OPTIMISING EFFICIENCY IN THE DEFROST PROCESS
A continuous cycle of defrosting is essential to prevent ice build-up in air coolers, ensuring that the cooling process is as efficient as possible. However, as the ice and fog that are often found in cold rooms around the world attest, cooling systems rarely work at an optimum level, leading to unnecessarily high energy usage – and higher bills. For this reason, Güntner has dedicated considerable time and investment to innovation in the defrost process in recent years.
At our Fürstenfeldbruck HQ in Germany, we have a purpose-built defrost laboratory. This real-world environment, opened in 2019, works exactly like a cold storage room, allowing us to dive deep and accurately analyse the whole refrigeration, cooling and defrosting cycle in real time. Over several years, it has allowed us to fully understand the ecosystem of a cold room and to find innovative ways to improve the efficiency of the defrost process.
No idea is out of bounds for our research team, which operates in many ways like a startup within Güntner, adopting a ‘fail fast’ approach. For this reason, the team members are chosen not only according to their expertise, but also their ability to think outside of the box. Serendipity also plays a part. At one point, the cooling system in the room nearly failed completely, but this led to an unexpected discovery that pointed in the direction of a new solution.
Several years of research have now resulted in Güntner’s new efficiency-optimised electrical defrost technology, which boosts the already outstanding defrost efficiency of our air coolers to a new level. At its heart is a redesigned heating topology within the coolers, using a specifically calculated number of heaters in exactly the right spots, together with other measures. “It’s about maxing out the physics and finding the sweet spot of energy usage,” says Herbert Schupfer, Head of Future Solutions at Güntner. “We created an algorithm for our heat exchangers so that we know how to perfectly position the correct heating elements within them, creating the ideal heat distribution.”
When the team compared units using this new defrost technology with conventional (albeit state-of-the-art) Güntner units, the results were remarkable. In a 12m by 8m cold storage room kept at 0°C, a conventional Güntner Cubic VARIO Air Cooler has a defrost efficiency of around 76%. Equipped with the new defrost technology, efficiency is boosted to 83%. “After about two years, the additional investment is paid off and you’re saving more than €200 a year,” says Schupfer.
The results are even more striking in a deep-freeze scenario at -24°C. Simply by combining conventional defrosting with efficiency-boosting accessories such as an inlet hood and defrost hose, the efficiency of a Güntner Cubic VARIO Air Cooler can be increased from 50% to 86%, generating annual savings of around €1,700 after the first year. However, further equipping that unit with the new efficiency-optimised electrical defrost results in a superior air cooler with outstanding defrost efficiency of 95% and annual savings of more than €2,000. This new technology pays for itself within a year and is our recommended solution for efficient cooling.
“Our figures are based on comparisons with Güntner’s current units, so imagine the savings that can be made if you’re replacing an old unit in an existing cold storage facility, and the opportunities those savings could bring,” says Schupfer.
A wide range of Güntner’s air coolers are now available with our new efficiency-optimised electrical defrost technology, for use with systems using flammable refrigerants such as propane, and the technology will be available in other applications in due course. We are also exploring the use of artificial intelligence in our control systems, which will create even greater efficiencies.