[sir saint]

I am tasked with designing a shell and tube heat exchanger for a final class project.
 
I must maintain an algae pond (surface area 120m^2) between 20-35deg celcius when exposed to winds of 0deg celcius (which may result in a forced convection coefficient of 140 W/m^2/deg celicius), heat loss to the ground is negligible.
 
My heat exchanger is supplied with unlimited amounts of 70deg celcius water which will flow into a nearby river, but cannot exceed 45deg celcius at outlet.
 
Shear rate cannot exceed 5 s^-1 and pressure drop cannot exceed 1 ATM.
 
I have no idea where to start with this. ANY, and I mean ANY, help with some starting ground would be greatly appreciated. Once I get going I know I can do this, but I need to actually have something to work off of first. I have been through tons of resources on shell and tube heat exchangers but all of the equations I come across require variables that are unknown to me.
 
TIA

[curiouscat]

Show us some equations.

[dipankarc84]

I am tasked with designing a shell and tube heat exchanger for a final class project.
 
I must maintain an algae pond (surface area 120m^2) between 20-35deg celcius when exposed to winds of 0deg celcius (which may result in a forced convection coefficient of 140 W/m^2/deg celicius), heat loss to the ground is negligible.
 
My heat exchanger is supplied with unlimited amounts of 70deg celcius water which will flow into a nearby river, but cannot exceed 45deg celcius at outlet.
 
Shear rate cannot exceed 5 s^-1 and pressure drop cannot exceed 1 ATM.
 
I have no idea where to start with this. ANY, and I mean ANY, help with some starting ground would be greatly appreciated. Once I get going I know I can do this, but I need to actually have something to work off of first. I have been through tons of resources on shell and tube heat exchangers but all of the equations I come across require variables that are unknown to me.
 
TIA

TIA,


You can design the exchanger for either 20 deg C or 35 deg C. You have to mention any one temperature. Or else, there have to be 2 different conditions for which the exchanger has to be optimized.


To design a heat exchanger you need to know the following things first:


1. Flowrate of Hot and Cold fluids (In this case flow rate of Algae Pond water and River water) to the exchanger
2. Inlet and outlet temperatures of the two fluids to and from the heat exchanger.
3. I see that you already know the allowable pressure drop and the shear stress (which is surprising!). Excellent! We should look at the shear stresses in terms of maximum velocity in the tube/ shell.


I understand, you need to establish the flow rates. For this you have to first establish, how much water from the Algae pond, you will circulate through the Heat Exchanger to keep the pond warm. Let us do this in steps. First establish the flow rates and then we should go to the next step. 






Regards
Dipankar