Re: [TRNSYS-users] TRNSYS Active Layer Flowrate

Dear Mr. Rohan!

In the 13 kg/m²h the “m²” are related to the wall/ceiling area and not to the pipe-diameter.

For the conversion to kg/s You may not use the pipe-area (7.1e-5 m²) but Your wall area.

With kind regards,

Matthias Kersken

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Dipl.-Ing. Matthias Kersken
Wissenschaftlicher Mitarbeiter / Abteilung Energiesysteme

Fraunhofer-Institut für Bauphysik
Institutsteil Holzkirchen

Fraunhoferstraße 10
83626 Valley

eMail: Matthias.Kersken@ibp.fraunhofer.de
Telefon 08024 / 643-204
Telefax 08024 / 643-366
www.ibp.fraunhofer.de

Dipl.-Ing. Matthias Kersken
Research Associate / Department Energy Systems

Fraunhofer Institute for Building Physics
Branch Holzkirchen

Fraunhoferstraße 10
D-83626 Valley

eMail: Matthias.Kersken@ibp.fraunhofer.de
Phone +49 8024 / 643-204
Fax +49 8024 / 643-366
www.ibp.fraunhofer.de

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Von: Devin Rohan [mailto:dmrohan@gmail.com]
Gesendet: Sonntag, 12. Juni 2011 02:10
An: trnsys-users@cae.wisc.edu
Betreff: [TRNSYS-users] TRNSYS Active Layer Flowrate

The Type 56 manual suggests that the specific mass flow rate be greater than 13 kg/h-m^2. Say I wanted to convert this to mass flow rate in kg/s and the fluid was flowing through a 3/8" (or 9.525 mm) inside diameter pipe. Here's what I'm doing...

A_pipe= (pi*D^2)/4 = (pi*.009525^2)/4= 7.1256 E-5 m^2

13 kg/h-m^2 x (7.1256 E-5 m^2) x (h / 3600 sec) = 2.573 E-7 kg/s

This seems like an awfully low mass flow rate, since what I've seen in literature for floor heating applications is around .05 kg/s. Am I missing something here?

--
Devin M. Rohan
drohan@purdue.edu