Compact Fluorescent Lamp (Tube) (CFL) :
Q. Explain with diagram construction and working of CFL lamp.
Q. Explain with diagram construction and working of CFL lamp.
- These are lamps of choice for those looking for an energy efficient alternative to incandescent lamps; they are paired for consuming and little as 1/5th of the power and lasting upto 13 times longer than incandescent lamps.
- Increasing variety in shape, colour and small size of CFL has made them move versatile and acceptable than traditional long tube fluorescent lamp.
- Atypical CFL consists of a gas filled gas tube with two electrodes mounted in an end cap. It contains a low pressure mix of argon gas, mercury vapour and liquid mercury and is coated on the inside with three different phosphors.
- They give off light when exposed to ultraviolet radiation released by mercury atoms as they are bombarded by electrons. The flow of electrons is produced by an arc between two electrodes at the end of the tube.
- Ballast provides the high initial voltage required to create the starting arc and then limit current to prevent the lamp from self destruction.
- Ballast themselves can be “standard" electromagnetic, "energy efficient electromagnetic or electronic and may have power factor correction, radio interference, suppression or other features unheard of in the world of incandescent light.
- With development of more efficient "tri-phosphor" coatings came smaller 'CF with light in red, blue and green giving white light when blended together.
- By changing relative balance of these phosphors, manufacturers can produce range of apparent colour temperature from a cool 4100°C to a warm 2700°K.
- Colour rendering index of lamp reflect how accurately colour of an object can be determined under given light source. CFL have CRI of 82 out of 100 while incandescent have 97 which is considered excellent for fluorescent sources.
Temperature Effects on Performance :
- The ambient temperature around a 'CFL' can have significant effect on light output and lamp efficiency. The optimum lamp wall temperature for CFL is generally 100°F ( 38°C ).
- At very low temperature (below 32°F or 0°C) lamp output can decline to one third of the rated value or less.
- Because of temperature below optimum, mercury vapour will condense at cold spot, reducing number of mercury atoms available to emit u.v. radiations, thus light output drops.
- Thus compact fluorescent lighting system offers potential for significant economic and environmental savings. Therefore, versatile range of different lamp ballast configurations is available that can provide a comfortable, productive and well-illuminated space if properly used.
- More energy efficient than incandescent lamps: When compared to incandescent lamps, fluorescent lamps can produce the same amount of light or lumens using lesser energy input. Residential and commercial grade fluorescent tubes and bulbs, including compact fluorescent lamps or CFL bulbs, can produce 50 to 100 lumens per watt. Meanwhile, a typical incandescent bulb produces 16 lumens per watt. This advantage translates to energy efficiency than in turn, leads to reduced electricity consumption and cost.
- Longer operational lifespan: Another advantage of fluorescent lamps over is their lifespan. A typical fluorescent bulb will last 10 to 20 times longer than an incandescent bulb. Specifically, fluorescent lamps have an operational lifespan of 6000 to 15000 hours while incandescent lamps only have 1000 hours. Due to their longer operational duration, one of the notable benefits of using fluorescent lamps involve reduced time and cost associated with replacement and maintenance.
- Better light diffusions and distribution: Fluorescent lamps are bigger light sources than incandescent lamps. Furthermore, most fluorescent bulbs or tubes readily diffuse light that results in better distribution of illumination within a particular area. In contrast, incandescent lamps are smaller light sources, and they produce undiffused light as evident from glares and uneven illumination.
- Less heat emission: Incandescent lamps generate too much excessive heat because they consume too much energy input. Hence, another advantage of fluorescent lamps is less heat emission due to their efficient energy consumption. Typical fluorescent bulbs such as CFLs convert of 22 percent energy input to visible light while incandescent lamps only use 5 percent of energy input to produce visible light and the remaining 95 percent is converted into heat. This advantage translates further to other benefits such as comfort and reduced cost from air conditioning and ventilation.