Thermal comfort and IAQ analysis of a decentralized DOAS system coupled with radiant cooling for the tropics

The deployment of low exergy concepts in buildings, which promotes high temperature cooling HVAC systems introduces alternative solutions in the tropical climate. This study evaluates the performance of a decentralized dedicated outdoor air system combined with a radiant cooling system (decentralized DOAS-RCS) in terms of occupant thermal comfort and indoor air quality for the tropical context. Different sets of operational scenarios (experiments) have been conducted in the BubbleZERO laboratory to realize the impact of system related parameters like ventilation rate and supply chilled water temperature on thermal comfort and indoor air quality. The results show that supply chilled water temperature and space cooling load have strong impacts respectively on the capacity of decentralized units and cooling panel, which consequently influence indoor air condition. Indoor air was predicted to be in comfort range (−0.2 < PMV < 0.2) only at specific periods of the day and an automatic control was required to modulate the system under various indoor and outdoor conditions. Main challenges of implementing DDOAS coupled with radiant cooling in the tropics include the condensation risk on the radiant panels, non-uniformity of panel surface temperature and low air movement inside the space.

[1]  Philippe Goffin,et al.  Low exergy building systems implementation , 2012 .

[2]  Zhen Tian,et al.  APPLICATION OF RADIANT COOLING IN DIFFERENT CLIMATES : ASSESSMENT OF OFFICE BUILDINGS THROUGH SIMULATION , 2009 .

[3]  S. Chirarattananon,et al.  Application of radiant cooling as a passive cooling option in hot humid climate , 2007 .

[4]  Hansjürg Leibundgut,et al.  The feasibility of performing high-temperature radiant cooling in tropical buildings when coupled with a decentralized ventilation system , 2013 .

[5]  Liwei Tian,et al.  Field study on occupants’ thermal comfort and residential thermal environment in a hot-humid climate of China , 2007 .

[6]  Victor W.-C. Chang,et al.  Human health and thermal comfort of office workers in Singapore , 2012 .

[7]  Standard Ashrae.  Thermal Environmental Conditions for Human Occupancy , 1992 .

[8]  Luca Baldini,et al.  Evaluating and adapting low exergy systems with decentralized ventilation for tropical climates , 2013 .

[9]  Stanley A. Mumma,et al.  Ceiling Panel Cooling Systems , 2001 .

[10]  Stanley A. Mumma,et al.  Chilled Ceilings in Parallel with Dedicated Outdoor Air Systems: Addressing the Concerns of Condensation, Capacity, and Cost , 2002 .

[11]  Chandra Sekhar,et al.  Thermal comfort evaluation of naturally ventilated public housing in Singapore , 2002 .

[12]  Ryozo Ooka,et al.  Adaptive model of thermal comfort for offices in hot and humid climates of India , 2014 .

[13]  Rizwan Ahmed Memon,et al.  Thermal comfort assessment and application of radiant cooling : A case study , 2008 .

[14]  Rupesh S. Iyengar,et al.  The Potential of Low Exergy Building Systems in the Tropics - Prototype Evaluation from the BubbleZERO in Singapore , 2015 .

[15]  P. Fanger,et al.  Extension of the PMV model to non-air-conditioned buildings in warm climates , 2002 .

[16]  D. Wyon,et al.  The Acceptable Air Velocity Range for Local Air Movement in The Tropics , 2006 .

[17]  R. J. Dear,et al.  Indoor climate and thermal comfort in high-rise public housing in an equatorial climate: A field-study in Singapore , 1990 .

[18]  Jian-Sheng Huang,et al.  Evaluation of cooling ceiling and mechanical ventilation systems on thermal comfort using CFD study in an office for subtropical region , 2012 .

[19]  Kian Wee Chen,et al.  BubbleZERO—Design, Construction and Operation of a Transportable Research Laboratory for Low Exergy Building System Evaluation in the Tropics , 2013 .

[20]  Y Zhu,et al.  Progress in thermal comfort research over the last twenty years. , 2013, Indoor air.

[21]  Christhina Cândido,et al.  Thermal acceptability assessment in buildings located in hot and humid regions in Brazil , 2010 .