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Last edited 17 Aug 2023

Types of fans

[edit] What is a fan ?

In construction and engineering, the term "fan" typically refers to a device used to create airflow by the use of rotating blades or vanes. Fans are commonly used to move air or other gases, to provide ventilation, or cool systems and components. They can be found in HVAC systems, electronic devices, industrial machinery, and other engineering applications.

[edit] History of the fan

The earliest forms of fans were simple handheld devices made of natural materials such as leaves, feathers, or palm fronds. They were used by civilisations including the Egyptians, Greeks, and Romans, for personal cooling and ceremonial purposes.

In Medieval times, fans became more elaborate and decorative. They were crafted from materials such as silk, lace and parchment and often featured intricate designs and paintings. These fans were primarily used by royalty and the upper classes as status symbols.

During the Renaissance period, fans became fashionable accessories in Europe. They were adorned with ornate handles and crafted with delicate materials such as ivory, mother-of-pearl and silk.

In the 18th century, mechanical fans started emerging, powered by hand-cranked mechanisms. The invention of steam power during the Industrial Revolution brought significant advances in fan technology. Steam-powered fans were used for industrial purposes, such as providing ventilation in mines and factories.

The advent of electricity in the late 19th century revolutionised fan design. Electric fans became popular in the early 20th century, offering more convenience and efficiency. Initially, these fans featured open-blade designs, but later they transitioned to safer enclosed designs.

Recently fans have undergone further technological advancements. They now come in various types, including ceiling fans, desk fans, tower fans, and axial fans used in HVAC systems. Modern fans feature improved blade designs, energy-efficient motors, remote controls, and smart connectivity options.

[edit] Type of fans

[edit] Air multiplier fan

Air multiplier fans blow air from an oval opening without exposed blades, the vanes are hidden within the frame. Air movement is created within the frame, directed and focussed to the central void (or toroid), to create the cooling effect through air flow. Unlike an axial fan, which creates intermittent air flow, pressure and some noise as the blades turn, an air multiplier fan separates the blades from the air flow thus creating a continual constant air flow and less noise. It is also called a bladeless air fan.

[edit] Attic fan

An attic fan normally describes an electrical fan installed in an uninsulated loft space. It is used in warmer climates to exhaust hot air build up in warmer months, but may also assist in moisture build-up in colder months.

[edit] Axial fan

An axial fan is a fan in which the direction of the airflow created is parallel to its axis, so it forces air out in the same direction within which it flows. They create high flow rates, supplying large volumes of air, but intermittently with some noise as the blades sit within the flow of the air.

[edit] Bladeless fan

Bladeless fans blow air from an oval opening without exposed blades, the vanes are hidden within the frame. Air movement is created within the frame, directed and focussed to the central void (or toroid), to create the cooling effect through air flow. Unlike an axial fan, which creates intermittent air flow, pressure and some noise as the blades turn, an air multiplier fan separates the blades from the air flow thus creating a continual constant air flow and less noise. It is also called an air multiplier fan.

[edit] Ceiling fan

Ceiling fans are used to move air around a room thus improving comfort through air flow in warm conditions. The first ceiling fans were called punkah, made from palm leaves and operated manually by servants in India in the 17th century. The first electric ceiling fan is said to be based on a sewing machine by German-American inventor, Philip Diehl which patented in 1889.

[edit] Centrifugal fan

A centrifugal fan (also called radial) moves air (and gases) at an angle to the incoming flow. These types of fans are often within ducted housing to direct the air in specific directions. They are also called blowers, blower fans, or squirrel-cage fans and can benefit from pressure created through their action.

[edit] Chimney fan

Chimney fans are electrically powered equivalents of what might also be called cowls. They are designed to extract smoke from a chimney stack, using electrically driven wind flow ( as opposed to the wind driven flow of wind cowls). This can prevent blowback or problems where back drafts blow soot and ash into the heated space.

[edit] Cross-flow fan

A cross-flow fan is a cylindrical fan tube, with fan circulating around a tubular volume, air is fed into one side. and similar to a centrifugal fan leaves at right angles to the flow air. Though in this case the fan works through a cascade (the void in the centre of the fan tube) and an impellor which rotates. The air enters the cascade to the centre of the impeller and exits at right angles through the impellor referred to as the volute.

[edit] Desk fan

A desk fan is a common place office and home item, used to improve comfort through air movement. It is a form of axial fan as it pulls air in from one side and expels the air on the same axis from the other side with increased velocity.

[edit] Evaporative cooling fan

An evaporative cooling fan has a reservoir of water on the incoming flow side of the fan, this water runs over an evaporative pad, which evaporates as the warm air is drawn through. The cooled, moist air is then blown through the fan which improves the cooling effect of the apparatus.

[edit] Extractor fan

An extractor fan is normally a small gauge electrically drive axial fan, used to extract stale or contaminated air from a space. They are commonly used in cooker hoods to extract smoke and warm air from cooking, usually through a set of filters.

[edit] Floor fan

A floor fan creates air flow at lower levels, often used in office spaces to circulate warm air created at lower levels such a from electrical outlets and computer systems. The air movement and circulation can improve comfort for the users of the office space working at desk height and help to encourage warm stale air to be extracted though opening lights.

[edit] Heat exchanger fan

A heat exchanger fan is essentially a small axial fan used as part of a heat exchange system, usually in pairs for incoming and outgoing air, which is passed through a heat exchanger to recycle waste heat from the outgoing air to preheat the fresh incoming air.

[edit] Hand fan

Hand fan, also referred to as Chinese, Japanese or Korean fans (danseon or jeobseon fan) or a rigid fan is a small hand held concertina paper fan used to increase localised air circulation around the body, normally the face. It is common in warm climates and often seen as a cultural symbol.

[edit] Industrial fan

Industrial fans are more robust and powerful than standard fans, they may be centrifugal or axial and normally floor standing, often encased in a short steel tube.

[edit] Misting fan

A misting fan is similar to an evaporative cooling fan, benefiting from the cooling effect of water, however as the name suggests a misting fan sprays a fine mist of water through the fan along with the air (rather than evaporated water). The cooled, moist air is then blown through the fan which improves the cooling effect of the apparatus.

[edit] Mixed flow fan

A mixed flow fans are similar to centrifugal fans, but may have two fans, the first axial and the second centrifugal. This has the benefit of increasing the initial air speed and air pressure due to centrifugal force, this helps deliver a high volume, balanced flow of air which can help to over come the initial resistance of ducts.

[edit] Pedestal fan

Pedestal fans are normally simple axial fans on an adjustable stand, bringing the air flow to around chest or face height which can improve the felt cooling effect.

[edit] Peltier fan

A Peltier fan is thermoelectric (also called thermal or stove fans) it makes use of thermoelectric effects, converting temperature difference into electrical voltage, which is used to turn a fan and distribute warm air more evenly around a room. The term Peltier comes from the Peltier device, which is the element that functions by thermal temperature (or potential) difference creating a voltage to drive the fan blades, without the need for external power.

[edit] Propeller fan

Propeller fans are generally axial fans, with specific curved blades on the impellor, which can increase efficiency of air flow.

[edit] Radial fan

A radial fan (also called a centrifugal fan) moves air (and gases) at an angle to the incoming flow. These types of fans are often within ducted housing to direct the air in specific directions. They are also called blowers, blower fans, or squirrel-cage fans and can benefit from pressure created through their action.

[edit] Stove fan

Stove fans make use of thermoelectric effects, converting temperature difference into electrical voltage, which is used to turn a fan and distribute warm air more evenly around a room. These fans normally sit on top of a wood burner or stove forcing the air outwards rather than upwards as the air is heated, they may also be referred to as a thermoelectric fans or Peltier fans.

[edit] Table fan

Table fan is another term for a desk fan, common in homes and offices, used to improve comfort through air movement at working height. It is a form of axial fan as it pulls air in from one side and expels the air on the same axis from the other side with increased velocity.

[edit] Thermoelectric fan

Thermoelectric fans (also called thermal or stove fans) make use of thermoelectric effects, converting temperature difference into electrical voltage, which is used to turn a fan and distribute warm air more evenly around a room. They may also be referred to as a Peltier fan, named after the Peltier device, which is the element that functions by thermal temperature (or potential) difference creating a voltage to drive the fan blades, without the need for external power.

[edit] Tower fan

Tower fans are tall slim fans and as such can advantageous in space saving. The blades of the fan are hidden within a tube casing and as such are often quieter than standard open axial or pedestal fans. They they may draw air into the tube from the top or bottom and release it at the side (centrifugal or cross flow), or draw air from the back through the tube (axial), they often have an oscillating function to distribute air more evenly in a space and may also have an evaporative cooling function.

[edit] Variable pitch fan

Variable pitch fans are complex, often industrial types of fan where the angle of the blades of the impellor are adjustable, this can help in starting efficiency and then adjusted to maximise running efficiency.

[edit] Whole-house fan

Whole-house fans can refer to a number of different actual types of fan, but in general it is a term used to describe mechanical ventilation of buildings or ducted whole house systems, usually incorporating a form of mechanical ventilation heat recovery, with a balanced number of intakes and outlets.

[edit] Window fan

Window fans are a variety of technical fan solutions installed into windows, in the glass or frame, as well as nearby windows through walls. In general they are electrically operated, with a relatively small aperture and used where it is not possible to instal a cooker hood with an extractor fan. The term window fan may also be used to describe a simple ventilator, normally circular, inset into a glass pane with a pull chord opening and closing mechanism.