Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
It looks like EnergyPlus expects any desiccant heat exchanger or system defined in the model to be solid and not liquid. While you could possibly model a liquid desiccant heat exchanger if you modify various heat exchange coefficients and equations, there is currently no way to directly model the liquid desiccant plant loop where the liquid desiccant returns to a heating device like a water heater or boiler for regeneration purposes.
According to this NREL paper from 2014:
EnergyPlus can model a wide variety of building systems, but in cases where technologies are newer or underutilized, EnergyPlus must often be coupled with external modeling software to add customized systems. The Dymola simulation environment was used to develop the LDAC model (Dassault Systèmes 2012). This model was based on the configuration of an installed LDAC system at Tyndall Air Force Base, in Panama City, Florida (Dean et al. 2012). The mathematical algorithms used to predict the performance of the conditioner and regenerator were based on a particular LDAC system and are not necessarily expected to predict the performance of systems built by other manufacturers. The model is also flexible enough to predict system performance in a variety of climates with different specifications for pumps; fans; control strategies; heating and cooling sources; and sizes for the desiccant storage, regenerator, and conditioner.
You may have to use a similar approach of defining the LDAC model in a separate tool than EnergyPlus. If you want to avoid developing an external LDAC model in parallel to your EnergyPlus model, then you could use EnergyPlus EMS controls to write custom programs to take the dehumidification load as an EMS sensor in order to manually calculate energy use and other changes for the liquid desiccant plant loop using Erl (EnergyPlus runtime language).
