Energy efficient air to air heat pump operating with R-1234yf

International audienceSignificant improvements in energy performance of air-to-air heat pumps are the major reason of their introduction in the late '90s for heating buildings in Japan and several European countries. They are installed in multi-dwelling units and in individual houses. Some of them are using variable speed compressors. European existing air-to-air heat pumps are not adapted for the low-energy building requirements. Their heating capacity is relatively higher than the heating demand and their energy efficiency is not sufficient. This paper presents a low-capacity heating system: a mini-heat pump (MHP). The MHP consists of mini-channel heat exchangers for the condenser and evaporator. In order to improve the overall energy efficiency, a recovery air-to-air heat exchanger (RHX) fulfills a significant part of a passive house heating demand. A first prototype of the MHP is realized and series of tests are presented in this paper with two refrigerants: R-134a and R-1234yf