May 17, 2020

The end of our fascination with fluorescents?

energy digital
Light Planet
5 min
Understanding LEDs
Written by Steve Edwards, Technical Director and advanced LED specialist, Light Planet Earlier this week, news emerged from the US that researchers h...


Written by Steve Edwards, Technical Director and advanced LED specialist, Light Planet


Earlier this week, news emerged from the US that researchers have developed a new type of lighting that could replace fluorescent bulbs. The new source is reportedly more efficient, produces a better quality of light and is flicker free. 

Whilst the concept of light from polymers is certainly intriguing, I was somewhat taken aback by the attention the story received. After all, we already have viable alternatives for the fluorescent tube that does all of the above. So why are we under the impression that we don’t?

To understand the context we need to look back. The UK has long had a fascination with the T8 fluorescent tube. Wherever you look; whether waiting for a train, riding a bus, working in an office, shopping in a department store, or parking in a car park, the T8 fluorescent is ever present.

Why is the T8 so popular? In a nutshell, a T8 tube emits a lot of light for relatively little power consumption. It also emits all of the way around its surface allowing lighting designers to use reflectors to bounce light around a room.

More recently, the T8 fluorescent has been superseded by the thinner T5. Despite a belief that the T5 is more efficient than the T8, the typical lumen efficacy of a T8 (86-94%) and T5 are, essentially, the same. Other forms of fluorescent technology also exist, including compact fluorescent, 2D, and PL lamps (the curly, low energy lamps sold in their thousands).

Despite this popularity, there are several facts about fluorescent lights that you won’t read on the box. A fluorescent lamp is filled with a gas containing low-pressure mercury vapour. The mercury vapour is excited by electricity to produce UV light. The inner surface of the bulb is coated with a fluorescent (and slightly phosphorescent) coating made of varying blends of metallic and rare-earth phosphor salts. The UV light causes the phosphor coating to ‘fluoresce’, which re-radiates the energy as visible light.

If a fluorescent light is broken, the mercury inside can be released into the air or ground and it is advisable to vacate the room for several minutes if this happens. The reason that we have to dispose of fluorescents in managed recycle centres is that they have to be carefully dismantled in a controlled environment to stop pollution of the ground and atmosphere. It is not just the construction and operation of the fluorescent that causes problems, in practice the performance of a fluorescent is often over played.

Typically a 58W T8 fluorescent claims to emit up to 5,600 lumen with an average lifespan of 20,000 hours, or 2.3 years at continuous run. A 54W T5 fluorescent is rated at up to at 5,000 lumen with the same lifespan. However, how these figures are arrived at needs some consideration.  This light output is measured at a room temperature of 35° C. With winter starting to bite, even those of us in over-heated offices know that the room temperature is no-where near this high in normal buildings. At a more comfortable 25°C, the light output is reduced to approximately 89% for the same power consumption. In addition, the lifetime figure is achieved when the light is run in a 3-hour switching cycle (3 hours on, 15 minutes off). When the light is run in any other way (which it almost certainly will be) the lifetime is reduced.

These factors have long since led luminaire designers to look for viable alternatives.  A LED (a light-emitting diode) is a semiconductor that converts electricity into light. Traditionally associated with the small red light on your TV monitor or remote, LED lighting technology has seen major development in recent years, fast-becoming a better alternative to traditional lighting technologies. LEDs emit a high light output for less power consumption (40-50% lower), have a higher luminous efficacy (up to 95%), a long-life (35,000 to 50,000 hours) and are safe with no strobing or flicker.

Architects, contractors and end-users are increasingly opting to install LED panel lights in place of the 4-tube fluorescent modular lights often seen in offices. So why not also retrofit LED tubes? The truth is that early adopters of LED tubes found them to be a disappointment. LED tubes are made, predominantly, from a plastic tube within which the LED chips and their driver electronics are mounted. When the LED heated up, the plastic tube could warp causing the light to fail. In addition, because LEDs emit light in one direction, when retrofitting into fluorescent fittings, the LED tubes could not always direct the light where it was needed.

But LED technology has moved on dramatically in recent years and design innovations have successfully eradicated these issues.  The introduction of aluminum to the external structure of the LED tube now provides a structurally sound product, eliminating the warping common in early models. The continual development of the luminous efficacy of LEDs (how much light is emitted for power consumed) has seen figures in excess of 100 lumens per watt, which matches that of a T5 fluorescent. In my company, for example, several design innovations within our LED tube product range have dramatically increased our ability to compete in the traditional fluorescent market, including the advent of rotatable end caps that allow the installer to easily retrofit the tube into any fitting, and the introduction of LED tubes that emit light upwards as well as downwards emulating the all round light distribution of fluorescents.

This kind of advanced technology is resulting in a steady increase in the adoption of LED tubes for property retrofit projects. Whilst the cost of LED is still relatively high compared to fluorescent, the high level of performance, length of reliable life span, safety and flexibility of these tubes positions them as an attractive and commercially viable alternative. The only real barrier to LED adoption is lack of understanding or experience with these products. New inventions in the field are welcome and will drive continued innovation, but perhaps we should pay more attention to the existing technology that’s ready and waiting.

Read More in Energy Digital's November Issue



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Oct 19, 2020

Itronics successfully tests manganese recovery process

Scott Birch
3 min
Nevada firm aims to become the primary manganese producer in the United States
Nevada firm aims to become the primary manganese producer in the United States...

Itronics - a Nevada-based emerging cleantech materials growth company that manufacturers fertilisers and produces silver - has successfully tested two proprietary processes that recover manganese, with one process recovering manganese, potassium and zinc from paste produced by processing non-rechargeable alkaline batteries. The second recovers manganese via the company’s Rock Kleen Technology.

Manganese, one of the four most important industrial metals and widely used by the steel industry, has been designated by the US Federal Government as a "critical mineral." It is a major component of non-rechargeable alkaline batteries, one of the largest battery categories sold globally.

The use of manganese in EV batteries is increasing as EV battery technology is shifting to use of more nickel and manganese in battery formulations. But according to the US Department of Interior, there is no mine production of manganese in the United States. As such, Itronics is using its Rock Kleen Technology to test metal recoverability from mine tailings obtained from a former silver mine in western Nevada that has a high manganese content. 

In a statement, Itronics says that its Rock Kleen process recovers silver, manganese, zinc, copper, lead and nickel. The company says that it has calculated – based on laboratory test results – that if a Rock Kleen tailings process is put into commercial production, the former mine site would become the only primary manganese producer in the United States.

Itronics adds that it has also tested non-rechargeable alkaline battery paste recovered by a large domestic battery recycling company to determine if it could use one of its hydrometallurgical processes to solubilize the manganese, potassium, and zinc contained in the paste. This testing was successful, and Itronics was able to produce material useable in two of its fertilisers, it says.

"We believe that the chemistry of the two recovery processes would lend itself to electrochemical recovery of the manganese, zinc, and other metals. At this time electrochemical recovery has been tested for zinc and copper,” says Dr John Whitney, Itronics president. 

“Itronics has been reviewing procedures for electrochemical recovery of manganese and plans to move this technology forward when it is appropriate to do so and has acquired electro-winning equipment needed to do that.

"Because of the two described proprietary technologies, Itronics is positioned to become a domestic manganese producer on a large scale to satisfy domestic demand. The actual manganese products have not yet been defined, except for use in the Company's GOLD'n GRO Multi-Nutrient Fertilisers. However, the Company believes that it will be able to produce chemical manganese products as well as electrochemical products," he adds.

Itronics’ research and development plant is located in Reno, about 40 miles west of the Tesla giga-factory. Its planned cleantech materials campus, which will be located approximately 40 miles south of the Tesla factory, would be the location where the manganese products would be produced.

Panasonic is operating one of the world's largest EV battery factories at the Tesla location. However, Tesla and other companies have announced that EV battery technology is shifting to use of nickel-manganese batteries. Itronics is positioned and located to become a Nevada-0based supplier of manganese products for battery manufacturing as its manganese recovery technologies are advanced, the company states.

A long-term objective for Itronics is to become a leading producer of high purity metals, including the U.S. critical metals manganese and tin, using the Company's breakthrough hydrometallurgy, pyrometallurgy, and electrochemical technologies. ‘Additionally, Itronics is strategically positioned with its portfolio of "Zero Waste Energy Saving Technologies" to help solve the recently declared emergency need for domestic production of Critical Minerals from materials located at mine sites,’ the statement continues.

The Company's growth forecast centers upon its 10-year business plan designed to integrate its Zero Waste Energy Saving Technologies and to grow annual sales from $2 million in 2019, to $113 million in 2025.

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