[Virtual-sim] IES VE: Radiant, hollow core ceiling - TermoDeck (ventilated hollow core slabs)

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Dear Timothy

We have tried to model TermoDeck together with IES in UK with the approach
you describe. Unfortunately, the results from IES simulations have differed
from the results we expect to find. There seems to be two major problems
with modelling TermoDeck in this way:

1. The actual air-to-slab heat transfer in a hollow core slab is quite
different from what you get from standard correlations for fully developed
duct flow.

2. The vertical conduction through the solid concrete ?walls? between
the cores is significant, also in a situation where both the zone below and
that above have similar conditions. This is because the film coefficients at
the floor and the ceiling will be significantly different. This conduction
process is completely neglected if the core ?walls? are treated as if they
were physical walls of a room. In a 1D model, and as I understand it also in
IES, a vertical wall will only conduct horizontally. As a result, the net
conduction over the TermoDeck slab is severely underestimated.

Our proprietary model of TermoDeck will treat both these phenomena with
sufficient accuracy and it has been experimentally validated (including a
test building). It has also been verified with regard to reality in more
than 380 projects world-wide.

We strongly advise consultants and clients to contact us to discuss and
correctly design projects incorporating ventilated hollow core slabs. There
are many aspects involved in these systems that must be carried out
correctly in order to perform properly: Slab customization, Slab layout
configuration, Thermal modelling and Controls. If the controls are not
properly designed the function will not be very good. Our experience tells
us that this is a big concern as our control specifications are not always
implemented correctly.

Best Regards

Alexander Engstr?m

TermoDeck International Ltd

Box 227, 133 02 Saltsjobaden, Sweden

Phone: +46 8 717 16 71

Mobile: +46 70 643 05 95

Fax: +46 8 748 95 11

PO Box 4805, London SW1W 0XA, United Kingdom

Phone: +44 207 821 5066

Fax: +44 207 828 1871

Email: alex at termodeck.com

Skype: alexander_engstrom


-----Ursprungligt meddelande-----
Fr?n: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] F?r Matutinovic, Luka
Skickat: den 6 mars 2009 14:13
Till: Timothy Moore; bldg-sim at lists.onebuilding.org;
virtual-sim at lists.onebuilding.org
?mne: Re: [Bldg-sim] IES VE: Radiant, hollow core ceiling


Thanks for the great summary. Do you know if it's possible to model
Thermodeck in eQuest by tricking the system somehow? I've bumped up the
thermal mass of the floors, but it's obviously not having as big an impact
as correctly modelling the CFD component. I had a thought about modelling a
pre-coil to simulate the damping effects of the slab in reducing peaks and
then manually removing that energy, but I'm not sure if this is correct.
Any thoughts?


Luka Matutinovic, B.A.Sc., LEED? AP

Green Building Consultant

T. 416.487.5257 ext. 317
F. 416.487.9766
Toll Free 1.888.425.7255

Toronto Richmond Hill Ottawa Sudbury
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2008 Globe and Mail

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