[franckl]

We are building the world's highest temperature heat pump. It can reach 1000℉, when other commercial heat pumps usually reach a maximum of 320 ℉.

It is a big deal because factories have to rely on polluting natural gas to produce their process heat.

We estimate that it represents 3% of the world’s annual CO2 emissions and a $10B+ annual market opportunity.

We are currently building a 5kW prototype at 480℉/250C to cook french fries for McCain (world's largest manufacturer of frozen potato products), our industrial partner for the first pilot.

If you would like to support our decarbonization efforts, feel free to email us on [e-mail] or to invest in our crowdfunding! https://wefunder.com/airthium

[i-use-nixos-btw]

This sounds very cool. Wait, no, hot.

In a factory setting, there is a bunch of heat wasted in other processes, e.g. waste heat from machines. Is this heat collected and fed into the air source?

[franckl]

Stirling engines like ours can go at cryogenic temperatures too :) They are used to reliquify natural gas at LNG terminals, but we decided to focus on industrial heat for now.

You are correct. In our case, we can go from ambient air to the desired process temperature, but the coefficient of performance will be much better if we have access to a waste heat source (the higher temperature the better).

[barelyauser]

What is the COP of a heat pump operating against this temperature gradient?

[Ndymium]

Quoting from their linked website:

> Our heat pump can generate up to 3 times as much heat as a resistor, using the same amount of electricity.

Though it doesn't mention the temperature at which this is achieved, only that the range is from 160 to 550°C.

[cornholio]

At 1000℉ (811K) the maximum achievable COP against an ambiental (300K) source is about 1.6, limited by the second principle of thermodynamics.

And that's the absolute theoretical maximum, you would be happy to breakeven in practice. Unless you have access to waste turbine exhaust, geothermal water, solar collectors or something along those lines, I don't see any practical application where the marginal energy savings would recover the capital costs of the pump at 1000F.

But hey, they have software modeling and venture financiers, so I'm sure they are not overselling it and it's all excellent and double plus innovative.

[byteware]

the maximum is given by the carnot cycle, which has COP=T_high/(T_high-T_cold) so from room temp 25°C to 250°C it is 2.3, but this is the theoretical limit

[whall6]

I’m having a hard time understanding the seasonal energy storage component. Can you dive into this a bit more? I wasn’t able to find much on your website.

I work in the energy industry and this is one of the largest issues that utilities (and plenty of others) face (and even go as far as installing thermostats that they can control in their customers’ homes).

I’m wondering if there’s anything that can be done to advance the 2030 timeline? Both from an investor and potential customer perspective, that’s a lengthy timeline for such an interesting value prop.

[franckl]

We are building more than a heat pump, it is a novel stirling architecture, that is, a machine that converts electricity to heat, and heat to electricity.

The idea is summarized on this picture https://imgur.com/a/f5T1NYi and is as follow: - solar/wind energy would be converted to heat using our engine and stored into a thermal storage unit (molten salts or sand). This would provide up to 30-40 hours of energy for day-to-day storage. - all year long, the unused energy is converted on-site to green ammonia (with H2 electrolyzers and a small haber-bosch plant) and stored in liquid form at -30C. The ammonia is then burned via a low NOx external burner, something other ammonia engines/turbines can't do well yet without expensive filters, and the combustion heat is turned to electricity with our engine.

This form of storage is much cheaper than storing hydrogen above ground. It competes with H2 storage in under-ground salt caverns without the geographical limitation. The efficiency is far from exceptional, but it is CO2 free and is only used as a "joker" a few days per year.

The whole system is a functional replacement for a natural gas fired power plant.

A company like Form Energy started in 2017, raised hundreds of millions and I think their first pilot is coming next year. Cash is key but not always the issue, I am glad they are helping storage companies with initiatives like the Long Duration Energy Storage group and all their lobbying efforts

[V__]

This is really cool. Can you talk about some interesting challenges/problems you encountered?

[franckl]

We started in 2016 with just an idea, and we probably encountered every problem you can think of !

- hard to raise funds for large deeptech projects (thank you YC and Wefunder for unlocking that one!)

- a corrosion issue in 2019 that nearly killed us (we found a way around it after months of brainstorming and completely got rid of corrosion issues)

- we had to build our own physics algorithm for very specific problems, and ended up selling the software we use internally to DENSO (a large japanese company) which funded the development. See https://tanatloc.com

- tackling a market that doesnt exist yet with a seasonal energy storage solution (a change of engine architecture allowed us to use the same engine but for industrial heat pumps, an existing market much easier to tackle)

- finding the right industrial space,

and so on :)

[MagicMoonlight]

Those chips should come in special packaging saying they're eco friendly

[inopinatus]

ball grid array perhaps has the right thermal properties

[franckl]

I agree! I would love to see the carbon intensity of each product I buy or some kind of scale from A to F.

[lionkor]

plastic packaging, of course

[nocobot]

this sounds like an interesting product and the team clearly has impressive credentials.

I am very sceptical of crowd funding however, I think these are largely terrible investments for consumers while explicitly targeting people who are not accredited investors.

what made you go that route instead of pursuing VC funding?

[franckl]

It is a combination of things. We hesitated a lot to do a crowdfunding but : - a corrosion issue nearly killed us and we had to "reboot"

- our team was in full lockdown in France for a while and we could not prototype as easily

- in 2021 we were still focused on seasonal energy storage, a very capital intensive endeavour, a market not ready and a very risky project.

- the rules for crowdfunding changed in 2021 and the use of SPV (special purpose vehicles) made it possible to raise big + have one line on the cap table.

We had to derisk the project further to be able to attract VC funding (patent, prototype, LOIs, financial model, etc.) and we ultimately followed the advice from another YC founder and friend who went the crowdfunding route with success. A lot of crowdfunding projects look like outright scams and probably are... but I feel that the SEC did a good job protecting the public. You cannot invest more than a certain amount if you are not accredited for example. Things are certainly not perfect, and getting better year after year.

[jgoodknight]

This is fascinating; I love hear pumps! Can you comment on why this might not have been done before? Maybe new materials make it possible, or it’s marginally more expensive but can be done with clean energy, which people have a premium on now?

[franckl]

Good question! I would say advances in numerical simulations, cheap renewable energy, and a lot of luck/perseverance (we would not have found this technology without spending 3 years on the first idea that didn't work out)