AW: [TRNSYS-users] Vacuum tubes with concentrator

Timo Sengewald timo.sengewald at
Thu Dec 8 07:14:14 PST 2005


I didn't have any experience with vacuum tubes and concentrators. But I have
modelled simple VTCs using type 71. If type 71 is applicable for your type
of collector I would suggest reading the very detailed message Michaël
Kummert posted on this topic some time ago:

But probably you need to use type 74.

Very good test results for many collectors (including the incidence angle
modifiers you need) are available at

Best regards


Timo Sengewald

BLS Energieplan GmbH
Elsenstraße 106
D-12435 Berlin
Tel.: +49 30 53 32 81-0
Fax: +49 30 53 32 81-40

-----Ursprüngliche Nachricht-----
Von: trnsys-users-bounces at
[mailto:trnsys-users-bounces at] Im Auftrag von Xavier Arino
Gesendet: Donnerstag, 8. Dezember 2005 12:23
An: trnsys-users at
Betreff: [TRNSYS-users] Vacuum tubes with concentrator

Dear TRNSYS group,
I am trying to model a solar hot water system using vacuum tubes with
concentrator (I am using Schott vacuum tubes). I only have the instant
efficiency test (quadratic equation) from the manufacturer. I am not sure if
I should use TYPE 74 (CPC collector) or TYPE 71 (Vacuum Tube), because I
don’t know if Type 71 –or the instant efficiency equation- will take account
of the “concentration effect” into the absorber. Does anyone have any
recommendations on what to do? Many thanks
Xavi Ariño

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