[esp-r] Re: Night-time ventilation

[Achim Geissler]

Hi Matt

some quick thoughts:
1) that would also be my approach without any detailed knowledge on existing "real leaks". If, for example, the building has a wooden roof and is otherwise mainly made of concrete, I would probably put more leaks in the roof and then think about how the cellar (simple windows?) is connected internally to the rest of the building. Also, leakage paths inside lightweight walls (think of plumbing etc) are often found. The ESP-r model is then a series of cracks and small openings, yes.

2) I am not entirely sure what a "MVHR" is, but the heat recovery you describe would work, yes. You could "tune" it by adapting the heat transfer coefficients of the thin wall. There is a heat recovery flow component, I think (there definitely should be a heat recovery plant component, I am quite sure).

Best
Achim



On Jun 18, 2013, at 6:23 PM, Matthew Wright <matthew.wright at c4ci.eu> wrote:

> Hi Achim, Jon (and all),
> 
> I have successfully modelled using air-flow networks, as I am interested in
> overheating in residential (and therefore often natural airflow) situations.
> 
> However, I have two questions
> 
> 1) When modelling air permeability in such a way that I could relate it to
> real world pressurisation (q50) tests, I used a set of external wall
> 'cracks', which linked to the air flow network. Is there an easier way of
> doing this?
> 2) If I wish to model an MVHR unit, is there a plant option or air network
> option that I could use? If one doesn't exist, how do I go about creating
> it? 
> For example, would the model work if I physical recreated the heat exchanger
> as two zones with a thin wall between, etc?
> 
> Any indication of where to look for helpful examples or 'buttons to push'
> would be good.
> 
> Regards
>  
> Matt
>  
> 
> 
> -----Original Message-----
> From: esp-r-bounces at lists.strath.ac.uk
> [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Achim Geissler
> Sent: 17 June 2013 18:12
> To: Archontiki, M.
> Cc: esp-r at lists.strath.ac.uk
> Subject: [esp-r] Re: Night-time ventilation
> 
> Dear Maria
> 
> there are four methods for ventilation simulation in ESP-r:
> a) via operations file, use "infiltration" for night time ventilation (note
> that "ventilation" in the operations files means "between zones", not
> to/from the ambient),
> b) by AIM ("air infiltration model" - I don't know anything about this, as I
> have never used it),
> c) via an external data file "tdf" and
> d) via an air flow network.
> 
> The latter is the most sophisticated and takes the most "setting up" work
> (and likely the most knowledge of "what you are doing") - if your study is
> really focussing on night time ventilation, then this may be the best bet -
> you can open and close windows and doors via control, the actual air
> movement is calculated based on temperature differences (stack) and wind
> velocities. 
> 
> "a)" is quickly set up (by schedule in "operations file" menu") but has the
> significant drawback that the air changes are fixed by you and need not have
> any bearing on actual flows possible at any given time. "c)" is in effect a
> variant of "a)", however you can use smaller time steps ("a)" allows only
> hourly changing values). You could also use measurement values, with "c)".
> 
> Hope that helps a bit.
> 
> Regards
> Achim
> 
> 
> On Jun 17, 2013, at 6:01 PM, "Archontiki, M." <m.archontiki at student.tue.nl>
> wrote:
> 
>> Dear all,
>> 
>> Could please somebody give me a hint on how to import night time
> ventilation during cooling period? I have defined the infiltration and
> ventilation flow values for certain periods and I would like to have
> increased flow rates during non occupied hours, in the cooling months. I
> show the thermostatic control option but it applies to all day types and
> periods. Thank you in advance.
>> 
>> Kind Regards,
>> Maria Archontiki
>> 
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>> http://lists.strath.ac.uk/mailman/listinfo/esp-r
>> 
> 
> achim.geissler at intergga.ch
> 
> 
> 
> 
> 
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achim.geissler at intergga.ch