Liquid cooling/heating calcs

[CCLPaul]

Can anyone help with formula to calculate surface area for heat transfer between liquids. I have 2 different jobs, one to chill water and one to heat water. The cooling job I would like to run refrigerant in a pipe within a pipe. The outer pipe will contain water to be cooled. I have a condensing set large enough for the duty, without trial and error I dont know how much surface area I need for the heat transfer. I know my refrigerant temperature, I know my water temperature and flow rate.
My second requirement is to use a glycol oil cooling circuit to preheat water. I know my glycol temperature, flow rate and amount of heat I can transfer. I will be using an indirect heating loop within a cylinder of water. Again I know the rate of water entering and leaving the vessel, I just need to know how to work out the surface area of my heating pipe.
Many thanks in anticipation.

[Squeezmo]

Thumbrule with water in this zone uses mass flow (lbm/hr) times delta T fluid A to fluid B.

20degree DT x 1000 lbm/hr = 10 degree delatT at 2000lbm/hr.

Use counter flow i8n the tube in a tube. MOst common mistake hooking up these things is haveing the two fluids in a common direction. Cuts efficiency too since the DT stays larger accross the heat exchanger for more of the length when the tweo fluid approaches to the heat exchanger happen at different ends.

SUrface area only affects effeivciency. Heat will flow in relation to the temperature difference much like water will race thru a small canyon (small Heat exchanger) and them open back into a stream.
The more surface area, the more effieicent... but it is never reaches perfect and the closer to 100% that it gets, the more surface area is needed to gain efficiency.

[Squeezmo]

Thumbrule with water in this zone uses mass flow (lbm/hr) times delta T fluid A to fluid B.

20degree DT x 1000 lbm/hr = 10 degree delatT at 2000lbm/hr.

Use counter flow in the tube in a tube. Most common mistake hooking up these things is haveing the two fluids in a common direction. Cuts efficiency too since the DT stays larger accross the heat exchanger for more of the length when the tweo fluid approaches to the heat exchanger happen at different ends.

Above a certian amount, surface area will only affect efficiency. Heat will flow in relation to the temperature difference much like water will race thru a small canyon (or heat thru a small Heat exchanger) and them open back into a stream at the same rate as the other water/heat flow.

The more surface area, the more effieicent... but it is never reaches perfect and the closer to 100% that it gets, the more surface area is needed to gain efficiency (hyperbolic diminishing return).