Energy simulation programs have in the past provided models of only certain fixed system types (VAV, induction, fan coils, etc). In practice, building systems do not conform to these rigid system types, and so it was necessary to accept a degree of compromise in the realism of the model.
Figure 1 - 14 : A multi-zone HVAC network—in this case variable-air-volume with indirect-direct evaporative cooling, energy recovery, variation of static pressure with bypass of heat exchangers, duct heat gain, return air plenums, controls for mixed-mode operation with natural ventilation, and primary, transfer, and exhaust airflow paths available to each of the zones in the layered multiplex region.
ApacheHVAC has been designed to impose minimal restrictions on the user in defining the system model. The user is offered a number of basic blocks, each describing a generic type of equipment (heating coil, fan, humidifier, etc.). These basic blocks can be assembled as required to model an actual system configuration, rather than an idealized simplification. The complexity of the model is limited only by the types of block available and some basic rules concerning their interconnection. Within these constraints, it is possible to assemble models of many different system and control configurations and to explore the benefits of variations on standard system types.
An item of plant or control can be described once, and then copied or referenced as many times as may be required to define the system.
