Replies

1. 
   Kerr | Feb 02, 2002 04:53am | #1

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   I bet that the pipe will be raised more than just 8 degrees because of the friction of the air moving thru it would also introduce some heat energy.

   Of course if you ignore friction, everything depends on how long the air is moving thru the pipe (eventually the 100F air would bring the whole pipe up to 100F, unless, of course, the conductivity of the pipe is able to get more of the heat energy out to its environment faster than it is being put in to it by the warm air...)

   For instance, if you had an ocean of 32F water around the 32F pipe and cycled the 100F air thru it you'd reach an equilibrium somewhere in between 32 and 100 that would be decided by the rate if heat input / heat loss.

   This answer is just what's still rolling around on the floor of my brain 18 years after heat transfer class so may not be quite the answer you're looking for.

1. 
   Mike_Smith | Feb 02, 2002 06:48am | #2

   *no.. the copper pipe is in an ambient medium... whatever the temperature of that medium is will effect the temp of the copper pipe also.. eg: if the copper is immersed in a brine solution at 29 deg.F then the copper will never get to rise 8 deg.if the copper passes thru room temperature air at say 72 deg., then the copper will still never reach the 8 deg. rise...yes... 8 deg. is being transferred to the copper, but it tells us nothing about the equilibrium temp of the copper this equilibrium temp. could best be predicted with a nomograph if the temp. of 32 is also the ambient temp. then .... the copper will still not gain the entire 8 deg...b but hey,whadda i no ?

1. 
   Joe_Hennessey | Feb 02, 2002 08:13am | #3

   *My guess for tonight is i "Short Pipe"and I'll try to have another equally wrong by tomorrow night. Joe H

1. 
   Boss_Hog | Feb 02, 2002 03:21pm | #4

   *I'd say the heat transferred to the pipe will raise the temperature of the pipe, but not by 8 degrees. The pipe is denser than the air travelling through it, so it would take more heat to raise it's temperature. Unless you run a whole lot of 100 degree air through the pipe, then it might go up more than 8 degrees. Maybe this isn't really an answer, just raises more questions ???

1. 
   piffin_ | Feb 02, 2002 03:32pm | #5

   *Lot of variables not given here,LikeHow long was the hot air blowing through the pipeHow fast was the air moving through the pipeWhat is the ambient temp of the air outside the pipeWhy not just use a bong

2. 
   Bob_Walker | Feb 02, 2002 04:49pm | #6

   *I'm only partway thru my first cuppa, but:"does this mean that 8 degrees is being transferred to the copper pipe eventually raising its temperature by 8 degrees"Degrees is a measurment, that is, an abstract entity, used to quantify heat (aka energy.)So, I think the caloric energy equivalent of an 8 degree drop of the air temp is transferred into the copper pipe, from whence it's tranferred into the ambient air by conduction and convection and perhaps some is trnsferred to surrounding objects by radiation.OTOH, maybe I ought to finish that cuppa

3. 
   Ryan_C | Feb 02, 2002 09:12pm | #7

   *I'll keep this as short as I can but I'm long winded so hold on tight.You're transfering HEAT from the air to the pipe. You're not transfering temperature. What I mean by that is that heat is the actual energy that is needed to change temperature. Just like light is the energy used to change brightness, you don't have brightness in a room, you have light in a room which effects the rooms brightness.Different things require different amounts of heat to warm up. If you add alittle heat to air, it will get alot warmer. Add the same amount of heat to copper and it only gets alittle warmer. The "Thermal Mass" of copper is high and it takes more heat to get it to warm up.But, we can look on a chart and find out the thermal mass of copper, and of air.If we know how much air (by diameter of the pipe and velocity of the air) and if we know how much copper (size, thickness, etc) we can figure out how much the temperature of the copper will change due to the heat transfered out of the air.But of course, the copper also looses or gains heat through its outside at the same time which screws everything up. But with enough info, I could give you the answer.

4. 
   Terry_Smiley | Feb 03, 2002 06:34pm | #8

   *It really depends on what's in the bowl of this pipe, which determines how long it will take before you don't care, and you forget what the question was and go get something to eat.Terry

5. 
   Rich_Beckman | Feb 04, 2002 05:50pm | #9

   *> how long it will take before you don't care, and you forget what the question was and go get something to eat. And since it's been three days since you've posted, I'm guessing you've already reached that point.Rich Beckman

2. 
   Mercer | Feb 04, 2002 05:50pm | #10

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   If I have air traveling through a copper pipe at 100 F and the copper pipe is a 32 F, the air exiting the pipe is at 92 F does this mean that 8 degrees is being transferred to the copper pipe eventually raising its temperature by 8 degrees. Explanation why later.