WHAT IS THE EFFECTIVENESS OF A CEILING FAN?
From Superfan, India’s first super energy efficient ceiling fan
The primary objective of a ceiling fan is to offer thermal comfort to the occupant. The effectiveness of a ceiling fan is the measure of its thermal comfort and its other aspects like efficiency, durability, noise limit, wellness, local influence, value, environmental impact.
The condition of people’s minds that expresses satisfaction with the thermal environment is called thermal comfort.
For many years, humans have been using fans to regulate thermal comfort. Ceiling fans regulate their occupants’ thermal comfort by pushing air beneath their blades swept area.
How ceiling fans offer thermal comfort?
The normal core body temperature of humans is about 37o C, the thermal regulation system in our body aims to keep the body at normal temperature. The normal bodily functions increase the core temperature and the excess heat is dispersed by blood to the skin by the phenomenon of conduction and convection. According to the second law of thermodynamics, heat is readily transferred from a hotter body to a cooler body. So, if the surrounding temperature is lower than the skin temperature, the heat from the skin is dissipated to the surrounding and leaving the skin to receive more heat from the core, for it to cool down.
The human body can cool down even if the temperature of the surrounding is hotter than the skin. This is accomplished by sweat, when the body core temperature rises above normal, the nervous system activates the sweat glands to secrete sweat through the skin. The sweat droplets absorb the heat from the skin and reach the same temperature as the skin. A liquid evaporates when it is in contact with another medium, this evaporation leaves the remaining liquid cooler, this type of cooling of a liquid is called evaporative cooling. When the sweat begins to evaporate the remaining sweat cools down and is ready to accept more heat from the body, thus continuing the process of cooling despite the surrounding being at a higher temperature. Physiology text quotes a loss in the amount of about 600 grams of moisture per day from the human skin due to body heat.
The rate of evaporation increases if the air in the surrounding moves, the increased rate cools the body more and quicker. Ceiling fans provide the movement of air and cool an occupant. Ceiling fans do not change the temperature of the space but cool down the occupant, whereas an AC cools the space and in turn, the cooler surrounding cools down the occupant.
Ceiling fans to effectively offer thermal comfort must deliver adequate airflow. Air delivery in ceiling fans represented in Cubic Meter Per Minute (CMM) is the measure of the volume of air moved by them per unit time.
Ceiling fans not only offer thermal comfort by cooling down in hot climates, they improve the air circulation in its operating space to make their occupants feel warm in cold climates. In an enclosed space or a room in cold climates, the hot air ascends upward near the ceiling due to the temperature difference creating several layers of air spheres with varying temperatures. Airflow delivery from the ceiling fans de-stratifies (mixes) those air spheres to provide a more consistent temperature inside the room.
Most of the ceiling fans provide the basic necessity of thermal comfort to their occupants, while the remaining aspects are trade-offs that may be compensated to offer the optimal thermal comfort.
The efficiency of a ceiling fan is the measure of the electrical power consumed by it for delivering the desired airflow. Ceiling fans are rated as efficient for running more hours at top speed (to provide the highest airflow) per unit of electricity. As the primary objective of ceiling fans is to offer thermal comfort, their trade-off with efficiency must be a thought-out process.
Reducing cooling energy requirements to 25 % to 40 % by 2037-38 is one of the significant objectives of the India Cooling Action Plan (ICAP) launched by the Ministry of Environment, Forests, and Climate Change of the Government of India. Ceiling fans being widespread appliances used for space cooling across India, marginal improvement in their efficiency could contribute a major outcome to fulfill the aim of ICAP.
The measure of efficiency in ceiling fans is its service value which is the air moved by the fan on its occupant for per unit of energy supplied. The air moved is called the air delivery of the ceiling fan and is measured in Cubic Meter Per Minute (CMM) and energy is measured in watts (W). The greater the service value, the higher is the efficiency, higher the electricity savings.
Bureau of Energy Efficiency (BEE), Government of India has devised an energy-efficient star rating system for ceiling fans above service value 6 labeled as 5-star and as 4-star so on. Choose ceiling fans with a 5-star energy rating for higher energy efficiency.
Ceiling fans are long-lasting and essential appliances. Therefore, a ceiling fan must offer reasonable years of warranty to inculcate confidence in the minds of their customers. Though the primary objective of ceiling fans is to provide thermal comfort for occupants, their longevity would offer more value to the consumer and maximize the utilization of the raw materials.
There are two sources of noise from a ceiling fan, noise from the moving parts of the motor, noise from the air interaction with the blades. The noise from the motor is usually minimal and heard only at lower speeds (RPM), the source is mostly mechanical and sometimes electronics. These are usually by design rather than some failure in the fan. The noise from the blades is commonly called air cutting noise, this depends on the speed (RPM) of the blades. The air cutting noise from the blade is directly proportional to the fan speed (RPM). If the fan speed is lower, it produces negligible noise.
Sometimes the noise from the blades of ceiling fans is permissible for the occupants. In spaces like bedrooms and study rooms, the noise from the ceiling fans blocks all sudden variations of sound in the environment. This useful noise is called the white noise. The white noise from ceiling fans especially in the bedrooms helps occupants to sleep without disturbance. While the noise from high speed ceiling fans may disturb conversations and entertainment (TV) in living rooms, halls, classes and auditorium hindering the auditory performance.
The airflow of ceiling fans eliminates the sensation of the stale or stuffy air and helps to dissolute odors. In a clean room, the mixing up of air helps better air circulation for breathing.
Generally, most ceiling fans are designed to offer thermal comfort delivering a smaller volume of air at a higher speed. A ceiling fan rotating at a higher speed produces high speed air. Exposure to a high speed air could cause health discomforts like congestion, dry eyes, nasal dryness, muscle stiffness, and tiredness, etc. (to know more in detail) especially when you sleep or sit under it for a longer duration.
There are high flow ceiling fans that offer the same or better thermal comfort while eliminating the health discomforts by increasing the airflow and reducing the speed. High speed ceiling fans are suitable for shorter duration exposure and high flow ceiling fans are suitable for longer duration exposure.
While choosing a fan, the usage hours must be taken into account to select either of the two types for getting better overall comfort.
Ceiling fans emit heat due to their motor operation. Though heat emission in BLDC ceiling fans is negligent in comparison to the AC ceiling fans, the reduction in heat emission can still be optimized to innovate the best energy-efficient ceiling fan that effectively converts 100 % of input power to rotate its blades for offering the desired airflow.
Power Factor (PF) is the measure of wastage of electricity to the national electrical grid to power ceiling fans. This wastage in electricity can be measured by dividing the power that a ceiling fan consumes with its Power Factor. This electricity wastage from ceiling fans for each domestic consumer seems negligent as they are not billed or fined for these additional units of their electricity consumption by the electrical grid. While commercial consumers, who buy ceiling fans for bulk usage are fined since their electricity wastage seems considerable. Therefore, this influence of power factor remains to be miscellaneous in the purchase journey of ceiling fans, unless customers make a bulk purchase.
In India, about 1.5 kg of CO2 is emitted and 2 liters of water is contaminated to generate 1 unit of electricity.
An appliance being efficient (consuming less energy) provides more benefit to our society than the individual electricity bill savings. Given that there are about 50 crores fans in India and about 5 crore new fans are sold every year, it would be prudent for consumers to choose energy-efficient fans to reduce the environmental impact and leave a better future for the next generations.
There are environmental concerns beyond energy consumption like the end of product life cycle plan, recyclability, reducing manufacturing wastes, energy-efficient manufacturing, eco-friendly business practices, eco-friendly packaging, eco-conscious logistics, reparable design, and so on. A truly energy eco-friendly product would strive to be conscious of all these aspects.
The value of ceiling fans is the sum of the above listed aspects that a customer receives for exchange of their price.
The initial cost of a ceiling fan must be priced at a cost to deliver the values to the consumer. The values that a consumer gets could be in the form of the optimality in the above-discussed aspects and how sooner they are about to get the return on investment through the savings in electricity bills.
Superfan produces BLDC ceilings fans with higher effectiveness, which gives the best thermal comfort for their occupants leaving minimal tradeoffs for efficiency, durability, noise level, wellness, local influence, value, and environmental impact.
Now let us estimate the effectiveness of the Super Q BLDC ceiling fan
Thermal comfort: Superfan offers the Super Q fan with patented energy-efficient BLDC motor design and Q flow blade design technology that claims to be the ceiling fan offering the optimal thermal comfort right now in the market.
Efficiency: Super Q fan comes with the most energy efficient BLDC motor design which is independently validated, contributes the best savings to electricity bills. Its heat emission and power factor electricity wastage also seem to be the most minimal compared to other BLDC ceiling fans.
Durability: All Superfan BLDC ceiling fan models including Super Q offers 5 years of warranty since Superfan is confident with the reliability of the patented BLDC ceiling fan design. Superfan was the first ceiling fan in India to introduce a 5-year warranty.
Wellness: Superfan offers both high speed and high flow ceiling fans, letting the consumers choose the right fan for their use. To Know how to choose a ceiling fan.
Eco-friendliness: Eco-friendliness of Superfan extends beyond its product. Superfan constantly strives to reduce the carbon footprints throughout its product life cycle by eco-friendly infrastructure, eco-conscious manufacturing, and plastic-free packaging.
Value: BLDC ceilings fans of Superfan are an investment for its customers in terms of money as the initial cost is paid back in electricity bill savings. The additional value of being an Indian product, environmentally friendly, higher warranty make it one of the best values among other ceiling fans.
Edit 29 June 2021
Super Q got featured as the MOST ENERGY EFFICIENT APPLIANCE OF THE YEAR in the SURVEY OF ENERGY CONSERVATION IN INDIA 2021 published by LABOUR & INDUSTRIAL CHRONICLE (3rd edition) in page no: 146
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