One of Christian Ellwein’s major takeaways after attending Chillventa 2024 was that natural refrigerants are “no longer just a niche but will be the future.” Ellwein is the CEO of Kriwan, a German HVAC&R electronics and sensor manufacturer. Another of his takeaways was that this shift to naturals is driving developments in new technologies.
“The market continues to grow,” Ellwein told NaturalRefrigerants.com. “Technical challenges are increasingly being solved, and it seems there is no real roadblock ahead of us.”
Kriwan is one of the companies solving those technical challenges. It recently released a line of liquid level monitors designed for higher discharge temperatures, icing and flammability and is currently developing variable-speed drives for compressors, pumps and fans operating in high ambient conditions.
NaturalRefrigerants.com spoke with Ellwein about the products his company is working on in an exclusive interview, which has been edited for length and brevity.
Kriwan recently released new liquid level monitors for natural refrigerant systems, noting that these refrigerants bring unique challenges, such as icing, flammability and higher discharge temperatures. How did the company solve these challenges?
Christian Ellwein: First of all, our comprehensive experience in the field of HVAC&R helped a lot. Icing is a critical issue that is difficult to simulate in the lab. Kriwan developed a solution several years ago and improved the products constantly. Hydrocarbons require effective solutions to protect an HVAC&R system against any threat from the flammable refrigerant. Without years of experience and valuable input from our partners and customers it would not have been possible to tailor-make this product for the application.
A special focus of our R&D department was selection of the right plastic compounds and the geometrical design of the sensor to achieve sufficient temperature gradients in the material and to protect the electronic components against the high discharge gas temperature
In what sector is Kriwan seeing the most growth for its natural refrigerant products, and what is driving this?
Europe is driving the usage of natural refrigerants. Nevertheless, we see a worldwide increase in demand for products compatible with low-GWP refrigerants. Most international companies have R&D plans for product launches that reflect this long-lasting trend.
R&D costs can be reduced and the expected lifetime of products is prolonged if HVAC&R systems are designed for low-GWP refrigerants. Due to this it is economically reasonable to bring more and more systems for natural refrigerants into the market in most regions of the world. We see this especially in heat pump applications but also in air-conditioning and refrigeration.
What natural refrigerant trends is Kriwan keeping an eye on and why?
Kriwan has started developing VSDs especially designed for rotating equipment such as compressors, pumps and fans. There are of course many inverters designed for general purpose usage on the market but only a very limited number of products designed specifically for these applications.
Our VSD is designed to be used in higher ambient temperatures than most products on the market. The weather conditions in many regions right now indicate that this is a very important and unique selling point. Failure rate and reliability will be increased significantly by this feature. Another topic is AI. We have more and more sensors where measured data requires more complex algorithms, like vibration data or measurement of two-phase mixtures (e.g., liquid in the suction line).
“One of our highlights is certainly the two-phase mixture sensor. It will be an optical sensor that can detect liquid in the suction line and protect the compressor against liquid slugging and help to optimize the superheat.”
Christian Ellwein, CEO of Kriwan
What natural refrigerant products is Kriwan currently working on?
One of our highlights is certainly the two-phase mixture sensor. It will be an optical sensor that can detect liquid in the suction line and protect the compressor against liquid slugging and help to optimize the superheat. This is one of the most critical problems in HVAC&R, and so far no reliable and economically reasonable solution is available. The new Kriwan product will solve this issue. We are right now in the development phase. Together with a local university we have made feasibility studies in the lab and now prototypes are available for field testing.
Why did Kriwan decide to join the NaturalRefrigerants.com marketplace?
Communication to the market is key. We launch new products with new features and are very happy to have the option of multi-channel communication. Face-to-face meetings and training, online sessions, digital platforms – all channels are important to help our partners and customers to find the best solution for their application.
