Using air-conditioning waste water and stormwater as supply management in a commercial building, case study

Abstract

The concept of rational use as applied to water conservation consists in managing water supply and demand by trying to meet lesser quality water demands with alternative or reused water supply. This project attempts to demonstrate the application of a system that uses water drained from air conditioning system evaporators and rainwater as alternative sources. Given that each evaporator produces 4.80 liters of water per hour and considering the average use of an air conditioning system to be approximately 10 hours per day, the daily total of a single evaporator would be 48 liters. This would implicate a daily volume of 4,298 liters for the whole 137 units spread throughout the building, which in time would represent 77.72% of the daily demand of wastewater (5,53 liter/day). For the rainwater collection system, the total accumulated volume corresponds to 10% of the site area multiplied by a factor of 0.05, for a retention time of 1 hour, which will produce a total volume 14.8m³ of water. This system´s primary objective is to significantly reduce the consumption of potable water, which nowadays is used for every single activity, thus contributing to a more sustainable building and minimizing the environmental impact caused by the construction.