Experimental investigation of the cooling capacity and thermal performance of the passive displacement dual cooling coil system in tropical climate

This paper focuses on the application of Passive Displacement Dual Cooling Coil (PDDCC) system in an indoor space based on a test lab. Parametric study, first, was carried out using Computational Fluid Dynamics (CFD) simulation to identify the optimum fall duct design for the PDDCC unit. Thermal profiles obtained through the simulations indicated that the fall duct with 300 mm height and 0◦ taper angle was most suitable as it generated the largest volume of cool air which sufficiently cooled the space. It was then applied to the experiment of the PDDCC units in the test lab to study the system’s thermal performance. The total cooling load removed by the two PDDCC units within the indoor space varied from 2.24 kW to 2.93 kW. The latent load removal over the entire experiment duration ranged from 0.7 kW to 1.35 kW where the highest latent heat was removed at the lowest chilled water setpoint temperature of 7.5 ◦C. Thermal stratification trends displayed that temperature within the room for all chilled water setpoint temperatures (7.5 ◦C, 8.5 ◦C, 9.5 ◦C, and 10.5 ◦C) corresponded with the increase in heat load within the indoor environment. The humidity level above 1 m ground level was not exceed 56%. The PDDCC system was found to have excellent latent heat removal capability. The PDDCC system was able to produce a thermally comfortable environment for 67% of the experimental permutations. The low humidity level within the test cell allowed to raise the boundary of the acceptable temperature range for achieving human thermal comfort to as high as 26.5 ◦C.