Numerical Simulation of the Aluminum Column-Wing Type Refrigerant-Direct Radiant Cooling System

Abstract

The refrigerant-direct radiant cooling (RDRC) systems have become increasingly popular owing to good thermal comfort and high energy efficiency. However, the existing RDRC terminal has complex structure and large occupation area. To tackle these problems, an aluminum column-wing type RDRC (ACT-RDRC) terminal is presented. The detailed numerical model is developed to explore the thermal performance of this system and validated with experimental data. Results shows that when the evaporating temperature increases from 6.0 o C to 14.0 o C, the ratio of the natural convection, condensation latent and radiant cooling capacities changes from 4.6:2.1:1 to 4.5:1.4:1, which indicates that the natural convection is a main contributor in the heat transfer process of this system. To meet the thermal comfort requirements, the relative humidity less than 60% is recommended with the indoor air temperature of 28 o C. A characteristic equation is proposed to accurately predict the cooling performance of the ACT-RDRC system, which is conductive to promote its application.