[Bldg-sim] Modelling Heat Pipe Question in eQUEST.

[Brian Fountain]

A couple of thoughts -

- in eQUEST, when a heat recovery device is added, a new report, "ERV" 
is added to the .sim file.  This shows monthly peak and total heat 
recovery along with the added energy for fans.

- static pressure added on the 2nd heat recovery tab does not show on 
the SV-A report but does show on the ERV report and is included in fan 
energy on the BEPS.  It could be that your heat recovery is being masked 
by your added fan energy

- the default control for ERV's is "float" which maximizes the heat 
recovery at all times (which is what will happen if there is no control 
on the ERV and is probably true of a heat pipe unless you are bypassing 
the OA during free cooling.  It could be lost free cooling is masking 
heat recovery.

- with regard to the fields you are running as parametric runs -- right 
click the field to get help on the inputs.

- finally -- how are you creating the make-up air unit?  If you are 
using the OA-FROM keyword, there are issues with how that is currently 
modelled which will prevent heat recovery from seeing the exhaust flow 
and exhaust temperature you are expecting.

Hope this helps.  Note that there is also an eQUEST specific list at 
onebuilding.org.




Kazim Mirza wrote:
> Hello All,
>               I am modelling a heat pipe in the parametric runs (/my 
> system has a Make-up air unit and I am adding a heat pipe to it/). The 
> Inputs eQUEST asks for the following:
>  
> (1) *Sensible Effectiveness*: I inputting a value of 0.48.
>  
>  
> (2) *Frac. Sensible HX Resistance from Air Films*: The heat pipe 
> manufacturer does not any thing about this coefficient neither they 
> list in the catalog. I tried varying the resistance values from 0 to 1 
> in incerments of 0.1 - Once I simulate the parametric runs, there are 
> zero savings from this measure
>  
> (3) *Exponent Varying Sensible Air films Resistance*: I varied the 
> values from 0 to 1 in terms of 0.1. My understanding is that the flows 
> in the Make up unit are turbulent and hence there has to some number 
> to this exponent.
>  
> After I varied these values, and I simulate the parametric runs, there 
> are zero savings from this measure. The reason I varied these values 
> was that there were zero savings even for the single value input. I am 
> looking for little guidance. Any help is appreciated. Thanks in advance!
>  
> Kazim Mirza
> Energy Engineer
> EMCOR Energy Services
>  
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