A four-step method based on sequential solution of relevant model equations to predict condensation risk for a radiant cooling system

Abstract

The problem of surface condensation constraints widespread application of radiant cooling (RC) system. Although, a dehumidification system is reported as a solution, the viability of using dehumidification for different climates is not conclusive. This study is conducted to determine the appropriation of dehumidification process for RC systems in different climates. An office building with an embedded RC system is modelled and simulated in EnergyPlus v9.6. Eighteen Asian cities are chosen based on ASHRAE's moisture zone classification for the simulation. Initially, the attainment of thermal comfort is assessed followed by an assessment of condensation. The results show that the system maintains required thermal comfort without an occurrence of condensation in eight cities with both dry and humid climates. It is noted that the condensation of an area does not depend on dry or humid zone of the area. Conversely, it is found that the outdoor humidity ratio is a major contributor towards the occurrence of condensation. A novel method is developed and validated that involves solving relevant model equations in a specific sequence to predict condensation risk based on outdoor humidity ratio. Results show that if the value of condensation risk is up to 20%, an RC system would provide thermal comfort without a dehumidification system and surface condensation. The proposed method will enable the designers and engineers to decide on provision of dehumidification for an RC system without going through rigorous simulation or experimental work.