IES DSM: Heating Plant Radiant Fraction

[RossThompson87]

Hi,

In a recent audit the issue of heating plant radiant fraction came up.

I'm not too familiar with how this works in SBEM, but from what I can see this is automatically derived from the system choice. So there is nothing to worry about.

However in DSM, there appears to be no link with the system. I create my compliance models by importing the NCM templates so in this case the radiant fraction defaults to 0. (100% convective heating). The IES default template uses 0.2.

If you change this to something like 0.7 for something that is mostly radiant (underfloor heating) this can make a huge impact on the results.

Is this something that needs to be set manually in order to fully comply with the NCM modelling guide? Or is IES taking account for this in the 'background' with the calculated 'SCOP'? If this is the case why is it an adjustable variable in VE compliance?

Ross

[jholgate]

Have you resolved this query?

I'm also curious how the 'Control Temperature Radiant Fraction' options in Building Settings in Apache should be set. (Dry Resultant vs Environmental)

[RossThompson87]

Hi,

No I'm afraid I've not heard anything further on this one....

Ross