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Maturity level of alternative AC technologies

In a recent review article, the authors assessed air conditioning technologies in Europe according to their Technology Readiness Level (TRL).

Vapour-compression technologies account for about 99% of the EU air-conditioning market. Thermally driven heat pumps supply the remaining 1%. Vapour compression systems dominate the market because of their low operating and investment costs and high efficiency. It is unlikely that any alternative technology capable of competing with vapour compression systems will reach the EU market before 2030.

 

Elnagar E. et al assessed existing and emerging air conditioning technologies in Europe according to their Technology Readiness Level (TRL). The authors used a TRL between 5 and 9 as the most promising baseline for an alternative technology to compete on the market in the near future.

Only ten technologies have a TRL between 5 and 9: absorption cycles, adsorption cycles, reverse Brayton cycle, membrane heat pumps, enthalpy recovery, transcritical cycle, natural convection, natural conduction, freeze/melt cycle and evaporative cooling. However, despite their potential, most of these technologies are still less efficient or more expensive than vapour compression technologies.

 

Membrane heat pumps, thermionic systems, thermotunnel systems, and evaporative liquid desiccant systems are cost-competitive and energy-efficient in certain applications. For example, researchers claim that the Energy Efficiency Ratio (EER) of membrane heat pumps could be twice that of vapour compression systems in commercial air conditioning. This would result in energy savings of 50%, with an estimated Seasonal Efficiency Energy Ratio (SEER) of 30.

 

The authors conclude that hybrid systems offer significant potential for improving the overall efficiency and performance of alternative technologies. By combining multiple cooling technologies, such as membrane heat pumps and evaporative liquid desiccant systems, researchers can leverage the strengths of each technology and achieve higher energy efficiency.

 

For more information, the review article has been published in open access in Renewable and Sustainable Energy Reviews.

 

Technology Readiness Level (TRL) of alternative air conditioning technologies (from Elnagar E. et al.)

 

 

Source

Elnagar, E., Pezzutto, S., Duplessis, B., Fontenaille, T., & Lemort, V. (2023). A comprehensive scouting of space cooling technologies in Europe: Key characteristics and development trends. Renewable and Sustainable Energy Reviews, 186, 113636. https://doi.org/10.1016/j.rser.2023.113636