Re: [TRNSYS-users] Radiation processor - bug in latest TRNSYS update?

[Flynn Ciaran <ciaran.flynn@aalto.fi>]

Hei Sarah,

1) The best way to set your start time is to add an equation, just like in the Radiation processing example (Trnsys17\Examples\Weather Data\Radiation Processing). This way you can modify the simulation start time without worrying about the type 16 start time.

2) If I'm not mistaken, you're right, the incidence angle is indeed the angle between the incident beam and the normal of the surface. However for me also the incidence angle profiles do not seem realistic for surfaces which are not horizontal (for horizontal surfaces the incidence angle profile is good, between 90 and 0ish degrees; but for example on a 45 degree slope facing south, the incidence angle jumps from 90 to approx. 120 degrees at dawn and dusk...). Maybe someone else can help you with that one (?)

BR,
Ciarán



-----Original Message-----
From: trnsys-users-bounces@cae.wisc.edu [mailto:trnsys-users-bounces@cae.wisc.edu] On Behalf Of Sarah Leenknegt
Sent: 14. helmikuuta 2013 19:36
To: trnsys-users@cae.wisc.edu
Subject: [TRNSYS-users] Radiation processor - bug in latest TRNSYS update?

Dear TRNSYS-users,

I have some problems with type 16. I have measured weather data, at an interval of 600 s, starting on May 19 2012, so day 139. 
I am reading in the data using a type 9, mode 2, instantaneous values, not interpolating and multiplying with 3.6 (from W/m² to kJ/hm²). I am using TRNSYS 17.01.0025.

Two questions:

- What is the best way to deal with the fact that the start of simulation is not day 1? How should you set simulation starting day and type 16 starting day?
I have tried to use type 99, but without success.  

- There is a problem in the calculation of the incidence angle (and I suppose other values as well): the profile is not realistic. The weird thing is that exactly the same data results in a more realistic profile when run under the previous version of TRNSYS 17, which makes me wonder if there is a bug in the latest update?
What is the definition of the incidence angle? I would expect the angle between the incident beam and the normal of the surface, but that would make maximum incidence angle equal to 90 °..

If possible, please answer to me privately as well, as I am not subscribed to the mailing list.

Any help is much appreciated!

Sarah

--
ir. - arch. Sarah Leenknegt,
Afdeling Bouwfysica, Dept. Burgerlijke Bouwkunde, Faculteit Ingenieurswetenschappen, KULeuven, Kasteelpark Arenberg 40 - bus 2447, 3001 Heverlee, België

sarah.leenknegt@bwk.kuleuven.be
tel. 016 321347
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