Numerical modelling and experimental validation of pcm-to-air heat exchangers: application of ventilated building envelopes

Abstract

The earlier applications of phase change material (PCM)-to-Air heat exchangers (PAHXs) reported the insufficient cooling charging energy due to system storage abilities, the profile of inlet air temperature, and the charging duration. This paper proposes a developed PAHX system for building envelope applications utilizing both convective and long-wave radiative heat transfer components. A 2D numerical model was proposed utilizing an apparent heat capacity method to represent the PCM latent thermal storage developing both convective and radiative thermal boundaries. The radiative component was developed to study the effect of the system exposure to the night-time sky during the PCM solidification period. The convective component was comprehensively developed mainly between the storage medium (PCM) and the air channel. A real-scale prototype was constructed for the whole model experimental validation. Field experiments were designed and conducted in the warm temperate climate of Lyon, France during summer. The validation criteria were proposed based on ASHRAE guideline 14. The results of the comparison between simulated data and experimentally obtained data showed that the system temperature was within the accepted range of the proposed criteria.