![]() Not only can the ventilation rate and delivery points be varied, but different envelope leakage characteristics can be investigated as well. minimum/maximum pressure differences between zones, one could use the ventilation system modeling capabilities to provide different airflow rates until these design conditions are met. It is fairly straightforward to establish building geometry and leakage characteristics for a given building within ContamW. While CONTAM is not a formal fan-sizing tool, it does enable an iterative approach of investigating multiple scenarios of building configuration and fan flow rates. Sizing Air Handling Systems - CONTAM can be used to size ventilation systems including the determination of airflow requirements to obtain relative pressurization of building zones or determining ventilation flow rates for whole house ventilation systems. For example, the fraction of outdoor air intake of simple air handling systems, fan on/off cycles, and airflow rates through forced flow elements can be scheduled. Each element of the duct system provides for the definition of friction losses, duct leakage, and dynamic losses.Īll of these ventilation systems can be configured to move air at varying rates according to user-defined schedules. ![]() An entire duct system can be defined including duct segments, junctions, transitions, terminals, dampers and fan performance curves. The duct system provides the most detailed method of modeling a mechanical ventilation system. It provides the ability to distribute the supply air to and return air from any building zone. This system enables the simulation of an air handler that can bring in varying amounts of outdoor air and re-circulate and exhaust return air. The simple air handling system is provided to simplify the amount of data input relative to defining an entire duct system. For example, a bathroom exhaust fan or attic ventilation fan can be implemented to move air directly across the building envelope. Simple forced airflow paths can be defined to move air between adjacent zones at a fixed rate. CONTAM provides several methods of simulating mechanical ventilation systems including: forced flow paths, a simple air handling system, and a duct system. ![]() A given building model can be easily reconfigured to compare different ventilation strategies within a given building geometry. Applications in this area include the ability to compare the use of different ventilation strategies within a given building, size air handling systems, analyze natural ventilation systems, and simulate demand-controlled ventilation (DCV) systems.Ĭomparison of Ventilation Strategies - CONTAM enables the analysis of ventilation systems to determine the impacts on building airflows, pressure differences, and contaminant concentrations. Ventilation StrategiesĬONTAM provides a rich set of tools to analyze different ventilation strategies. These systems are described below in more detail. CONTAM provides three types of mechanical ventilation systems: fixed flow airflow paths, simple air handling systems, and detailed duct models. Indirect affects are less obvious and can include duct leakage and relative zone pressurization/depressurization. Direct effects include those due to the intake of outdoor air by air handling systems. These systems affect building air change rates directly and indirectly. Wind pressure can be define using either surface-average methods or detailed methods with spatially varying wind pressures that are either constant or variable in time for each envelope penetration.ĬONTAM also enables the analysis of mechanically-induced airflows via mechanical ventilation systems. These models provide the ability to define leakage paths using various physical descriptions such as cracks, orifices, and effective leakage areas. CONTAM provides the ability to define leakage paths using several different models that relate pressure difference to airflow. Infiltration analysis with CONTAM requires the definition of leakage paths in the building envelope that are distributed vertically over each facade along with the definition of wind conditions at each facade. The determination of air infiltration rates can be useful for a variety of purposes including the estimation of energy impacts due to building envelope leakage, the effects of weather, and the effectiveness of natural ventilation systems. Knowing infiltration rates, outdoor weather conditions, and desired indoor conditions, one can then estimate the contribution of infiltration to heating and cooling loads. ![]() Unintentional airflow into the building is referred to as infiltration. The determination of building air change rates requires knowledge of airflow into a building through the building envelope whether intentional or unintentional. ![]()
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