[TRNSYS-users] New TESS Solar components

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After installing v17.1 and the latest/associated TESS components, I have three new parabolic trough collectors I'd like to study (types 1288 (x2) and 1245). I notice that the documentation refers to type1288, but its own proforma labels it type288 (Description tab, and Files->Source Code File). I've fixed those manually to 'type1288', but the only pdf documentation in the 'Tess Models->Solar Library' folder is 'Temporary Documents', and in that folder there are no files for 'Type1245.pdf' or 'Type1288.pdf'. Is there a schedule when these will be forthcoming?

Also, I was familiar with the 1D IAM datafile format for a collector that follows the zenith/altitude angle of the sun, but I am unfamiliar with how to setup a 2D IAM file for such a collector. The default proforma for the type1288 component references a sample 2D IAM file, so I assume 2D is applicable and 1D is not. If the collector will track the altitude angle automatically, why do I need a 2D IAM datafile?

Thx,
Rick.

Horocholyn, Rick's picture
Joined: 2016-04-05
Reputation: 0

collector that follows the zenith/altitude angle of the sun, but I am
unfamiliar with how to setup a 2D IAM file for such a collector. The
default proforma for the type1288 component references a sample 2D IAM
file, so I assume 2D is applicable and 1D is not. If the collector will
track the altitude angle automatically, why do I need a 2D IAM
datafile?>

There are three TESS models that incoporate the test
results from the EN12975-2 collector standard.

Type 1288 takes a 2-D
IAM file based on the longitudinal and transverse angles

Type 1289
takes a 1-D IAM file based on the incidence angle for beam radiation

Type 1290 takes the b0 and b1 parameters popularized by ASHRAE for the
1-D IAM calculations based on the incidence angle of beam radiation

To
answer your question about why you would need 2-D IAMs, it's the most
rigorous of all the solutions - by far. The collector you are studying
may track the altitude angle automatically but another collector may not
track at all. Or the user may want to study the impact of imperfect
tracking, or limitations in the tracking angles. The other reason is
much simpler - many collector tests report 2-D IAMs for tracking
collectors based on the longitudinal and transverse angles. That's why
there are three version (88,89,90), differing only in IAM. Just there to
give the user an option corresponding to the information he/she may have
available.

Jeff

Jeff Thornton

President - TESS

Jeff Thornton's picture
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Dear Jeff,

I have a few questions about type1288.

The first one is related to the flow rates. Other components let users to
enter the test flow rate for a specific collector but I was surprised since
this Type doesn?t include this variable. Why is this? How to select the
best flow rate since the one reported on the test standard report is much
higher than the one the manufacturer recommends?

The second question is about the correct manner to configure a solar array
of X numbers of collector in series times Y numbers of collector in
parallel. Do I have to use a calculator in order to construct such
configuration or is there another way by using Type1288 only?

The third one is about IAM for diffuse radiation. I tried to set a value of
1.015 (according to a certified report) but Trnsys got stuck and I had to
use Ctrl+Alt+Del in order to end the task. So I used a value of 1 and
calculations were performed without any problem. Do you know the reason for
this problem?

And the last question. What is the best way to calculate the efficiency of
collectors using the EN-12975 standard? How do I get this value in Trnsys?

Thank you!

--
Andr?s Montero I.
+34-680705256

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Reputation: 0

the flow rates. Other components let users to enter the test flow rate
for a specific collector but I was surprised since this Type doesn't
include this variable. Why is this? How to select the best flow rate
since the one reported on the test standard report is much higher than
the one the manufacturer recommends?>

The "other" collector models are
based on a first-principles approach where you can solve for the impact
of varying flow rate on the performance of the collector (Beckman and
Duffie provide an example). With the 12975 standard, the performance is
based on a best-fit parameter estimation technique from measured data.
I'm not sure the 12975 equation can be solved in order to adjust the
parameters for flow rates other than that at which the collector was
tested. Good research question.

correct manner to configure a solar array of X numbers of collector in
series times Y numbers of collector in parallel. Do I have to use a
calculator in order to construct such configuration or is there another
way by using Type1288 only?>

A calculator - no. Simply enter the total
array area in the proforma (parameter 2) and then the number of
collectors in series per parallel loop (parameter 1) and the model will
take care of the rest for you. test it against the full array in the
studio to see if you got it right!

diffuse radiation. I tried to set a value of 1.015 (according to a
certified report) but Trnsys got stuck and I had to use Ctrl+Alt+Del in
order to end the task. So I used a value of 1 and calculations were
performed without any problem. Do you know the reason for this problem?>

Well the model should have generated an error as I'm not sure how a
collector can collect more diffuse radiation than is incident upon the
collector... This value should be limited to one theoretically but
should still work with a value greater than one. I just checked the code
- the model generates an error when the diffuse IAM coefficient is
greater than one so I'm not sure how your simulation is even running...

efficiency of collectors using the EN-12975 standard? How do I get this
value in Trnsys?>

Efficiency is typically defined as useful energy
gain divided by the product of incident radiation and collector area. So
this would be output 3 from the model divided by the collector area
(parameter 2) and then divided by the sum of the incident beam radiation
on tilt, the incident sky diffuse radiation on tilt and the incident
ground-reflected diffuse radiation on tilt:

Efficiency = Quseful /
Area / (Gb+Gds+Gdg)

Jeff

---

Jeff Thornton

_President - TESS LLC_

_22 N. Carroll Street, Madison WI USA 53703_

_Office: (608) 274-2577
Fax: (608) 278-1475_

_www.tess-inc.com_

_E-Mail:
thornton at tess-inc.com_

first one is related to the flow rates. Other components let users to
enter the test flow rate for a specific collector but I was surprised
since this Type doesn't include this variable. Why is this? How to
select the best flow rate since the one reported on the test standard
report is much higher than the one the manufacturer recommends?
The second question is about the correct manner to configure a solar
array of X numbers of collector in series times Y numbers of collector
in parallel. Do I have to use a calculator in order to construct such
configuration or is there another way by using Type1288 only?
third one is about IAM for diffuse radiation. I tried to set a value of
1.015 (according to a certified report) but Trnsys got stuck and I had
to use Ctrl+Alt+Del in order to end the task. So I used a value of 1 and
calculations were performed without any problem. Do you know the reason
for this problem?
calculate the efficiency of collectors using the EN-12975 standard? How
do I get this value in Trnsys?
I.

Jeff Thornton's picture
Offline
Joined: 2011-10-02
Reputation: 0

Dear Jeff,

I have a few questions about type1288.

The first one is related to the flow rates. Other components let users to
enter the test flow rate for a specific collector but I was surprised since
this Type doesn?t include this variable. Why is this? How to select the
best flow rate since the one reported on the test standard report is much
higher than the one the manufacturer recommends?

The second question is about the correct manner to configure a solar array
of X numbers of collector in series times Y numbers of collector in
parallel. Do I have to use a calculator in order to construct such
configuration or is there another way by using Type1288 only?

The third one is about IAM for diffuse radiation. I tried to set a value of
1.015 (according to a certified report) but Trnsys got stuck and I had to
use Ctrl+Alt+Del in order to end the task. So I used a value of 1 and
calculations were performed without any problem. Do you know the reason for
this problem?

And the last question. What is the best way to calculate the efficiency of
collectors using the EN-12975 standard? How do I get this value in Trnsys?

Thank you!

Andr?s Montero I.

Tel: +34.977.25.78.87

-------------------------------------------------------------------

CREVER

Grup d'Enginyeria T?rmica Aplicada

Departament d'Enginyeria Mec?nica

Escola T?cnica Superior Enginyeria Qu?mica

Universitat Rovira i Virgili

Avda. Pa?sos Catalans, 26

43007 - TARRAGONA (SPAIN)

=?iso-8859-1?Q?Andr=E9s_Montero?='s picture
Joined: 2016-04-05
Reputation: 0

Dear Jeff,

One more thing about Type1288. Can I use a different flow rate than the one
used to test the collector? or the type is only intended to model collector
at specific conditions?

Thank you

Andr?s

2012/6/28 Andr?s Montero

--
Andr?s Montero I.
+34-680705256

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