Dynamic economic dispatch of islanded water-energy microgrids with smart building thermal energy management system

In this paper, a mixed integer nonlinear programming formulation is proposed to intelligently dispatch the distributed generators, manage buildings’ thermal energy, and support the water demand in an islanded water-energy microgrid. To optimize the demand of water distribution system, pump's nonlinear scheduling and hydraulic factors, and daily water usage of buildings are added to the formulation. In addition, thermal management of electric chillers considering customers’ comfort level and outside temperature forecast was formulated. For a summer cooling schedule, it is shown that adjusting the indoor temperature settings at 20–25 °C for both occupied and unoccupied hours offers the lowest daily operation cost and peak demand charges. A fixed temperature setting of 25 °C during the occupied and unoccupied hours results in a lower daily cost and demand charges than a wide temperature setting of 15–30 °C. Lowest daily costs and electricity demand can be achieved within the proposed integrated water-energy microgrid with optimal water demand and building thermal energy management. By incorporating the water system constraints in the optimization model, hourly cost savings up to $150 can be achieved. In addition, incorporating building's thermal management in the proposed economic dispatch model can result in up to $20 hourly energy saving in the water-energy system.