We assess the potential to preheat space air and water using a prototype of photovoltaic-thermal array installed on the roof a wine warehouse in southern France. The system comprises a horizontal arrangement of conventional PV modules fitted to a novel metal structure that serves both as mechanical support and ventilation duct. The warehouse requires a steady interior air temperature of 14-18°C throughout the year. The load profile of the building is strongly affected by the mass of the vats. Simulations were performed with TRNSYS, using a combination of existing library components and a bespoke Type to model the steady state behaviour of the aspirated solar array structures. The potential for air preheating was assessed by calculating the enthalpy change due to the injection of outside air into the building. The potential for space preheating and hot water generation were found to be complementary, with hot water generation proving of interest during the portion of the year where the heating load of the building is negligible. Sensitivity of system performance to weather conditions is highlighted, and in particular the impact of wind on panel heat dissipation