how to selsct the calorifier.........

There are several things that you need to know:

1. What is the BTU/hr rating for each heater? When totaled this will tell you your required BTU/hr output from the calorifier.

2. What temperature needs to be supplied at each heater?

3. What is initial water temperature to the calorifier?

4. What is the diameter of the piping distribution system to the heater, as well as the return diameter? You will need to calculate friction loss & ft of head in the pipe based on the calculated mass water flow needed.

5. How much heat loss will occur in the pipe to the heater?

6. Are you using steam to heat the water? If yes, what steam pressure are you going to use?

Please post additional information so we can help guide you in the right direction.

The following link will provide you with some additional engineering formulas:

http://www.spiraxsarco.com/resources/steam-engineering-tutorials/steam-engineering-principles-and-heat-transfer/energy-consumption-of-tanks-and-vats.asp

http://www.spiraxsarco.com/resources/steam-engineering-tutorials/steam-engineering-principles-and-heat-transfer/heat-transfer.asp