Using EnergyPlus, we're modeling a borefield that uses a proprietary tubing (Gi-4 from Geothermal Innovations) that has very different geometry than typical U-tubes. Prior to this, we've used "typical" g-function data sets in the GroundHeatExchanger:ResponseFactors object which matched the borefield size.
For this model, we want to make sure we're representing the proprietary ground heat exchange properly, so we asked the manufacturer for their g-factors. They graciously sent a data sheet with a single g-factor - and our previous models have had 30-80 sets of Ln and g-factor values.
Frankly, I'm planning to try to absorb the Engineering Reference discussion on g-functions, but it looks pretty painful, so I'm asking two questions in hopes of experiencing less pain:
1) What is the purpose and difference between each of the multiple sets of Ln / G-function values?
2) Is there a simpler way to model a borefield that, for example, can use the manufacturer's calculated (single) g-function?
Thanks in advance.
