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primary-secondary heating

asked 2017-09-30 23:22:44 -0600

gsuscalo gravatar image

updated 2017-10-02 03:00:19 -0600

I am currently using openstudio 1.14, trying to set up some HVAC details based on the documentation for my project. In my building, spaces are heated from a boiler plant in the basement, and heat is distributed through a 'primary' loop that serves the main VAV coil & zone reheat coils; while a secondary hot water loop serves a system of perimeter fin radiators & unit heaters. The secondary system pumps hot water from the primary loop. According to forum responses regarding similar attempts at primary/secondary cooling systems, this pumped-secondary-loop setup is discouraged (here).

So does the OS interface in fact not support a pump-connected secondary loop setup for hot water, and should I stick to using the HX object to 'connect' the two loops (that's what I have now)? Or is there some way that I can connect the primary/secondary loops with a pump instead of the current fluid/fluid HX?

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answered 2017-10-01 01:59:25 -0600

Chandan Sharma gravatar image

EnergyPlus PlantLoop object has input field Common Pipe Simulation which specifies a primary secondary configuration. Though this field eliminates the need of specifying two different EnergyPlus loops each for Primary and Secondary half loops, it is not a recommended approach and in the future the common pipe is expected to be obsolete. A recommended approach for primary/secondary pumping arrangement is using a heat exchanger and two separate loops . Refer to Plant Application Guide Chapter 8, Example System 3: Primary/Secondary Pumping for more details. A pump is quite simply the component that drives the flow in plant and condenser loops. It doesn't connect the two loops. The thread (and E+ example file mentioned there) also have pumps in supply side inlet of both the loops.

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"common piping"...yes, that is the terminology I was looking for...but it sounds like it will be a pain implementing that. Thanks for clearing that up. I'll stick with the heat exchanger for now.

gsuscalo gravatar imagegsuscalo ( 2017-10-03 09:40:00 -0600 )edit

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Asked: 2017-09-30 23:22:44 -0600

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Last updated: Oct 02 '17