Will Hawkins, editor of the ACR Journal, caught up with James Cooper, product manager at ebm papst, to learn more about the background to its new AxiTop Diffuser.
The fans manufacturer, ebm papst, won two awards at the National ACR Awards in January 2015, namely the ‘Refrigeration Product of the Year’ and the ‘Company Environmental Champion’.
The first award you won in January was for the AxiTop Diffuser. To use the judges’ words, they said ‘it is a clever product and it makes a marked difference’. They were impressed.
It is not just airflow. There is noise too. The diffuser converts some of the unused, or the useless dynamic power, into static, usable energy. Therefore, it regains some of the lost energy that you get from your electricity supply to the actual air power that is doing the work.
The diffuser does that by slowing down the velocity of the air leaving. We can do other things like straightening the air slightly, which improves the ‘throw’. Overall system improvements can mean that you could improve an application perhaps because they were getting a bit of recirculation. By throwing the air further you can get that improvement.
As a straight improvement on the impeller, we are seeing up to 27% improvement in energy saving for the same performance and the same duty.
However, actually we can improve an impeller's capability by a further 9% running at full speed purely by adding the AxiTop on, and so converting some of that energy.
Less noise, more performance
You can improve the way the air leaves the impeller to improve the flow. And, we can also reduce the noise. But, of course, by turning the fan speed down you get extra performance, which is also part of that noise reduction. It is partially the guard and partially the reduction in speed.
We have seen from trials and retrofits significant improvements on overall performance of a condenser or a piece of kit that is on a roof. That can range from anything from 15% to 51% depending upon the application and the speed of the fan because some of these installations are only doing part-load.
You wouldn't expect to get full energy saving. But, we have seen 51% improvements in some cases purely because the installation was a bad installation. That has helped to stop or improve recirculation.
Have you have been surprised by the applications where the AxiTop is being used? Or, is it where you predicted?
Sometimes products can a while to be understood by customers and then bought. Are your customers quickly adopting it?
So, yes, it has been adopted and people are using it and seeing the benefits of it in varying degrees. And even on retrofit upgrades installations it has been seen as a positive. There have big roll outs on various sites where they are adding this onto an existing EC impeller. It is already a fairly new piece of kit but then they are looking to adopt even further benefits and savings.
Have you had to use any different type of materials to make it? Or, does it purely come down to materials you have been using for a while but a different way you have gone about designing it?
Our R&D team spend a lot of time designing new products on computers and can ‘iron out’ many of the ‘wrinkles’ in a product before making it. We also have our test labs where we can combine airflow and noise testing in one chamber. We listen to the tones and frequencies while it is being tested.
It costs more to produce but the speed at which you can come up with something and test it. Even though it may be more fragile than a finished tooled product, it still allows you to test it and prove the aerodynamics and acoustics before you really start putting the money into proper tooling.
With the efficiencies you can gain, I imagine you can get some pretty good paybacks with the AxiTop diffuser?
Think of chiller, for instance. If you have a free cooling coil on a chiller, which some of our OEMs have, and you can produce another 9% more airflow than you did previously for the same size of impeller, the same size of equipment, then it means that the system can run better. You can ‘free cool’ a bit longer, be activated a degree or so earlier, in which case the compressors are not needed as much.
We might be talking a few kilowatts of savings with the fan. But, if you are switching compressors off, you might be saving huge amounts of energy. Even if they are just switched off for an extra month per year. Or a few a year. It is significant over the course of a year on running a big chiller plant or several chillers.