Scroll Compressors and Low-GWP Refrigerants: IIR Develops a New Design Approach

The use of refrigerants with a low Global Warming Potential (GWP) may require a rethink of how scroll compressors are designed and optimized. This is one of the key findings of a study published in Applied Thermal Engineering and conducted by a team of researchers including Eckhard A. Groll, Chair of Section B of the International Institute of Refrigeration (IIR), together with Haotian Liu and Riley B. Barta.

At the heart of the study is a computational model developed to describe and predict the behavior of scroll compressors when operating with refrigerants whose thermophysical properties differ from those of conventional fluids.

The issue is becoming increasingly important as lower-impact refrigerants gain wider adoption. Changing the refrigerant does not only affect the operating conditions of the system: parameters such as density, heat transfer, internal losses, and compressor efficiency can also be significantly affected. As a result, in certain applications, replacing the refrigerant cannot simply be regarded as a “drop-in” operation.

A Model Based on Compressor Physics

To address this challenge, the researchers developed a physics-based mechanistic model that was subsequently validated experimentally. The methodology was applied specifically to R454C and R290, taking into account several phenomena that contribute to the overall performance of the compressor.

The model considers parameters including heat transfer within the compressor, mechanical losses, refrigerant leakage, compressor geometry, and the behavior of individual components.

The aim is therefore to move beyond an approach based solely on the compressor’s overall performance and provide a more detailed description of the mechanisms that determine capacity and efficiency.

The Limitations of Direct Replacement

The simulation results indicate that using R290 and R454C in a compressor originally designed for R410A can lead to a reduction in performance.

One of the key factors identified by the researchers is the difference in vapor density among the refrigerants. Variations in this parameter can result in a mismatch between the refrigerant and the existing compressor geometry, negatively affecting the machine’s operation.

The study therefore highlights an important consideration for the development of refrigeration systems: adopting low-GWP refrigerants should not be addressed solely by replacing the refrigerant, but also by assessing potential changes to compressor design.

Towards Compressors Optimized for New Refrigerants

The next phase of the research will focus on optimizing the reference compressor for operation with R290 and R454C. Further work will make it possible to quantify the improvements achievable through dedicated design and assess the extent to which the approach can be applied to other refrigerants and different compressor configurations.

The model proposed by the IIR therefore provides a tool for linking refrigerant characteristics to compressor design, supporting a more targeted approach to improving the efficiency of compressors intended for next-generation refrigerants.

The industrial and commercial refrigeration, logistics, freezing and cryogenics sectors will meet at REFRIGERA, the international industry event, taking place at BolognaFiere from November 10 to 12, 2027.