20 ans de contribution du LENI-EPFL à la recherche sur les pompes à chaleur

Throughout the years LENI-EPFL spent a significant part of its research activities on heat pumps be it for industrial heat recovery or for domestic or district heating and cooling. Methodological contributions include the improvement of the formulation of the exergy efficiency indicators, including for a cantonal law on energy and in the energy integration techniques for industrial processes. Novel, socalled environomic, mono- and multi-objective optimisation analyses of large integrated systems with heat pumps, including for tri-generation have been published. LENI also contributed to a novel physically based correlation for tubular boiling of various refrigerants that received an international award. The main technological innovations include major contributions to scroll compressors with intermediate vapor injection, two-stage domestic heat pumps and small high speed radial compressors on self-acting refrigerant vapor bearings with direct thermal or electric drives. New concepts of district heating and cooling systems with centralized and decentralized heat pumps have been proposed. Supercritical heat pumps cycles for novel electricity storage concepts have also been studied.