23 September 2011

ENERGY EFFICIENT AIR TO AIR HEAT PUMP OPERATING WITH R-1234yf


Significant 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.