It Takes Water and Energy in a Block

Sammanfattning: This report investigates sustainable solutions for electricity and water savings in an urban neighbourhood consisting of a block of buildings in Sege Park, Malmö. The solutions were evaluated in terms of sharing, producing, recycling and saving. The proposed solution includes a solar panel system on the available rooftop area for electricity production. Recycling and water savings includes collecting rainwater and reusing greywater for daily water demand in terms of flushing toilets, laundry and irrigation. Energy savings are achieved by using heat exchangers for space and water heating. Results from simulations in MATLAB and Excel showed that the electricity production reached a coverage ratioof 20% of the yearly consumption with hourly matching. However, the block has an excess electricity production, a total of 17,400 kWh, that does not correlate with the demand. Water demand for flushing toilets, laundering and irrigation during an average day can be matched by the reuse of greywater alone. Collection of rainwater is not required, although possible. The amount of reusable water, 18,540 litres a day, can cover the greywater need for three blocks equivalent to the one investigated. The conclusion is that water demand can be covered by greywater but electricity demand is too high for self-sustainability, even with the best solar panels available today.