MACROFLOW not working?

Works in conjunction with ApacheSim to provide bulk airflow analysis for passive/hybrid ventilation system design and simulation.
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shonaw
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MACROFLOW not working?

Post by shonaw »

Hi,

I am modelling a simple building with high level windows running around the top of the walls on 2 sides. I have modelled these in macroflow to open every day by 20% when the temp is above 18C. the results are no different to the windows being closed all the time. I have double and triple checked my openings database and am not doing anything different to usual. What am I missing? or do top hung, wide by low height windows not have much of an impact of models? I am expecting cross flow ventilation to take place.

thanks,
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Complex Potential
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Re: MACROFLOW not working?

Post by Complex Potential »

Check within the vista results file to ensure that the windows are actually opening or not. Drill right down to the window surface itself and interrogate the areodynamic free area variable. I suspect your windows are actually not opening for some reason.
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PCully
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Re: MACROFLOW not working?

Post by PCully »

Hi,

Was there ever any resolution on this (might help others).

The advice is good if you don't see much of an impact form your MacroFlo or you want to confirm for example that the formula profile you created is working then you should choose a typical opening on a typical room and go down to opening level variables so you can see the orifice area and that way you can check how much the window is actually opening and compare it to the relevant room or weather variables (can be easier to do this in VistaPro) to assess the values your profile should be taking at key timesteps.

Oh and always remember to actually tick the MacroFlo link on Apache sim settings before you run the sim!

MacroFlo is another one that is fairly easy to trace all the way through your model from inputs to outputs, room variables showing air flow and gain from the MacroFlo can be affected by e.g. relative temperatures and climate conditions but if you look at a single opening and if it si open or not then you can easily check that your MacroFlo profiles are working properly

Phil
IES Worldwide Technical Support
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