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