Pump Sizing for Heating Hot Water System

[Jamieo]

Hello All,

I am designing a heating system that uses hot water piped to heating coils located through out the building. I have determined the heating loss for each area and sized the heating coils. I have laid the system out and sized the piping based on an acceptable friction loss for the required flow (using the system syzer wheel). When sizing the pump do I take the sum of the friction loss in all loops (supply and return piping, loss through coils, valves, etc.) or just the loss in the loop that is the longest run of supply and return piping i.e. furthest from the pump. Your help is much appreciated. Thanks.

J

 

[BigInch]

Take the length of however far you need the water to run. Yes, the lengths of pipe going to the coils plus those lengths returning to the pump.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[BigInch]

OK, misunderstood, you've got BRANCHES!

If you take the total pump flow through the longest branch, its likely to be conservative, provided that all the pipes in the shorter runs have at least the same diameter and all coils are the same.

It may also be too conservative.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[Zapster]

I assume that you have a circuit setter (automatic flow limiting valve) on every coil:

Assume all zones are in service and calculate the friction loss through every pipe segment. Look at the total flow resistance for every coil circuit (total resistance is found by the sum of friction loss through all of the pipe segments and equipment that flows to/from that coil and includes the coil hydraulic loss.) Coil and associated piping with the greatest hydraulic loss will determine the required head from the pump.

 

[Jamieo]

Thanks for the help. This is a great resource for engineers!