This paper describes a novel solar-assisted HVAC system developed for the Team UOW 'Illawarra Flame' Solar Decathlon house, the winner of the Solar Decathlon China 2013 competition. This HVAC system consists of an air-based photovoltaic-thermal (PVT) collector and a phase change material (PCM) thermal storage unit integrated with a reverse cycle heat pump, in a ducted system. The system was designed for operation during both winter and summer using daytime solar radiation and night-time sky radiative cooling, respectively. The PVT collector heats or cools fresh air from ambient and thereby provides heating or cooling either directly to the indoor space, or to the PCM storage unit. The heat stored in the PCM can be used later to condition the space or precondition the air entering the air handling unit. Analytical models for the PVT collector and PCM unit were developed in order to be easily implemented into a practical building management system (BMS). Experimental studies on the PVT collector and PCM unit were carried out and the data was used to validate the effectiveness of the models. It is shown that there is a good agreement between the model simulation results and experimental test data. A simple optimisation methodology of the operating modes that involve these components is also presented.