Abstract
A feasibility study of the COP improvement in two-stage ammonia heat pumps modified with the ejectoroperated
economizer was carried out. A novel system architecture incorporating the ejector-driven flash gas
removal from the economizer tank was discussed. A set of numerical simulations for the steady-state 0D
model was carried out in order to estimate potential COP gains due to the introduced modification. The
estimated COP improvement ranged between 2% and 5%, dependent on the system application (refrigeration
unit or heat pump), operating conditions (evaporation temperature, condensing temperature) and ejector
energy performance. Preliminary geometry sizing for the ammonia ejector was performed based on a 1D
modelling approach.
economizer was carried out. A novel system architecture incorporating the ejector-driven flash gas
removal from the economizer tank was discussed. A set of numerical simulations for the steady-state 0D
model was carried out in order to estimate potential COP gains due to the introduced modification. The
estimated COP improvement ranged between 2% and 5%, dependent on the system application (refrigeration
unit or heat pump), operating conditions (evaporation temperature, condensing temperature) and ejector
energy performance. Preliminary geometry sizing for the ammonia ejector was performed based on a 1D
modelling approach.
