejection. By analyzing each process, engineers can identify sources of inefficiency and evaluate the impact of factors like pressure drop on overall cycle performance. This analysis is foundational in optimizing energy systems and improving efficiency.

Numerical Simulation and Modeling

Numerical simulation using software like EES (Engineering Equation Solver) facilitates the evaluation of complex thermodynamic cycles by solving relevant equations that describe energy and mass balances. Such simulations allow engineers to explore the effects of varying system parameters, such as pressure drops, on performance metrics like thermal efficiency, enabling more informed design and optimization decisions.

Transcript

00:01 Here we're asked to repeat problem 22 in which we were looking at an ideal ranking cycle.

00:07 And what i did, they want us to use software.

00:10 And so what i did is i explored the, they basically asked us to just look at if the change, if there was a 50 kilopascal pressure drop across the boiler, i just basically looked at a range of pressure drops.

00:23 Since basically you have it in software, you can just make a loop and get a bunch of values.

00:31 So if you remember we had a ranking cycle here, we had from problem 22.

00:38 We had super cooled down here in the condenser by 6 .3 degrees c.

00:47 Pump, boiler, we had a non -ideal turbine and then condenser here.

00:56 So what i actually did is i made an accurate two -scale.

01:03 T .s diagram here.

01:06 And what you can see is that basically the stuff over here all basically happens on this condensation line.

01:15 I mean it's pretty much you can't even see.

01:18 So we have a condenser here and it gets super chill the tad and then the compressor compresses it up just a tad and then in the boiler basically you're heating the water water water it starts to boil.

01:33 Finish, all of it's boiled off, and then it starts to get superheated, and then it goes through the turbine.

01:38 And you can see that this line is slightly tilted.

01:45 So the entropy here is slightly greater than the entropy here.

01:50 So if you compare over here, basically, this whole region is very much exaggerated just for illustration purposes, because it really all basically occurs very close to this on this condensation line here.

02:05 Um, so i exploit the effect of the pressure drop.

02:09 This is just for a zero pressure drop across the boiler.

02:12 Um, i wasn't sure exactly, you know, you could basically say how does it drop? does it drop? you know, as the, as the temperature goes up, does it drop linearly or? so again, you could basically say, okay, now, you know, again, maybe when it's boiled, it drops to down the heat or a little bit.

02:30 So that would just change this line here or, you know, change where this comes over and make this line drop a little bit...

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