Internal Source

Internal Source tab on Constructions Dialog.

 

The internal source tab is visible only when the model is set to use Detailed HVAC. It allows data on the position and nature of any heating or cooling pipes included within the construction. Internal sources are associated with one of these components:

 

Internal source

Check this option if the construction includes a heating or cooling source.

Layer after which the internal source is positioned

Enter a number between 1 and 1-the number of layers. Entering 1 means that the source is positioned between the outermost layer and the next layer. If you are defining a heated floor construction then you will normally enter 1-the number of layers. The easiest way to do this is to use the Set source position below innermost layer tool described below. When defining a chilled ceiling as a floor construction you should enter a value of 1 here.

Dimensions

This field refers to the detail level of the calculation. Select from the 2 options below for a 1-D or 2-D solution:

 

Note: Because the 1-D solution method does not allow the return water temperature to be accurately calculated it is not recommended for when accurate plant energy consumption outputs are required. In this case choose the 2-D option.

The 2-D solution method generally takes about 20% longer to run a simulation relative to the 1-D option.

Tube spacing

This field defines how far apart (in m or in) the hydronic tubing are spaced in the direction perpendicular to the main direction of heat transfer. This parameter is only used when the 2-D solution is selected (above).

Set source position below innermost layer

A tool is provided in the info panel when using learning mode which calculates which is the innermost layer and adds the source between this and the next layer. For example in a chilled ceiling construction you might have 0.5 mm steel ceiling panel as the innermost layer with 3 other layers. In this case when clicking on the Set source position below innermost layer link, the innermost layer value would be set to 3.