Hi,
My PhD research is?about the?use of a?tilted solar chimney?to enhance natural?ventilation by stack effect, in Brazil.
I have built a test cell (picture attached) and I want to do computer simulations of?the solar chimney I proposed, in order to do some parametric analysis and to verify the performance in several locations through the country.
I tried to use EnergyPlus but it wasn't very successfull.
I need a suggestion of sotware that is suitable for what I need. Does anyone have an indication?
In case of using TRNSYS, it is possible to do this kind of simulation with the demo version, or do I have to have the TRNFlow module? (not available at demo version)
Thanks.
Leticia
Leticia,
Due to the specific geometry and convection based airflow that might
occur in the chimney, I'd suggest you to run a CFD (computational
fluid dynamics) analysis for this. You can assign different heat
gains from your solar surfaces (base on weather data I assume), then
figure out the flow rate and flow regime inside the chimney. I think
this is more a airflow/heat transfer problem than an energy simulation problem.
The good thing about using CFD in this case is that you can then do a
parametric analysis for many different variables you might consider
to look into. As for what CFD program to use, it will depend on what
your university have available. I would think Fluent Airpak will do
nicely in your case.
hope this helps
L. James Lo
We are using FLUENT for simulating solar chimneys and the results are quite
good. But you need lot of patience to model it correctly in FLUENT or any
other CFD software.
another option is Design Builder, since it also has CFD feature in it. While
doing this, basically you would be using energyplus only but creating
gometry and defining CFD parameters is relatively easier through this route.
jyotirmay mathur
Is there a resource which details the differences in A90.1 from the year '99 section 11 and , '04's and '07's Appendix G?
Basically there are times when we have to create a base case for different versions of A90.1 for different incentive programs. It would be nice to have a list to tell what to look for quickly to change a model from one year of A90.1 to another.
I'm about to start one, but was wondering if such a resource already exists somewhere.
Thanks in advance.
Phylroy Lopez B.Eng LEED A.P.
I?d love to see the same comparison!
James V. Dirkes II, P.E., LEED AP
If you look at appendix f, it lists all the addenda incorporated into the printed version from the previous version with a small description. This may help.
Leonard Sciarra
Hi Leticia
I note you are going to be attending the DesignBuilder webinar I'm giving
soon, so hopefully I'll be able to cover things in that which will allow you
to see how this could to some extent be carried out in DesignBuilder E+ and
CFD.
I would however note, the issue of flow instability will be difficult to
correctly establish and model in many tools. Further, as you will need to
consider the effects of buoyancy combined with wind effects on chimneys, I'm
not certain that the algorithms used in the E+ will be able to deal with
this sufficiently accurately to allow comparison with the test cell.
Perhaps others on this list might be able to provide further insight on
this, but things that spring to mind include unsteady flow effects and
discharge coefficient variation. At the very least your modelling will
require careful application of appropriate wind surface coefficient values
in the E+ model but I won't go into too much here as it will bore everyone
else rigid. It is possible to get reasonable comparison as is pointed out
in the following IJoV paper, but I think you may be forced down the route of
complex turbulence modelling to get good accuracy of your CFD which may
force you down an alternative software route. That being the case, it will
still be worth carrying out the E+ model and getting some boundary
conditions that puts your CFD simulations in the right area first off and
hence should increase the accuracy of them or at least allow them to get
somewhere near a reasonable solution. You might want to check out FDS which
will allow you to carry out transient LES turbulence models which I think
will be better for your research.
I'll try and get an electronic copy of my PhD thesis together for you and
you might also wish to check out the links to following papers that might
help you:
http://www.ijovent.org.uk/IJV%20Vol%204/IJV%20V4%20No%204/IJV%20Abstract%20V
ol%204%20No4%20Paper%204.htm
http://bse.sagepub.com/cgi/content/abstract/20/3/131 (CIBSE BSERT paper
based on early portion of my research)
http://linkinghub.elsevier.com/retrieve/pii/S0167610599001361
Regards
Dr Paul Carey