Renergen (ASX: RLT) creates vaccine storage solution, page-34

it looks like i owe "stuckinhouse" some sort of apology....

In order to gain some understanding and clarity on on house`s post, i reached out to Stefano for some feedback. Stefano`s response is below...
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Hi Michael

Thanks for your mail asking for clarification on @stuckinhouse’s question around helium vs nitrogen. This is hopefully a little explainer to address @stuckinhouse and the presented calculations. Let me firstly say that I appreciate his comments, unless people test assumptions, the world follows on blind assumptions and therefore this kind of scrutiny is highly appreciated. Whilst I not only welcome @stuckinhouse’s question, I also applaud it as this is a person who has done research and is sharing insights. Given the patent is pending, Renergen cannot divulge much more than I am saying here, but suffice it to say, the latent heat of vaporisation is definitely NOT the only property you want to leverage if you are keeping goods cold in transit for long periods of time as you would be limited to the temperature at which the substance undergoes this phase change. We did have 4 engineers, 2 independent, scrutinise the patent application to ensure the thermal calculations work, so this isn’t just a publicity stunt.

What @stuckinhouse presented is correct, but it is only a very small part of the whole system. Trust me, the whole calculation isn’t pretty – thermodynamics isn’t for the feint of heart. But this is where our device is considered novel in how it delivers cooling, which is why we had the ability to apply for a patent. To maximise the longevity of the cooling, one needs a liquid whose latent energy of vaporisation is incredibly low in order to maintain more effective control of the temperature in the case, hence from what we see this is unique.

What @stuckinhouse misses is the last piece of information; the total energy transferred to either gas in its progression from liquid at boiling point to gas at around -70 degrees. Helium will absorb approximately 1,003kj/kg whereas nitrogen can only capture 320kj/kg, so 3x more. Now here is the “but”: the majority of nitrogen’s energy is transferred during vaporisation (as shown by @stuckinhouse), which is useful if you are using the saturated liquid directly to cool the vaccines. Helium phase changes very quickly, and most of its available energy capacity is in the gas phase (opposite to nitrogen). Nitrogen uses a lot of its “power” to keep the “battery” operational, and only delivers about 1/5^th of the usable energy to the vaccines that helium can because the majority of the available energy goes into the vaporisation process.

If you want a really simple way of looking at it: helium has a much further way to go from -269 to -70 than nitrogen’s -195 to -70. This is massively over-simplified, but an easy way to think about what is happening inside the case without seeing the diagrams or calculations. The last point: helium is arguably around 60-90x more expensive than nitrogen, no doubt. We got several competitive quotes from global shipping firms moving a hypothetical payload of a ton of Cryo-Vacc cases into Southern Africa from the US, and the weight/time constraints made the overall delivery cost of helium vastly cheaper than nitrogen. More than 80% of the cost is freight. Helium is cheap at the price.

Cheers

Stef

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Super excited about this innovation as it can present a very important logistical solution in both the current environment, and for other applications moving forwards...