My experience installing DiFluid Airwave - further thoughts appreciated!

Hello Everyone! So I recently bought and installed a DiFluid Airwave and I thought I’d share my experience and seek out any further advice people might have on my setup.

TLDR: It’s not been straightforward, my experience is that it broadly achieves the elimination of smoke through the external venting but I would question in my experience whether it is really appropriate for roasting 1kg if you’re taking it at all dark (albeit how much of this is the equipment vs. my own venting setup is what I’d like to ask the wisdom of the crowd on!). DiFluid have been reasonably helpful in providing advice to resolve the issues, but overall I would still say my current setup is sub-optimal from an air quality perspective.

Context - I started roasting commercially a couple of months ago on the Bullet R2 Pro, having converted my garage into a roastery. I typically roast 1kg batches and maybe do 7 batches or so in a roasting session. I live in a residential area and while my neighbours are fully supportive I’ve felt like I want to do as much as possible to eliminate external smoke and odour, with the Airwave therefore naturally fitting the bill based on the promotional material. I bought a 220v airwave and then started my various attempts to incorporate it into my setup.

The original setup

This is how I setup the roastery venting pre-airwave. 150mm rigid spiral ducting being powered by a Cloudline S6 fan. I typically had the fan close to its maximum and my air quality meter (measuring CO2, CO, HCHO, PM etc) stayed in the green on all fronts even when roasting dark. Naturally there was quite a lot of visible smoke and odour outside the back of the garage where the venting exits.

Airwave installation attempt 1

Airwave installed on a shelf just above the roaster. One thing that’s worth noting is that the airwave has only 100mm inlet and outlet which automatically suggests it is designed for moving a much lower quantity of air than the setup I had before. I therefore used a couple of reducers to get from the 150mm setup in my ducting down to the 100mm. Needless to say this setup was a complete failure. Previously, I didn’t need a separate duct going down to the cooling tray as the capacity/draw from the cloudline and positioning of the gather was such that cooling tray smoke at drop would ascend vertically and get gathered. The draw from the Airwave is WAY lower and therefore all the cooling tray smoke was just going into the garage. In addition, there was so much backdraft from this setup that it appeared to cause the Bullet fan to have to work too hard and resulted in an electrical overload/shutdown when the cooling tray fans kicked in. Therefore, I had a very smoky roastery and a roaster that kept shutting down!

Airwave installation attempt 2

So the first part of this second attempt actually involved changing some of my recipes to have more fan before dropping the beans to attempt to even the smoke volume rather than having so much just coming out in one go. I also added the hose down to the cooling fan to try and capture that (and started roasting with the back door open). While the combination of these things resolved the power overload, the suction just didn’t seem powerful enough to manage the split, combined with my installation of the roaster coming off the junction rather than the straight bit of the “T” which was sub-optimal and Air Quality spiked even worse than in attempt 1…

Airwave installation attempt 3

Based on various back and forths with DiFluid, as well as some helpful advice on the setup from Aillio and my own research, I attempted to lengthen the ducting run into the Airwave to provide for more capacity. I also moved the cooling tray run to come straight off the Cloudline and skip out the airwave for smoke coming from the cooling tray given it’s relatively minimal. I’d say this made things better but overall Air Quality, HCHO and PM readings were still very much spiking into the red so I hoped that I could do better.

Airwave installation attempt 4 - current setup

Based on further advice from DiFluid and own research, I have further attempted to lengthen and straighten the run into the airwave, removing the right-angled section which was causing constraint and moving my roaster further away. So far, this is the best of all the setups with Air Quality readings typically showing PM in the Green and HCHO never really spiking above 1.0 mg/m3. There still can be spiked in TVOC above 3.0 mg/m3 for a minute or so before they come back down when I open up the front door of the garage as well as the back to create a cross draft and flush out residual VOCs after the drop, closing the front door again once it stabilises.

Ideally I’d like to continue to improve on this setup to see if there’s any way I can go back to roasting with the doors closed once we get into colder months in particular. I don’t think the Airwave will ever give me the kind of extraction capability I had just using the Cloudline but overall it’s a trade off I’m comfortable with, at least at the moment. I think the next step is to replace the flexible duct going into the Airwave with rigid spiral to further minimise the static pressure and get a bit more efficiency on the intake side.

DiFluid have been reasonably helpful and responsive on trying to resolve the issues, but the challenge is I feel like this is such a new product with likely very few people using it to the capacities that I’m trying to put through it, albeit it is marketed as being suitable for up to 1kg roasts which is what I’m doing!

Massive thread but I hope this is helpful for anyone else looking at the Airwave and any further thoughts and guidance is greatly appreciated!

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Oh, also, thanks to Aillio for various pieces of advice also provided on the overall setup, particularly in the earlier phases!

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Thank you for your detailed post.

When I first saw the DiFluid Airwave I was under the impression that it would completely avoid the need for external venting. Your post (and some other videos) clearly suggests otherwise. Good on you for going to all that effort to keep your neighbours happy! Also good to hear that both DiFluid and Aillio have been of assistance.

I hope that the venting solutions in 10 years from now will blow our minds!!!

I certainly wouldn’t use it with no external venting. To get anywhere near the draw to intake most of the smoke from 1kg I need to run the intake fan on it at 100% which reduces the effectiveness of the catalyst meaning that there is still PM and VOCs coming out (I can see it from the flue outside). If you’re doing smaller quantities and roasting light then I imagine that could be OK though.

Thanks!

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Nice looking ductwork! I’m not sure how close one can get to removing everything, but you have certainly done your part.

I recently began thinking about the afterburner on the Behmor roasters and wondering if something like it could be added to my R2 Pro. Some recent roasts ending at 224C inside my shed have really driven that home! A web search turned up an article from ‘Coffee Snobs’ that gives details for building an afterburner that looks promising. I am including a link in case anyone is interested.

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I used the same Coffee Snobs article to build an even cruder version myself, where I simply put a few mist valves on a stick that I then pushed up the flexible exhaust duct.

I used that on a Gene Cafe roaster.

As a proof of concept, I thought it worked OK, with steam smelling of coffee exiting the exhaust duct (as well as water from the mist collecting inside the duct) instead of toxic smelling smoke.

However, when one mist valves stopped working, the remaining four valves struggled to work effectively and I was not venting the cooling tray, so I decided against a water scrubber solution for the R2.

I feel that if you could design a wet scrubber solution for the cost of the DiFluid, you might end up with a fairly effective solution.

That DiFluid looks like a solid device. I’ve been holding off on building a smoke evacuation system until I have a solution I am comfortable with. Since I roast in a shed and my R2 is sitting right next to a large door that I keep open I am not in an immediate need of one. I guess every design has its weak points and the spray nozzles would be that weak point since the water mist is what removes the fumes. I guess using a catalytic converter from a car would do the job, but the exhaust pipe connection might be a bottleneck.

I’ve made a further improvement today which seems to have helped. Replaced the flexi I had going into the Airwave with rigid. Also added a little foil hood to try and gather more of the smoke before it disperses into the roastery

Well, I’ve just had some completely counterintuitive learning today. It turns out that when I roast with the door closed rather than open then even at 1kg the air quality spike at drop doesn’t seem to be going up to anything concerning at all. Discovered this by accident because (ironically) I was trying to keep the roastery cooler by having the doors closed given the heatwave we’re having in the UK. It seems like the additional draft that was coming from having the door open was probably disrupting the air flow into the gather and causing less smoke to be captured vs. roasting in a more still air environment.

I’ve also started pressing the PRS to engage the cooling fan about 5 seconds or so before I actually open the door to drop the beans to make sure the colling tray fan is fully engaged before the beans leave the roaster.

Although you already have a very practical exhaust setup, I really admire your decision to add the AirWave out of consideration for your neighbors by reducing outdoor smoke. I bought an AirWave back in March to pair with SR800, and wife recently ordered an R2 Pro for me, which is expected to arrive next month. So I wanted to share some of my findings so far, as well as my planned exhaust design going forward.

Most of my neighbors are actually wildlife, so I’m not too concerned about outdoor exhaust affecting other people. The main reason I bought the AirWave was to make it comfortable for me to roast coffee in my basement workshop.

I’m still relatively new to coffee roasting. When first started roasting, I focused almost entirely on the bean color changes inside the chamber and power/fan adjustments on PC, and the smell was obvious enough that I didn’t think much beyond that. Then one day, I looked up from the beans and noticed a mushroom-cloud-like layer of smoke above my head — that was the moment I decided to buy the AirWave.

I typically roast 250g batches at light to medium-light levels, anywhere from 1 to 4 batches per session. Before getting the AirWave, indoor PM2.5 levels could peak above 200. My indoor air purifier would need around 20–30 minutes to bring PM levels back down to around 10, while the ERV system would take several hours to fully clear the lingering smell. After adding the AirWave, PM2.5 peaks are now usually around 25–30.

With the R2 arriving soon, I’m currently redesigning my exhaust system. My plan is to leave the AirWave outlet venting directly without additional ducting to the outside, while the inlet side will connect through a Y-splitter to both the R2 exhaust port and the cooling tray. I also plan to install dampers on both branches to independently control airflow from the exhaust and cooling tray.

Whether this initial design works well or not, I suppose I’ll find out in a few weeks.

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You won’t be able to pass both from the cooler and from the drum, the fan in the cooler is too powerful

Another safety recommendation for anyone thinking of installing the Airwave. Have a secondary ventilation hose that is connected directly to a fan that is NOT the Airwave. The airwave (at least mine…) can have a tendency to generate a random error code that shuts it down (I’ve been told it can be to do with the external heat sensor). Just happened to me right on First Crack and I was able to deploy the secondary hose connected directly to my Cloudline so at least the roastery didn’t go completely hazardous with the smoke. If the airwave becomes your only extractor source then if it shuts down randomly then you won’t have anything to remove smoke