Ceiling fan
A ceiling fan is a fluid flow machine to support air circulation in a residential or commercial space. While ceiling fans were already part of everyday life in tropical areas when electrification was introduced, especially in public buildings, the devices are now also gaining increasing acceptance in northern latitudes. They represent an alternative to the standing fans , which are often loud and noticeably drafts , and can sometimes replace an expensive air conditioning system. Operating a ceiling fan in winter can help reduce heating costs through better air distribution in the room.
Mode of action
The fan sets the air mass in motion, especially in closed living spaces. The resulting air flow creates evaporative cooling on the human skin . In contrast to air conditioning, the fan is not able to cool the room air itself. Placing the device on the ceiling ensures that the air mass in a room is evenly and effectively circulated and is therefore not comparable with table fans that usually work at a point. Even at high temperatures, a room climate that is perceived as pleasant can be achieved and the use of a more expensive and environmentally harmful air conditioning system can be dispensed with.
Executions
Ceiling fans come in many designs. These range from the simple equipment, which only underlines the technical practical value and is kept correspondingly simple, to the elaborate and decorative design, which sometimes has high-quality materials such as brass or chrome as well as wood with rattan inlays . High-quality devices are mostly intended for use in living rooms and their design is based on classic devices, while standard devices are more likely to be used in the catering or snack bar area. Many devices also have lighting (which can be switched on and off separately from the motor) . This means that a ceiling fan installed in the middle of the room can be used as a complete replacement for the necessary room lighting.
construction
In view of its own weight and the rotational movement, the ceiling fan must be mounted firmly and securely on the ceiling. For this purpose, a stable metal construction, which is shaped as a rod, cross or plate, is anchored in the ceiling with screws and dowels. A canopy is then screwed onto this metal structure. An extension rod, which is provided with ball joints on both the canopy and the motor housing, is used to compensate for any possible imbalance . If the ceiling height does not permit the use of the extension rod, the canopy and motor housing can also be screwed directly. Here, however, noise can develop due to the lack of compensation for the imbalance. The drive motor is housed in the motor housing and the brackets for the rotor blades are attached directly to its rotor . The latter are attached to the brackets with several screws . If there is lighting, it completes the entire construction.
engine
An electric motor is used to drive the fan . The stator with its windings has a flat, fixed design and is surrounded by the likewise flat rotating cylinder. The latter is screwed on top and bottom with two heavy, plate-like housing covers that serve as a flywheel. Usually the wings are screwed onto the lower housing cover, less often from the top. With high-quality devices, greased bearings, ball bearings and the use of silicon steel as transformer sheet metal as well as ventilation openings are essential quality features that have a positive effect on the service life as well as on the noise development during operation.
Size and performance
Ceiling fans are available in standard diameters of 70, 105 and 132 cm, but also in individual sizes up to 300 cm. In the usual design, the speeds are approx. 90 min −1 in the lowest, approx. 160 min −1 in the middle and approx. 210 min −1 in the highest level. Two, three, four or five-leaf models are available. In principle, the largest available diameter should always be selected, because a large model in the lowest level still provides a higher air flow rate than a smaller model in a higher level. This must be taken into account in particular when considering the energy consumption and when choosing the location (e.g. bedroom). The higher the power level, the higher the noise generated by air movement and the motor.
business
Cord switches are mostly used to operate the device . The switch for operating the fan has i. d. Usually three levels for regulating the speed. Since starting at low speed is to be avoided, the device starts up at the highest level and is reduced by one level each time the cord switch is operated. The lighting is also switched on using a cord switch, while the direction of rotation is usually selected using a slide switch.
Direction of rotation
The selection of the direction of rotation is equivalent to summer or winter operation. While the draft is directed downwards in the warm seasons, the draft is directed upwards in the cold seasons. Using the ceiling fan during the heating season has a positive effect on energy consumption . For physical reasons, warm air rises upwards. This can result in a temperature difference of up to 15 ° C between floor and ceiling, depending on the height and size of the room. The upward direction of rotation creates a pressure that carries the warm air down the walls. Thus, instead of remaining useless in the upper area of the room, the warm air reaches the area of the living room where it is actually required. In winter operation it is important that the fan only runs on the lowest level in order to avoid a noticeable draft.
Power consumption
The power consumption of a ceiling fan is approx. 60 watts at the highest level and approx. 20 watts at the lowest level. In view of the performance of the device - both in summer and in winter - these values are very acceptable. Furthermore, the energy consumption is very easy to control, especially in summer. Since the device does not cool the air, it can always be switched off when there are no people in the room. For devices with lighting, the energy consumption of the respective light source must be added. The use of energy-saving lamps is possible if the lamps are dimmable or the device does not have a dimming function.
Wall or remote control
To increase the ease of use, there is the option of wall or remote control . Very few devices are equipped with these devices as standard and are usually retrofitted accordingly. The wall control usually replaces the existing light switch and requires the presence of a five-wire cable . It allows the control of the speed as well as the lighting and its dimming. The remote control does not require any changes to the existing electrical installation and is attached to the fan canopy in the form of an infrared receiver . In addition to the wall control functions already mentioned, the remote control usually also has the function of a timer . This allows the time-controlled use of the running time or the performance level. Some newer models replace the wall or remote control with a smartphone app .
Changing the direction of rotation is not possible with any of the solutions mentioned. To do this, a switch must be operated directly on the fan.
hazards
When properly installed, the device hardly poses any danger. The prerequisite for this is a stable ceiling construction. Factors stressing the material are the weight of the fan and the rotational movement. Even if the fan and the suspension are largely decoupled by the extension rod, a permanent load on the suspension cannot be completely avoided. This is particularly important for plasterboard , even when using special dowels. Compensating for an imbalance can be time-consuming. It can be done by exchanging the blades with one another as well as by attaching the weights already supplied by many manufacturers, which are attached securely above the blades. The powerful motors are suitable for continuous operation and are appropriately protected. In the case of direct assembly without an extension rod, the screw connection of the motor housing and canopy should be checked from time to time, as a possible imbalance acts directly on these components and is not absorbed by the ball-bearing rod. Touching the rotor blades during operation can cause injuries, as well as throwing objects into the rotating fan.
history
Room fans were used even before electrification. In 180 AD, a fan in China is said to have been powered by muscle power to air-condition a room. From the year 1800 models were used in the Middle East that used water power as a drive. Finally, with the expansion of the power grid, the first electrically operated ceiling fans came into being. In 1887, the German-American Philip Diehl applied for a patent for an electric ceiling fan.
Web links
Individual evidence
- ↑ a b c d e f g Success story ceiling fan. In: creoven, Tobias Krist. 2019, accessed July 23, 2019 .
- ↑ a b ceiling fan: the perfect solution for hot summers. Retrieved October 1, 2013 .
- ↑ fan. Retrieved October 1, 2013 .
- ↑ The ceiling fan. Archived from the original on October 4, 2013 ; accessed on July 23, 2019 .