26. Cyber-Physical System for Improving Building Water Use Efficiency

The world population continues to increase while the water resources required to cater to this population are not increasing in proportion. In light of factors such as lack of availability of fresh water, depletion in groundwater levels, land pollution impacting water sources, high financial and environmental costs associated with water desalination, climate change effects and the list goes on, water stress is only expected to increase globally which calls for measures to manage this resource even more carefully. A significant increase in urbanization is further adding to the pressure with buildings being a major contributor to the water consumption footprint. If we are to break down the water use in buildings, a major part of this could be attributed to cleaning activities. The main objective of this work is to identify opportunities to reduce water consumption in buildings through the optimization of cleaning cycles. This would have other desirable side effects in the form of a reduction in operational costs as well as a corresponding positive impact on the environment achieved through the reduction in the use of chemicals and reduced CO₂ emissions resulting from less water use. To accomplish these objectives, we present a cyber-physical system called ‘Dew’. Dew is made up of a hardware device and the necessary software system. The hardware device comprises sensors connected to a microcontroller platform. One of the sensors passively tracks (in a privacy-preserving manner) visitors to washroom facilities and makes this data available at a backend system. Such data when analyzed yields insights that are then leveraged for decision-making to reduce the number of cleaning cycles. Details of the ‘Dew’ system are provided in this article. In particular, we highlight the design and implementation of the proof-of-concept solution, a small-scale pilot trial carried out on our university campus, and the findings from this study that throw light on the potential of this solution. These findings support our hypothesis that the Dew system can reduce water wastage, reduce operational costs, and can bring about a positive impact on the environment. In the small-scale study we conducted, we observed the potential for savings as high as 50% for two locations and 30% on average over the three locations considered in this study. This shows the promising potential that exists for scaled-up deployments over a large number of buildings over a prolonged period. In addition to water and monetary savings, Dew also has the potential to be used as an aid in tracking and contributing to sustainability-related metrics.