Experimental and numerical investigations of a new high temperature heat pump for industrial heat recovery using water as refrigerant

• New high temperature heat pump using water as refrigerant has been designed and built.
• Experimental investigations were carried out at high temperature levels.
• Transient heat pump model has been developed using Modelica.
• Start-up phase has been experimentally and numerically simulated and compared.
• The results show the energy savings and the environmental benefits of the prototype.

A new high temperature heat pump using water as refrigerant has been designed and built for testing on a laboratory test bench that reproduces the operating conditions of real-case industrial applications. Experimental investigations of this heat pump were carried out in the condensing temperature range of 130–140 °C. A new dynamic model has also been developed using Modelica to take into account the presence of non-condensable gases and the purging mechanism. In addition, a new combined finite-volume and moving boundary method (FV-MB) approach is applied for the plate heat-exchanger models and a moving boundary (MB) approach between phases is implemented for the models of the purging and the flash evaporation systems. The start-up phase of this high-temperature heat recovery and heat enhancement of the heat pump are simulated experimentally and numerically. A comparison between both results is presented and analyzed. Global energy savings and the environmental benefits have been illustrated.