Simulating greywater reuse in a residential building

The last few weeks I’ve been coding a simulator for greywater reuse scenarios based on real water usage data from HSB Living Lab. The input data is disaggregated hot and cold water consumption, with a time resolution of 10 minutes.

The simulation code allows the researcher to define from what micro-use points greywater is to be collected, and for what purposes it should be reused. The simulation of the treatment system itself is rather archaic, but the output is still kind of cool. The graph above show the levels in the untreated and treated water tanks over a period of 8 days. Tank volumes are 0.3 cbm and the treatment capacity in this run was set to 2 liters per minute, while collecting from sink and shower and reusing for sink, shower and WC. This scenario typically results in 50-60% reduction in total mains hot water consumption and 20-30% total mains cold water consumption.

Another cool feature of the simulator is the possibility to incorporate rain harvesting from real precipitation data into the equation. In the Hadley-cell zone wich defines Gothenburg this gives some pretty interesting numbers.

The results from this simulation should appear in a journal paper “shortly” (meaning maybe before summer 2020).