• Cooling India
  • Jul 15, 2016

New Generation Fans

There are 3 things that are done to improve the efficiency of fans in super efficient fans


In modern world electrical appliances have become basic need. It is difficult to imagine life without electrical appliances. Most commonly used electrical appliance in house is ceiling fan. It is used for circulating air in the room, thereby giving cooling effect due to breeze around us. Some of the ceiling fan myths are: a) It cools the air- fact is that it gives feeling of cooling due to breeze b) It is not useful in winters- fact is that if it is rotated in opposite direction, it can be used to keep room warm. Table, wall mounted, exhaust and pedestal are the other types of fans used at home. Based on power consumption electrical home appliances are classified as a) high power appliances such as room air-conditioners, heaters and refrigerators b) medium power appliances such as fans, lamps, washing machine, mixers etc c) low power appliances such as television set, music system, LED lamps and other electronic appliances. In the race of cost, size and weight reduction, lot of advancement have been achieved in further power reduction of low power appliances. While most people target only heaters, room air-conditioners and refrigerators when they think about electricity savings, but fans contribute much more to the electricity bills and could be close to about 30% of the electricity bills. Compared to lights that are switched on only in the evening, ceiling fans are on for most part of the day and even during night time. Their number is also high and could be close to one per head. Ceiling fans consume more electricity than conventional tube light. Thus lot of energy can be saved through improvement in ceiling fan.

  In only 2006, Bureau of Energy Efficiency (BEE) launched its standards and labeling program. Since then most of the electrical appliances are being rated on a scale of 1 to 5 on their efficiency. Most appliances are labeled and sold as BEE star rated appliances. The level of efficiency of appliances in India has not reached the level of efficiency established in most efficient appliances in technically advanced countries. A rapid market transformation is done to only three appliances: Heaters, room air conditioners and refrigerators. In view of this, BEE has launched a new scheme to promote manufacturing of BEE 5 star rated fans and super efficient ceiling fans.

  Most people believe that BEE 5 star rated fans deliver less air and using the same may not give similar comfort as a regular fan. BEE 5 star rated fans have minimum air delivery of about 210-220 CMM whereas regular fans have the value of 250 CMM. Air delivery depends on blade pitch, blade shape and size, speed and power of motor used in fan and height of fan from ceiling. Regular fans are rated at 75 Watts, but the new fans are rated at 50 Watts (30% savings). In fact some BEE 5 star rated fans are also rated at about 45 Watts. Thus there is clear cut saving. Super efficient fans are the further advancement in ceiling fans. Tata Power and Reliance Energy are promoting user to go for these kinds of energy efficient fans. As ceiling fans contributions to the total electricity bill is significant for most of electricity bills, the interest in super efficient fans is inevitable. Comparison of normal fan, BEE 5 star fan and superefficient fans is available in literature on fans. It was decided to do analysis of super efficient fan operation in slightly different manner.

  The new super efficient fans that are available in the market use a different type of electronic motor, which is also called Brushless DC (BLDC) motor. Conventional ceiling fan consumes about 75 Watts of power for 1200mm sweep. This new technology with efficient blade designs makes ceiling fans far more efficient, and the fans consume 28-35 Watts of electricity, which is about 50% less than the old regular fans. Some of such ceiling fans have air delivery of about 230 CMM that makes them almost the same in performance as compared to the regular ceiling fans. They use advanced composite materials which is light in weight and with better surface look coming in variety of color combinations. The one downside of a super efficient fan is that the power factor of such fans is 0.9 as compared to 0.95 of regular fans with induction motors. It may impact commercial connections with demand charges in their tariff plan. Lot of electronics has come in fan systems. Now, fan speed regulators are remote controlled. Concept of rheostatic fan regulator or power electronic devices based regulator has gone. Today these super efficient fans work with remote control for its functional operations. Timers and auto speed reduction features has come to these super efficient fans. In built LED lamp has become feature of these fans. In future concept of super efficient fans will be extended to table fans, pedestal fans, wall mounted fans and exhaust or ventilation fans. Currently various manufacturers of these super efficient fans are superfan, Luxaire, gorilla fan and orbit green fan. Block diagram of super efficient fan is shown in Fig1. On the face of it, the price of the super efficient fans look high, but if we look at current and rising electricity costs, opting for super efficient fans makes a lot of sense especially to replace the high usage fans. The current specifications of these super efficient fans look really good, and if there is good response from the market, there will be significant savings of electricity for the consumers as well as nation in the future. Looking at the high costs for buying a super efficient fan, most people would be interested in comparing numbers before making a buying decision. A super efficient fan will pay back for itself in about three and half years. Also it offers a 5 year warranty.

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There are 3 things that are done to improve the efficiency of fans in super efficient fans:
1. Performance is improved by improving the induction motor.
2. Use of BLDC (or Brushless DC technology).
3. Improving the design of the blades.
The above implementations involve replacing some electrical components with electronic components thus allowing for a smoother control of the fans. As per BEE specifications, these changes should allow super efficient fans to give:
1. Higher air flow at full speed;
2. Low noise through the use of better quality blades;
3. In order to be more suitable for Indian conditions:
a. Very low degradation in performance at lower voltages;
b. Reliable even under high ambient temperature;
4. Lowest power consumption reasonably possible.
Power consumption of regular fan and super efficient fans of 2 companies is compared at various speed positions of speed regulator. Power consumption of super efficient fan at various speed positions and air delivery corresponding to it is given in Table 1.

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  Air delivery of super efficient fan is @ 70% to 80% for fan speed positions 4 to 3. In these positions, power consumption is very small. In fact, lowest power consumption of regular fan at speed at regular position is higher than highest power consumption of super efficient fans. Most of the time, we operate fan at lower speed settings. At these positions, power consumption is extremely small. Thus, even though it has rotating parts, its power consumption is comparable to LED power consumption. Thus, super efficient fan is the latest change in fan technology and it will replace all regular fans in coming decade.


AUTHOR CREDIT AND PHOTOGRAPH

ATHUL

Athul Raj
Research Scholar,
Army Institute of
Technology, Pune

KARANDIKAR

Dr P B Karandikar
Associate Professor,
E&TC Department,
Army Institute of
Technology, Pune

SANKPAL

Dr J B Sankpal
Professor and
HoD- Mechanical,
Army Institute
of Technology,
Pune