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EUROVENT KÄLTE KOLLOQUIUM: Second presentation
"Refrigeration system comparison (R744 / R290) of long-term fruit storage rooms."
Concentrating on the DyNatCool project, the second presentation from the 2024 EUROVENT KÄLTE KOLLOQUIUM by Kratschmayer Kälte-Klima-Lüftung GmbH, focuses in on the comparison of identical, optimised cold rooms, using propane vs CO2. As the natural refrigerants battle it out, discover the findings so far, as the project seeks to discover the most energy efficient solution for long-term apple storage.
About the EUROVENT KÄLTE KOLLOQUIUM
Over two days, from 4th - 5th June 2024, operators, planners and manufacturers explored reliable refrigeration systems for the cold chain, "From Farm to Supermarket," in Wiesbaden, Germany. A comprehensive technical programme took delegates from theory to practical, with a mix of seminars and excursions, perfectly blended to encourage learning, discussion and networking in inspiring surroundings.
Organised by Eurovent Certification and COOLPLAN, with media partners CCI and KKA, day-one was hosted at the historic Kloster Eberbach. The extensive technical programme scrutinised the latest trends in refrigeration, decarbonisation and boldly tackled issues such as underperformance and its impact on food quality and energy efficiency.
Day-two put the theory into practice, with the chance to go explore cold food chain technology in its natural habitat, with excursions to a green farming market and NH3/CO2 logistics warehouse.
The presentation
"Refrigeration system comparison (R744 / R290) of long-term fruit storage rooms."
Micha Kluge, Head of Refrigeration Department at Kratschmayer Kälte-Klima-Lüftung GmbH, gave the second presentation on day-one at the Kloster Eberbach. He began his presentation by giving a brief introduction to his role and experience working with cold rooms. Micha laughingly told how he’d been inspired to put forward ammonia plant as a solution since 2010, and had been trying to convince his boss ever since. However, after undertaking much research into natural refrigerants, Micha discounted ammonia for the project, and narrowed his choices down to propane vs CO2 for smaller systems. With propane offering an intriguing solution, but with CO2 already well established, which was best to choose? It was time to experiment.
Micha took the audience on a journey through the DyNatCool project. With the objective of delivering the most energy efficient solution for long-term apple storage, the project aimed to:
- Minimise the use of resources for the construction and operation of refrigeration systems (full and partial load)
- Determine heat transfer in fruits
- Influence the cooling phase duration on the preservation of product quality
- Undertake a system comparison using identical cold rooms:
- Construction of 2 x optimised test plants (propane and CO2)
- Metrological verification of the transient heat loads
- Product physiological tests
- Monitoring and validation
- Development of a dynamic demonstrator tool.
Via funding from Landwirtschaftliche Rentenbank, the DyNatCool research project examined:
- Heat transfer: In fruit and in large crates (Basis for the calculation of the transient heat load in the cooling phase)
- Cooling phase: Influence of duration on the preservation of product quality (product physiological studies)
- Refrigeration system comparison: Energy efficiency of future refrigeration systems (alternative/natural refrigerants R744, R290).
The respective systems were equipped with a Eurovent certified Kelvion DX R744 evaporator and a Eurovent certified Kelvion indirect R290 air cooler. A total of 40 4-wire temperature sensors were installed in each case to monitor the system. While the final energy efficiency data from the sensors was not ready in time for the presentation, Micha had experienced enough to emphasise how important using certified products was to ensure they could calculate the full & partial load accurately. Micha concluded by summarising the findings to date and taking questions from the floor.