A computational investigation of a room heated by subcutaneous convection—A case study of a replica Roman bath

•In this study we analyze the thermal environment inside a subcutaneous convectively heated room.•The setup replicates a replica of an ancient Roman bathing complex.•The purpose is to provide a better understanding of the capabilities of this unique system.•The average temperature for the final run is 35 °C.

Floor and wall subcutaneous convective heating is a common and efficient supplementary system of heating, ventilation, and air conditioning (HVAC) but the concept dates back nearly 2500 years to when ancient Greeks and Romans used it to warm their bathing facilities. This paper explores the thermal environment of a replica Roman bath resulting from purely subcutaneous convective heating by modelling the bath using computational fluid dynamics (CFD). Previous studies examining the interior of baths have used either heat fluxes or lumped-mass thermodynamics, but neither approach possesses the detail of CFD. The average temperature in the 3 m × 4 m room modelled is 35 °C; however, the hottest air is trapped in the high vault leaving the region inhabited by the patrons significantly cooler than the average. The results also show that stratification is prominent and that the open doorway connecting to the next room heavily influences the room temperature. The results also suggest a relative insensitivity to changes in the convective heat transfer coefficient and addition of humidity to the model. Furthermore, this study not only provides further knowledge about an alternative HVAC system but enhances our understanding of ancient Roman baths. In addition, it offers an insight to a unique thermal environment on the basis of multi-phase and species modelling.