• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education skip experiences global resources cider press projects digital market permies.com pie forums private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Anne Miller
  • Nicole Alderman
  • Pearl Sutton
  • paul wheaton
  • r ranson
  • Joseph Lofthouse
master gardeners:
  • John F Dean
  • jordan barton
  • Carla Burke
  • Leigh Tate
  • Steve Thorn
  • Greg Martin
  • Jay Angler
  • Mike Barkley

Water heating calculation using the Engineering Toolbox

Posts: 9002
Location: Victoria British Columbia-Canada
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I often make use of the Engineering Toolbox when I have some problem to solve.

Since I'm trying to heat water with wood,  I want to find out how much wood I'm likely to need. It appears that perfectly dry wood contains 7000 BTUs per pound. One btu is the amount of heat required to raise one pound of water by one degree Fahrenheit.

Let's go with 10 gallons of water. I will calculate the amount of weight in the water and burn one pound of fuel to see how much hotter it could become in perfect conditions. Let's start with well water that is 50 degrees Fahrenheit. I'll use the American gallons. Somebody, somewhere in history, needs a good slap for making two different gallons.

An American gallon weighs 8.34 pounds. 10 gallons weighs 83.4 lb.  A pound of dry wood contains 7000 BTUs.   7000÷ 83.4=83.93  ----- So, we can raise our 50 degree water by roughly 84 degrees.  84+50=134   In perfect conditions,  one pound of wood is needed to have a hot bath.  In real world conditions it may take 2 or 3 pounds, but not 20.

Thank you Engineering Toolbox.

Posts: 37
Location: N.W. Washington
  • Likes 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Interesting. Thanks Dale!
Your mother was a hamster and your father was a tiny ad:
advertising for free (and not-free) on permies.com
    Bookmark Topic Watch Topic
  • New Topic