Heat Exchanger Sizing
Heat Exchanger Sizing
(OP)
I am looking for some simple equations or rules of thumb for determining the straight length of tubing required to acheive a desired amount of heat transfer. The tubing would be formed into a coil. The coil would be immeresed in both still or agitiated water.
I would like to analyze both single phase and two phase flow. The two phase analysis would be used to make low cost evaporators.
The knowns are evap. temp, water final and initial temp, cooling medium mass flow rate, and tubing diameter.
In a nutshell:
"I want to make a 2 ton evaporator out of 1/2" coppper tubing in a tank of water. I am using R22, need 60 deg F water, and the water in the tank is not moving. What is the total length of tubing required"
Thanks,
Jeff Johnson
I would like to analyze both single phase and two phase flow. The two phase analysis would be used to make low cost evaporators.
The knowns are evap. temp, water final and initial temp, cooling medium mass flow rate, and tubing diameter.
In a nutshell:
"I want to make a 2 ton evaporator out of 1/2" coppper tubing in a tank of water. I am using R22, need 60 deg F water, and the water in the tank is not moving. What is the total length of tubing required"
Thanks,
Jeff Johnson





RE: Heat Exchanger Sizing
This is a handy book - you can look up solutions for odd problems like the minumum flow of water through an above ground pipe to prevent freezing. It provides a couple of pages each for 150 or so problems. One page is a short write-up, with a formula, and the other page is a nomograph showing the solution. Just plug your numbers in, and it'll give you a quick answer that in most cases is "close enough". If nothing else, you'll have a good indication of whether or not it makes sense to persue something further.
RE: Heat Exchanger Sizing
I suggest you a kind of bible for heat-exchangers:
"Heat-Exchangers-Thermal-Hydraulic Fundamentals and Design"
Edited by S.Kakaç, A.E.Bergles and F.Mayinger, MacGRAW-HILL,1980, ISBN 0-07-033284-3 .
Just go to the 559 through 700 pages, and you will find anything about any kind of heat-exchanger, even unsolved problems, at that time.
Good luck!
zzzo
RE: Heat Exchanger Sizing
feel free to contactme at k281969@hotmail.com but keep posting here .
Pardal
RE: Heat Exchanger Sizing
To Pardal: "It will work", but allow me, if you put more than you need, then you have to pay more than for it! After all, what the engineering process serves for??
zzzo
RE: Heat Exchanger Sizing
RE: Heat Exchanger Sizing
Air is aviable any where.
Water could be "hard" so it need water pretreatment.
Pardal
RE: Heat Exchanger Sizing
RE: Heat Exchanger Sizing
RE: Heat Exchanger Sizing
Chemically, CaCO3 is found in nature in chalk, in limestone, coral, stalactites, stalagmites, shell, marble, etc. Most common forms of pure CaCO3 are calcite and aragonite.
Cooling (hard) water problems start when these salts deposit on warm H/E surfaces due to their very low solubility (CaCO3: less than 10 ppm at 25oC) fouling them, and increasing resistance to heat transmission. CaCO3 and CaSO4 have negative coefficients of solubility as function of temperature, meaning they are less soluble as temperature rises.
On hot surfaces, as in boilers, the crust thus formed is mainly composed of CaSO4 and CaCO3 accompanied by varying proportions of Ca(OH)2, Mg(OH)2, complex calcium phosphates, silicates, etc. Part of the precipitation of calcium carbonate in boilers is done by the bicarbonate's decomposition in the water proper, thus it tends to form a sludge rather than a crust. Bicarbonate's is called temporary hardness.
There is a whole chapter in Chemistry dealing with water hardness and softening procedures.
RE: Heat Exchanger Sizing
RE: Heat Exchanger Sizing