The Ersa hits field testing

It’s been a bumpy road. We’ve run through many designs including basic mock-ups, those with only partial-functionality and those that have ended in failure. We’ve also had our engineering roadblocks. Mainly electronics & control, and performance characterization. The latter is extremely important. If you can’t reliably measure the functionality of your system, how will you ever know if you’ve improved it?

Quantifying the amount of carbon dioxide captured in real-time while having to take into account a host of other influences such as varying airflow, pressure and temperature have proven an enormous challenge. But we overcame it, and the test-rig (which we geekily but lovingly call the AX400) represents Skytree’s deepest know-how and expertise. It measures the capability of any solid material to adsorb CO2 under simulated conditions (think temperature, airflow, humidity and varying CO2 levels). It can do this automatically, and if need be over 100’s of cycles, so it can understand the potential lifetime of sorbents. The one caveat is that the material must be regenerable using heat, but in the Direct Air Capture field, most are.

After understanding Ersa’s performance, we put it through its trials in a simulated environment. A simulated environment is important as it allows us to control inputs & outputs, and measure the effect Ersa has on them. The ‘simulated environment’ is a tent about the size of a car cabin connected to a CO2 and humidity supply as well as dried air from our lab. We can accurately control the amount of each element added to the tent, and measure their build-up inside. Once we knew what the build-up was without Ersa, we simply compared the measurements to those with Ersa operating within the tent. The difference gave us a realistic idea of what we could expect from the prototype and eventually, inside a car too.

Lab testing is our thing, and we find it fun. But in other worlds, seeing something actually operating in its final application environment is far more tangible and clearly represents a potential product. So we decided to rent a car and so the same thing as we did for our tent tests; input CO2 with and without Ersa, measure the difference. A problem here was that very few car models achieve 100% air-recirculation. The two we found were the Tesla Model X and Jaguar XJ. Being all electric and providing more space, we went for the Model X. Here is where we give our heartfelt thanks to Mister Green ( for kindly lending us one for free for 6 weeks, simply out of their pure belief in what we were doing. Thank you guys!

Model X testing. Right: Ersa in the foreground on a base-plate full of electronics, surrounded by sensors and measurement equipment in the background.

The testing was a success, not only because it gave us great shots of Ersa inside an awesome car, but it showed the stabilization of CO2 & H2O levels at 100% recirculation. Graphs we now show in almost every presentation we give. At this point, it’s important to acknowledge the valed support of Sogefi in funding this phase of development of Ersa and the testing thereafter. Sogefi and Skytree have since kicked off a follow-on project to develop a version of Ersa closer to its production design and tested to meet automotive requirements.

For now, we’re so happy to announce that the Ersa is available for demonstrations at car companies. If you represent or you know of a car company you believe would be open to integrating an energy saving and air quality product such as ours into one of their models, please contact our business development lead, Hans Poolman at or call our office on +31 20 237 49 80.

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