Thermal comfort levels in a conditioned environment with displacement ventilation and radiant cooling floor calculated using computational fluid dynamics

Abstract

In a society in continuous development, the requirements for thermal comfort and indoor air quality are increasing. However, these should be achieved by rational energy consumption. With this in mind, the combined use of displacement ventilation (DV) and radiant cooling floor (RCF) is an innovative concept that has become popular as a cooling system in high-rise public enclosures. To provide a high thermal comfort, the effects of buoyancy, supplied air temperature, air discharge angle and surface floor temperature should be treated with special care. Therefore, this paper presents a sensitivity analysis considering these critical parameters in different numerical simulations. The results of the simulations are used to calculate the thermal comfort index, according to ISO 7730 standard, in high ceiling enclosures using a DV + RCF system. The general thermal sensation has been predicted using the PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) indices. The local thermal discomfort has been evaluated by radiant temperature asymmetry, draught, vertical air temperature differences and floor surface temperatures. According to these indices, the classification of Category A is reached using DV + RCF system, exception of the radiant temperature asymmetry index. That fact will be discussed in detail, analyzed the suitability of the calculation indicates in ISO 7730 for systems involved in radiating surfaces.