EnergyPlus packaged heat pumps energy meter difference from the coil to energy balance

edit

Thank you very much for this quick response. I also noted that when looking at the "Zone Air Heat Balance:System Air Transfer Rate" for the heat pump the contribution to the heat balance actually sums up to "Heating:EnergyTransfer" value rather than the "HeatingCoils:EnergyTransfer ". Does this mean the latent part does not contribute to the zone heat balance?

At the zone level heating is a sensible only heat transfer so the latent component is not included. At the coil model, the heating is usually total heat transfer and would include fan heat and outdoor air when necessary. So these 2 are very different depending on the simulation model. Latent contributes to the zone heat balance with respect to zone conditions, whether or not the latent is included in the energy tranfer meter or report. When you see "Zone" in a report variable, think supply air entering the zone wrt the zone conditions. And if heating, then sensible only is typical (MdotCpDt).

"At the zone level heating is a sensible only heat transfer so the latent component is not included." Well it really depends on the report variable in question, whether it is sensible heat transfer or total heat transfer. You have to review what the report variable represents to know if latent is included (i.e., sensible or total heat transfer).

Thank you for the further pointers. I verified that your explanation is correct for the heat pump cooling. The sensible portion is used for the heat balance. The concern is where there is a difference for the heating pump heating operation as well. This cant be explained from the above explanation (thought process) because the latent component for the heating operation is really small.

Since I don't see a meter that could be used to figure this out, if you look at the zone inlet node Mdot * deltaH (use Output:Variable,your node name,System Node Mass Flow Rate,hourly; and Output:Variable,your node name,System Node Enthalpy,hourly;) you should see where the difference is. It's probably a difference of latent between these 2 meters.