DOE/ORNL Heat Pump Design Model
Revisions to Mark VII Web Model (7/2013)
Because the Mark VII run time is longer than for earlier versions, there is more opportunity for one user's run to overlap onto another's, especially when running parametrics. The result could sometimes be that a user's run would fail for no apparent reason. The setup for model execution has been changed so that multiple runs of the model can be made simultaneously by different users.
A correction was made to the parametrics interface to enable the ambient control option to be available to the outdoor ambient parametric selection as either the first or second parameter. Previously it was only active if the outdoor ambient was the first parametric selection.
A revision was made to the compressor map correction approach based on research done under ASHRAE TRP1173. The change was to drop the power correction due to the theoretical change in compressor power per unit mass.
A problem was corrected with unintended refrigerant switching when changing from cooling to heating mode. In some cases, this could cause the model to switch from R-410A to R-22 when using the sample data set with the summary output indicating incorrectly that R-410A was being used. This was caused by a failure of the interface to update the default compressor refrigerant when switching modes, which caused the system refrigerant to be changed to match that for the compressor. Only by noting the change in operating pressures could one identify the unintended switch on the summary page. (One could also see a warning message on the detailed text output that can be viewed by clicking on any component diagram on the summary page.)
The content on the Related Reports/Papers on the home page has also been updated with more recent references related to uses and new capabilities of the research version of the DOE/ORNL HPDM.