A Photovoltaic-Thermal (PV-T) module is a solar hybrid collector which converts part of incident solar energy into electricity and recovers a fraction of the remainder dissipated as heat. A new high efficiency, covered, water PV-T component was developed in the context of a partnership between CETHIL, Fraunhofer ISE and EDF R&D. Tested under controlled conditions, the module demonstrated unparalleled electrical and thermal efficiencies. Within the framework of the project PHOTOTHERM an array of modules was integrated into a domestic hot water system installed on the BESTLab laboratory at EDF R&D, France, so that the performance of a complete system could be monitored under real conditions. In parallel, a numerical model was developed taking into account the heterogeneity of PV cell temperature, and the geometrical complexity of the Fractherm® heat exchanger developed by Fraunhofer ISE. The model, developed in TRNYS, was validated for steady state and transient conditions. The aim of the work now is to assess the energetic and exergetic performance of systems integrating this new PV-T module. The PV-T prototype, as well as the entire domestic hot water system, and the complete TRNSYS model are presented in this paper. Model validation was performed using measurements taken under real conditions. The model allows a rapid energetic analysis of the domestic hot water system.