Integrating Rainwater Harvesting System and A/C Condensate for Water Efficiency in the Commercial Building of Dhaka City

Water conservation, efficiency, and reuse are becoming more important as the level of groundwater and surface water are decreasing at an alarming rate. Alternative sources of water need to be adopted sooner. Dhaka is a city with a tropical climate where plenty of rainfall takes place over the years and rainwater is a good source of clean water for daily use. Another substitute for water resources can be the reuse of A/C condensate water produced in the HVAC system. The hot and humid weather allows capturing a great deal of condensate water which can be considered as pure distilled water. Both the water types are treated as wastewater and are discarded out of the building. This paper discusses the possibility of the integration of using rainwater and condensate water in a commercial building as a secondary water source. Hence a commercial building (Midas Center) is taken as a study area. It involves extensive field survey, water demand calculations of the building, collection, storage, and use of the rainwater harvested and AC condensate. The result indicates that 15% of water saving is possible monthly which can approximately conserve 202500 liters per month and 32% efficiency is possible for toilet use in a single day. Thus if this method is embraced cumulatively for all commercial buildings of Dhaka city, a lot of water could be saved yearly and the huge pressure in ground and surface water can be reduced