Speed in evaporator tube

[Peter_1]

I think you have used a vapour density 1/10th of what it actually will be, so, your vapour velocity is of course 10 times faster than it actually will be. I get a total pressure drop of 0.2Bar along the 70m. Your liquid calcs look okay though. Have a look at the modified spread sheet attached...

There are 4 sheets now:

1. Copper Tube Dimension Choices
2. Refrigerant and tube values converted to velocity if all liquid and then again velocity if all vapour and thereafter, based on average X (kg/kg) values for each 5th pipe length, a total pressure drop is calculated based on the implied proportions of liquid versus vapour.
3. R410A values
4. R407C values.

But these calcs will be, seriously, estimates only. Very simple assumptions are being made.

I think DTLarca enlightened a little bit my confusion. The entire length of 70 m was divided in 5 different sections where in each section we have each time a new 'mixture' due to the ever increasing gas phase (and decreasing liquid phase) of the refrigerant along the copper tube.
But, I see a big difference between DTLarca and desA. I think I will make a practical setup for this and test this once.