RE: Collector Arrays

[Michaël Kummert <kummert@xxxxxxxxxxxxx>]

Dear Juan,

You are right, you should simulate solar collectors connected in parallel as
one big collector.

Assuming that you want to simulate the following configuration:
- Array of 100 collectors
- Collectors arranged in 10 parallel strings 
  of 10 series connected modules
- Each module is 2 m2 

You should enter the following parameters:
- Collector area (Total): 200 m2
- Collector in series: 10

You can use Type 30 to take into account the fact that collectors shade one
another. Simply connect the "total shaded radiation" output of Type 30to the
"incident radiation" input of Type 1.

Concerning the deviation from real performance, I think that the most
important simplifications are:
- You neglect all pipes between collectors 
  (thermal losses)
- You assume the flowrate is equal in each 
  series string of collector
- You neglect shading from other objects than 
  the collector themselves
- Type 1 implements a steady-state model of 
  the collectors, i.e. you neglect the thermal 
  mass of the collectors and piping

You should have a good accuracy if these hypotheses are reasonably valid for
your system. It is usually the case for well-designed systems if you look at
the hourly energy flows (This is for the collectors only, you will have to
simulate the rest of the system as well!)

I hope this helps,

Michaël Kummert

_________________________________________________________

Michaël Kummert

Solar Energy Laboratory - University of Wisconsin-Madison
1303 Engr Res Bldg, 1500 Engineering Drive
Madison, WI 53706

Tel: +1 (608) 263-1589
Fax: +1 (608) 262-8464
E-mail: kummert@engr.wisc.edu (*****NEW*****)

SEL Web Site: http://sel.me.wisc.edu 
TRNSYS Web Site: http://sel.me.wisc.edu/trnsys


> -----Original Message

-----
> From: owner-trnsys@relay.doit.wisc.edu 
> [mailto:owner-trnsys@relay.doit.wisc.edu] On Behalf Of Juan 
> Pablo Salazar - LABSOLAR
> Sent: Thursday, December 12, 2002 09:02
> To: trnsys@relay.doit.wisc.edu
> Subject: Collector Arrays
> 
> 
> Dear TRNSYS Users,
> 
> I am in doubt about how I should simulate an array of 10 
> collectors connected in parallel. The flat-plate collector 
> types speak only of collectors connected in series. I assume 
> that I should model such an array as a "big" single 
> collector. A "matrix" arrangement with 10 rows (each one 
> consisting of 10 collectors connected in parallel) connected 
> in parallel should be simulated. This means I should use one 
> Type 1 Unit with an area equivalent to 100 collectors 
> (10x10), since the effect of the parallel connections is to 
> guarantee the same inlet temperature in each collector, 
> together with  Type 30 unit for consideration of shading 
> effects. Output of Type 30 is then used in Type 1. Am I 
> wrong? I would be very grateful if those that already have 
> simulated such situations could help me out with their gained 
> experience. Does such simplification deviate from real 
> performance significantly?
> 
> Best regards,
> Juan Pablo de L. C. Salazar
> 
>