I've sized a water/refrigerant shell and tube heat exchanger. I need some practical advice how to configure the tube and baffle pattern. Here is a 3d model of my design:

HX Top.png
The box is 14' x 3' x 7". The baffles for the water side are 16" apart, and 7 inches high. I choose this spacing based on the Hazen Williams Head Loss, but the biggest guess in the equation was the length of the water path. Specifically the extra equivalent length for the u turns. In this case the path length was 14.5 feet and the u-turn equivalent length was 58 feet, for 72.5 feet total.
HX Layers.png
There are 3 layers of tubes.
HX End.png
The PID section below shows more detail. Note the low delta T available. The water flow actually ranges from 200 to 350 GPM. There is very little head available on the water side, about 18".
HX PID.jpg
Please advise how you would improve this design.