[EnergyPlus_Support] GroundHeatExchanger:Vertical - g-function inputs.

[Peter Henniger <hennigerp@xxxxxxxxxxx>]

Folks



The Engineering Reference and the papers by Yavuztruk,  Spitler, Murugappan, Xu do a very good job of explaining the theory and method for simulating Vertical Ground Source Heat loops in the EnergyPlus object.



However, the description of input for GroundHeatExchanger:Vertical in the Input Output Reference is vague with respect to the g-function.



There are two possible scenarios:

A)     The g-function input is Long-Time-Step g-function per Eskilson, while the borehole inputs and Time Period are used to calculate Short-Time-Step Response Factors, and parameters for the Load Aggregation algorithm.

OR

B)      The g-function input includes the Short-Time-Step Response Factors as calculated by the software package GLHEPro (Spitler et.al).

Presumably, inaccurate results may occur if one does not enter the intended g-function.

Regardless, it should probably be clarified and updated in the Input Output Reference .



Many thanks



Peter



From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Peter Henniger
Sent: Thursday, April 29, 2010 12:34 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Vertical Ground Heat Exchanger g-functions



Dear EnergyPlus Team

For the object GroundHeatExchanger:Vertical, the .idf file requires pairs of g-function values as definitions (see .idd definition below).