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Question regarding Type15

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Topic starter

Dear TRNSYS users,

I have a question regarding Type15 (Weather Data Reading) in connection with EPW Files.

Nowadays, solar collector modelling need the IR radiation as input. Within Type15, we have access to sky temperature, but we do not have access to the Horizontal Infrared Radiation Intensity (despite this data is included in EPW file).

Based on TRNSYS18 manual, we can find the following equation (Eq4.12.1-5) :

TempSky=SkyEmissivity^(1/4)*(TempDryBulb+273.13)-273.13

thus, it comes :

SkyEmissivity=[(TempSky+273.13)/(TempDryBulb+273.13)]^4

According to https://bigladdersoftware.com/epx/docs/8-0/engineering-reference/page-031.html, we have :

HorizontalInfraredRadiation = SkyEmissivity * Sigma * (TempDryBulb+273.13)^4

I tried this option to calculate HorizontalInfraredRadiation, but the result is quite different from the data included in EPW file (as illustrated in enclosed file).

Based on this, my questions are :

1/ do I make a mistake somewhere ?

2/ Is there other equation ?

3/ Would it be possible having Horizontal Infrared Radiation Intensity as an output of Type 15 ?

Sunny regards

Philippe

1 Answer
0
Topic starter

The enclosed file was the wrong one. The good one is enclosed

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