Instruct: Given a question, retrieve documents that answer the question.
Query: Are ceiling fans good for saving energy?
Meanwhile, electric ceiling fans became very popular in other countries, particularly those with hot climates, such as India and the Middle East, where a lack of infrastructure and/or financial resources made energy-hungry and complex freon-based air conditioning equipment impractical. In 1973, Texas entrepreneur H. W. (Hub) Markwardt began importing highly efficient ceiling fans to the United States that were manufactured in India by Crompton Greaves, Ltd. Crompton Greaves had been manufacturing ceiling fans since 1937 through a joint venture formed by Greaves Cotton of India and Crompton Parkinson of England, and had perfected the world's most energy efficient ceiling fans thanks to its patented 20 pole induction motor with a highly efficient heat-dissipating cast aluminum rotor. These Indian manufactured ceiling fans caught on slowly at first, but Markwardt's Encon Industries branded ceiling fans (which stood for ENergy CONservation) eventually found great success during the energy crisis of the late 1970s and early 1980s, since they consumed far less energy (under 70 watts of electricity) than the antiquated shaded pole motors used in most other American made fans. The fans became very effective energy saving appliances for residential and commercial use by supplementing expensive air conditioning with a cooling wind-chill effect. Fans used for comfort create a wind chill by increasing the heat transfer coefficient, but do not lower temperatures directly.
Fan coil units are an excellent delivery mechanism for hydronic chiller boiler systems in large residential and light commercial applications. In these applications the fan coil units are mounted in bathroom ceilings and can be used to provide unlimited comfort zones - with the ability to turn off unused areas of the structure to save energy.
Many studies have been conducted to demonstrate the energy and cost performance of DOAS in terms of simulations. Khattar and Brandemuehl simulated the parallel system and a conventional single system for a large retail store in Dallas, St. Louis, Washington DC, and New Orleans. The study demonstrated annual energy savings of 14% to 27% and 15% to 23% smaller equipment capacity for the parallel cooling system. Jeong et al. compared the energy and cost performance of a DOAS with parallel ceiling radiant panels to a conventional VAV system with air-side economizer for a nearly office space in an educational building in Pennsylvania. A 42% reduction of the annual energy usage for the DOAS system with substantial savings in both fan and chiller energy use was reported in this study. Emmerich and McDowell evaluated the potential energy savings of DOAS in U.S. commercial buildings. The building model was developed to be consistent with typical new construction and meet the ASHRAE Standard 90.1 (ASHRAE 90.1) requirements. The simulation results indicated that the full DOAS resulted in the annual HVAC energy cost savings ranging from 21% to 38%.
Energy conservation measures are often combined into larger guaranteed Energy Savings Performance Contracts to maximize energy savings while minimizing disruption to building occupants by coordinating renovations. Some ECMs cost less to implement yet return a higher energy savings. Traditionally, lighting projects were a good example of “low hanging fruit” that could be used to drive implementation of more substantial upgrades to HVAC systems in large facilities. Smaller buildings might combine window replacement with modern insulation using advanced building foams to improve energy performance. Energy dashboard projects are a new kind of ECM which relies on the behavioral change of building occupants to save energy. When implemented as part of a program, case studies (such as that for the DC Schools) report energy savings up 30%. Under the right circumstances, open energy dashboards can even be implemented for free to improve upon these savings even more.
Many styles of ceiling fans have been developed over the years in response to several different factors such as growing energy-consumption consciousness and changes in decorating styles. The advent and evolution of electronic technology has also played a major role in ceiling fan development. Following is a list of major ceiling fan styles and their defining characteristics:
Under the National Energy Efficient Fan Programme, EESL provides BEE 5 Star rated ceiling fans which are 30% more energy efficient than conventional fans. Fans will be sold for Rs. 1,150 per fan. EESL has distributed 6.2 lakh energy efficient fans under this scheme which will save 2.4 lakh kWh and Rs 8.2 lakh per day to the consumers. The price difference is Rs. 500 which is the primary reason for its low penetration, along with the lack of awareness. With the usage of these energy efficient fans it is estimated that consumer’s electricity bills will reduce by about Rs. 700-730 per year, and recover the extra cost in less than 2 years.
In 1998, Walter K. Boyd invented the HVLS ceiling fan. A lifelong inventor, Boyd was charged with developing a system to cool dairy cattle. Dairy cattle, when overheated, decrease milk production. Using the laws of physics and airflow, Boyd developed a slow moving fan that incorporated 10 aluminum blades and was 8-feet diameter. Unlike traditional ceiling fans that move quickly, this large fan moved slowly. Due to its diameter size, the fan moved a large column of air down and out 360 degrees and continuously mixed fresh air with the stale air inside the barn. They are used in many industrial and agricultural settings, because of their energy efficiency. It also cooled the inside of the barn without causing the dairy cattle undue stress or kicking up dust.
Belt-driven ceiling fans. As stated earlier in this article, the first ceiling fans used a water-powered system of belts to turn the blades of fan units (which consisted of nothing more than blades mounted on a flywheel). For period-themed decor, a few companies (notably Fanimation and Woolen Mill) have created reproduction belt-drive fan systems. The reproduction systems feature an electric motor as the driving force, in place of the water-powered motor. DC ceiling fans. These fans use a brushless DC motor that offer much better efficiency than traditional fans driven with AC motors. They usually are quieter than AC motor fans due to the fact they are commutated electronically and use permanent magnet rotors. Among many advantages these fans offer some are higher efficiency, lower noise level, less rotor heat, integration of remote control and other convenience technologies etc. The only drawbacks are the high cost and the presence of complex electronics which may be more likely to fail, making them not ideal for commercial installs containing a large number of fans. However, with the advent of new technologies and better quality control techniques, the latter is becoming less of a concern.[5] Hugger ceiling fans (also known as "flush mount" or "low profile" ceiling fans) have no downrod or canopy like a traditional mount fan, and the motor housing is mounted directly to the mount. Hugger style fans generally have spinner motors, and use a special mounting bracket that holds the motor assembly and the motor housing. They are typically used in rooms with low ceilings. A disadvantage to this design it that since the blades are mounted so close to the ceiling, the air movement is greatly reduced. Bladeless ceiling fans. This type was introduced in 2012 by Exhale fans and uses a bladeless turbine to push air outwards from the fan, which is also the case of regular ceiling fans on updraft mode. These feature a brushless DC motor instead of a normal direct drive motor. High-volume low-speed fans (HVLS fans) are large-diameter ceiling fans intended for large spaces such as warehouses and gymnasiums. These fans generally spin at a low speed and they use airfoil-style blades for optimized air movement. One of the most popular manufactures of HVLS fans is Big Ass Fans. Synchronous motor mini ceiling fans- these are relatively small in size and are made almost completely out of plastic. Punkah style ceiling fans. These fans are based on the earliest form of a fan, that was developed in India which was originally cut from an Indian palmyra leaf. A punkah fan moves slowly in a pendular manner with a rather large blade and is nowadays electrically powered using a belt-driven system. In comparison to a rotating fan it creates a gentle breeze rather than an airflow.
The hot climate at Le Port led the team in charge of the INNOVAL project to prepare a cooling strategy for different seasons. During the winter, natural ventilation is sufficient to cool offices and during the mid-season between the winter and the summer, natural ventilation is completed with ceiling fans. However, during the summer, natural ventilation coupled with ceiling fans are not sufficient, consequently, air conditioning has to be used. In buildings in Reunion Island, a significant percentage of the energy consumed is due to air conditioning, therefore, the air conditioning system selected here is an efficient one with a Variable Refrigerant Flow ensuring reliability and energy savings. Moreover, a software tool automatically regulates the power of cooling in relation to office use. Finally, while in Reunion Island, people are used to cooling below 24 °C, the air conditioning of the building cannot cool below 26 °C which is adequate with ceiling fans and natural ventilation. Indeed, with the assistance of ceiling fans, the felt temperature is reduced by 5 °C allowing a final felt temperature of 21 to 22 °C. In order to optimize the refrigerated unit power, the temperature adjustment consists of applying a difference of 5 °C between the outside and the inside. For example, if the outside temperature is 34 °C, the temperature adjustment will be 29 °C. All these choices in operation have led to a decrease from 100 kW to 30 kW in the power required by the refrigerated unit.
Window and central air conditioning in the 1960s caused many companies to discontinue production of fans. But in the mid 1970s, with an increasing awareness of the cost of electricity and the amount of energy used to heat and cool homes, turn-of-the-century styled ceiling fans became immensely popular again as both decorative and energy efficient units.
Big Ass Fans entered the commercial business market in 2008, debuting a line of fans ranging from to in diameter. The following year, it began manufacturing fans in sizes suitable for residential settings. In late 2011, Big Ass Fans acquired a manufacturer of energy efficient residential fans. Haiku models incorporate direct current, permanent magnetics and aerodynamic airfoils making them 80% more efficient than conventional ceiling fans. They held the top 10 spots on Energy Star's Most Efficient 2014 list. In 2014, the company added smart technology SenseME to the Haiku ceiling fan. Haiku with SenseME integrates with the Nest Learning Thermostat through a smartphone app.
Axial destratification fans are self-contained units that are installed in an array at the ceiling with the goal of blowing conditioned air in the ceiling down to the floor, where people live and work. Because axial fans are designed to blow air straight down at the floor, they can be used in ceiling and roof structures over 100 ft. tall. Because axial destratification fans can achieve destratification with low CFMs, it is imperative that the air leaving the nozzle achieve an air speed at the floor of between 0.2 and 0.5 m/s. The result of this level of air movement is the integration of conditioned air from the ceiling with air at the floor level. Failing to impact the floor will result in destratification of medial layers of air but not achieve destratification at the floor. Since the area around the thermostat will not be destratified in this instance, it is hypothesized that there will be little or no cost savings, as the thermostat will continue to overheat or overcool the room.
For heating, ceiling fans should usually be set to turn the opposite direction (usually clockwise; the blades should spin with the downward turned side leading) and on a low speed (or the lowest speed the fan is able to circulate the air down to the floor). Air naturally stratifies—that is, warmer air rises to the ceiling while cooler air sinks. Unfortunately, this means it is colder on or near the floor where human beings spend most of their time. A ceiling fan, with its direction of rotation set so that air is drawn upward, pulls up the colder air below, forcing the warmer air nearer the ceiling to move down to take its place, without blowing a stream of air directly at the occupants of the room. This action works to even out the temperature in the room, making it cooler nearer the ceiling, but warmer nearer the floor. Thus the thermostat in the area can be set a few degrees lower to save energy, while maintaining the same level of comfort. It is important to run the fan at a low speed (or a lowest speed the fan is able to circulate the air down to the floor) to minimize the wind chill effect described above. However if the ceiling is high enough, or the lowest speed downdraft would not create wind chill effect, it can be left on downdraft year around.
Besides the advantages presented above, parallel radiant cooling panels offer other advantages as well, such as compact design, vertical shaft space area savings, and quick accommodation of dynamic controls. Energy savings in DOAS/radiant ceiling cooling panel system can by linked to: cooling coil load reduction, chiller energy reduction, pumping energy consumption and fan energy consumption reduction. In general, due to the total energy recovery and small supply air quantity of DOAS, the chiller energy consumption can be reduced significantly compared to the conventional VAV system. In a study of a pilot DOAS/radiant ceiling cooling panel system, hourly energy simulation predicts that the annual electrical energy consumption of the pilot DOAS/radiant panel cooling system is 42% less than that of the conventional VAV system with economizer control.
Mixing systems generally supply air such that the supply air mixes with the room air so that the mixed air is at the room design temperature and humidity. In cooling mode, the cool supply air, typically around 55 °F (13 °C) (saturated) at design conditions, exits an outlet at high velocity. The high velocity supply air stream causes turbulence causing the room air to mix with the supply air. Because the entire room is near-fully mixed, temperature variations are small while the contaminant concentration is fairly uniform throughout the entire room. Diffusers are normally used as the air outlets to create the high velocity supply air stream. Most often, the air outlets and inlets are placed in the ceiling. Supply diffusers in the ceiling are fed by fan coil units in the ceiling void or by air handling units in a remote plant room. The fan coil or handling unit take in return air from the ceiling void and mix this with fresh air and cool, or heat it, as required to achieve the room design conditions. This arrangement is known as 'conventional room air distribution'.Displacement ventilation systems supply air directly to the occupied zone. The air is supplied at low velocities to cause minimal induction and mixing. This system is used for ventilation and cooling of large high spaces, such as auditoria and atria, where energy may be saved if only the occupied zone is treated rather than trying to control the conditions in the entire space.
Another advantage is energy savings and reduced wear. VAV fan control, especially with modern electronic variable-speed drives, reduces the energy consumed by fans, which can be a substantial part of the total cooling energy requirements of a building. Modulating control of the compressor also reduces wear and delivers further energy savings.
Finally, the DC motor is a Brushless DC Motor that uses less energy than a conventional ceiling fan motor.
Another concern with installing a ceiling fan relates to the height of the blades relative to the floor. Building codes throughout the United States prohibit residential ceiling fans from being mounted with the blades closer than seven feet from the floor; this sometimes proves, however, to not be high enough. If a ceiling fan is turned on and a person fully extends his or her arms into the air, as sometimes happens during normal tasks such as stretching or changing bedsheets, it is possible for the blades to strike their hands, potentially causing injury. Also, if one is carrying a long and awkward object, one end may inadvertently enter the path of rotation of a ceiling fan's blades, which can cause damage to the fan. Building codes throughout the United States also prohibit industrial ceiling fans from being mounted with the blades closer than 10 feet from the floor for these reasons.
Most households in India are cooled by fans, and less than 10% of households have air conditioning. The average rating of the fans installed and sold in the market is between 75-80W, whereas energy efficient fans provide the same level of comfort at about 45-50W. Considering that almost 30 million fans are sold every year, the potential to reduce demand is significant. Replacing the country's 35 crore inefficient ceiling fans in with BEE 5-Star-rated ceiling fans could save 47 billion KWh and reduce load by over 12,250 MW.
Stack-motor ceiling fans. In the late 1970s, due to rising energy costs prompted by the energy crisis, Emerson invented a new style of electric motor designed specifically for ceiling fans, the "stack" motor. Along with Encon's cast aluminum 20 pole motor, this powerful, energy-efficient motor aided in the comeback of ceiling fans in America, since it was far less expensive to operate than air conditioning. With this design (which consists of a basic stator and rotor), the fan's blades mount to a central hub, known as a flywheel. The flywheel can be made of either metal or reinforced rubber, and can be mounted either flush with the fan's motor housing (concealed) or prominently below the fan's motor housing (known as a "dropped flywheel"). Many manufacturers used and/or developed their own stack motors, including (but not limited to) Casablanca, Emerson, FASCO, Hunter, and NuTone. Some manufacturers trademarked their personal incarnation of this motor: for example, Emerson came out with the "K55" and "K63" motors, Fanimation with the "FDK-2100", and Casablanca with the "XLP-2000". One of the earliest stack-motor fans was the Emerson "Heat-Fan", aka the "Universal Series", a utilitarian fan with a dropped metal flywheel and blades made of either fiberglass or plastic depending on the model. This fan was produced from 1976 through 1983 and, while targeted at commercial settings, also found great success in residential settings. Casablanca Fan Co. also made stack-motor fans with concealed flywheels rather than dropped flywheels. While this motor is not nearly as widely used as in the 1970s and 1980s, it can still be found in certain high-end Emerson, and Fanimation fans. One disadvantage of this type of fan is that the flywheel, if it is made from rubber, will dry out and crack over time and eventually break; this is usually not dangerous, but it renders the fan inoperable until the flywheel is replaced.
Germany established its requirements of building energy efficiency in 1977, and the first energy code-the Energy Saving Ordinance (EnEV) which based on the building performance was introduced in 2002. And the 2009 version of the Energy Saving Ordinance increased the minimum R-values of the thermal insulation of the building shell and introduced requirements for air-tightness tests. The Energy Saving Ordinance (EnEV) 2013 clarified the requirement of thermal insulation of the ceiling. And it mentioned that if the ceiling was not fulfilled, thermal insulation will be needed in accessible ceilings over upper floor’s heated rooms. [U-Value must be under 0.24 Watts/(m²•K)]
Spinner fans employ a direct-drive motor and do not have a stationary decorative cover (motor housing). This accounts for most industrial-style fans (though such fans sometimes have more moderate-quality motors), and inexpensive residential fans used in most asian countries. Spinner-motor fans, sometimes incorrectly referred to as "spinners", employ a direct-drive (spinner) motor and do have a stationary decorative cover (motor housing). "Spinner-motor" fans account for nearly all fans manufactured from the late 1980s to the present. Skeletal motors, which are a high-quality subset of direct-drive motors, can be found on some higher-quality fans. Examples of skeletal motors include Hunter's "AirMax" motor, Casablanca's "XTR200" motor, and the motors made by Lasko for use in their ceiling fans, and as of 2002 Hunter Original have oil-bath skeletal motor. Skeletal motors differ from regular direct-drive motors in that: They have an open ("skeletal") design, which allows for far better ventilation and therefore a longer lifespan. This is in comparison to a regular direct-drive motor's design, in which the motor's inner workings are completely enclosed within a tight metal shell which may or may not have openings for ventilation; even when openings are present, they are almost always small to the point of being inadequate. They are typically larger than regular direct-drive motors and, as a result, are more powerful and less prone to burning out. Friction-drive ceiling fans. This short-lived type of ceiling fan was attempted by companies such as Emerson and NuTone in the late 1970s with little success. Its advantage was its tremendously low power consumption, but the fans were unreliable and very noisy, in addition to being grievously underpowered. Friction-drive ceiling fans employ a low-torque motor that is mounted transversely in relation to the flywheel. A rubber wheel mounted on the end of the motor's shaft drove a hub (via contact friction, hence the name) which, in turn, drove the flywheel. It was a system based on the fact that a low-torque motor spinning quickly can drive a large, heavy device at a slow speed without great energy consumption (see Gear ratio). Gear-drive ceiling fans. These were similar to (and even less common than) the friction drive models; however, instead of a rubber wheel on the motor shaft using friction to turn the flywheel, a gear on the end of the motor shaft meshed with gear teeth formed into the flywheel, thus rotating it. The company "Panama" made gear driven ceiling fans and sold them through "Family Handyman" magazine in the 1980s. Internal belt-drive ceiling fans. These were also similar in design to gear-drive and friction-drive fans; however, instead of a rubber friction wheel or toothed gear, a small rubber belt linked the motor to the flywheel. The most notable internal belt-drive ceiling fan was a model sold by Toastmaster.
Finally, large ceiling fans are installed in every room, even those using air conditioning. Ceiling fans ensure that even in the absence of the necessary breezes, the airflow needed to feel comfortable in the room is provided for the users. This solution significantly reduces the amount of energy consumed. The overall consumption of the ceiling fans and the split system (the latter used to cool the technical rooms) is only 3.7kWh/m².yr compared to a classic air conditioning system in a standard building consuming 80kWh/m².yr.
Due to this renewed commercial success using ceiling fans effectively as an energy conservation application, many American manufacturers also started to produce, or significantly increase production of, ceiling fans. In addition to the imported Encon ceiling fans, the Casablanca Fan Company was founded in 1974. Other American manufacturers of the time included the Hunter Fan Co. (which was then a division of Robbins & Myers, Inc), FASCO (F. A. Smith Co.), and Emerson Electric; which was often branded as Sears-Roebuck.
A ceiling fan is a mechanical fan mounted on the ceiling of a room or space, usually electrically powered, suspended from the ceiling of a room, that uses hub-mounted rotating blades to circulate air. Ceiling fans typically rotate more slowly than other types of circulating fans, such as electric desk fans. They cool people effectively by introducing slow movement into the otherwise still, hot air of a room. Fans never actually cool air, unlike air-conditioning equipment, they in fact heat the air due to the waste heat from the motor and friction, but use significantly less power (cooling air is thermodynamically expensive). Conversely, a ceiling fan can also be used to reduce the stratification of warm air in a room by forcing it down to affect both occupants' sensations and thermostat readings, thereby improving climate control energy efficiency.