Calculate boiling rate of water

Click For Summary

Discussion Overview

The discussion revolves around calculating the rate at which water boils off in a specific experimental setup. Participants explore the relevant equations, heat transfer mechanisms, and the influence of ambient conditions on boiling rate, particularly under reduced pressure and elevated temperatures.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions the validity of their initial calculation for the boiling rate, suggesting that the equation they found may not be appropriate for their conditions.
  • Another participant corrects the unit of latent heat energy, confirming it as 2438 kiloJoules per kilogram.
  • Several participants inquire about the heat transfer rate and its calculation, emphasizing the need for specific details about the experimental setup.
  • There is a discussion about the thermal conductivity of water and its relevance to the boiling process, with some participants suggesting that direct measurement of heat transfer might be more practical than theoretical calculations.
  • One participant clarifies that the water is being heated from all sides in a closed container, while others express confusion about the specifics of the heating method and the environment.
  • Participants discuss the heat generation rate of a compost pile and its impact on the boiling rate, with one estimating it to be around 100 watts based on the size of the compost.
  • There is a mention of the convective heat transfer coefficient for boiling water, with participants noting the variability in values found across different sources.
  • One participant calculates that it would take approximately 25 hours to boil away one gallon of water based on their estimated heat input and latent heat of vaporization.
  • Another participant expresses surprise at the amount of heat generated by compost, indicating a potential underestimation of its heating capability.
  • There is uncertainty regarding the appropriate convective heat transfer coefficient to use, with participants discussing various ranges found in literature.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method for calculating the boiling rate, and there are multiple competing views regarding the relevance of different parameters and equations. The discussion remains unresolved with ongoing questions about specific conditions and calculations.

Contextual Notes

Participants express limitations in their understanding of heat transfer calculations and the specific conditions of their experimental setup. There are unresolved questions about the measurement of heat input and the variability of the convective heat transfer coefficient.

  • #31
Well I was just interested in using compost as a way to produce steam and yes I know I would have to use a pump to reduce the pressure in the chamber initially
 
Physics news on Phys.org
  • #32
I know I would need an energy source to produce the initial vacuum and just curiosity I suppose, I'd like to know
 
  • #33
AamsterC2 said:
I know I would need an energy source to produce the initial vacuum and just curiosity I suppose, I'd like to know
Depending on what you are doing with the steam, you may or may not need the vacuum continuously maintained:

-If you want to use this to purify water, you'll need to continuously suck away the condensed water.
-If you want to heat a house, it can naturally circulate via convection.
 
  • #34
I'm not planning on purifying it so hopefully I'll only need to produce the vacuum once and keep the system closed also as a side note I've found something intriguing. Compost Power Jean Pain Mound Project Summer 2011 by anenergyoptomist on YouTube, his mound of mulch is 40 meters cubed and with the density of mulch at around 600 lbs per cubic meters is around one ton. Instead of 1000 btu/h his mound is producing 17,000 btu/h according to his measurements so in the end it looks like if I really want to figure this out I'll have to just get to it and test it
 
  • #36
(1) How do you propose to make use of any steam which is generated ?

(2) Have you looked at other possible ways of extracting energy from the composting process ?
 
  • #37
Oh woops, it's 24,000 but I didn't process that extra 0 on the end and thought it was only 2,400 and actually yes I have thought of another way to get energy from this process but it's much simpler so I think I'll just try testing it out first and see how it goes
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
7K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
4
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
15
Views
3K
  • · Replies 31 ·
2
Replies
31
Views
10K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
25
Views
4K
  • · Replies 13 ·
Replies
13
Views
2K