Thermal Batteries: Can You Help Me Potentially Save a Billion Human Lives? Global Warming and Infrared LEDs.

In January 2016 NASA put out a call for engineers to design an impossible light fixture that produced zero heat. This was because excess heat on a space ship is always a potential catastrophe. Once produced, thermal kinetic energy can only leave the spacecraft after converting to infrared radiation. The amount of time this conversion process takes is considerable, so heat has ample time to build up. This accumulation, along with the prolonged time it takes to dissipate, can lead to catastrophe. That’s where we come in.

I started investigating the dissipation problem in 2016. My engineering team focused on accelerating the conversion of thermal kinetic energy to infrared radiation and then radiating it away from the spacecraft. With this potential invention, the spacecraft could radiate all waste heat away ensuring temperature equilibrium. As a result, spacecraft, astronauts, and any devices on board would not suffer from catastrophic heat build up.

Then we had an idea. We recognized that the Earth may have a similar temperature equilibrium problem, Global Warming. Since the Earth is insulated in the vacuum of space, like a spacecraft, we can’t eliminate heat without beaming it away. Unfortunately, the human race produces a significant amount of waste heat. 50% of the energy from human activity is wasted as thermal kinetic energy or heat, through electrical infrastructure, internal combustion engines, camp fires and even body heat. With the elimination of this kinetic heat being extremely difficult, and the production of kinetic heat at historical highs, we have a problem.

Previous to this, scientists have rejected the impact of our civilizations heat production here on earth. Compared to the sun we only produce trace amounts of heat energy, leaving climate scientists to dismiss waste kinetic heat as a cause of global warming. That’s true until you look at the “thermal battery effect”. Once kinetic heat energy is created inside a system, the molecules and atoms move and vibrate in that system until the energy is converted to infrared radiation. Because this energy “state change” takes time, this leads to a significant temperature increase inside every closed system. In the case of the Earth, I now think it is the root cause of global warming (not greenhouse gases).

To eliminate climate change we have contracted Dr. Brett Teeple to generate a paper outlining the physics and math involved in the “heat piling”. Our project proposal is to use a heat capture compressor (X 10,000 units per country) to filter thermal kinetic energy out of the atmosphere and radiate it into space. The key part is our reaction catalyst which will accelerate thermal kinetic energy’s state change into infrared radiation. As you might imagine, this would ensure the climates stability in the immediate and long-term future.

It is true that The water vapour and carbon dioxide in the atmosphere are big absorbers of infrared radiation. This reduces the efficiency of the photonic “dump”, but physics can find “optical windows” that optimize the specific wavelengths require to efficiently penetrate our atmosphere.

What do you think? Have we missed any critical points? Let us know! On the other hand, should you wish to add value to the project or submit your resume for consideration, contact Jode Himann. You can also request the Comprehensive Research Package from www.crselectronics.comalong with the answers to any questions you have.

Image 1.0. A macro image of a fly melted into acrylic. Notice the fly wings and hair are undamaged despite the high optical radiation.

Image 1.1. A Flir thermal image of two flies on a 800 Watt LED fixture.

Image 1.3. A image of two flies on a 800 Watt LED fixture.

The chances may be small but not impossible that a bottle of water, in the presence of a hazardous location environment in the right conditions of sunlight and geometry may exceed the threshold for combustion. Standards organizations would need to make accurate measurements to validate the potential threat.

Optical Ignition in LED Luminaires

While the bottled water example is interesting, it is not the primary concern of a lighting manufacturer. It does, however, help us to recognize that there is an explosion danger with excessive optical radiation in a hazardous location, and we must be cognizant of this in our luminaire designs. The IEC 60079-28 Ignition, Optical Radiation standard covers the range from 380 nm to 10 um and recognizes the following as potential sources of industrial optical radiation:

Electrical lamps
Lasers
LEDs
Optical Fiber

Mechanisms of optical ignition are:

Optical Radiation is absorbed and heated by surfaces or particles. Under ideal conditions, this may result in a sufficiently high temperature causing ignition of the surrounding atmosphere.
The wavelength of the optical radiation source matches with the Absorption band of a gas volume to cause thermal ignition.
Photochemical ignition due to photo dissociation of oxygen molecule by ultraviolet radiation.
Direct laser induced breakdown of the gas at the focus of a strong beam producing plasma and shock wave, supported by a solid material close to the breakdown point.

The IEC standard assesses ignition hazard according as Annex C and breaks down optical ignition into 3 components. The approved Equipment Protection Level (EPL) is based on combinations of these components:

Both luminaire manufacturers and facility managers must pay attention to the possibility of an optical ignition hazard when any high brightness light source is considered for installation in a hazardous location. Optical ignition often goes un-recognized as a potential hazard by the general public and site safety officers. Whenever optical radiation exceeds a certain threshold for optical power density, extra care must be taken in luminaire design, site design, and operating procedures to mitigate this risk. As the US and Canadian standards do not explicitly evaluate for this risk, it goes un-noticed by many luminaire manufacturers.

In our experience, the presence of debris or dirt on the lens of the luminaire poses the most direct risk for most real-world installations in hazardous locations. Most hazloc environments are inherently dirty, and oils, mud, dirt, and biological material can often be found on luminaire surfaces and lens. We’ve experienced cases where upward facing luminaires have a compromised enclosure due to flying and crawling insects that are attracted by the light, but subsequently killed by the exposure to the luminaires intense heat. Their bodies have been found melted through the lens or plastic enclosure. Since the integrity of the enclosure is critical for safety in most Class I Division 2 product designs, the compromised seal can result in a critical failure.

Any concentration of light can heat up a surface or particles. The IEC standard provides a safe upper limit of optical radiation of 5 mW/mm², which is a specification that guides our circuit board design. When Light Emitting Diodes (LEDs) fail due to excessive power in fault conditions, the boards are designed to be failsafe. Failure characteristic of certain optical sources are used to limit optical radiation in case of a fault.

Fixture Analysis

Given this knowledge, we established a standard engineering procedure to calculate and verify the optical ignition photon flux for all our fixtures designed for hazardous location application. The fixutures that use LEDs which exceed 5 mW/mm²all employ secondary diverging optics which have a focal point in an imaginary plane. This means that by the time the light is outside the lens, it is attenuated to below 5 mW/mm². As the table of optical flux at the window shows, most of the fixtures that we manufacture turn out to be safely under the maximum optical radiation limit of 5 mW/mm². Those that exceed it are rejected for hazardous location application.

As an example of a typical calculation, for a hazardous location model XCANLED, with a fixture size of 5” diameter (12.7 mm²)the maximum optical power is 63.3W evenly distributed across the fixture window. This means that for Zone 0, Zone 1, and Zone2, the max drive power we can use in an XCAN size fixture is around 190W (assuming 33% of LED power is converted to light out) or else the light output could be sufficient to cause an explosion (the most frequent ignition source in this case seems to be debris or absorbing materials landing on the lens or in the beam path). This only applies to a wide beam or flood luminaire without secondary optics. In the case of the secondary optics we have to consider the power density at the light emitting surface (LES) of the LED as the limiting factor for what power density can be obtained with an appropriate optical element to focus the light.

Radiometric efficiency is 33% (previously measured for a cool while XML at 113lm/W efficacy, should be slightly better than what the XCAN or RS LEDs will be operated at)
All optical power passes within the FWHM cone (a conservative estimate)

Conclusion

We started the discussion with bottled water. IEC 60079-28 does not cover fusion driven light sources, and our bottled water magnifying glass example unfortunately remains outside of its scope. Should we be concerned with magnifying glasses and water bottles left in the sun? Absolutely. With no written code to guide us, however, we only have our own engineering calculations and verifiable stories of bottled water causing combustion in non-hazardous location scenarios. These should be enough to warn us of the potential dangers. The long and short of it, keep and drink your bottled water in safe areas only. Or use a non-magnifying container, like a thermos!

Optical ignition is scientifically recognized as a real danger in hazardous location area and LED luminaire design and installation must respect these findings. While not currently regulated by US or Canadian standards due to industry policy adoption lagtimes, optical ignition hazards are one area where additional precaution should be proactively taken in both the design and installation of luminaires, in order to mitigate this seldom noticed risk. In the design process, maximum lumens must be traded off with staying under the optical ignition threshold. This impacts the choice of LEDs, secondary diverging optics and failsafe circuitry. In the field, while good practice indicates high brightness fixtures should always be located in the lowest hazard area possible, the orientation of those luminaires should also be carefully planned to reduce the possibility of light absorbing dirt, debris, or equipment being located in the region of highest light intensity in order to minimize the possibility of optical ignition. Windows should be facing down, and positioned away from probably splatter zones.