Publication Details

Gokarakonda, S. & Kokogiannakis, G. (2014). Integrated dehumidification and downdraft evaporative cooling system for a hot-humid climate. 30th International PLEA Conference (PLEA 2014) (pp. 1-8). Ahmedabad, India: CEPT University Press.


Unlike in hot-dry climates, in hot-humid climates evaporative cooling techniques are not readily suitable for space cooling. In order to effectively use evaporative cooling in hot-humid climates, dehumidification of ambient air is necessary before it passes over an evaporative medium for cooling. The present study explores the combined process of dehumidification and evaporation and its effect on thermal comfort in a typical small residential building located in a hot humid climate. A novel system has been investigated with the combination of an Earth Tube Ventilation (ETV) (for pre-cooling of air), a rotary wheel desiccant dehumidifier (for dehumidification) along with a Passive Downdraught Evaporative Cooling (PDEC) tower (for evaporation) in that order.Parametric simulations using the EnergyPlus tool have been conducted in order to determine the critical dimensions and parameters of the proposed system, such as desiccant system sizing, PDEC tower height, and air and water flow rate at various points of the system. Results of indoor air temperature, humidity levels and volumetric air flow rates in the building spaces were obtained to study the influence of the proposed combined system on human thermal comfort. On a typical hot day the results from the proposed system show a relatively constant indoor air temperature of 28 °C (as opposed to peak indoor temperature of 36 °C occurred by means of natural ventilation) and indoor relative humidity in the range of 62 % - 68 %. The volumetric airflow rate from the outlet of the PDEC tower is in the range of 2.97 - 3.41 m3/s which is well within recommended levels for a dwelling unit. The proposed system displays a significant potential for providing space cooling in hot-humid climates as it paves an alternate way to the conventional energy consuming vapour compression Air Conditioning units.