Inrease in water pressure as a function of temperature under constant volume

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Discussion Overview

The discussion revolves around the increase in water pressure as a function of temperature within a closed pipe network, specifically examining the scenario where the temperature of water rises from 25°C to 55°C while maintaining constant volume. Participants explore methods for calculating the resulting pressure change, referencing thermodynamic principles and tables.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests using steam tables and the first law of thermodynamics to determine the pressure increase due to temperature change.
  • Another participant argues that since the water temperature is between 25°C and 55°C, steam tables may not be applicable, proposing that this is a pressure versus temperature versus volume problem.
  • Some participants note that steam tables include compressed liquid water, which raises questions about their nomenclature and applicability in this context.
  • A participant emphasizes that the heat transferred to the water can be calculated using mass and specific heat capacity, and that all internal energy comes from this transferred heat, which should be referenced against steam tables for pressure.
  • One participant expresses uncertainty about the application of steam tables and thermodynamics, indicating a need to refresh their knowledge on the topic.

Areas of Agreement / Disagreement

There is no consensus on the appropriate method to calculate the pressure increase. Participants present competing views on the use of steam tables and the relevance of thermodynamic laws in this scenario.

Contextual Notes

Participants highlight the potential limitations of using steam tables for water in this temperature range and the need for clarity on the definitions and assumptions involved in the calculations.

ageorgakis
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Hi all. I have a large pipe network that can hold say 1000 cubic meters of water. The pipe network is closed and pressurized to say 10 barg at 25 deg C. If the temperature of the water increases to 55 deg C, how much will the pressure in the pipe network increase?

I would appreciate if you could point out the method of solving the problem including tables and formulas.

Thanks.
 
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This ia a job for steam tables and the first law of thermo and possibly a H-S chart.
 
The water is between 25 to 55 degC so I don't think the steam tables or the thermo laws will do any good. This is a pressure vs temp vs volume problem. if it was a gas then a simple ideal gas law would work.
 
ageorgakis said:
The water is between 25 to 55 degC so I don't think the steam tables or the thermo laws will do any good. This is a pressure vs temp vs volume problem. if it was a gas then a simple ideal gas law would work.

Steam tables, in an odd use of the nomenclature, include compressed liquid water. No idea why they are still called steam tables but they are.

You came and asked the question as to how to solve is. I've told you. It's water, therefore you use the steam tables, there is no debate about that. You find the heat transferred to the water (using the mass and specific heat capacity). As no work is being done (from the first law) we know that all internal energy comes from transferred heat. You can then look up from a steam table the pressure.

I've not used steam tables or done anything with thermodynamics of fluids in quite a while (since uni in fact), I can't remember exactly what you have to do i'll have to read up for that.
 
Last edited:
xxChrisxx said:
Steam tables, in an odd use of the nomenclature, include compressed liquid water. No idea why they are still called steam tables but they are.

You came and asked the question as to how to solve is. I've told you. It's water, therefore you use the steam tables, there is no debate about that. You find the heat transferred to the water (using the mass and specific heat capacity). As no work is being done (from the first law) we know that all internal energy comes from transferred heat. You can then look up from a steam table the pressure.

I've not used steam tables or done anything with thermodynamics of fluids in quite a while (since uni in fact), I can't remember exactly what you have to do i'll have to read up for that.

It's been such a long time since uni I can barely remember any of this. I wish I had my old books. I'm doing some research on the net but it isn't easy.
 

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