On Thursday, March 17, 2005 10:29:15 AM UTC-7, firstname.lastname@example.org wrote:
Dimensions and Physical Characteristics of Copper Tube: TYPE ACR
3/4 OUTER IS .750 INNER IS .666 CONTENT GAL .242 PER FT
Dimensions and Physical Characteristics of Copper Tube: TYPE M
3/4 OUTER IS .875 INNER IS .811 CONTENT GAL FT .269 PER FT
Dimensions and Physical Characteristics of Copper Tube: TYPE L
3/4 OUTER IS .875 INNER IS .785 CONTENT GAL FT .251 PER FT
I am putting a tankless gas water heater in my home. All of the copper
is in the concrete slab so I am going to run an insulated copper tube
"up and over" to the kitchen. The water heater will be a foot from the
two bathrooms and showers. the "up and over" tube will feed the kitchen
sink and dish water - nothing else.
How much water is in a 100 foot by 1/2 inch copper tube?
How much water is in a 100 foot by 3/4 inch copper tube?
How much water is in a 100 foot by 1/4 inch copper tube?
I am too lazy to look it up - I am wondering if any of you experts on
here have the info off-hand. I am thinking of putting thinning tubing to
the kitchen because less water would be in it to cool down etc.
Right now I am running two 50 gallon electric water heaters in a house
for two adults - I am wasting alot of energy keeping all that water hot
- and the tanks are far away from where the hot water is needed anyway
running thru a cold concrete slab.
This is ReRe
1/2" = .0158 gallons per lineal foot or 1.58 gallons in 100'
3/4" = .0277 gallons per lineal foot or 2.77 gallons in 100'
Check your references. You have it backwards. Refrigeration tubing (ACR)
is sized by the actual OD. Plumbing & heating tubing is sized by the
nominal I.D. Therefore 1/2" plumbing tubing has an actual OD of 5/8". I
just checked my textbooks to verify this so as not to give dis-information.
Source: Refrigeration & Air Conditioning Technology, 3rd Edition, 1995,
No need to argue. I just wanted to find out how much water was in a 1/2
inch by 100 foot copper tubing. Just a ball park amount. I was surprised
at just how little an amount of water it is. I am not worrying about
wasting water - I am trying to cut down the time it takes for hot water
to get to my showers. I am surprised it hold less than a gallon of
water. If I insulated that 100 feet of copper tubing - the water in it
will not cool off so quickly. Presently it is running through a 3/4
copper tube that is buried in the concrete slab. It is a double whammy -
since it is in concrete and not insulated - you lose heat thru the heat
sink - and since it is 3/4 copper the tube holds much more water.
Let me write this down first you are probably right and I worked a hard day
7/8 Refrigeration equals.........3/4 Plumbing
I just bought a few hundred refrigeration fittings today too!
My bad, thanks for the correction. My brain is right my hands are stupid
Dear William -
Thanks for the chart. I appreciate all the work.
Does that mean 100 feet of 3/4 inch holds .282 gallons?
1/2 inch holds .120 gallons? 1/4 inch holds .026 gallons?
I expected 100 feet of pipe to hold so much more.
Not a good guess. The formula is A = pi * radius SQUARED,
not pi * radius / 2.
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
I agree with Doug: i.e. pi times, the radius raised to the power 2 (squared)
Inside diameter divided by two = Radius of X.Section.
In this case one half divided by 2 = one quarter.
Area of X.Section = Radius squared, multiplied by pi.
This is one quarter times one quarter times pi = 1/16 x 3.142 = 0.196
Length of 100 feet = 100 x 12 inches.
Thus (1/4 x 1/4 x 3.142 x 1200) = 236 cubic inches.
Multiply that 236 by 0.004 to get gallons = 0.9 gallons approx. (Not sure if
that's US or Imperial gallons but "A bit less than a gallon" is close
Anybody else agree?
BTW those 236 cubic inches will weigh approx 8.5 pounds.
Those 8.5 pounds will require 8.5 BTUs for every degree Fahrenheit change of
temperature. So if that 8.5 lbs comes out of the tank at temperature of,
say, 160 degrees, sits in the pipe and cools down, to say 60 degrees it will
lose 100 x 8.5 = 850 BTUs of heat. If electrically heated that's equivalent
to about one quarter of a kilowatt hour (unit) of electricity. If your
electricity costs 10 cents per kilowatt hour that's a waste (sort of) of 2
to 3 cents. Of course that heat, slight though it is, could end up helping
to heat the house!
BTW There is a very good site at < www.tedmongomery.com/convrsns/ > for
those NOT too lazy to look it up!
PS. In school we remembered circular area by "Two are(a) squared pies".
i.e. Pies were normally round; not square. Even if we were!
People can sense honestly. :-)
I really like this group - no one ripped me - and I got great answers.
Now I must decide whether I want to run 100 feet of 1/4 inch - 1/2 inch
- 3/4 inch to a kitchen sink and dishwasher 100 feet away from the
tankless water heater. The tube will be overhead and insulated.
Opinions on that?
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