Re: [TRNSYS-users] Shading & solar radiation

Hello David,

thank you for your reply.

As weather data reader i use the type 15-7. The output from the weather file is definitly in W/m².

But in the Type15-7 the unit for radiation is given in kJ/hr m² (see attached picture).

So does Type 15-7 calculate the e.g. 250 W/m² out of the data file internally to kJ/hr m² and my output is then 900 kJ/hr m² or does it only use the 250 without unit from the data file as output ?

I hope this is understandable…

Best regards

Sascha Heinze

Von: David BRADLEY [mailto:d.bradley@tess-inc.com]
Gesendet: Montag, 18. Juni 2012 17:29
An: Heinze
Cc: trnsys-users@cae.wisc.edu
Betreff: Re: [TRNSYS-users] Shading & solar radiation

Sascha,
The equation is simply comparing two values; it doesn't know about the units. So if Radiation_Input (the output from your weather data reader probably - Type99?) is in W/m2 then X also needs to be in W/m2. It is more likely that Radiation_Input is in kJ/h.m2 though, in which case X also needs to be in kJ/h.m2.
Best,
David

On 6/15/2012 05:04, Heinze wrote:

Hello again,

i have another question about external shading and the radiation.

I know that it can be controlled with an equation using the radiation as input like: Radiation_Input → Equation: =gt(Radiation_Input, X) → Output linked to type 56 Shading

But with the X in the equation i am not sure. I have a german TRY (.dat) weather file and the radiation in this file is already given in W/m². Do i still need to convert this to kJ/hr m² ?

Best regards

Sascha Heinze

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