Monitoring of gas driven absorption heat pumps and comparing energy efficiency on primary energy

This paper describes the methodology and results of monitoring several heat pump systems installed in public buildings in the North of Italy. The three-year project, led by the Energy Department of Politecnico di Milano, aimed at evaluating the performance of heat pump systems on field; it involved several kinds of technologies, including gas driven absorption heat pumps. We developed a new monitoring procedure, based on performance indicators expressed in terms of primary energy; the indicators are calculated on specific system boundaries, in order to characterize the performance of each meaningful subsystem of the monitored plants. Moreover, further indicators are defined in order to characterize the operating conditions of the system; through them, it is possible to understand the significance of the main performance indicators and detect possible faults in the design and management of the plants. The results of the monitoring of the five gas absorption heat pump plants are then presented. They highlight that the performance of a system is not determined solely by the efficiency of the heat pump, but depends also on the good integration of the machine in the system, that should be addressed at design level, and on the coherent management of the system. (C) 2016 Published by Elsevier Ltd.