Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question
2

How is the mass flow distributed in LowTemperatureRadiant:VariableFlow?

asked 2016-06-22 07:48:37 -0600

A.Pressler gravatar image

updated 2016-10-20 19:41:22 -0600

Hi there,

I am modelling a low temperature radiant system in EnergyPlus for cooling purposes. Since there are several circuits per zone I assigned the ceiling as radiant surface and specified the circuit lenght in order to let e+ calculate the number of circuits.

Now I am wondering if the specified max. cold water flow will be distributed among those circuits or will that number be valid for every single circuit? I have found nothing in the engineering reference...

Thanks in advance!

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
2

answered 2016-07-01 10:49:45 -0600

I couldn't find anything specific in the reference either, but I ran a test and I believe that for ZoneHVAC:LowTemperatureRadiant:VariableFlow objects, the 'Maximum Hot/Cold Water Flow' inputs are maximum for the whole system, regardless of number of circuits.

For the test I had one model with hard-sized radiant system coil flow rates, and 'Number of Circuits' set to OnePerSurface, and Autosized Hydronic Tubing Length. The comparison model was identical, but with 'Number of Circuits' = CalculateFromCircuitLength, and various combinations of 'Circuit Length' and 'Hydronic Tubing Length'. For each model I output the System Node Standard Density Volume Flow Rate at the outlet node of the radiant system coils. Each run showed that the maximum flow rate at the coil outlet nodes equals the input maximum flow rate. Thus if the system has multiple circuits, the maximum flow is indeed split among those circuits.

edit flag offensive delete link more

Comments

Alright sounds quite plausibe to me... thanks a lot for the effort!

A.Pressler gravatar imageA.Pressler ( 2016-07-01 16:30:01 -0600 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

 

Question Tools

2 followers

Stats

Asked: 2016-06-22 07:48:37 -0600

Seen: 83 times

Last updated: Jul 01 '16