ApacheHVAC supports the detailed definition, configuration, control, and modeling of HVAC systems. It interacts ASHRAE Loads for system sizing and, via Apache Thermal during simulation, with other thermal applications, such as MacroFlo. The simulation program itself is run from within Apache Thermal.
ApacheHVAC is invoked as an adjunct to Apache Simulation by linking to a particular HVAC system file when the building model simulation is run, as described in the Apache User Guide.
There are two distinct means of space conditioning and HVAC simulation in the IES Virtual Environment, and these are suitable for very different tasks, levels of analysis, and stages of design.
Apache Systems – Simplified system modeling for schematic design and code compliance in ApacheSim:
Autosized and ideally controlled systems condition spaces exactly to set points via pre-defined HVAC system-type algorithms and minimal room, system, and plant inputs within ApacheSim. This simplified HVAC modeling is fully integrated with the thermal, solar, and bulk-airflow modeling at every simulation time step. However, because the systems are approximated, it is far less representative of actual system equipment, configurations, and controls. Thus, while it may be very useful in early design phases and space loads analyses, this type of modeling is not generally used in detailed design development, documentation of energy use for the ASHRAE 90.1 performance rating method, thermal comfort studies, or other detailed analysis.
ApacheHVAC – Detailed HVAC systems modeling:
Detailed dynamic modeling of systems, equipment, and controls in ApacheHVAC is also fully integrated with the thermal, solar, and bulk-airflow modeling at every simulation time step. Component-based system models can be built from scratch or by modifying autosizable prototype systems, or the prototype systems can be used in their pre-defined configuration.
When ApacheHVAC is invoked, all spaces in the model that are assigned to a room component in the active ApacheHVAC system at the time of simulation will be served by that system. So long as this is true, these rooms will not be served by the simpler systems otherwise defined in the Apache Systems dialog.
Like infiltration, however, air changes or flow rates for Auxiliary ventilation and Natural ventilation as defined in the Air Exchanges tab of the Thermal Conditions template or Space Data remain in effect for all rooms to which they have been applied, regardless of whether or not these rooms are served by an ApacheHVAC system.
