Carboxylic acids as REAcTIVE refrigerants to make heat pumps efficient

Aiming to contribute to a substantial increase in the sustainability of thermal power plants, heat pumps, and climatization systems, the ERC-StG-REACHER is introducing new working fluids for the thermodynamic cycle underlying these systems.

These new fluids are mixtures of dimers “A2” and monomers “A” undergoing a reversible dimerization reaction, A2 ⇄ 2 A, evolving instantaneously and spontaneously in the unit operations of the machine. REACHER has introduced about 200 of these reactive fluids.

Among them, the family of carboxylic acids (e.g., formic, acetic, propionic acid) seems very promising as working fluids for residential heat pumps: other than owing excellent environmental properties, their use promises an outstanding 17-43% relative efficiency improvement compared to state-of-the-art heat pumps.

In this context, the main objective of the ERC-PoC-CREATIVE is to perform the first step towards the realisation of a residential heat pump prototype operating with formic acid, enabling the validation of the -theoretically observed- positive chemical reaction effects.

This step consists of preliminary verifying the feasible compression of formic acid with a finely controlled series of available compression technologies, using air as working fluid in the sub-atmospheric pressure conditions characterising operation with formic acid.

Within CREATIVE, these results will further allow the design of a pilot operating with formic acid to test, in a future PoC, the compressors preliminarily selected and pre-tested with air, in CREATIVE.

The realisation and design of the experimental setups for the formic acid compression feasibility assessment are supported by thermodynamic calculations carried out in CREATIVE, using tools developed in REACHER.

This PoC is supported by the expertise of two industrial partners, and involves the Host Institution’s Technology Transfer Office which will handle IP management and explore valorisation pathways for the key exploitable results.