How much reduction in temperature can be achieved?

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Discussion Overview

The discussion revolves around the potential temperature reduction achievable in a condenser of a power plant using a cooling system with a specified capacity. Participants explore the theoretical implications of cooling steam and the efficiency of various methods, including refrigeration cycles versus direct heat exchange.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant proposes a scenario involving a 3 MW power plant with a steam flow of 1800 kg/hr and questions how much temperature reduction can be achieved with a 2000 ton cooling system.
  • Another participant argues that the cooling capacity of 2000 tons is excessive and would lead to impractical outcomes, such as producing a large amount of ice.
  • A different participant calculates that extracting heat to convert water to ice would require significant energy, suggesting a power consumption of around 250 kW for the cooling process.
  • Some participants assert that simply removing 250 kW from the steam would not significantly reduce its temperature, as it would only condense a small fraction of the steam.
  • There is a suggestion that using a refrigeration cycle to condense steam in a power plant is inefficient compared to direct heat dumping methods.
  • Multiple participants emphasize the importance of understanding thermodynamics and suggest that further study in this area would benefit the original poster's inquiry.
  • Some participants express skepticism about the feasibility of the proposed cooling method, stating that if it were effective, it would already be in use.
  • Concerns are raised about the originality and practicality of the proposed ideas, with some suggesting that many innovative ideas come from a solid understanding of the subject matter.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility and efficiency of using a refrigeration cycle in a power plant's condenser. While some participants agree on the need for a better understanding of thermodynamics, there is no consensus on the effectiveness of the proposed cooling method.

Contextual Notes

Participants reference specific calculations and assumptions about heat extraction and energy requirements, but these calculations are not universally accepted or agreed upon. The discussion remains open-ended regarding the practical application of the proposed cooling system.

pranj5
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I want put here an imaginary, but close to reality scenario. We have 3 MW power plant here having 1800 kg/hr or 0.5 kg/sec steam flow and the exhaust will be steam at 1 bara pressure and 100C temperature. If a cooling system of 2000 ton capacity is fitted to the Condenser, how much it can reduce the temperature in the Condenser?
 
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It's not really close to reality, you'll end up with a lot of very very cold ice.
2000 cooling tons is about 7 MW - a lot of cooling power.
 
2000 ton of ice means extracting 2000X80X1000 kCal 16 million kCal of heat in a single day. In fact, I want to mean the cooler can convert 2000 kg or 2 ton of water to ice every hour and that means 48 tons of refrigeration. That by my calculations, it will take around 250 kW. Sorry for the mistake!
 
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This is the kind of problem worked through by someone who's taken a college-level course in Thermodynamics. Based on your interests over the past weeks, have you considered taking a course and/or purchasing a textbook to increase your knowledge in this area?
 
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billy_joule said:
The temperature won't be reduced, removing 250kW from the steam will only condense a fraction of the steam (about 112g/s) and reduce the quality;

https://en.m.wikipedia.org/wiki/Vapor_quality

http://m.wolframalpha.com/input/?i=250kW/+specific+heat+of+vaporization+water+&x=0&y=0
That is assuming the steam is saturated to start with.
I wouldn't mean that this system will just remove 250 kW of heat from the steam, but rather to get this 48 ton of refrigeration, the power consumption would be 250 kW.
 
48 tons of cooling is only 170 kW.

How much power your cooling system requires to achieve this cooling is irrelevant.

It makes no sense to use a refrigeration cycle to condense steam at a power plant. We just dump the waste heat directly to the atmosphere, river or lake.

I second mech engineer's suggestion, I'd recommend Thermodynamics by Cengal and Heat and Mass Transfer, also by Cengal.
Or at least start by reading this:
https://en.m.wikipedia.org/wiki/Thermal_power_station
 
The purpose of this process is to lower the temperature of the Condenser so that efficiency and output can be increased.
 
pranj5 said:
The purpose of this process is to lower the temperature of the Condenser so that efficiency and output can be increased.
If it worked we'd already be doing it.
 
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billy_joule said:
If it worked we'd already be doing it.
That can be said about any new innovative idea.
 
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pranj5 said:
The purpose of this process is to lower the temperature of the Condenser so that efficiency and output can be increased.
The condenser uses a process (probably either direct air or water to air heat exchanger) that requires less input power than a mechanical chiller, so adding a mechanical chiller would reduce the efficiency and output, not increase it.

It is nice that you are trying to think of ways to make existing systems more efficient, but I agree that it would be better if you started by learning how they work by taking a thermodynamics class. It will save you a lot of wasted effort.
pranj5 said:
That can be said about any new innovative idea.
That's true, but unfortunately you don't have any way to know if your ideas are new, innovative or even functional. Most are just wrong. People don't like hearing this, but it is the truth: new/innovative ideas almost never come from people who don't understand the subject they are investigating. So please do yourself and us a favor and make your time more productive by starting with more rigorous study of thermodynamics instead of continuing with all of this pointless idle speculation.

Thread locked.
 
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