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Basic study for the assessment of the energy efficiency of air conditioning refrigeration systems for the new SIA standard 384/4

Refrigeration experts from the ZHAW Institute of Energy Systems and Fluid Engineering (IEFE) are developing a basis for assessing the energy efficiency of air-conditioning refrigeration systems for the new SIA 384/4 standard - air-conditioning refrigeration.

Das Bild zeigt die Festlegung von Grenzwerten anhand der am Markt verfügbaren Kältemaschinen

With a comprehensive market analysis of over 50,000 chillers and the fine-tuning of the calculation method used to calculate the efficiency requirements in the new SIA standard 384/4 - Air-Conditioning Refrigeration, the IEFE has contributed an important basis for the new standard.

With a separate standard for air-conditioned cooling, the SIA is recognising the increasing importance of air-conditioned cooling in terms of energy efficiency. The new SIA standard will also specify the minimum efficiency of air-conditioning refrigeration systems. The EU has already developed initial parameters on this topic with the new Ecodesign Regulation. These take into account the various temperature conditions and therefore also the load conditions of the air conditioning refrigeration system. The new Ecodesign Regulation is a valuable basis for the definition of minimum efficiency requirements in the future SIA 384/4 standard.

SIA has commissioned the IEFE to determine suitable limit values for the minimum efficiency requirements. To do this, IEFE analysed the data of over 50,000 chillers from the Eurovent Certita database using a comprehensive market analysis. In order to understand the new, seasonal key figures, the IEFE also had to analyse the EU Ecodesign Regulation 2016/2281 in detail for the SIA Working Group on Air Conditioning and Refrigeration. The focus here was on the new requirements for liquid chillers in comfort applications and the Seasonal Energy Efficiency Ratio (SEER).

However, the core of the work of the IEFE refrigeration specialists was the fine-tuning of the bonus/malus system designed by the experts of the SIA 384/4 working group. The IEFE drew up a proposal for the requirements for the minimum efficiency of the chiller (basic limit value). In addition, the various bonus and malus factors for the location, refrigerant type, refrigerant charge and operating modes had to be determined on the basis of market analyses, cycle simulations and empirical values from the experts. The corresponding calculation model was then verified and checked for plausibility using concrete examples from practice.

The results of the IEFE study were actively discussed by the SIA 384/4 working group and have now been incorporated into the draft standard. The SIA standard prSIA 384/4 with the new efficiency calculation is currently undergoing consultation until 20 December 2023. The feedback - particularly on the energy efficiency specifications developed by the IEFE - is awaited with interest.



SIA 384/4 – Klimakälte : Grundlagen zum Vertiefungsprojekt Energieeffizienz bei Klimakälte-Anlagen.

Diem, Manuel; Stahel, Christian; Tillenkamp, Frank, 2023

IEFE Energy Papers ; 12, 1. Winterthur: ZHAW Zürcher Hochschule für Angewandte Wissenschaften.

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