ESP-r: Infiltration Ventilation and Multizone air flow
ESP-r offers multiple approaches to air movement from schedules to flow networks as well as an in-built CFD domain solver. Users are thus able to set the level of resolution to fit the requirements of projects as they evolve.
Infiltration
In ESP-r the term infiltration is flow from the outside whether naturally driven or forced. Scheduled infiltration is defined within zone operation files. Control may be applied based on temperature, wind-speed or time. Within a mass flow network infiltration is possible along flow connections which have connections with boundary nodes. Find our more here.
Ventilation
In ESP-r the term ventilation denotes air movement between zones either natural or forced. Scheduled ventilation definitions are also held in the zone operation file. Within a mass flow network ventilation is associated with all flow connections that do not involve a boundary node. Find our more here.
Mechanical ventilation
Scheduled ventilation can approximate mechanical ventilatio. Within flow networks two options exist to induce forced air flow via fan components with pressure/volume flow descriptions or fixed volume (or mass) flow rate components. The flow induced by such components becomes part of the overall solution of the network. Control imposed for specific flow connections or to all instances of a specific flow component type. Find our more here.
In ESP-r flows derived from a network solution or flows imposed via schedules are treated together when the zone energy balance is solved. There are, however ideal zone controls for VAV and CAV that mimic the impact of air movement without actually involving the infiltration and ventilation data structures.
Air flow solvers
ESP-r includes a network flow solver for air and water flows within a model. Details of the node and component entities involved are covered here. The flow solver communicates with the zone solver to access the current node temperatures and ambient temperature and passing back the predicted infiltration and ventilation applicable to each zone. Find out more about the solution technique here
The nominal performance characteristics of most flow components can be adapt via control actions. Each control has a sensor which as attributes specifying its location what the sensed conditions, a component or specific flow connection where an action is to be taken and control laws (can be scheduled). This allows fans to be adjusted or windows opened. Complex controls can be created by linking separate controls in parallel or sequence as well as using AND / OR logic constructs.
Mixed scheduled and calculated air flow
In ESP-r network flow calculations take precedence over scheduled flows. Users are encouraged to use scheduled flow representations early in the design process and then introduce a flow network. The precedence rule allows for the schedules to remain in place so as to be available if the network is dereferenced.Indoor air quality
It is possible to define contaminate sources and skinks and associate these with a flow network. The movement of air then transports the contaminates.
Contaminates can also be defined for inclusion in a CFD
domain. Mean age of air calculations can also be done in the
contect of a CFD domain.
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