Diffusers are in most cases the preferred choice for ceiling applications. Depending on the configuration of its deflectors, diffusers can produce radial, directional horizontal or even perpendicular air patterns. There are numerous typed of diffusers available in the market.
Diffusers are installed at the terminal point of ducting systems and they introduce or extract air to or from the conditioned space in order to achieve the desired indoor conditions. There is a plethora of different types and diffuser designs, each with unique characteristics and each suitable for specific applications. This article aims in presenting the main types of diffusers as well as providing an insight into the selection process of the proper type and size of air outlets.
Slot diffusers, or linear diffusers as they are sometimes called, are a very popular diffuser type for HVAC systems due to their aesthetically pleasing design and their ability to satisfy high performance applications. One of their most significant advantage is their ability to be combined from various smaller, straight or angled, sections to achieve continuous lengths that can satisfy any room geometry. Slot diffusers can have a single or multiple slots based on the requested air flow or width constrains and can produce both vertical or horizontal air patterns according to the configuration of the deflectors inside the slots.
Swirl diffusers are a type of ceiling diffuser that consists of radially patterned openings placed around the center of the face of the diffuser. They are designed for high induction requirements and high ceiling applications. Their main characteristic is high entrainment of ambient air into the supply stream which results in rapid mixing near the face of the diffuser. Swirl diffusers can have circular or square face with adjustable or fixed blades. They are available in a number of aesthetically pleasing pattern designs and mounting options.
Jet diffusers are almost exclusively used in commercial applications with large open spaces and high ceilings, such as concert halls, theaters, museums, galleries, airports and shopping centres, as they have the ability to produce high throw air streams without increasing significantly the noise levels. They can be manually or electronically adjusted over 360o. Jet diffusers are available in short and long pipe models.
Ceiling diffusers can have a square or round profile and can produce a variety of air patterns, depending on their type. In general, ceiling diffusers can produce radial or directional (1, 2 or 4 way) air streams so its very important to select the right type to satisfy the needs of the conditioned area, taking into consideration the geometry of the space. In addition ceiling diffusers may have fixed or adjustable deflectors to give additional options regarding the resulting air pattern.