Volumen de aire variable (VAV)

El sistema VAV tiene una unidad central de procesamiento de aire para producir aire a una temperatura y humedad relativa específicas. El aire acondicionado de la unidad principal se conduce a través de conductos a difusores de techo que incorporan actuadores controlados termostáticamente. Estos pueden cambiar el volumen de aire para adaptarse a la carga de cada habitación. En una habitación grande, varias de estas unidades de techo VAV pueden controlarse mediante un termostato de ambiente. Varias habitaciones/zonas pueden tener termostatos separados para controlar el flujo de aire a cada habitación. El ventilador de entrada puede tener impulsores de paso variable operados por aire comprimido. Un interruptor de presión controla el ángulo de paso. La distribución del aire suele ser de velocidad media a alta. La temperatura del aire en cada zona se puede variar con la energía térmica en el volumen de aire de entrega, pero el sistema sólo es adecuado para edificios que tengan una carga de refrigeración distribuida de manera bastante uniforme.

Nota: Los accesorios de iluminación pueden requerir una compuerta cortafuegos. Sección a través del techo plenum.

FREQUENTLY ASKED QUESTIONS

What are the main components of a VAV system?
A VAV system consists of a central air-processing unit, ductwork, ceiling diffusers, and thermostatically controlled actuators. The central unit produces air at a specified temperature and relative humidity, which is then conveyed through the ductwork to the ceiling diffusers. The actuators in the diffusers can change the air volume to suit each room’s load.
How do VAV ceiling units control the air flow in a room?

VAV ceiling units incorporate thermostatically controlled actuators that can change the air volume to suit each room’s load. These actuators are typically controlled by a room thermostat, which senses the room temperature and adjusts the air flow accordingly. In a large room, several VAV ceiling units may be controlled by one room thermostat.

What are the advantages of using VAV systems in buildings with varying cooling loads?

VAV systems are suitable for buildings with fairly evenly distributed cooling loads. They offer several advantages, including energy efficiency, improved indoor air quality, and increased flexibility. By adjusting the air flow to each room based on its specific needs, VAV systems can reduce energy waste and provide a more comfortable indoor environment.

How does the inlet fan in a VAV system control the air flow?

The inlet fan in a VAV system may have variable pitched impellers operated by compressed air. A pressure switch controls the pitch angle of the impellers, which in turn adjusts the air flow. This allows the system to maintain a consistent air pressure and flow rate, even as the cooling load varies.

What is the typical air distribution velocity in a VAV system?

The air distribution velocity in a VAV system is usually medium to high velocity. This allows for efficient air distribution and mixing, which helps to maintain a consistent indoor air quality and temperature. The exact velocity may vary depending on the specific system design and the building’s requirements.

Can VAV systems be used in buildings with highly variable cooling loads?

VAV systems are generally not suitable for buildings with highly variable cooling loads. They are designed to work best in buildings with fairly evenly distributed cooling loads, where the air flow can be adjusted to meet the specific needs of each room. In buildings with highly variable cooling loads, other HVAC systems, such as constant air volume (CAV) systems, may be more appropriate.