Active and passive methods for cooling load reduction in a tropical building: A case study

•Active and passive cooling methods were proposed for a topical hostel building.•The total cooling load of a hostel building was reduced by 34.7% with ECMs.•ECMs and EAHE reduced transmission load by 81 TR and ventilation load by 18 TR.•The payback time and GHG mitigation was 3.2 year and 378 tCO2/year respectively. In the present study, energy saving potential and economical viability of implementing various active and passive cooling methods to a hostel building was accessed for tropical climate. The transmitted load for the building envelope was reduced by proposed Energy conservation measures (ECMs) including Gypsum-based cow dung plaster at the walls, double glazing glass for the windows and cool paint in conjunction with Photovoltaic panel for the roof. The experimentally calculated U-values for proposed plastered wall, double glazing window and cool painted with Photovoltaic shaded roof were 1.85 W/m2 K, 3.45 W/m2 K and 1.1 W/m2 K respectively. The ventilation load for the proposed centralized air conditioning system was reduced by connecting an Earth Air Heat Exchanger (EAHE) to the outlet vent port. The sizing of EAHE system was done using a MATLAB code validated with own experimental data. By parametric analysis, EAHE system of 16 pipe configuration with each of length 100 m and diameter 0.4 m was selected as a good compromise between effectiveness of heat transfer and pressure drops. Using eQuest simulation software, the total peak cooling load calculated for base and proposed case was 285 TR and 186 TR respectively. For the proposed case, the ventilation load was reduced by 18 TR and transmission load was reduced by 81 TR. The energy saving, payback time, and Greenhouse house gas mitigation for the proposed case with ECMs and EAHE was 344 MWh/year, 3.2 year, and 378 t CO2/year respectively.