[TRNSYS-users] Type 71 and type 538

[Jeff Thornton]

<I am simulating a system using vacuum tube collectors type 71 and type
538. I found some data in order to create IAM data files. While doing that
i realized that the there are two types of vacuum tube collerctor: Some
with an additional concentrator part CPC and some without. My question now
is if these TRNSYS types can be used for both types of vacuum tubes
(obviously modifieing the efficiancy factors ...) ??>

It depends on how the collector efficiency is presented.  If the
efficiency equation is a function of total incident radiation then you can
use Type 538.  If the Rabl method is used (efficiency is a function of the
direct normal solar radiation) then you'll have to use a model that takes
into account that efficiency approach and deals with the collector
concentration ratio.  We have one avalaible that will go into the next
version of our libraries (XCPC).  Either way - make sure you get the
incident angle modifiers correctly entered - they can make a major
difference in your performance estimates.

Jeff


Jeff Thornton
President - TESS, LLC

2916 Marketplace Drive - Suite 104
Madison WI 53719 USA

Phone: 608-274-2577
Fax: 608-278-1475
E-mail: thornton at tess-inc.com
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