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[EnergyPlus_Support] Re: Generating input for SOLAR COLLECTOR PARAMETERS:FLAT PLATE

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: Generating input for SOLAR COLLECTOR PARAMETERS:FLAT PLATE
From: "Elmer Morrissey" <elmofuddly@xxxxxxxxx>
Date: Thu, 12 Jan 2006 12:02:57 -0000
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Hi Peter,

Once again, thank you for the reply. My final question (I hope) for 
my solar loop is a logic question. I am trying to emulate control on 
the solar loop which also contain heat exchanger which preheats 
water into the source side of a heat pump (which increases the 
efficiency of a heat pump). 

The solar system will generate heat which will provide hot water in 
the domestic hot water pre-heat cylinders. When the cylinder 
temperature is higher than the loop temperature the water will be 
diverted to a plat heat exchanger which will pre-heat the aquifer 
water before it enters the heat pump.

Is there a means of setting this kind of control in E+

Kind regards

-Elmer


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Ellis, Peter" 
<peter_ellis@n...> wrote:
>
>  
> Hi Elmer,
>  
> I do not know what differences in results you might expect when 
substituting water for glycol.  We have that problem in general for 
any plant loop, not just solar collector loops.  Perhaps someone 
else on the list has an idea.  
>  
> For a BRANCH, there should technically be only one component that 
is ACTIVE.  This indicates which component will try to regulate the 
flow through the BRANCH.  However, with solar collectors, they are 
fairly dumb; all they can do is request their maximum flow rate (see 
the Maximum Volumetric Flow Rate field in SOLAR COLLECTOR:FLAT 
PLATE).  The system may or may not actually meet this flow rate.  
Since it looks like all of your collectors on the BRANCH are 
identical models, then they presumably all have the same maximum 
flow rate.  Therefore, it doesn't matter which one is ACTIVE.  
EnergyPlus may even let you set all of the collectors to ACTIVE, but 
it might throw an error in that case, I don't know.  
>  
> If you look at the InputOutputReference, you'll see that the Gross 
Area is mainly for reference and is not used in any calculation.  
The actual surface area of the associated SURFACE:HEATTRANSFER 
object is what is used in the calculation.  Whether you choose to 
make your surface area match the "useful area" or the gross area, 
depends on the manufacturer's testing assumptions.  Here in the US, 
we have ANSI/ASHRAE Standard 96 which clearly specifies that the 
gross area should be used for the efficiency and performance 
calculations.  I might double-check with the manufacturer, but 
probably it is gross area.  
>  
> P
>  
>  
> -----Original Message-----
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx 
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]On Behalf Of Elmer 
Morrissey
> Sent: Wednesday, January 11, 2006 10:06 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Generating input for SOLAR 
COLLECTOR PARAMETERS:FLAT PLATE
> 
> 
> Hi Peter,
> 
> Thank you kindly for the detailed replies. 
> 
> Is there a large mismatch in the results when substituting water 
> circuits and for glycol circuits? Do you know of any documentation 
> that details the difference in performance characteristics?
> 
> If I have several solar arrays circuits that are in parallel. And 
if 
> within these circuits, individual solar arrays are connected in 
> series, are these all assumed to be ACTIVE within the branch lists?
> 
> e.g. is the following correct...
> 
> BRANCH,
>     Vitosol 100 SW Branch,      !- Branch Name
> 0,                       
>     SOLAR COLLECTOR:FLAT PLATE,  
>     Vitosol 100 SW No1/6 Collector,             
>       Vitosol 100 SW No1/6 Collector Inlet Node,
>       Vitosol 100 SW No1/6 Collector Outlet Node,
>     ACTIVE,                  !- Comp1 Branch Control Type
> SOLAR COLLECTOR:FLAT PLATE,
>       Vitosol 100 SW No2/6 Collector,
>       Vitosol 100 SW No1/6 Collector Outlet Node,
>       Vitosol 100 SW No2/6 Collector Outlet Node,
>       ACTIVE,
> SOLAR COLLECTOR:FLAT PLATE,
>       Vitosol 100 SW No3/6 Collector,
>       Vitosol 100 SW No2/6 Collector Outlet Node,
>       Vitosol 100 SW No3/6 Collector Outlet Node,
>       ACTIVE,
> SOLAR COLLECTOR:FLAT PLATE,
>       Vitosol 100 SW No4/6 Collector,
>       Vitosol 100 SW No3/6 Collector Outlet Node,
>       Vitosol 100 SW No4/6 Collector Outlet Node,
>       ACTIVE,
> SOLAR COLLECTOR:FLAT PLATE,
>       Vitosol 100 SW No5/6 Collector,
>       Vitosol 100 SW No4/6 Collector Outlet Node,
>       Vitosol 100 SW No5/6 Collector Outlet Node,
>       ACTIVE,            
> SOLAR COLLECTOR:FLAT PLATE,
>       Vitosol 100 SW No6/6 Collector,
>       Vitosol 100 SW No5/6 Collector Outlet Node,
>       Vitosol 100 SW No6/6 Collector Outlet Node,
>       ACTIVE;
> 
> Finally, I have a question about the input field for `gross area' 
in 
> SOLAR COLLECTOR PARAMETERS:FLAT PLATE. Should this be the area of 
> the panel that contains `useful' interaction with solar levels 
(i.e. 
> collector area)? 
> 
> Kind regards
> 
> -Elmer
> 
> 
> 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Ellis, Peter" 
> <peter_ellis@n...> wrote:
> >
> > 
> > Elmer,
> > 
> > (a) Test Fluid
> > The only option for EnergyPlus right now is WATER.  If the 
> collector is a solar hot water panel, then most likely is was 
tested 
> using water as the test fluid, unless the manufacturer specified 
> otherwise.  We cannot yet model a glycol mixture in the solar loop 
> (or any loop in EnergyPlus), so you must assume that is water.  
> > 
> > 
> > (b) Test Volumetric Flow Rate {m3/s}
> > This is the flow rate condition under which the performance of 
the 
> collector was tested by the manufacturer.  The efficiency 
> coefficients (d)-(f) are calculated for this specific flow rate.  
> The flow rate should be indicated somewhere by the manufacturer, 
> maybe called "nominal flow rate" or "recommended flow rate"?  If 
> not, try to ask the manufacturer. 
> > 
> > 
> > (c) Test Correlation Type
> > This indicates whether the collector efficiency curve is 
> correlated according to the INLET fluid temperature (Tin), the 
> OUTLET fluid temperature (Tout), or the AVERAGE of inlet and 
outlet 
> (Tavg).  So basically you have to figure out if the "dt" in the 
> manufacturer's equation is:
> > 
> > dt = Tin-Tair
> > dt = Tout-Tair
> > dt = Tavg-Tair
> > 
> > In the US the INLET correlation is the norm, but this may be 
> different in Europe (thus the ability to choose).
> > 
> > 
> > (d)-(f)
> > The efficiency equation that you describe from the manufacturer 
> can be found in the EnergyPlus EngineeringReference.pdf, and 
appears 
> as follows:   
> > 
> > n = c0 + c1*(Tin-Tair)/Isolar + c2*(Tin-Tair)^2/Isolar
> > 
> > The manufacturer's coefficients are therefore related in this 
way:
> > (d) Coefficient 1 of Efficiency Equation (Y-Intercept) 
> {dimensionless}
> > c0 = n0
> > 
> > (e) Coefficient 2 of Efficiency Equation (1st Order) {W/m2-K}
> > c1 = -k1
> > 
> > (f) Coefficient 3 of Efficiency Equation (2nd Order) {W/m2-K2}
> > c2 = -k2
> > 
> > 
> > (g) Coefficient 2 of Incident Angle Modifier (1st Order)
> > (h) Coefficient 3 of Incident Angle Modifier (2nd Order)
> > These are usually provided by the manufacturer.  I don't know 
what 
> to tell you if you don't have them.  Try to ask the manufacturer.  
> Setting 
> > 
> > Good luck,
> > 
> > P
> > 
> > 
> > -----Original Message-----
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx 
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]On Behalf Of Elmer 
> Morrissey
> > Sent: Tuesday, January 10, 2006 10:57 AM
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > Subject: [EnergyPlus_Support] Generating input for SOLAR 
COLLECTOR 
> PARAMETERS:FLAT PLATE
> > 
> > 
> > Hella all,
> > 
> > I am interested in simulating the performance of solar panels 
> > distributed by a German manufacturer (Vitosol). 
> > 
> > I do have catalog data from the distributer. The catalog 
> stipulates 
> > that.. 
> > 
___________________________________________________________________
> > 
> > "The thermal loss coefficient and optical efficiency combine to 
> form 
> > the collector efficiency curve which can be calculated on the 
> basis 
> > of the following formula:
> > 
> > n = n0 - k1 . (dt/Eg) - k2 . (dt^2/Eg)."
> > 
> > 
> 
_____________________________________________________________________
> > 
> > However, E+'s idf requires:
> > 
> > (a) Test Fluid
> > (b) Test Volumetric Flow Rate {m3/s}
> > (c) Test Correlation Type
> > (d) Coefficient 1 of Efficiency Equation (Y-Intercept) 
> > {dimensionless}
> > (e) Coefficient 2 of Efficiency Equation (1st Order) {W/m2-K}
> > (f) Coefficient 3 of Efficiency Equation (2nd Order) {W/m2-K2}
> > (g) Coefficient 2 of Incident Angle Modifier (1st Order)
> > (h) Coefficient 3 of Incident Angle Modifier (2nd Order)
> > 
> > As a result, I am unsure of the values I should instantiate in 
my 
> > input file. I would appear to have direct input for (d) only as 
> the 
> > solar circuits have a mixture of glycol in order to provide 
frost 
> > protection.
> > 
> > Does anyone have advice from previous experiences?
> > 
> > Kind regards
> > 
> > -Elmer
> > 
> > 
> > 
> > 
> > 
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> > 
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> > 
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> > 
> > 
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> 
> 
> 
> 
> 
> 
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> 
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References:
- RE: [EnergyPlus_Support] Re: Generating input for SOLAR COLLECTOR PARAMETERS:FLAT PLATE
  - From: Ellis, Peter

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