Integrated design and dynamic simulation of ventilation and radiant ceiling systems for the UniZEB prototype building

The present work has as its objective the integrated design and the dynamic simulation of the mechanical ventilation system and the radiant ceiling system of the UniZEB pilot building, the first nearly Zero Energy Building laboratory of the University of Padova. The building is a single-storey residential unit of approximately 80 square meters with a Cross Laminated Timber (CLT) structure and a highly insulated envelope. The HVAC system is composed of a radiant ceiling for sensible heating and cooling, and a mechanical ventilation unit with heat recovery and a dehumidification chiller for indoor air quality and latent load control. The design and the analysis have been carried out through the dynamic simulation of the thermal and hygrometric behavior of the building, considering realistic operating hypotheses on the occupancy schedule and on the internal gains. The multi-zone building has been implemented in TRNBuild (Type~56), with the radiant ceiling represented as a chilled-ceiling active layer with parameters calibrated against a previous Heat2 finite-element analysis. The mechanical ventilation, the heat recovery, the dehumidification and the integrated control logic of the two systems have been implemented as equation blocks in Simulation Studio. The annual simulation has been performed using the Test Reference Year weather data of the Venezia-Tessera station, the closest reference station to Padova. The analysis focuses on the modelling decisions, the calibration of the radiant active layer, the implementation of the control strategy that couples the radiant and the ventilation systems, and the evaluation of the resulting zone temperatures, ventilation supply temperature and sensible and latent energy demand throughout the year. The analyses were carried out using TRNSYS~18.